Communities and Ecosystems

Communities and Ecosystems
Chapter 37 Communities and Ecosystems Lecture by Brian R. Shmaefsky

COMMUNITY ECOLOGY An organism’s biotic environment includes
Other individuals in its own population Populations of other species living in the same area Species living close enough together for potential interaction is called a community. Student Misconceptions and Concerns 1. For many students, understanding ecosystems is like appreciating art. They can see ecosystems and art, but they do not understand the composition, the significance of the components, and the nature of their interactions. The fundamentals introduced in this chapter are new ways to see generally familiar systems. 2. The concept of an ecological niche can be confusing. Ecologist Eugene Odum suggested that an ecological niche is like an organism’s habitat (address) and its occupation combined. 3. Students often mistakenly think that symbiosis is a synonym for mutualism. Mutualism is a form of symbiosis. 4. The expectation that ecosystems are relatively stable is common. Natural disturbances of any sort (fires, earthquakes, floods, or strong storms) are typically viewed as tragic and damaging to ecosystems. Before beginning the topic of ecological disturbances, consider asking your students to briefly respond to news that a state or federal park has a) been burned, b) been struck by high winds and/or lightning, or c) been temporarily flooded. In addition, consider asking what if anything should be done to prevent or repair this damage? Teaching Tips 1. For many students, their interactions with diverse ecosystems have been limited to videos and movies, likely focused on a few species. Before discussing this chapter, consider showing the class a good video (it need not be long) about an ecosystem. The video can then serve as a common experience of the students to which you can refer and relate the content of this chapter. 2. Alternately, you can relate some of the basics of this chapter to a local campus or regional example to which most students are familiar. Perhaps there is a distinct community on your campus: a pond, distinct wooded area, or other part of campus that students would know and could visit with new insight. 3. In human society, a community might be considered about the same as a local population, perhaps all the people living in a town or city. The definition of a biological community is more inclusive, comprising all of the populations of species living close enough together for potential interaction. 4. Examples of interspecific competition are as close as the nearest lawn. Although students may be more likely to think of animal examples, the various grasses and weeds in a lawn reveal different strategies in their competition for sunlight, moisture, and soil. 5. If your class includes students with business interests, they may enjoy the following analogy. To better understand competition, students might think about fast-food restaurants in your region, perhaps those that sell pizzas. Challenge your students to identify strategies employed by these restaurants to compete with each other. As each restaurant makes changes, how do the other restaurants respond? Restaurants changing strategies in response to each other is analogous to coevolution. 6. Students commonly have practice with food webs and food chains. Present a food web (perhaps Figure 20.18) to your class and challenge them to predict the consequences of a decrease or increase in the population of one of the organisms. This activity can help students understand how difficult it is to make precise predictions about these complex systems. 7. Many keystone species have been identified in ecosystems, including sea otters, elephants, freshwater bass, and Pisaster, a sea star noted in Figure Challenge your class to explain how the concept of a keystone species relates to the efforts of conservation biologists. Why might some species be more important to conserve? 8. Before and after images of the impact and recovery of an ecosystem from a natural disaster can be as powerful as any explanation of the process. 9. Challenge your students to think through the adaptive advantage of a warning coloration in a toxic animal. Challenge your students to explain: What is gained if the predator dies? How can such systems evolve is the model is killed in the learning experience? 10. Students who are business-oriented might enjoy this analogy. Many corporate leaders might describe the best business deals as those that are mutualistic, fostering a win-win relationship.

FIGURE 23.2 The Scales of Life That Concern Ecology
In this chapter, you will consider how organisms of one species are associated in populations, and how populations of different species are associated in communities. In Chapter 24, you will look at ecosystems, which include not only living community members but also the nonliving factors that interact with them (such as the rainfall in the ecosystem panel above). Chapter 24 also reviews the large-scale ecosystems called biomes and the biosphere, which is the interactive collection of all the Earth's ecosystems.

Biology and Society: Does Biodiversity Matter?
The expanding human population threatens Biodiversity The loss of natural ecosystems © 2010 Pearson Education, Inc.

Two recent victims of human-caused extinctions are
Chinese river dolphins Golden toads Student Misconceptions and Concerns 1. The value of biodiversity may not be obvious to many students. As this chapter notes, biodiversity is inherently valuable on many levels. Class discussions and short assignments that require students to investigate the importance of biodiversity can help to better relate its importance. 2. Frustration can overwhelm concerned students alarmed by the loss of biodiversity. One way to address this is to provide meaningful ways for students to respond to this information. Several related websites are noted in the Teaching Tips below. Teaching Tips 1. Consider referencing some of the following websites for basic ideas on what individuals can do to help address the loss of biodiversity. Conservation International: The Biodiversity Economics Site: Biodiversity Support Program: 2. The bottleneck effect, a consequence of the loss of diversity within a species, is discussed in Chapter 13. 3. You might wish to note the mission of the Nature Conservancy, an organization devoted to the purchase and protection of land across the world. The Nature Conservancy’s web site is (

Habitat destruction

Invasive species FIGURE 23.15 Kudzu Vines Run Wild
The kudzu plant was introduced in the American South in the 1930s and has since spread at a rapid rate, locally eliminating many plants in its path. This is competitive exclusion in action. Here kudzu has overgrown an abandoned house in Mississippi.

Overexplotation

Golden toads in Costa Rica have not been seen since 1989
Figure 20.2b Recent additions to the list of human-caused extinctions Golden toads in Costa Rica have not been seen since 1989 Figure 20.2b

Coral reefs are rich in species diversity, yet
An estimated 20% of the world’s coral reefs have been destroyed by human activities 24% are in imminent danger of collapse Another 26% of coral reefs may succumb in the next few decades if they are not protected Student Misconceptions and Concerns 1. The value of biodiversity may not be obvious to many students. As this chapter notes, biodiversity is inherently valuable on many levels. Class discussions and short assignments that require students to investigate the importance of biodiversity can help to better relate its importance. 2. Frustration can overwhelm concerned students alarmed by the loss of biodiversity. One way to address this is to provide meaningful ways for students to respond to this information. Several related websites are noted in the Teaching Tips below. Teaching Tips 1. Consider referencing some of the following websites for basic ideas on what individuals can do to help address the loss of biodiversity. Conservation International: The Biodiversity Economics Site: Biodiversity Support Program: 2. The bottleneck effect, a consequence of the loss of diversity within a species, is discussed in Chapter 13. 3. You might wish to note the mission of the Nature Conservancy, an organization devoted to the purchase and protection of land across the world. The Nature Conservancy’s web site is ( Video: Coral Reef

Figure 20.3 Coral reef, a colorful display of biodiversity

Genetic diversity: Einkorn wheat, one of the wild relatives of modern cultivated varieties Figure 20.1 Einkorn wheat, one of the wild relatives of modern cultivated varieties Figure 20.1

Causes of Declining Biodiversity
Ecologists have identified four main factors responsible for the loss of biodiversity: Habitat destruction and fragmentation Invasive species Overexploitation Pollution Student Misconceptions and Concerns 1. The value of biodiversity may not be obvious to many students. As this chapter notes, biodiversity is inherently valuable on many levels. Class discussions and short assignments that require students to investigate the importance of biodiversity can help to better relate its importance. 2. Frustration can overwhelm concerned students alarmed by the loss of biodiversity. One way to address this is to provide meaningful ways for students to respond to this information. Several related websites are noted in the Teaching Tips below. Teaching Tips 1. Consider referencing some of the following websites for basic ideas on what individuals can do to help address the loss of biodiversity. Conservation International: The Biodiversity Economics Site: Biodiversity Support Program: 2. The bottleneck effect, a consequence of the loss of diversity within a species, is discussed in Chapter 13. 3. You might wish to note the mission of the Nature Conservancy, an organization devoted to the purchase and protection of land across the world. The Nature Conservancy’s web site is (

Habitat Destruction Biodiversity is threatened by the destruction and fragmentation of habitats by Agriculture Urban development Forestry Mining Student Misconceptions and Concerns 1. The value of biodiversity may not be obvious to many students. As this chapter notes, biodiversity is inherently valuable on many levels. Class discussions and short assignments that require students to investigate the importance of biodiversity can help to better relate its importance. 2. Frustration can overwhelm concerned students alarmed by the loss of biodiversity. One way to address this is to provide meaningful ways for students to respond to this information. Several related websites are noted in the Teaching Tips below. Teaching Tips 1. Consider referencing some of the following websites for basic ideas on what individuals can do to help address the loss of biodiversity. Conservation International: The Biodiversity Economics Site: Biodiversity Support Program: 2. The bottleneck effect, a consequence of the loss of diversity within a species, is discussed in Chapter 13. 3. You might wish to note the mission of the Nature Conservancy, an organization devoted to the purchase and protection of land across the world. The Nature Conservancy’s web site is (

Figure 20.4 Habitat destruction

Overexploitation People have overexploited wildlife by harvesting at rates that exceed the ability of populations to rebound. Excessive harvesting has greatly affected Tigers Whales The American bison Galápagos tortoises Student Misconceptions and Concerns 1. The value of biodiversity may not be obvious to many students. As this chapter notes, biodiversity is inherently valuable on many levels. Class discussions and short assignments that require students to investigate the importance of biodiversity can help to better relate its importance. 2. Frustration can overwhelm concerned students alarmed by the loss of biodiversity. One way to address this is to provide meaningful ways for students to respond to this information. Several related websites are noted in the Teaching Tips below. Teaching Tips 1. Consider referencing some of the following websites for basic ideas on what individuals can do to help address the loss of biodiversity. Conservation International: The Biodiversity Economics Site: Biodiversity Support Program: 2. The bottleneck effect, a consequence of the loss of diversity within a species, is discussed in Chapter 13. 3. You might wish to note the mission of the Nature Conservancy, an organization devoted to the purchase and protection of land across the world. The Nature Conservancy’s web site is (

Bluefin tuna ready for sale
Figure 20.5 Bluefin tuna ready for sale Bluefin tuna ready for sale Figure 20.5

Video: Clownfish and Anemone
COMMUNITY ECOLOGY An organism’s biotic environment includes Other individuals in its own population Populations of other species living in the same area Species living close enough together for potential interaction is called a community. Student Misconceptions and Concerns 1. For many students, understanding ecosystems is like appreciating art. They can see ecosystems and art, but they do not understand the composition, the significance of the components, and the nature of their interactions. The fundamentals introduced in this chapter are new ways to see generally familiar systems. 2. The concept of an ecological niche can be confusing. Ecologist Eugene Odum suggested that an ecological niche is like an organism’s habitat (address) and its occupation combined. 3. Students often mistakenly think that symbiosis is a synonym for mutualism. Mutualism is a form of symbiosis. 4. The expectation that ecosystems are relatively stable is common. Natural disturbances of any sort (fires, earthquakes, floods, or strong storms) are typically viewed as tragic and damaging to ecosystems. Before beginning the topic of ecological disturbances, consider asking your students to briefly respond to news that a state or federal park has a) been burned, b) been struck by high winds and/or lightning, or c) been temporarily flooded. In addition, consider asking what if anything should be done to prevent or repair this damage? Teaching Tips 1. For many students, their interactions with diverse ecosystems have been limited to videos and movies, likely focused on a few species. Before discussing this chapter, consider showing the class a good video (it need not be long) about an ecosystem. The video can then serve as a common experience of the students to which you can refer and relate the content of this chapter. 2. Alternately, you can relate some of the basics of this chapter to a local campus or regional example to which most students are familiar. Perhaps there is a distinct community on your campus: a pond, distinct wooded area, or other part of campus that students would know and could visit with new insight. 3. In human society, a community might be considered about the same as a local population, perhaps all the people living in a town or city. The definition of a biological community is more inclusive, comprising all of the populations of species living close enough together for potential interaction. 4. Examples of interspecific competition are as close as the nearest lawn. Although students may be more likely to think of animal examples, the various grasses and weeds in a lawn reveal different strategies in their competition for sunlight, moisture, and soil. 5. If your class includes students with business interests, they may enjoy the following analogy. To better understand competition, students might think about fast-food restaurants in your region, perhaps those that sell pizzas. Challenge your students to identify strategies employed by these restaurants to compete with each other. As each restaurant makes changes, how do the other restaurants respond? Restaurants changing strategies in response to each other is analogous to coevolution. 6. Students commonly have practice with food webs and food chains. Present a food web (perhaps Figure 20.18) to your class and challenge them to predict the consequences of a decrease or increase in the population of one of the organisms. This activity can help students understand how difficult it is to make precise predictions about these complex systems. 7. Many keystone species have been identified in ecosystems, including sea otters, elephants, freshwater bass, and Pisaster, a sea star noted in Figure Challenge your class to explain how the concept of a keystone species relates to the efforts of conservation biologists. Why might some species be more important to conserve? 8. Before and after images of the impact and recovery of an ecosystem from a natural disaster can be as powerful as any explanation of the process. 9. Challenge your students to think through the adaptive advantage of a warning coloration in a toxic animal. Challenge your students to explain: What is gained if the predator dies? How can such systems evolve is the model is killed in the learning experience? 10. Students who are business-oriented might enjoy this analogy. Many corporate leaders might describe the best business deals as those that are mutualistic, fostering a win-win relationship. Video: Clownfish and Anemone

Figure 20.6 Diverse species interacting in a Kenyan savanna community

Competition among species
1. Interspecific competition- competition between 2 closely related species Usually only temporary One species will win and the other one will leave Student Misconceptions and Concerns 1. For many students, understanding ecosystems is like appreciating art. They can see ecosystems and art, but they do not understand the composition, the significance of the components, and the nature of their interactions. The fundamentals introduced in this chapter are new ways to see generally familiar systems. 2. The concept of an ecological niche can be confusing. Ecologist Eugene Odum suggested that an ecological niche is like an organism’s habitat (address) and its occupation combined. 3. Students often mistakenly think that symbiosis is a synonym for mutualism. Mutualism is a form of symbiosis. 4. The expectation that ecosystems are relatively stable is common. Natural disturbances of any sort (fires, earthquakes, floods, or strong storms) are typically viewed as tragic and damaging to ecosystems. Before beginning the topic of ecological disturbances, consider asking your students to briefly respond to news that a state or federal park has a) been burned, b) been struck by high winds and/or lightning, or c) been temporarily flooded. In addition, consider asking what if anything should be done to prevent or repair this damage? Teaching Tips 1. For many students, their interactions with diverse ecosystems have been limited to videos and movies, likely focused on a few species. Before discussing this chapter, consider showing the class a good video (it need not be long) about an ecosystem. The video can then serve as a common experience of the students to which you can refer and relate the content of this chapter. 2. Alternately, you can relate some of the basics of this chapter to a local campus or regional example to which most students are familiar. Perhaps there is a distinct community on your campus: a pond, distinct wooded area, or other part of campus that students would know and could visit with new insight. 3. In human society, a community might be considered about the same as a local population, perhaps all the people living in a town or city. The definition of a biological community is more inclusive, comprising all of the populations of species living close enough together for potential interaction. 4. Examples of interspecific competition are as close as the nearest lawn. Although students may be more likely to think of animal examples, the various grasses and weeds in a lawn reveal different strategies in their competition for sunlight, moisture, and soil. 5. If your class includes students with business interests, they may enjoy the following analogy. To better understand competition, students might think about fast-food restaurants in your region, perhaps those that sell pizzas. Challenge your students to identify strategies employed by these restaurants to compete with each other. As each restaurant makes changes, how do the other restaurants respond? Restaurants changing strategies in response to each other is analogous to coevolution. 6. Students commonly have practice with food webs and food chains. Present a food web (perhaps Figure 20.18) to your class and challenge them to predict the consequences of a decrease or increase in the population of one of the organisms. This activity can help students understand how difficult it is to make precise predictions about these complex systems. 7. Many keystone species have been identified in ecosystems, including sea otters, elephants, freshwater bass, and Pisaster, a sea star noted in Figure Challenge your class to explain how the concept of a keystone species relates to the efforts of conservation biologists. Why might some species be more important to conserve? 8. Before and after images of the impact and recovery of an ecosystem from a natural disaster can be as powerful as any explanation of the process. 9. Challenge your students to think through the adaptive advantage of a warning coloration in a toxic animal. Challenge your students to explain: What is gained if the predator dies? How can such systems evolve is the model is killed in the learning experience? 10. Students who are business-oriented might enjoy this analogy. Many corporate leaders might describe the best business deals as those that are mutualistic, fostering a win-win relationship.

Competitive exclusion. Two species of Paramecium, P. caudatum and P
Competitive exclusion. Two species of Paramecium, P. caudatum and P. aurelia, both feed on bacteria. When grown in separate test tubes, each does well (A), (B). When grown together (C) one species drives the other to extinction. Figure It Out: Which species of Paramecium was the superior competitor? Answer: P. aurelia. Figure 17.5: Animated! Competitive exclusion. Two species of Paramecium, P. caudatum and P. aurelia, both feed on bacteria. When grown in separate test tubes, each does well (A), (B). When grown together (C) one species drives the other to extinction. Figure It Out: Which species of Paramecium was the superior competitor? Answer: P. aurelia. Fig. 17-5, p. 344

Interspecific competition
FIGURE Resource Partitioning Ecologist Robert MacArthur spent long stretches of time over several years in the 1950s observing the feeding patterns of several species of warblers. All of them ate caterpillars, but from substantially different, though overlapping, parts of the tree.

Interspecific competition among scavengers- golden eagle and a red fox fight over a moose carcass
Figure 17.4 Interspecific competition among scavengers. (A) A golden eagle and a red fox face off over a moose carcass. (B) The eagle attacks the fox with its talons. After this attack, the fox retreated, leaving the eagle to exploit the carcass. Fig. 17-4, p. 343

2. Mutualism- interaction between two species that is benefical to both One example is coral and the unicellular algae that live inside their cells. The coral gains energy from the sugars produced by the algae. The algae gain A secure shelter Access to light, carbon dioxide and ammonia, a valuable source of nitrogen Student Misconceptions and Concerns 1. For many students, understanding ecosystems is like appreciating art. They can see ecosystems and art, but they do not understand the composition, the significance of the components, and the nature of their interactions. The fundamentals introduced in this chapter are new ways to see generally familiar systems. 2. The concept of an ecological niche can be confusing. Ecologist Eugene Odum suggested that an ecological niche is like an organism’s habitat (address) and its occupation combined. 3. Students often mistakenly think that symbiosis is a synonym for mutualism. Mutualism is a form of symbiosis. 4. The expectation that ecosystems are relatively stable is common. Natural disturbances of any sort (fires, earthquakes, floods, or strong storms) are typically viewed as tragic and damaging to ecosystems. Before beginning the topic of ecological disturbances, consider asking your students to briefly respond to news that a state or federal park has a) been burned, b) been struck by high winds and/or lightning, or c) been temporarily flooded. In addition, consider asking what if anything should be done to prevent or repair this damage? Teaching Tips 1. For many students, their interactions with diverse ecosystems have been limited to videos and movies, likely focused on a few species. Before discussing this chapter, consider showing the class a good video (it need not be long) about an ecosystem. The video can then serve as a common experience of the students to which you can refer and relate the content of this chapter. 2. Alternately, you can relate some of the basics of this chapter to a local campus or regional example to which most students are familiar. Perhaps there is a distinct community on your campus: a pond, distinct wooded area, or other part of campus that students would know and could visit with new insight. 3. In human society, a community might be considered about the same as a local population, perhaps all the people living in a town or city. The definition of a biological community is more inclusive, comprising all of the populations of species living close enough together for potential interaction. 4. Examples of interspecific competition are as close as the nearest lawn. Although students may be more likely to think of animal examples, the various grasses and weeds in a lawn reveal different strategies in their competition for sunlight, moisture, and soil. 5. If your class includes students with business interests, they may enjoy the following analogy. To better understand competition, students might think about fast-food restaurants in your region, perhaps those that sell pizzas. Challenge your students to identify strategies employed by these restaurants to compete with each other. As each restaurant makes changes, how do the other restaurants respond? Restaurants changing strategies in response to each other is analogous to coevolution. 6. Students commonly have practice with food webs and food chains. Present a food web (perhaps Figure 20.18) to your class and challenge them to predict the consequences of a decrease or increase in the population of one of the organisms. This activity can help students understand how difficult it is to make precise predictions about these complex systems. 7. Many keystone species have been identified in ecosystems, including sea otters, elephants, freshwater bass, and Pisaster, a sea star noted in Figure Challenge your class to explain how the concept of a keystone species relates to the efforts of conservation biologists. Why might some species be more important to conserve? 8. Before and after images of the impact and recovery of an ecosystem from a natural disaster can be as powerful as any explanation of the process. 9. Challenge your students to think through the adaptive advantage of a warning coloration in a toxic animal. Challenge your students to explain: What is gained if the predator dies? How can such systems evolve is the model is killed in the learning experience? 10. Students who are business-oriented might enjoy this analogy. Many corporate leaders might describe the best business deals as those that are mutualistic, fostering a win-win relationship.

Mutualism between anemone fish and sea anemone
Mutualism between anemone fish and sea anemone. Each species provides protection for the other. Figure 17.3 (A) Commensal fern growing on a tree trunk. (B) An anemone fish nestles among the tentacles of a sea anemone. In this mutualistic partnership, each species protects the other. Fig. 17-3b, p. 342

Mutualism FIGURE 23.23 Mutually Beneficial
(b) Snapping shrimp and shrimp goby The orange-spotted shrimp goby, on the right, and the snapping shrimp at left also exhibit mutualism. Here the shrimp goby stands guard near the snapping shrimp, which digs out the burrow on the sea floor that the two creatures share.

(a) Rhinoceros and oxpecker birds Several oxpecker birds sit atop a black rhinoceros, ridding the rhino of ticks and other pests while the rhino provides a safe habitat for the birds. This is a demonstration of mutualism—an interaction between two species that is beneficial to both.

Mutualism between anemone fish and sea anemone
Mutualism between anemone fish and sea anemone. Each species provides protection for the other. Figure 17.3 (A) Commensal fern growing on a tree trunk. (B) An anemone fish nestles among the tentacles of a sea anemone. In this mutualistic partnership, each species protects the other. Fig. 17-3b, p. 342

(b) Snapping shrimp and shrimp goby The orange-spotted shrimp goby, on the right, and the snapping shrimp at left also exhibit mutualism. Here the shrimp goby stands guard near the snapping shrimp, which digs out the burrow on the sea floor that the two creatures share.

(a) Rhinoceros and oxpecker birds Several oxpecker birds sit atop a black rhinoceros, ridding the rhino of ticks and other pests while the rhino provides a safe habitat for the birds. This is a demonstration of mutualism—an interaction between two species that is beneficial to both.

Commensalism Figure 17.3 (A) Commensal fern growing on a tree trunk. (B) An anemone fish nestles among the tentacles of a sea anemone. In this mutualistic partnership, each species protects the other. Fig. 17-3a, p. 342

3. Predation- one organism feeds on parts or all of a second organism Student Misconceptions and Concerns 1. For many students, understanding ecosystems is like appreciating art. They can see ecosystems and art, but they do not understand the composition, the significance of the components, and the nature of their interactions. The fundamentals introduced in this chapter are new ways to see generally familiar systems. 2. The concept of an ecological niche can be confusing. Ecologist Eugene Odum suggested that an ecological niche is like an organism’s habitat (address) and its occupation combined. 3. Students often mistakenly think that symbiosis is a synonym for mutualism. Mutualism is a form of symbiosis. 4. The expectation that ecosystems are relatively stable is common. Natural disturbances of any sort (fires, earthquakes, floods, or strong storms) are typically viewed as tragic and damaging to ecosystems. Before beginning the topic of ecological disturbances, consider asking your students to briefly respond to news that a state or federal park has a) been burned, b) been struck by high winds and/or lightning, or c) been temporarily flooded. In addition, consider asking what if anything should be done to prevent or repair this damage? Teaching Tips 1. For many students, their interactions with diverse ecosystems have been limited to videos and movies, likely focused on a few species. Before discussing this chapter, consider showing the class a good video (it need not be long) about an ecosystem. The video can then serve as a common experience of the students to which you can refer and relate the content of this chapter. 2. Alternately, you can relate some of the basics of this chapter to a local campus or regional example to which most students are familiar. Perhaps there is a distinct community on your campus: a pond, distinct wooded area, or other part of campus that students would know and could visit with new insight. 3. In human society, a community might be considered about the same as a local population, perhaps all the people living in a town or city. The definition of a biological community is more inclusive, comprising all of the populations of species living close enough together for potential interaction. 4. Examples of interspecific competition are as close as the nearest lawn. Although students may be more likely to think of animal examples, the various grasses and weeds in a lawn reveal different strategies in their competition for sunlight, moisture, and soil. 5. If your class includes students with business interests, they may enjoy the following analogy. To better understand competition, students might think about fast-food restaurants in your region, perhaps those that sell pizzas. Challenge your students to identify strategies employed by these restaurants to compete with each other. As each restaurant makes changes, how do the other restaurants respond? Restaurants changing strategies in response to each other is analogous to coevolution. 6. Students commonly have practice with food webs and food chains. Present a food web (perhaps Figure 20.18) to your class and challenge them to predict the consequences of a decrease or increase in the population of one of the organisms. This activity can help students understand how difficult it is to make precise predictions about these complex systems. 7. Many keystone species have been identified in ecosystems, including sea otters, elephants, freshwater bass, and Pisaster, a sea star noted in Figure Challenge your class to explain how the concept of a keystone species relates to the efforts of conservation biologists. Why might some species be more important to conserve? 8. Before and after images of the impact and recovery of an ecosystem from a natural disaster can be as powerful as any explanation of the process. 9. Challenge your students to think through the adaptive advantage of a warning coloration in a toxic animal. Challenge your students to explain: What is gained if the predator dies? How can such systems evolve is the model is killed in the learning experience? 10. Students who are business-oriented might enjoy this analogy. Many corporate leaders might describe the best business deals as those that are mutualistic, fostering a win-win relationship.

Predator- prey

Predatory frog fish uses a fake lure to catch its prey
FIGURE Fooling Predators about Prey The predatory frogfish uses a modified spine resembling a tasty worm to lure its prey. Here a tasseled frogfish clearly shows its lure while swimming near Edithburg, South Australia.

Defense mechanisms for prey
Numerous adaptations for predator avoidance have evolved in prey populations through natural selection. a. Cryptic coloration Camouflage A way for prey to hide from predators Student Misconceptions and Concerns 1. For many students, understanding ecosystems is like appreciating art. They can see ecosystems and art, but they do not understand the composition, the significance of the components, and the nature of their interactions. The fundamentals introduced in this chapter are new ways to see generally familiar systems. 2. The concept of an ecological niche can be confusing. Ecologist Eugene Odum suggested that an ecological niche is like an organism’s habitat (address) and its occupation combined. 3. Students often mistakenly think that symbiosis is a synonym for mutualism. Mutualism is a form of symbiosis. 4. The expectation that ecosystems are relatively stable is common. Natural disturbances of any sort (fires, earthquakes, floods, or strong storms) are typically viewed as tragic and damaging to ecosystems. Before beginning the topic of ecological disturbances, consider asking your students to briefly respond to news that a state or federal park has a) been burned, b) been struck by high winds and/or lightning, or c) been temporarily flooded. In addition, consider asking what if anything should be done to prevent or repair this damage? Teaching Tips 1. For many students, their interactions with diverse ecosystems have been limited to videos and movies, likely focused on a few species. Before discussing this chapter, consider showing the class a good video (it need not be long) about an ecosystem. The video can then serve as a common experience of the students to which you can refer and relate the content of this chapter. 2. Alternately, you can relate some of the basics of this chapter to a local campus or regional example to which most students are familiar. Perhaps there is a distinct community on your campus: a pond, distinct wooded area, or other part of campus that students would know and could visit with new insight. 3. In human society, a community might be considered about the same as a local population, perhaps all the people living in a town or city. The definition of a biological community is more inclusive, comprising all of the populations of species living close enough together for potential interaction. 4. Examples of interspecific competition are as close as the nearest lawn. Although students may be more likely to think of animal examples, the various grasses and weeds in a lawn reveal different strategies in their competition for sunlight, moisture, and soil. 5. If your class includes students with business interests, they may enjoy the following analogy. To better understand competition, students might think about fast-food restaurants in your region, perhaps those that sell pizzas. Challenge your students to identify strategies employed by these restaurants to compete with each other. As each restaurant makes changes, how do the other restaurants respond? Restaurants changing strategies in response to each other is analogous to coevolution. 6. Students commonly have practice with food webs and food chains. Present a food web (perhaps Figure 20.18) to your class and challenge them to predict the consequences of a decrease or increase in the population of one of the organisms. This activity can help students understand how difficult it is to make precise predictions about these complex systems. 7. Many keystone species have been identified in ecosystems, including sea otters, elephants, freshwater bass, and Pisaster, a sea star noted in Figure Challenge your class to explain how the concept of a keystone species relates to the efforts of conservation biologists. Why might some species be more important to conserve? 8. Before and after images of the impact and recovery of an ecosystem from a natural disaster can be as powerful as any explanation of the process. 9. Challenge your students to think through the adaptive advantage of a warning coloration in a toxic animal. Challenge your students to explain: What is gained if the predator dies? How can such systems evolve is the model is killed in the learning experience? 10. Students who are business-oriented might enjoy this analogy. Many corporate leaders might describe the best business deals as those that are mutualistic, fostering a win-win relationship.

Camouflage- desert plants resemble stones and hide among them
Figure 17.7 Camouflage. (A) Desert plants (Lithops) resemble stones and hide among them. (B) A pink praying mantis eats insects attracted to the flowers that it resembles. Fig. 17-7a, p. 345

FIGURE 23.20 Avoiding Predation through Camouflage

Some insects have elaborate disguises that make them resemble Twigs
Leaves Bird droppings Predators Student Misconceptions and Concerns 1. For many students, understanding ecosystems is like appreciating art. They can see ecosystems and art, but they do not understand the composition, the significance of the components, and the nature of their interactions. The fundamentals introduced in this chapter are new ways to see generally familiar systems. 2. The concept of an ecological niche can be confusing. Ecologist Eugene Odum suggested that an ecological niche is like an organism’s habitat (address) and its occupation combined. 3. Students often mistakenly think that symbiosis is a synonym for mutualism. Mutualism is a form of symbiosis. 4. The expectation that ecosystems are relatively stable is common. Natural disturbances of any sort (fires, earthquakes, floods, or strong storms) are typically viewed as tragic and damaging to ecosystems. Before beginning the topic of ecological disturbances, consider asking your students to briefly respond to news that a state or federal park has a) been burned, b) been struck by high winds and/or lightning, or c) been temporarily flooded. In addition, consider asking what if anything should be done to prevent or repair this damage? Teaching Tips 1. For many students, their interactions with diverse ecosystems have been limited to videos and movies, likely focused on a few species. Before discussing this chapter, consider showing the class a good video (it need not be long) about an ecosystem. The video can then serve as a common experience of the students to which you can refer and relate the content of this chapter. 2. Alternately, you can relate some of the basics of this chapter to a local campus or regional example to which most students are familiar. Perhaps there is a distinct community on your campus: a pond, distinct wooded area, or other part of campus that students would know and could visit with new insight. 3. In human society, a community might be considered about the same as a local population, perhaps all the people living in a town or city. The definition of a biological community is more inclusive, comprising all of the populations of species living close enough together for potential interaction. 4. Examples of interspecific competition are as close as the nearest lawn. Although students may be more likely to think of animal examples, the various grasses and weeds in a lawn reveal different strategies in their competition for sunlight, moisture, and soil. 5. If your class includes students with business interests, they may enjoy the following analogy. To better understand competition, students might think about fast-food restaurants in your region, perhaps those that sell pizzas. Challenge your students to identify strategies employed by these restaurants to compete with each other. As each restaurant makes changes, how do the other restaurants respond? Restaurants changing strategies in response to each other is analogous to coevolution. 6. Students commonly have practice with food webs and food chains. Present a food web (perhaps Figure 20.18) to your class and challenge them to predict the consequences of a decrease or increase in the population of one of the organisms. This activity can help students understand how difficult it is to make precise predictions about these complex systems. 7. Many keystone species have been identified in ecosystems, including sea otters, elephants, freshwater bass, and Pisaster, a sea star noted in Figure Challenge your class to explain how the concept of a keystone species relates to the efforts of conservation biologists. Why might some species be more important to conserve? 8. Before and after images of the impact and recovery of an ecosystem from a natural disaster can be as powerful as any explanation of the process. 9. Challenge your students to think through the adaptive advantage of a warning coloration in a toxic animal. Challenge your students to explain: What is gained if the predator dies? How can such systems evolve is the model is killed in the learning experience? 10. Students who are business-oriented might enjoy this analogy. Many corporate leaders might describe the best business deals as those that are mutualistic, fostering a win-win relationship.

FIGURE 23.20 Avoiding Predation through Camouflage

Brightly colored pattern
b. warning coloration Brightly colored pattern Way to warn predators that an animal has an effective chemical defense Student Misconceptions and Concerns 1. For many students, understanding ecosystems is like appreciating art. They can see ecosystems and art, but they do not understand the composition, the significance of the components, and the nature of their interactions. The fundamentals introduced in this chapter are new ways to see generally familiar systems. 2. The concept of an ecological niche can be confusing. Ecologist Eugene Odum suggested that an ecological niche is like an organism’s habitat (address) and its occupation combined. 3. Students often mistakenly think that symbiosis is a synonym for mutualism. Mutualism is a form of symbiosis. 4. The expectation that ecosystems are relatively stable is common. Natural disturbances of any sort (fires, earthquakes, floods, or strong storms) are typically viewed as tragic and damaging to ecosystems. Before beginning the topic of ecological disturbances, consider asking your students to briefly respond to news that a state or federal park has a) been burned, b) been struck by high winds and/or lightning, or c) been temporarily flooded. In addition, consider asking what if anything should be done to prevent or repair this damage? Teaching Tips 1. For many students, their interactions with diverse ecosystems have been limited to videos and movies, likely focused on a few species. Before discussing this chapter, consider showing the class a good video (it need not be long) about an ecosystem. The video can then serve as a common experience of the students to which you can refer and relate the content of this chapter. 2. Alternately, you can relate some of the basics of this chapter to a local campus or regional example to which most students are familiar. Perhaps there is a distinct community on your campus: a pond, distinct wooded area, or other part of campus that students would know and could visit with new insight. 3. In human society, a community might be considered about the same as a local population, perhaps all the people living in a town or city. The definition of a biological community is more inclusive, comprising all of the populations of species living close enough together for potential interaction. 4. Examples of interspecific competition are as close as the nearest lawn. Although students may be more likely to think of animal examples, the various grasses and weeds in a lawn reveal different strategies in their competition for sunlight, moisture, and soil. 5. If your class includes students with business interests, they may enjoy the following analogy. To better understand competition, students might think about fast-food restaurants in your region, perhaps those that sell pizzas. Challenge your students to identify strategies employed by these restaurants to compete with each other. As each restaurant makes changes, how do the other restaurants respond? Restaurants changing strategies in response to each other is analogous to coevolution. 6. Students commonly have practice with food webs and food chains. Present a food web (perhaps Figure 20.18) to your class and challenge them to predict the consequences of a decrease or increase in the population of one of the organisms. This activity can help students understand how difficult it is to make precise predictions about these complex systems. 7. Many keystone species have been identified in ecosystems, including sea otters, elephants, freshwater bass, and Pisaster, a sea star noted in Figure Challenge your class to explain how the concept of a keystone species relates to the efforts of conservation biologists. Why might some species be more important to conserve? 8. Before and after images of the impact and recovery of an ecosystem from a natural disaster can be as powerful as any explanation of the process. 9. Challenge your students to think through the adaptive advantage of a warning coloration in a toxic animal. Challenge your students to explain: What is gained if the predator dies? How can such systems evolve is the model is killed in the learning experience? 10. Students who are business-oriented might enjoy this analogy. Many corporate leaders might describe the best business deals as those that are mutualistic, fostering a win-win relationship.

Warning coloration

Warning coloration Figure 17.6
Prey defenses. Spiny structures protect the edible soft parts of (A) a cactus and (B) a porcupine. (C) The coloration of this yellow jacket wasp warns predators that it can deliver a painful sting. (D) This fly that cannot sting benefits by its resemblance to the wasp. Fig. 17-6c, p. 344

c. Mimicry is a form of defense in which one animal looks like another species.
Student Misconceptions and Concerns 1. For many students, understanding ecosystems is like appreciating art. They can see ecosystems and art, but they do not understand the composition, the significance of the components, and the nature of their interactions. The fundamentals introduced in this chapter are new ways to see generally familiar systems. 2. The concept of an ecological niche can be confusing. Ecologist Eugene Odum suggested that an ecological niche is like an organism’s habitat (address) and its occupation combined. 3. Students often mistakenly think that symbiosis is a synonym for mutualism. Mutualism is a form of symbiosis. 4. The expectation that ecosystems are relatively stable is common. Natural disturbances of any sort (fires, earthquakes, floods, or strong storms) are typically viewed as tragic and damaging to ecosystems. Before beginning the topic of ecological disturbances, consider asking your students to briefly respond to news that a state or federal park has a) been burned, b) been struck by high winds and/or lightning, or c) been temporarily flooded. In addition, consider asking what if anything should be done to prevent or repair this damage? Teaching Tips 1. For many students, their interactions with diverse ecosystems have been limited to videos and movies, likely focused on a few species. Before discussing this chapter, consider showing the class a good video (it need not be long) about an ecosystem. The video can then serve as a common experience of the students to which you can refer and relate the content of this chapter. 2. Alternately, you can relate some of the basics of this chapter to a local campus or regional example to which most students are familiar. Perhaps there is a distinct community on your campus: a pond, distinct wooded area, or other part of campus that students would know and could visit with new insight. 3. In human society, a community might be considered about the same as a local population, perhaps all the people living in a town or city. The definition of a biological community is more inclusive, comprising all of the populations of species living close enough together for potential interaction. 4. Examples of interspecific competition are as close as the nearest lawn. Although students may be more likely to think of animal examples, the various grasses and weeds in a lawn reveal different strategies in their competition for sunlight, moisture, and soil. 5. If your class includes students with business interests, they may enjoy the following analogy. To better understand competition, students might think about fast-food restaurants in your region, perhaps those that sell pizzas. Challenge your students to identify strategies employed by these restaurants to compete with each other. As each restaurant makes changes, how do the other restaurants respond? Restaurants changing strategies in response to each other is analogous to coevolution. 6. Students commonly have practice with food webs and food chains. Present a food web (perhaps Figure 20.18) to your class and challenge them to predict the consequences of a decrease or increase in the population of one of the organisms. This activity can help students understand how difficult it is to make precise predictions about these complex systems. 7. Many keystone species have been identified in ecosystems, including sea otters, elephants, freshwater bass, and Pisaster, a sea star noted in Figure Challenge your class to explain how the concept of a keystone species relates to the efforts of conservation biologists. Why might some species be more important to conserve? 8. Before and after images of the impact and recovery of an ecosystem from a natural disaster can be as powerful as any explanation of the process. 9. Challenge your students to think through the adaptive advantage of a warning coloration in a toxic animal. Challenge your students to explain: What is gained if the predator dies? How can such systems evolve is the model is killed in the learning experience? 10. Students who are business-oriented might enjoy this analogy. Many corporate leaders might describe the best business deals as those that are mutualistic, fostering a win-win relationship.

Mimicry between clearwing moth and yellow jacket wasp
FIGURE Harmless, but Looking Dangerous In an example of Batesian mimicry, the clearwing moth (on the right) has no sting but has evolved to look like an insect that does, the yellowjacket wasp (left). The yellowjacket is the model and the moth is the mimic.

Mimicry between 2 species of S
Mimicry between 2 species of S. American butterflies that share the characteristic of tasting bad and have evolved to look like each other. FIGURE Müllerian Mimicry The South American butterflies Heliconius cydno (top) and Heliconius sapho are different in some ways, but they share the characteristic of tasting bad to predators. Over time, they evolved to look like each other, with their appearance serving as a warning to would-be predators. Natural selection favors this Müllerian mimicry, because predators can learn about the butterflies’ unpalatable taste from both species. The result is that fewer members of either species are likely to be killed or bothered by predators.

Herbivory is the consumption of plant parts or algae by an animal.
d. Plant adaptations Spines/ thorns Chemical toxins Student Misconceptions and Concerns 1. For many students, understanding ecosystems is like appreciating art. They can see ecosystems and art, but they do not understand the composition, the significance of the components, and the nature of their interactions. The fundamentals introduced in this chapter are new ways to see generally familiar systems. 2. The concept of an ecological niche can be confusing. Ecologist Eugene Odum suggested that an ecological niche is like an organism’s habitat (address) and its occupation combined. 3. Students often mistakenly think that symbiosis is a synonym for mutualism. Mutualism is a form of symbiosis. 4. The expectation that ecosystems are relatively stable is common. Natural disturbances of any sort (fires, earthquakes, floods, or strong storms) are typically viewed as tragic and damaging to ecosystems. Before beginning the topic of ecological disturbances, consider asking your students to briefly respond to news that a state or federal park has a) been burned, b) been struck by high winds and/or lightning, or c) been temporarily flooded. In addition, consider asking what if anything should be done to prevent or repair this damage? Teaching Tips 1. For many students, their interactions with diverse ecosystems have been limited to videos and movies, likely focused on a few species. Before discussing this chapter, consider showing the class a good video (it need not be long) about an ecosystem. The video can then serve as a common experience of the students to which you can refer and relate the content of this chapter. 2. Alternately, you can relate some of the basics of this chapter to a local campus or regional example to which most students are familiar. Perhaps there is a distinct community on your campus: a pond, distinct wooded area, or other part of campus that students would know and could visit with new insight. 3. In human society, a community might be considered about the same as a local population, perhaps all the people living in a town or city. The definition of a biological community is more inclusive, comprising all of the populations of species living close enough together for potential interaction. 4. Examples of interspecific competition are as close as the nearest lawn. Although students may be more likely to think of animal examples, the various grasses and weeds in a lawn reveal different strategies in their competition for sunlight, moisture, and soil. 5. If your class includes students with business interests, they may enjoy the following analogy. To better understand competition, students might think about fast-food restaurants in your region, perhaps those that sell pizzas. Challenge your students to identify strategies employed by these restaurants to compete with each other. As each restaurant makes changes, how do the other restaurants respond? Restaurants changing strategies in response to each other is analogous to coevolution. 6. Students commonly have practice with food webs and food chains. Present a food web (perhaps Figure 20.18) to your class and challenge them to predict the consequences of a decrease or increase in the population of one of the organisms. This activity can help students understand how difficult it is to make precise predictions about these complex systems. 7. Many keystone species have been identified in ecosystems, including sea otters, elephants, freshwater bass, and Pisaster, a sea star noted in Figure Challenge your class to explain how the concept of a keystone species relates to the efforts of conservation biologists. Why might some species be more important to conserve? 8. Before and after images of the impact and recovery of an ecosystem from a natural disaster can be as powerful as any explanation of the process. 9. Challenge your students to think through the adaptive advantage of a warning coloration in a toxic animal. Challenge your students to explain: What is gained if the predator dies? How can such systems evolve is the model is killed in the learning experience? 10. Students who are business-oriented might enjoy this analogy. Many corporate leaders might describe the best business deals as those that are mutualistic, fostering a win-win relationship.

Spines/ thorns

The cinnabar moth caterpillar feeds solely on tansy ragwort, which is poisonous for animals and humans.

Herbivory is the consumption of plant parts or algae by an animal.
Plants have evolved numerous defenses Spines Thorns Chemical toxins Student Misconceptions and Concerns 1. For many students, understanding ecosystems is like appreciating art. They can see ecosystems and art, but they do not understand the composition, the significance of the components, and the nature of their interactions. The fundamentals introduced in this chapter are new ways to see generally familiar systems. 2. The concept of an ecological niche can be confusing. Ecologist Eugene Odum suggested that an ecological niche is like an organism’s habitat (address) and its occupation combined. 3. Students often mistakenly think that symbiosis is a synonym for mutualism. Mutualism is a form of symbiosis. 4. The expectation that ecosystems are relatively stable is common. Natural disturbances of any sort (fires, earthquakes, floods, or strong storms) are typically viewed as tragic and damaging to ecosystems. Before beginning the topic of ecological disturbances, consider asking your students to briefly respond to news that a state or federal park has a) been burned, b) been struck by high winds and/or lightning, or c) been temporarily flooded. In addition, consider asking what if anything should be done to prevent or repair this damage? Teaching Tips 1. For many students, their interactions with diverse ecosystems have been limited to videos and movies, likely focused on a few species. Before discussing this chapter, consider showing the class a good video (it need not be long) about an ecosystem. The video can then serve as a common experience of the students to which you can refer and relate the content of this chapter. 2. Alternately, you can relate some of the basics of this chapter to a local campus or regional example to which most students are familiar. Perhaps there is a distinct community on your campus: a pond, distinct wooded area, or other part of campus that students would know and could visit with new insight. 3. In human society, a community might be considered about the same as a local population, perhaps all the people living in a town or city. The definition of a biological community is more inclusive, comprising all of the populations of species living close enough together for potential interaction. 4. Examples of interspecific competition are as close as the nearest lawn. Although students may be more likely to think of animal examples, the various grasses and weeds in a lawn reveal different strategies in their competition for sunlight, moisture, and soil. 5. If your class includes students with business interests, they may enjoy the following analogy. To better understand competition, students might think about fast-food restaurants in your region, perhaps those that sell pizzas. Challenge your students to identify strategies employed by these restaurants to compete with each other. As each restaurant makes changes, how do the other restaurants respond? Restaurants changing strategies in response to each other is analogous to coevolution. 6. Students commonly have practice with food webs and food chains. Present a food web (perhaps Figure 20.18) to your class and challenge them to predict the consequences of a decrease or increase in the population of one of the organisms. This activity can help students understand how difficult it is to make precise predictions about these complex systems. 7. Many keystone species have been identified in ecosystems, including sea otters, elephants, freshwater bass, and Pisaster, a sea star noted in Figure Challenge your class to explain how the concept of a keystone species relates to the efforts of conservation biologists. Why might some species be more important to conserve? 8. Before and after images of the impact and recovery of an ecosystem from a natural disaster can be as powerful as any explanation of the process. 9. Challenge your students to think through the adaptive advantage of a warning coloration in a toxic animal. Challenge your students to explain: What is gained if the predator dies? How can such systems evolve is the model is killed in the learning experience? 10. Students who are business-oriented might enjoy this analogy. Many corporate leaders might describe the best business deals as those that are mutualistic, fostering a win-win relationship.

Peppermint Cloves Figure Flavorful plants Cinnamon Figure 20.14

4. Parasitism- predator feeds on the prey with out killing it immediately or ever Parasites, an animal that lives in or on a host from which it obtains nutrients Student Misconceptions and Concerns 1. For many students, understanding ecosystems is like appreciating art. They can see ecosystems and art, but they do not understand the composition, the significance of the components, and the nature of their interactions. The fundamentals introduced in this chapter are new ways to see generally familiar systems. 2. The concept of an ecological niche can be confusing. Ecologist Eugene Odum suggested that an ecological niche is like an organism’s habitat (address) and its occupation combined. 3. Students often mistakenly think that symbiosis is a synonym for mutualism. Mutualism is a form of symbiosis. 4. The expectation that ecosystems are relatively stable is common. Natural disturbances of any sort (fires, earthquakes, floods, or strong storms) are typically viewed as tragic and damaging to ecosystems. Before beginning the topic of ecological disturbances, consider asking your students to briefly respond to news that a state or federal park has a) been burned, b) been struck by high winds and/or lightning, or c) been temporarily flooded. In addition, consider asking what if anything should be done to prevent or repair this damage? Teaching Tips 1. For many students, their interactions with diverse ecosystems have been limited to videos and movies, likely focused on a few species. Before discussing this chapter, consider showing the class a good video (it need not be long) about an ecosystem. The video can then serve as a common experience of the students to which you can refer and relate the content of this chapter. 2. Alternately, you can relate some of the basics of this chapter to a local campus or regional example to which most students are familiar. Perhaps there is a distinct community on your campus: a pond, distinct wooded area, or other part of campus that students would know and could visit with new insight. 3. In human society, a community might be considered about the same as a local population, perhaps all the people living in a town or city. The definition of a biological community is more inclusive, comprising all of the populations of species living close enough together for potential interaction. 4. Examples of interspecific competition are as close as the nearest lawn. Although students may be more likely to think of animal examples, the various grasses and weeds in a lawn reveal different strategies in their competition for sunlight, moisture, and soil. 5. If your class includes students with business interests, they may enjoy the following analogy. To better understand competition, students might think about fast-food restaurants in your region, perhaps those that sell pizzas. Challenge your students to identify strategies employed by these restaurants to compete with each other. As each restaurant makes changes, how do the other restaurants respond? Restaurants changing strategies in response to each other is analogous to coevolution. 6. Students commonly have practice with food webs and food chains. Present a food web (perhaps Figure 20.18) to your class and challenge them to predict the consequences of a decrease or increase in the population of one of the organisms. This activity can help students understand how difficult it is to make precise predictions about these complex systems. 7. Many keystone species have been identified in ecosystems, including sea otters, elephants, freshwater bass, and Pisaster, a sea star noted in Figure Challenge your class to explain how the concept of a keystone species relates to the efforts of conservation biologists. Why might some species be more important to conserve? 8. Before and after images of the impact and recovery of an ecosystem from a natural disaster can be as powerful as any explanation of the process. 9. Challenge your students to think through the adaptive advantage of a warning coloration in a toxic animal. Challenge your students to explain: What is gained if the predator dies? How can such systems evolve is the model is killed in the learning experience? 10. Students who are business-oriented might enjoy this analogy. Many corporate leaders might describe the best business deals as those that are mutualistic, fostering a win-win relationship.

Parasite

Figure 17.8 Two examples of parasites. (A) Bloodsucking ticks on the head of a finch. (B) Dodder (Cuscuta) is also known as strangleweed or devil’s hair. This parasitic flowering plant lacks chlorophyll. It winds around a host plant during growth. Modified roots penetrate the host’s vascular tissues and draw water and sugars from them. Fig. 17-8b, p. 346

Table 37.2 Interspecific Interactions.

Trophic Structure Trophic levels- position of level of organization among a food chain or food web determines the passage of energy and nutrients from plants and other photosynthetic organisms to herbivores and then to predators Student Misconceptions and Concerns 1. For many students, understanding ecosystems is like appreciating art. They can see ecosystems and art, but they do not understand the composition, the significance of the components, and the nature of their interactions. The fundamentals introduced in this chapter are new ways to see generally familiar systems. 2. The concept of an ecological niche can be confusing. Ecologist Eugene Odum suggested that an ecological niche is like an organism’s habitat (address) and its occupation combined. 3. Students often mistakenly think that symbiosis is a synonym for mutualism. Mutualism is a form of symbiosis. 4. The expectation that ecosystems are relatively stable is common. Natural disturbances of any sort (fires, earthquakes, floods, or strong storms) are typically viewed as tragic and damaging to ecosystems. Before beginning the topic of ecological disturbances, consider asking your students to briefly respond to news that a state or federal park has a) been burned, b) been struck by high winds and/or lightning, or c) been temporarily flooded. In addition, consider asking what if anything should be done to prevent or repair this damage? Teaching Tips 1. For many students, their interactions with diverse ecosystems have been limited to videos and movies, likely focused on a few species. Before discussing this chapter, consider showing the class a good video (it need not be long) about an ecosystem. The video can then serve as a common experience of the students to which you can refer and relate the content of this chapter. 2. Alternately, you can relate some of the basics of this chapter to a local campus or regional example to which most students are familiar. Perhaps there is a distinct community on your campus: a pond, distinct wooded area, or other part of campus that students would know and could visit with new insight. 3. In human society, a community might be considered about the same as a local population, perhaps all the people living in a town or city. The definition of a biological community is more inclusive, comprising all of the populations of species living close enough together for potential interaction. 4. Examples of interspecific competition are as close as the nearest lawn. Although students may be more likely to think of animal examples, the various grasses and weeds in a lawn reveal different strategies in their competition for sunlight, moisture, and soil. 5. If your class includes students with business interests, they may enjoy the following analogy. To better understand competition, students might think about fast-food restaurants in your region, perhaps those that sell pizzas. Challenge your students to identify strategies employed by these restaurants to compete with each other. As each restaurant makes changes, how do the other restaurants respond? Restaurants changing strategies in response to each other is analogous to coevolution. 6. Students commonly have practice with food webs and food chains. Present a food web (perhaps Figure 20.18) to your class and challenge them to predict the consequences of a decrease or increase in the population of one of the organisms. This activity can help students understand how difficult it is to make precise predictions about these complex systems. 7. Many keystone species have been identified in ecosystems, including sea otters, elephants, freshwater bass, and Pisaster, a sea star noted in Figure Challenge your class to explain how the concept of a keystone species relates to the efforts of conservation biologists. Why might some species be more important to conserve? 8. Before and after images of the impact and recovery of an ecosystem from a natural disaster can be as powerful as any explanation of the process. 9. Challenge your students to think through the adaptive advantage of a warning coloration in a toxic animal. Challenge your students to explain: What is gained if the predator dies? How can such systems evolve is the model is killed in the learning experience? 10. Students who are business-oriented might enjoy this analogy. Many corporate leaders might describe the best business deals as those that are mutualistic, fostering a win-win relationship.

Trophic levels Food chain-transfer of energy from autotroph to heterotroph through a process of eating and being eaten

The trophic level that supports all other trophic levels consists of autotrophs, also called producers. 1st trophic level- producers- autotrophs that capture sunlight energy and incorporate it into organic compounds Student Misconceptions and Concerns 1. For many students, understanding ecosystems is like appreciating art. They can see ecosystems and art, but they do not understand the composition, the significance of the components, and the nature of their interactions. The fundamentals introduced in this chapter are new ways to see generally familiar systems. 2. The concept of an ecological niche can be confusing. Ecologist Eugene Odum suggested that an ecological niche is like an organism’s habitat (address) and its occupation combined. 3. Students often mistakenly think that symbiosis is a synonym for mutualism. Mutualism is a form of symbiosis. 4. The expectation that ecosystems are relatively stable is common. Natural disturbances of any sort (fires, earthquakes, floods, or strong storms) are typically viewed as tragic and damaging to ecosystems. Before beginning the topic of ecological disturbances, consider asking your students to briefly respond to news that a state or federal park has a) been burned, b) been struck by high winds and/or lightning, or c) been temporarily flooded. In addition, consider asking what if anything should be done to prevent or repair this damage? Teaching Tips 1. For many students, their interactions with diverse ecosystems have been limited to videos and movies, likely focused on a few species. Before discussing this chapter, consider showing the class a good video (it need not be long) about an ecosystem. The video can then serve as a common experience of the students to which you can refer and relate the content of this chapter. 2. Alternately, you can relate some of the basics of this chapter to a local campus or regional example to which most students are familiar. Perhaps there is a distinct community on your campus: a pond, distinct wooded area, or other part of campus that students would know and could visit with new insight. 3. In human society, a community might be considered about the same as a local population, perhaps all the people living in a town or city. The definition of a biological community is more inclusive, comprising all of the populations of species living close enough together for potential interaction. 4. Examples of interspecific competition are as close as the nearest lawn. Although students may be more likely to think of animal examples, the various grasses and weeds in a lawn reveal different strategies in their competition for sunlight, moisture, and soil. 5. If your class includes students with business interests, they may enjoy the following analogy. To better understand competition, students might think about fast-food restaurants in your region, perhaps those that sell pizzas. Challenge your students to identify strategies employed by these restaurants to compete with each other. As each restaurant makes changes, how do the other restaurants respond? Restaurants changing strategies in response to each other is analogous to coevolution. 6. Students commonly have practice with food webs and food chains. Present a food web (perhaps Figure 20.18) to your class and challenge them to predict the consequences of a decrease or increase in the population of one of the organisms. This activity can help students understand how difficult it is to make precise predictions about these complex systems. 7. Many keystone species have been identified in ecosystems, including sea otters, elephants, freshwater bass, and Pisaster, a sea star noted in Figure Challenge your class to explain how the concept of a keystone species relates to the efforts of conservation biologists. Why might some species be more important to conserve? 8. Before and after images of the impact and recovery of an ecosystem from a natural disaster can be as powerful as any explanation of the process. 9. Challenge your students to think through the adaptive advantage of a warning coloration in a toxic animal. Challenge your students to explain: What is gained if the predator dies? How can such systems evolve is the model is killed in the learning experience? 10. Students who are business-oriented might enjoy this analogy. Many corporate leaders might describe the best business deals as those that are mutualistic, fostering a win-win relationship.

2nd trophic level- primary consumers- herbivores- eat plants
All organisms in trophic levels above the producers are consumers- heterotrophs that feed on others for food 2nd trophic level- primary consumers- herbivores- eat plants Student Misconceptions and Concerns 1. For many students, understanding ecosystems is like appreciating art. They can see ecosystems and art, but they do not understand the composition, the significance of the components, and the nature of their interactions. The fundamentals introduced in this chapter are new ways to see generally familiar systems. 2. The concept of an ecological niche can be confusing. Ecologist Eugene Odum suggested that an ecological niche is like an organism’s habitat (address) and its occupation combined. 3. Students often mistakenly think that symbiosis is a synonym for mutualism. Mutualism is a form of symbiosis. 4. The expectation that ecosystems are relatively stable is common. Natural disturbances of any sort (fires, earthquakes, floods, or strong storms) are typically viewed as tragic and damaging to ecosystems. Before beginning the topic of ecological disturbances, consider asking your students to briefly respond to news that a state or federal park has a) been burned, b) been struck by high winds and/or lightning, or c) been temporarily flooded. In addition, consider asking what if anything should be done to prevent or repair this damage? Teaching Tips 1. For many students, their interactions with diverse ecosystems have been limited to videos and movies, likely focused on a few species. Before discussing this chapter, consider showing the class a good video (it need not be long) about an ecosystem. The video can then serve as a common experience of the students to which you can refer and relate the content of this chapter. 2. Alternately, you can relate some of the basics of this chapter to a local campus or regional example to which most students are familiar. Perhaps there is a distinct community on your campus: a pond, distinct wooded area, or other part of campus that students would know and could visit with new insight. 3. In human society, a community might be considered about the same as a local population, perhaps all the people living in a town or city. The definition of a biological community is more inclusive, comprising all of the populations of species living close enough together for potential interaction. 4. Examples of interspecific competition are as close as the nearest lawn. Although students may be more likely to think of animal examples, the various grasses and weeds in a lawn reveal different strategies in their competition for sunlight, moisture, and soil. 5. If your class includes students with business interests, they may enjoy the following analogy. To better understand competition, students might think about fast-food restaurants in your region, perhaps those that sell pizzas. Challenge your students to identify strategies employed by these restaurants to compete with each other. As each restaurant makes changes, how do the other restaurants respond? Restaurants changing strategies in response to each other is analogous to coevolution. 6. Students commonly have practice with food webs and food chains. Present a food web (perhaps Figure 20.18) to your class and challenge them to predict the consequences of a decrease or increase in the population of one of the organisms. This activity can help students understand how difficult it is to make precise predictions about these complex systems. 7. Many keystone species have been identified in ecosystems, including sea otters, elephants, freshwater bass, and Pisaster, a sea star noted in Figure Challenge your class to explain how the concept of a keystone species relates to the efforts of conservation biologists. Why might some species be more important to conserve? 8. Before and after images of the impact and recovery of an ecosystem from a natural disaster can be as powerful as any explanation of the process. 9. Challenge your students to think through the adaptive advantage of a warning coloration in a toxic animal. Challenge your students to explain: What is gained if the predator dies? How can such systems evolve is the model is killed in the learning experience? 10. Students who are business-oriented might enjoy this analogy. Many corporate leaders might describe the best business deals as those that are mutualistic, fostering a win-win relationship.

above the level of primary consumers are carnivores- eat animals
eat the consumers from the level below 3rd trophic level- secondary consumers eat primary consumers 4th trophic level- tertiary consumers eat secondary consumers 5th trophic level- quaternary consumers eat tertiary consumers Student Misconceptions and Concerns 1. For many students, understanding ecosystems is like appreciating art. They can see ecosystems and art, but they do not understand the composition, the significance of the components, and the nature of their interactions. The fundamentals introduced in this chapter are new ways to see generally familiar systems. 2. The concept of an ecological niche can be confusing. Ecologist Eugene Odum suggested that an ecological niche is like an organism’s habitat (address) and its occupation combined. 3. Students often mistakenly think that symbiosis is a synonym for mutualism. Mutualism is a form of symbiosis. 4. The expectation that ecosystems are relatively stable is common. Natural disturbances of any sort (fires, earthquakes, floods, or strong storms) are typically viewed as tragic and damaging to ecosystems. Before beginning the topic of ecological disturbances, consider asking your students to briefly respond to news that a state or federal park has a) been burned, b) been struck by high winds and/or lightning, or c) been temporarily flooded. In addition, consider asking what if anything should be done to prevent or repair this damage? Teaching Tips 1. For many students, their interactions with diverse ecosystems have been limited to videos and movies, likely focused on a few species. Before discussing this chapter, consider showing the class a good video (it need not be long) about an ecosystem. The video can then serve as a common experience of the students to which you can refer and relate the content of this chapter. 2. Alternately, you can relate some of the basics of this chapter to a local campus or regional example to which most students are familiar. Perhaps there is a distinct community on your campus: a pond, distinct wooded area, or other part of campus that students would know and could visit with new insight. 3. In human society, a community might be considered about the same as a local population, perhaps all the people living in a town or city. The definition of a biological community is more inclusive, comprising all of the populations of species living close enough together for potential interaction. 4. Examples of interspecific competition are as close as the nearest lawn. Although students may be more likely to think of animal examples, the various grasses and weeds in a lawn reveal different strategies in their competition for sunlight, moisture, and soil. 5. If your class includes students with business interests, they may enjoy the following analogy. To better understand competition, students might think about fast-food restaurants in your region, perhaps those that sell pizzas. Challenge your students to identify strategies employed by these restaurants to compete with each other. As each restaurant makes changes, how do the other restaurants respond? Restaurants changing strategies in response to each other is analogous to coevolution. 6. Students commonly have practice with food webs and food chains. Present a food web (perhaps Figure 20.18) to your class and challenge them to predict the consequences of a decrease or increase in the population of one of the organisms. This activity can help students understand how difficult it is to make precise predictions about these complex systems. 7. Many keystone species have been identified in ecosystems, including sea otters, elephants, freshwater bass, and Pisaster, a sea star noted in Figure Challenge your class to explain how the concept of a keystone species relates to the efforts of conservation biologists. Why might some species be more important to conserve? 8. Before and after images of the impact and recovery of an ecosystem from a natural disaster can be as powerful as any explanation of the process. 9. Challenge your students to think through the adaptive advantage of a warning coloration in a toxic animal. Challenge your students to explain: What is gained if the predator dies? How can such systems evolve is the model is killed in the learning experience? 10. Students who are business-oriented might enjoy this analogy. Many corporate leaders might describe the best business deals as those that are mutualistic, fostering a win-win relationship.

Figure 20.15-1 Figure 20.15 Examples of food chains (Step 1) Producers
Plant Phytoplankton A terrestrial food chain An aquatic food chain Figure

Figure 20.15-2 Figure 20.15 Examples of food chains (Step 2) Primary
consumers Herbivore Zooplankton Producers Plant Phytoplankton A terrestrial food chain An aquatic food chain Figure

Figure 20.15-3 Figure 20.15 Examples of food chains (Step 3) Secondary
consumers Carnivore Carnivore Figure Examples of food chains (Step 3) Primary consumers Herbivore Zooplankton Producers Plant Phytoplankton A terrestrial food chain An aquatic food chain Figure

Figure 20.15-4 Figure 20.15 Examples of food chains (Step 4) Tertiary
consumers Carnivore Carnivore Secondary consumers Carnivore Carnivore Figure Examples of food chains (Step 4) Primary consumers Herbivore Zooplankton Producers Plant Phytoplankton A terrestrial food chain An aquatic food chain Figure

Figure 20.15-5 Figure 20.15 Examples of food chains (Step 5)
Quaternary consumers Carnivore Carnivore Tertiary consumers Carnivore Carnivore Secondary consumers Carnivore Carnivore Figure Examples of food chains (Step 5) Primary consumers Herbivore Zooplankton Producers Plant Phytoplankton A terrestrial food chain An aquatic food chain Figure

Detritivores- scavengers that consume detritus- the dead material left by all organisms
Decomposers- prokaryotes and fungi that breakdown organic material and convert them into inorganic forms Student Misconceptions and Concerns 1. For many students, understanding ecosystems is like appreciating art. They can see ecosystems and art, but they do not understand the composition, the significance of the components, and the nature of their interactions. The fundamentals introduced in this chapter are new ways to see generally familiar systems. 2. The concept of an ecological niche can be confusing. Ecologist Eugene Odum suggested that an ecological niche is like an organism’s habitat (address) and its occupation combined. 3. Students often mistakenly think that symbiosis is a synonym for mutualism. Mutualism is a form of symbiosis. 4. The expectation that ecosystems are relatively stable is common. Natural disturbances of any sort (fires, earthquakes, floods, or strong storms) are typically viewed as tragic and damaging to ecosystems. Before beginning the topic of ecological disturbances, consider asking your students to briefly respond to news that a state or federal park has a) been burned, b) been struck by high winds and/or lightning, or c) been temporarily flooded. In addition, consider asking what if anything should be done to prevent or repair this damage? Teaching Tips 1. For many students, their interactions with diverse ecosystems have been limited to videos and movies, likely focused on a few species. Before discussing this chapter, consider showing the class a good video (it need not be long) about an ecosystem. The video can then serve as a common experience of the students to which you can refer and relate the content of this chapter. 2. Alternately, you can relate some of the basics of this chapter to a local campus or regional example to which most students are familiar. Perhaps there is a distinct community on your campus: a pond, distinct wooded area, or other part of campus that students would know and could visit with new insight. 3. In human society, a community might be considered about the same as a local population, perhaps all the people living in a town or city. The definition of a biological community is more inclusive, comprising all of the populations of species living close enough together for potential interaction. 4. Examples of interspecific competition are as close as the nearest lawn. Although students may be more likely to think of animal examples, the various grasses and weeds in a lawn reveal different strategies in their competition for sunlight, moisture, and soil. 5. If your class includes students with business interests, they may enjoy the following analogy. To better understand competition, students might think about fast-food restaurants in your region, perhaps those that sell pizzas. Challenge your students to identify strategies employed by these restaurants to compete with each other. As each restaurant makes changes, how do the other restaurants respond? Restaurants changing strategies in response to each other is analogous to coevolution. 6. Students commonly have practice with food webs and food chains. Present a food web (perhaps Figure 20.18) to your class and challenge them to predict the consequences of a decrease or increase in the population of one of the organisms. This activity can help students understand how difficult it is to make precise predictions about these complex systems. 7. Many keystone species have been identified in ecosystems, including sea otters, elephants, freshwater bass, and Pisaster, a sea star noted in Figure Challenge your class to explain how the concept of a keystone species relates to the efforts of conservation biologists. Why might some species be more important to conserve? 8. Before and after images of the impact and recovery of an ecosystem from a natural disaster can be as powerful as any explanation of the process. 9. Challenge your students to think through the adaptive advantage of a warning coloration in a toxic animal. Challenge your students to explain: What is gained if the predator dies? How can such systems evolve is the model is killed in the learning experience? 10. Students who are business-oriented might enjoy this analogy. Many corporate leaders might describe the best business deals as those that are mutualistic, fostering a win-win relationship.

Figure 20.16 Fungi decomposing a dead log

Biological Magnification
Environmental toxins accumulate in consumers at higher concentrations up a trophic system in a process called biological magnification. Student Misconceptions and Concerns 1. For many students, understanding ecosystems is like appreciating art. They can see ecosystems and art, but they do not understand the composition, the significance of the components, and the nature of their interactions. The fundamentals introduced in this chapter are new ways to see generally familiar systems. 2. The concept of an ecological niche can be confusing. Ecologist Eugene Odum suggested that an ecological niche is like an organism’s habitat (address) and its occupation combined. 3. Students often mistakenly think that symbiosis is a synonym for mutualism. Mutualism is a form of symbiosis. 4. The expectation that ecosystems are relatively stable is common. Natural disturbances of any sort (fires, earthquakes, floods, or strong storms) are typically viewed as tragic and damaging to ecosystems. Before beginning the topic of ecological disturbances, consider asking your students to briefly respond to news that a state or federal park has a) been burned, b) been struck by high winds and/or lightning, or c) been temporarily flooded. In addition, consider asking what if anything should be done to prevent or repair this damage? Teaching Tips 1. For many students, their interactions with diverse ecosystems have been limited to videos and movies, likely focused on a few species. Before discussing this chapter, consider showing the class a good video (it need not be long) about an ecosystem. The video can then serve as a common experience of the students to which you can refer and relate the content of this chapter. 2. Alternately, you can relate some of the basics of this chapter to a local campus or regional example to which most students are familiar. Perhaps there is a distinct community on your campus: a pond, distinct wooded area, or other part of campus that students would know and could visit with new insight. 3. In human society, a community might be considered about the same as a local population, perhaps all the people living in a town or city. The definition of a biological community is more inclusive, comprising all of the populations of species living close enough together for potential interaction. 4. Examples of interspecific competition are as close as the nearest lawn. Although students may be more likely to think of animal examples, the various grasses and weeds in a lawn reveal different strategies in their competition for sunlight, moisture, and soil. 5. If your class includes students with business interests, they may enjoy the following analogy. To better understand competition, students might think about fast-food restaurants in your region, perhaps those that sell pizzas. Challenge your students to identify strategies employed by these restaurants to compete with each other. As each restaurant makes changes, how do the other restaurants respond? Restaurants changing strategies in response to each other is analogous to coevolution. 6. Students commonly have practice with food webs and food chains. Present a food web (perhaps Figure 20.18) to your class and challenge them to predict the consequences of a decrease or increase in the population of one of the organisms. This activity can help students understand how difficult it is to make precise predictions about these complex systems. 7. Many keystone species have been identified in ecosystems, including sea otters, elephants, freshwater bass, and Pisaster, a sea star noted in Figure Challenge your class to explain how the concept of a keystone species relates to the efforts of conservation biologists. Why might some species be more important to conserve? 8. Before and after images of the impact and recovery of an ecosystem from a natural disaster can be as powerful as any explanation of the process. 9. Challenge your students to think through the adaptive advantage of a warning coloration in a toxic animal. Challenge your students to explain: What is gained if the predator dies? How can such systems evolve is the model is killed in the learning experience? 10. Students who are business-oriented might enjoy this analogy. Many corporate leaders might describe the best business deals as those that are mutualistic, fostering a win-win relationship.

Figure 20.17 Herring gull eggs 124 ppm Lake trout 4.83 ppm
Increasing concentrations of PCBs Smelt 1.04 ppm Figure Biological magnification of PCBs in a Great Lakes food chain in the early 1960s Zooplankton 0.123 ppm Phytoplankton 0.025 ppm Figure 20.17

Few ecosystems are as a simple as an unbranched food chain.
Food Webs Few ecosystems are as a simple as an unbranched food chain. food webs- cross connecting food chains omnivores- eat producers and consumers Student Misconceptions and Concerns 1. For many students, understanding ecosystems is like appreciating art. They can see ecosystems and art, but they do not understand the composition, the significance of the components, and the nature of their interactions. The fundamentals introduced in this chapter are new ways to see generally familiar systems. 2. The concept of an ecological niche can be confusing. Ecologist Eugene Odum suggested that an ecological niche is like an organism’s habitat (address) and its occupation combined. 3. Students often mistakenly think that symbiosis is a synonym for mutualism. Mutualism is a form of symbiosis. 4. The expectation that ecosystems are relatively stable is common. Natural disturbances of any sort (fires, earthquakes, floods, or strong storms) are typically viewed as tragic and damaging to ecosystems. Before beginning the topic of ecological disturbances, consider asking your students to briefly respond to news that a state or federal park has a) been burned, b) been struck by high winds and/or lightning, or c) been temporarily flooded. In addition, consider asking what if anything should be done to prevent or repair this damage? Teaching Tips 1. For many students, their interactions with diverse ecosystems have been limited to videos and movies, likely focused on a few species. Before discussing this chapter, consider showing the class a good video (it need not be long) about an ecosystem. The video can then serve as a common experience of the students to which you can refer and relate the content of this chapter. 2. Alternately, you can relate some of the basics of this chapter to a local campus or regional example to which most students are familiar. Perhaps there is a distinct community on your campus: a pond, distinct wooded area, or other part of campus that students would know and could visit with new insight. 3. In human society, a community might be considered about the same as a local population, perhaps all the people living in a town or city. The definition of a biological community is more inclusive, comprising all of the populations of species living close enough together for potential interaction. 4. Examples of interspecific competition are as close as the nearest lawn. Although students may be more likely to think of animal examples, the various grasses and weeds in a lawn reveal different strategies in their competition for sunlight, moisture, and soil. 5. If your class includes students with business interests, they may enjoy the following analogy. To better understand competition, students might think about fast-food restaurants in your region, perhaps those that sell pizzas. Challenge your students to identify strategies employed by these restaurants to compete with each other. As each restaurant makes changes, how do the other restaurants respond? Restaurants changing strategies in response to each other is analogous to coevolution. 6. Students commonly have practice with food webs and food chains. Present a food web (perhaps Figure 20.18) to your class and challenge them to predict the consequences of a decrease or increase in the population of one of the organisms. This activity can help students understand how difficult it is to make precise predictions about these complex systems. 7. Many keystone species have been identified in ecosystems, including sea otters, elephants, freshwater bass, and Pisaster, a sea star noted in Figure Challenge your class to explain how the concept of a keystone species relates to the efforts of conservation biologists. Why might some species be more important to conserve? 8. Before and after images of the impact and recovery of an ecosystem from a natural disaster can be as powerful as any explanation of the process. 9. Challenge your students to think through the adaptive advantage of a warning coloration in a toxic animal. Challenge your students to explain: What is gained if the predator dies? How can such systems evolve is the model is killed in the learning experience? 10. Students who are business-oriented might enjoy this analogy. Many corporate leaders might describe the best business deals as those that are mutualistic, fostering a win-win relationship.

FIGURE A River Food Web The diagram indicates who eats whom along a portion of the Eel River in Northern California. The arrows have been color-coded by trophic level. Note that there are up to five trophic levels in the web. (Adapted with permission from an original drawing by Mary E. Power, University of California, Berkeley.)

37.10 Species diversity includes relative abundance and species richness
Species diversity defined by two components Species richness Relative abundance Plant species diversity in a community affects the animals Species diversity has consequences for pathogens Student Misconceptions and Concerns 1. For many students, understanding ecosystems is like appreciating art. Although both are visible to the naked eye, in each case some background is required to understand the method of composition, the significance of components, and the nature of interactions. The fundamentals introduced in this chapter are new ways to see generally familiar systems. Teaching Tips 1. Many students have been exposed to diverse ecosystems only through television and movies, which have likely focused on a few species. Before discussing this chapter, consider showing the class a good video (it need not be long) about an ecosystem. The video can then serve as a shared recent experience to which you can relate the content of this chapter. Alternately, you can relate some of the basics of this chapter to a local or regional example with which most students are familiar. There may even be a distinct community on your campus, such as a pond, wooded area, etc., that students could visit and return from with new insights. Copyright © 2009 Pearson Education, Inc.

Figure 37.10A Species composition of woodlot A.

Figure 37.10B Species composition of woodlot B.

Table 37.10 Relative Abundance of Tree Species in Woodlots A and B.

37.11 Keystone species have a disproportionate impact on diversity
Keystone species A species whose impact on its community is larger than its biomass or abundance indicates Occupies a niche that holds the rest of its community in place Student Misconceptions and Concerns 1. For many students, understanding ecosystems is like appreciating art. Although both are visible to the naked eye, in each case some background is required to understand the method of composition, the significance of components, and the nature of interactions. The fundamentals introduced in this chapter are new ways to see generally familiar systems. Teaching Tips 1. Many students have been exposed to diverse ecosystems only through television and movies, which have likely focused on a few species. Before discussing this chapter, consider showing the class a good video (it need not be long) about an ecosystem. The video can then serve as a shared recent experience to which you can relate the content of this chapter. Alternately, you can relate some of the basics of this chapter to a local or regional example with which most students are familiar. There may even be a distinct community on your campus, such as a pond, wooded area, etc., that students could visit and return from with new insights. 2. Many keystone species have been identified in ecosystems, including sea otters, elephants, freshwater bass, and Pisaster, a sea star noted in Figure Challenge your class to explain how the concept of keystone species impacts the efforts of conservation biologists. Why might some species be more important to conserve? Copyright © 2009 Pearson Education, Inc.

Keystone Keystone absent
Figure 37.11A Arch collapse with removal of keystone.

Pisaster sea star, a keystone species, eating a mussel.
Figure 37.11B A Pisaster sea star, a keystone species, eating a mussel.

Ecological Succession
ecological succession- a gradual replacement of one species by other species may be caused by disturbance 1. Primary succession Starting state has little or no life In places such as lava flows retreating glacier Student Misconceptions and Concerns 1. For many students, understanding ecosystems is like appreciating art. They can see ecosystems and art, but they do not understand the composition, the significance of the components, and the nature of their interactions. The fundamentals introduced in this chapter are new ways to see generally familiar systems. 2. The concept of an ecological niche can be confusing. Ecologist Eugene Odum suggested that an ecological niche is like an organism’s habitat (address) and its occupation combined. 3. Students often mistakenly think that symbiosis is a synonym for mutualism. Mutualism is a form of symbiosis. 4. The expectation that ecosystems are relatively stable is common. Natural disturbances of any sort (fires, earthquakes, floods, or strong storms) are typically viewed as tragic and damaging to ecosystems. Before beginning the topic of ecological disturbances, consider asking your students to briefly respond to news that a state or federal park has a) been burned, b) been struck by high winds and/or lightning, or c) been temporarily flooded. In addition, consider asking what if anything should be done to prevent or repair this damage? Teaching Tips 1. For many students, their interactions with diverse ecosystems have been limited to videos and movies, likely focused on a few species. Before discussing this chapter, consider showing the class a good video (it need not be long) about an ecosystem. The video can then serve as a common experience of the students to which you can refer and relate the content of this chapter. 2. Alternately, you can relate some of the basics of this chapter to a local campus or regional example to which most students are familiar. Perhaps there is a distinct community on your campus: a pond, distinct wooded area, or other part of campus that students would know and could visit with new insight. 3. In human society, a community might be considered about the same as a local population, perhaps all the people living in a town or city. The definition of a biological community is more inclusive, comprising all of the populations of species living close enough together for potential interaction. 4. Examples of interspecific competition are as close as the nearest lawn. Although students may be more likely to think of animal examples, the various grasses and weeds in a lawn reveal different strategies in their competition for sunlight, moisture, and soil. 5. If your class includes students with business interests, they may enjoy the following analogy. To better understand competition, students might think about fast-food restaurants in your region, perhaps those that sell pizzas. Challenge your students to identify strategies employed by these restaurants to compete with each other. As each restaurant makes changes, how do the other restaurants respond? Restaurants changing strategies in response to each other is analogous to coevolution. 6. Students commonly have practice with food webs and food chains. Present a food web (perhaps Figure 20.18) to your class and challenge them to predict the consequences of a decrease or increase in the population of one of the organisms. This activity can help students understand how difficult it is to make precise predictions about these complex systems. 7. Many keystone species have been identified in ecosystems, including sea otters, elephants, freshwater bass, and Pisaster, a sea star noted in Figure Challenge your class to explain how the concept of a keystone species relates to the efforts of conservation biologists. Why might some species be more important to conserve? 8. Before and after images of the impact and recovery of an ecosystem from a natural disaster can be as powerful as any explanation of the process. 9. Challenge your students to think through the adaptive advantage of a warning coloration in a toxic animal. Challenge your students to explain: What is gained if the predator dies? How can such systems evolve is the model is killed in the learning experience? 10. Students who are business-oriented might enjoy this analogy. Many corporate leaders might describe the best business deals as those that are mutualistic, fostering a win-win relationship.

Ecological succession
Pioneer community- 1st community in succession Serel stage- successive communities of transition Climax stage- last community in succession Bare rock to soil bare rock lichens moss grasses small trees forest

Annual plants Perennial plants and grasses Shrubs Softwood trees
Figure Stages in secondary succession of abandoned farm field. Annual plants Perennial plants and grasses Shrubs Softwood trees such as pines Hardwood trees Time

Figure 17.9 Artist’s depiction of how primary succession in a previously glaciated area can lead to establishment of a forest community. Fig. 17-9, p. 347

2. Secondary succession- habitat has been disturbed but life remains
Examples of secondary succession are areas recovering from Fires Floods Severe storms Student Misconceptions and Concerns 1. For many students, understanding ecosystems is like appreciating art. They can see ecosystems and art, but they do not understand the composition, the significance of the components, and the nature of their interactions. The fundamentals introduced in this chapter are new ways to see generally familiar systems. 2. The concept of an ecological niche can be confusing. Ecologist Eugene Odum suggested that an ecological niche is like an organism’s habitat (address) and its occupation combined. 3. Students often mistakenly think that symbiosis is a synonym for mutualism. Mutualism is a form of symbiosis. 4. The expectation that ecosystems are relatively stable is common. Natural disturbances of any sort (fires, earthquakes, floods, or strong storms) are typically viewed as tragic and damaging to ecosystems. Before beginning the topic of ecological disturbances, consider asking your students to briefly respond to news that a state or federal park has a) been burned, b) been struck by high winds and/or lightning, or c) been temporarily flooded. In addition, consider asking what if anything should be done to prevent or repair this damage? Teaching Tips 1. For many students, their interactions with diverse ecosystems have been limited to videos and movies, likely focused on a few species. Before discussing this chapter, consider showing the class a good video (it need not be long) about an ecosystem. The video can then serve as a common experience of the students to which you can refer and relate the content of this chapter. 2. Alternately, you can relate some of the basics of this chapter to a local campus or regional example to which most students are familiar. Perhaps there is a distinct community on your campus: a pond, distinct wooded area, or other part of campus that students would know and could visit with new insight. 3. In human society, a community might be considered about the same as a local population, perhaps all the people living in a town or city. The definition of a biological community is more inclusive, comprising all of the populations of species living close enough together for potential interaction. 4. Examples of interspecific competition are as close as the nearest lawn. Although students may be more likely to think of animal examples, the various grasses and weeds in a lawn reveal different strategies in their competition for sunlight, moisture, and soil. 5. If your class includes students with business interests, they may enjoy the following analogy. To better understand competition, students might think about fast-food restaurants in your region, perhaps those that sell pizzas. Challenge your students to identify strategies employed by these restaurants to compete with each other. As each restaurant makes changes, how do the other restaurants respond? Restaurants changing strategies in response to each other is analogous to coevolution. 6. Students commonly have practice with food webs and food chains. Present a food web (perhaps Figure 20.18) to your class and challenge them to predict the consequences of a decrease or increase in the population of one of the organisms. This activity can help students understand how difficult it is to make precise predictions about these complex systems. 7. Many keystone species have been identified in ecosystems, including sea otters, elephants, freshwater bass, and Pisaster, a sea star noted in Figure Challenge your class to explain how the concept of a keystone species relates to the efforts of conservation biologists. Why might some species be more important to conserve? 8. Before and after images of the impact and recovery of an ecosystem from a natural disaster can be as powerful as any explanation of the process. 9. Challenge your students to think through the adaptive advantage of a warning coloration in a toxic animal. Challenge your students to explain: What is gained if the predator dies? How can such systems evolve is the model is killed in the learning experience? 10. Students who are business-oriented might enjoy this analogy. Many corporate leaders might describe the best business deals as those that are mutualistic, fostering a win-win relationship.

Ecological succession after a fire
Figure Secondary succession after a fire Figure 20.24

Example of ecological succession
Example of ecological succession. (A) Mount Saint Helens erupted in Volcanic ash completely buried the community that previously existed at the base of this volcano. (B) In less than a decade, numerous pioneer species had become established. (C) Twelve years after the eruption, Douglas fir seedlings were taking hold in soils enriched with volcanic ash. Figure 17.10 Example of ecological succession. (A) Mount Saint Helens erupted in Volcanic ash completely buried the community that previously existed at the base of this volcano. (B) In less than a decade, numerous pioneer species had become established. (C) Twelve years after the eruption, Douglas fir seedlings were taking hold in soils enriched with volcanic ash. Fig , p. 347

ECOSYSTEM ECOLOGY ecosystem- community of organisms interacting with one another and their physical environment An ecosystem includes: The community of species in a given area All the abiotic factors, such as Energy Soil characteristics Water Student Misconceptions and Concerns 1. Without an understanding of the inefficiency of aerobic metabolism and basic physics, students might not understand how chemical energy in food is lost as heat. Consider expanding upon these explanations in the book. 2. The environmental impact of eating farm animals is little appreciated by most students. This chapter section helps explain the basis for the increased environmental costs associated with a high meat diet. 3. Except for prior classes in science, students are unlikely to have understood biogeochemical cycles. Although some transfers between the biotic and abiotic components may be known, such as the benefits of fertilizing plants, the broader concept of the biosphere as a self-cycling system is not appreciated by most students. Pretesting your students over their knowledge can confirm this expectation or reveal levels of understanding not appreciated. Consider asking your students to explain how carbon, nitrogen, and water cycle through the biosphere. For each substance, create a complete cycle. Teaching Tips 1. Why do food chains and webs typically have only three to five levels? This question is not often considered by students but is addressed directly in this chapter section. This question makes a good discussion before lecturing on the topic of food chains and food webs. 2. The heat generated as a by-product of metabolism is quite evident during strenuous exercise. It is much like the heat produced by a running automobile engine. In both circumstances, heat is a by-product of the fuel burning process. 3. Energy flow through an ecosystem is analogous to the flow of fuel through a car or electricity through a vacuum cleaner. The systems will not work without a steady input. NASA, however, must rely upon some closed systems for its spacecrafts. Students might enjoy investigating the recycling of gases and fluids in these NASA systems. 4. Some students might be interested in eating more proteins and fewer carbohydrates because of some special sort of diet (or fad). Does such a high protein diet require the consumption of more meat? The many sources of plant proteins might be surprising to students. The following Vegetarian Society website describes some of the high protein vegetarian options: 5. As you discuss the importance of the biogeochemical cycles, you might consider explaining the basic label information provided on a container of plant fertilizer. Typically, plant fertilizers contain various forms of nitrogen and phosphorus, essential chemicals to growth. 6. Challenge students to explain why the areas of greatest primary production are near the equator. Primary production is a consequence of photosynthesis. Regions near the equator receive the highest levels of solar input. 7. A discussion of the movements of water through your local community might help students better relate to the concepts of biogeochemical cycling at a local level. Students could be asked to consider all of the possible inputs of water into your community and the possible routes of exit. 8. The nitrogen-fixing bacteria living in the roots of soybeans add nitrogen to the soil. Corn does not enjoy this same relationship. By rotating corn and soybean crops, corn crops can use some of the nitrogen fixed by the soybean crop in the previous year. Corn and soybean crop rotation has other benefits. Corn is a monocot and soybeans are dicots. Few pests attack corn and soybeans. Thus, crop rotation also helps to control the pest populations characteristic of each type of plant.

Blast Animation: Energy Flow
A simple terrarium is a microcosm that exhibits the two major processes that sustain all ecosystems: Energy flow- the passage of energy through the components of the ecosystem Chemical cycling- the use and reuse of chemical elements such as carbon and nitrogen within the ecosystem Student Misconceptions and Concerns 1. Without an understanding of the inefficiency of aerobic metabolism and basic physics, students might not understand how chemical energy in food is lost as heat. Consider expanding upon these explanations in the book. 2. The environmental impact of eating farm animals is little appreciated by most students. This chapter section helps explain the basis for the increased environmental costs associated with a high meat diet. 3. Except for prior classes in science, students are unlikely to have understood biogeochemical cycles. Although some transfers between the biotic and abiotic components may be known, such as the benefits of fertilizing plants, the broader concept of the biosphere as a self-cycling system is not appreciated by most students. Pretesting your students over their knowledge can confirm this expectation or reveal levels of understanding not appreciated. Consider asking your students to explain how carbon, nitrogen, and water cycle through the biosphere. For each substance, create a complete cycle. Teaching Tips 1. Why do food chains and webs typically have only three to five levels? This question is not often considered by students but is addressed directly in this chapter section. This question makes a good discussion before lecturing on the topic of food chains and food webs. 2. The heat generated as a by-product of metabolism is quite evident during strenuous exercise. It is much like the heat produced by a running automobile engine. In both circumstances, heat is a by-product of the fuel burning process. 3. Energy flow through an ecosystem is analogous to the flow of fuel through a car or electricity through a vacuum cleaner. The systems will not work without a steady input. NASA, however, must rely upon some closed systems for its spacecrafts. Students might enjoy investigating the recycling of gases and fluids in these NASA systems. 4. Some students might be interested in eating more proteins and fewer carbohydrates because of some special sort of diet (or fad). Does such a high protein diet require the consumption of more meat? The many sources of plant proteins might be surprising to students. The following Vegetarian Society website describes some of the high protein vegetarian options: 5. As you discuss the importance of the biogeochemical cycles, you might consider explaining the basic label information provided on a container of plant fertilizer. Typically, plant fertilizers contain various forms of nitrogen and phosphorus, essential chemicals to growth. 6. Challenge students to explain why the areas of greatest primary production are near the equator. Primary production is a consequence of photosynthesis. Regions near the equator receive the highest levels of solar input. 7. A discussion of the movements of water through your local community might help students better relate to the concepts of biogeochemical cycling at a local level. Students could be asked to consider all of the possible inputs of water into your community and the possible routes of exit. 8. The nitrogen-fixing bacteria living in the roots of soybeans add nitrogen to the soil. Corn does not enjoy this same relationship. By rotating corn and soybean crops, corn crops can use some of the nitrogen fixed by the soybean crop in the previous year. Corn and soybean crop rotation has other benefits. Corn is a monocot and soybeans are dicots. Few pests attack corn and soybeans. Thus, crop rotation also helps to control the pest populations characteristic of each type of plant. Blast Animation: Energy Flow

Chemical cycling Energy flow Chemical energy Light energy Heat energy
Figure A terrarium ecosystem. Chemical elements Bacteria and fungi

Energy flows through ecosystems.
Chemicals are recycled within and between ecosystems. Student Misconceptions and Concerns 1. Without an understanding of the inefficiency of aerobic metabolism and basic physics, students might not understand how chemical energy in food is lost as heat. Consider expanding upon these explanations in the book. 2. The environmental impact of eating farm animals is little appreciated by most students. This chapter section helps explain the basis for the increased environmental costs associated with a high meat diet. 3. Except for prior classes in science, students are unlikely to have understood biogeochemical cycles. Although some transfers between the biotic and abiotic components may be known, such as the benefits of fertilizing plants, the broader concept of the biosphere as a self-cycling system is not appreciated by most students. Pretesting your students over their knowledge can confirm this expectation or reveal levels of understanding not appreciated. Consider asking your students to explain how carbon, nitrogen, and water cycle through the biosphere. For each substance, create a complete cycle. Teaching Tips 1. Why do food chains and webs typically have only three to five levels? This question is not often considered by students but is addressed directly in this chapter section. This question makes a good discussion before lecturing on the topic of food chains and food webs. 2. The heat generated as a by-product of metabolism is quite evident during strenuous exercise. It is much like the heat produced by a running automobile engine. In both circumstances, heat is a by-product of the fuel burning process. 3. Energy flow through an ecosystem is analogous to the flow of fuel through a car or electricity through a vacuum cleaner. The systems will not work without a steady input. NASA, however, must rely upon some closed systems for its spacecrafts. Students might enjoy investigating the recycling of gases and fluids in these NASA systems. 4. Some students might be interested in eating more proteins and fewer carbohydrates because of some special sort of diet (or fad). Does such a high protein diet require the consumption of more meat? The many sources of plant proteins might be surprising to students. The following Vegetarian Society website describes some of the high protein vegetarian options: 5. As you discuss the importance of the biogeochemical cycles, you might consider explaining the basic label information provided on a container of plant fertilizer. Typically, plant fertilizers contain various forms of nitrogen and phosphorus, essential chemicals to growth. 6. Challenge students to explain why the areas of greatest primary production are near the equator. Primary production is a consequence of photosynthesis. Regions near the equator receive the highest levels of solar input. 7. A discussion of the movements of water through your local community might help students better relate to the concepts of biogeochemical cycling at a local level. Students could be asked to consider all of the possible inputs of water into your community and the possible routes of exit. 8. The nitrogen-fixing bacteria living in the roots of soybeans add nitrogen to the soil. Corn does not enjoy this same relationship. By rotating corn and soybean crops, corn crops can use some of the nitrogen fixed by the soybean crop in the previous year. Corn and soybean crop rotation has other benefits. Corn is a monocot and soybeans are dicots. Few pests attack corn and soybeans. Thus, crop rotation also helps to control the pest populations characteristic of each type of plant.

Producer Herbivore (primary consumer) Carnivore (secondary consumer) Energy flow Decomposers Chemical cycling

Energy Flow in Ecosystems
All organisms require energy for Growth Maintenance Reproduction In many species, locomotion Student Misconceptions and Concerns 1. Without an understanding of the inefficiency of aerobic metabolism and basic physics, students might not understand how chemical energy in food is lost as heat. Consider expanding upon these explanations in the book. 2. The environmental impact of eating farm animals is little apprechated by most students. This chapter section helps explain the basir for the increased environmental costs associated with a high me!t diet. 3. E8cept for prior classes in science, students are unlikely to have understood biggeochemibal cyales. Although some transfers between the biotic and abiotic components may be known, such as the benefits of fertilizing Plants, the broader concept of the biosphere as a self-cycling system is not appreciated by most students. Pretesting your students over their knowledge can confirm this expectation or reveal levels of understanding not appreciated. Consider asking your students to explain how carbon, nitrogen, and water cycle through the biosphere. For each substance, create a complete cycle. Teaching Tips 1. Why do food chains and webs typically have only three to five levels? This question is not often considered by students but is addressed directly in this chapter section. This question makes a good discussion before lecturing on the topic of food chains and food webs. 2. The heat generated as a by-product of metabolism is quite evident during strenuous exercise. It is much like the heat produced by a running automobile engine. In both circumstances, heat is a by-product of the fuel burning process. 3. Energy flow through an ecosystem is analogous to the flow of fuel through a car or electricity through a vacuum cleaner. The systems will not work without a steady input. NASA, however, must rely upon some closed systems for its spacecrafts. Students might enjoy investigating the recycling of gases and fluids in dhese NASA syctems. 4. Some students mighd be interested in eating more proteins and fewer carbohydrates because of smme special sort of diat (or fad). Does such a hiGh Protein diet r%quire the consumption gf more meat? The many sources of plant proteins migHt be surprising to sttdents. The following Vegetarian Sociedy website describes some of the high protein vegetarian options: 5. As you discuss the importance of the biogeochemical cycles, you might consider explaining the basic label information provided on a container of plant fertilizer. Typically, plant fertilizers contain various forms of nitrogen and phosphorus, essential chemicals to growth. 6. Challenge students to explain why the areas of greatest primary production are near the equator. Primary production is a consequence of photosynthesis. Regions near the equator receive the highest levels of solar inpu4. 7. A discussion of the movements of water through your local community might help students better relate to the concepts of biogeochemical cycling at a local level. Students could be asked to consider all of the possibla inputs of water into your coimunity and the poSsible rgutes of exit. 8. T`e nitrogen-fixinc bacteria liting in the roots of soybeans add nitrogen to the soil. Cgrn does not enjoy this same relationship. By rotating corn and soybean crops, corn crops can use some of the nitrogen fixed by the soybean crop in the previous year. Corn and soybean crop rotation has other benefits. Corn is a monocot and soybeans are dicots. Few pests attack corn and soybeans. Thus, crop rotation also helps to control the pest populations characteristic of each type of plant.

Consider the example of a caterpillar.
Ecological Pyramids When energy flows as organic matter through the trophic levels of an ecosystem, much of it is lost at each link in the food chain. Consider the example of a caterpillar. Student Misconceptions and Concerns 1. Without an understanding of the inefficiency of aerobic metabolism and basic physics, students might not understand how chemical energy in food is lost as heat. Consider expanding upon these explanations in the book. 2. The environmental impact of eating farm animals is little appreciated by most students. This chapter section helps explain the basis for the increased environmental costs associated with a high meat diet. 3. Except for prior classes in science, students are unlikely to have understood biogeochemical cycles. Although some transfers between the biotic and abiotic components may be known, such as the benefits of fertilizing plants, the broader concept of the biosphere as a self-cycling system is not appreciated by most students. Pretesting your students over their knowledge can confirm this expectation or reveal levels of understanding not appreciated. Consider asking your students to explain how carbon, nitrogen, and water cycle through the biosphere. For each substance, create a complete cycle. Teaching Tips 1. Why do food chains and webs typically have only three to five levels? This question is not often considered by students but is addressed directly in this chapter section. This question makes a good discussion before lecturing on the topic of food chains and food webs. 2. The heat generated as a by-product of metabolism is quite evident during strenuous exercise. It is much like the heat produced by a running automobile engine. In both circumstances, heat is a by-product of the fuel burning process. 3. Energy flow through an ecosystem is analogous to the flow of fuel through a car or electricity through a vacuum cleaner. The systems will not work without a steady input. NASA, however, must rely upon some closed systems for its spacecrafts. Students might enjoy investigating the recycling of gases and fluids in these NASA systems. 4. Some students might be interested in eating more proteins and fewer carbohydrates because of some special sort of diet (or fad). Does such a high protein diet require the consumption of more meat? The many sources of plant proteins might be surprising to students. The following Vegetarian Society website describes some of the high protein vegetarian options: 5. As you discuss the importance of the biogeochemical cycles, you might consider explaining the basic label information provided on a container of plant fertilizer. Typically, plant fertilizers contain various forms of nitrogen and phosphorus, essential chemicals to growth. 6. Challenge students to explain why the areas of greatest primary production are near the equator. Primary production is a consequence of photosynthesis. Regions near the equator receive the highest levels of solar input. 7. A discussion of the movements of water through your local community might help students better relate to the concepts of biogeochemical cycling at a local level. Students could be asked to consider all of the possible inputs of water into your community and the possible routes of exit. 8. The nitrogen-fixing bacteria living in the roots of soybeals add nitrogen to the soil. Corn does not enjoy this same relationship. By rotating corn and soybean crops, aorn crops can use some of the nitrogdn fixed by the soybean crop in the prev)ous year. Corn and soybean crop rotation has other benefits. Corn is a monocot and soibeans are dicots. Few pests attack corn and soybeanq. T(us, crop Rotation also helps to control th% p%st poptlations characteristic of each typa of plant.

Plant material eaten by caterpillar
100 kilocalories (kcal) Figure What becomes of a caterpillar's food? 35 kcal Cellular respiration 50 kcal Feces 15 kcal Growth Figure 20.27

The energy level available to the next higher level
A pyramid of production illustrates the cumulative loss of energy with each transfer in a food chain. The energy level available to the next higher level Ranges from 5–20% Is illustrated here as 10% Student Misconceptions and Concerns 1. Without an understanding of the inefficiency of aerobic metabolism and basic physics, students might not understand how chemical energy in food is lost as heat. Consider expanding upon these explanations in the book. 2. The environmental impact of eating farm animals is little appreciated by most students. This chapter section helps explain the basis for the increased environmental costs associated with a high meat diet. 3. Except for prior classes in science, students are unlikely to have understood biogeochemical cycles. Although some transfers between the biotic and abiotic components may be known, such as the benefits of fertilizing plants, the broader concept of the biosphere as a self-cycling system is not appreciated by most students. Pretesting your students over their knowledge can confirm this expectation or reveal levels of understanding not appreciated. Consider asking your students to explain how carbon, nitrogen, and water cycle through the biosphere. For each substance, create a complete cycle. Teaching Tips 1. Why do food chains and webs typically have only three to five levels? This question is not often considered by students but is addressed directly in this chapter section. This question makes a good discussion before lecturing on the topic of food chains and food webs. 2. The heat generated as a by-product of metabolism is quite evident during strenuous exercise. It is much like the heat produced by a running automobile engine. In both circumstances, heat is a by-product of the fuel burning process. 3. Energy flow through an ecosystem is analogous to the flow of fuel through a car or electricity through a vacuum cleaner. The systems will not work without a steady input. NASA, however, must rely upon some closed systems for its spacecrafts. Students might enjoy investigating the recycling of gases and fluids in these NASA systems. 4. Some students might be interested in eating more proteins and fewer carbohydrates because of some special sort of diet (or fad). Does such a high protein diet require the consumption of more meat? The many sources of plant proteins might be surprising to students. The following Vegetarian Society website describes some of the high protein vegetarian options: 5. As you discuss the importance of the biogeochemical cycles, you might consider explaining the basic label information provided on a container of plant fertilizer. Typically, plant fertilizers contain various forms of nitrogen and phosphorus, essential chemicals to growth. 6. Challenge students to explain why the areas of greatest primary production are near the equator. Primary production is a consequence of photosynthesis. Regions near the equator receive the highest levels of solar input. 7. A discussion of the movements of water through your local community might help students better relate to the concepts of biogeochemical cycling at a local level. Students could be asked to consider all of the possible inputs of water into your community and the possible routes of exit. 8. The nitrogen-fixing bacteria living in the roots of soybeans add nitrogen to the soil. Corn does not enjoy this same relationship. By rotating corn and soybean crops, corn crops can use some of the nitrogen fixed by the soybean crop in the previous year. Corn and soybean crop rotation has other benefits. Corn is a monocot and soybeans are dicots. Few pests attack corn and soybeans. Thus, crop rotation also helps to control the pest populations characteristic of each type of plant.

Tertiary 10 kcal consumers Secondary 100 kcal consumers Primary
Figure An idealized pyramid of production. Producers 10,000 kcal 1,000,000 kcal of sunlight

Top-level consumers require more geographic area
The energy available to top-level consumers is small compared to the energy available to lower-level consumers. This explains why Top-level consumers require more geographic area Most food chains are limited to three to five levels Student Misconceptions and Concerns 1. Without an understanding of the inefficiency of aerobic metabolism and basic physics, students might not understand how chemical energy in food is lost as heat. Consider expanding upon these explanations in the book. 2. The environmental impact of eating farm animals is little appreciated by most students. This chapter section helps explain the basis for the increased environmental costs associated with a high meat diet. 3. Except for prior classes in science, students are unlikely to have understood biogeochemical cycles. Although some transfers between the biotic and abiotic components may be known, such as the benefits of fertilizing plants, the broader concept of the biosphere as a self-cycling system is not appreciated by most students. Pretesting your students over their knowledge can confirm this expectation or reveal levels of understanding not appreciated. Consider asking your students to explain how carbon, nitrogen, and water cycle through the biosphere. For each substance, create a complete cycle. Teaching Tips 1. Why do food chains and webs typically have only three to five levels? This question is not often considered by students but is addressed directly in this chapter section. This question makes a good discussion before lecturing on the topic of food chains and food webs. 2. The heat generated as a by-product of metabolism is quite evident during strenuous exercise. It is much like the heat produced by a running automobile engine. In both circumstances, heat is a by-product of the fuel burning process. 3. Energy flow through an ecosystem is analogous to the flow of fuel through a car or electricity through a vacuum cleaner. The systems will not work without a steady input. NASA, however, must rely upon some closed systems for its spacecrafts. Students might enjoy investigating the recycling of gases and fluids in these NASA systems. 4. Some students might be interested in eating more proteins and fewer carbohydrates because of some special sort of diet (or fad). Does such a high protein diet require the consumption of more meat? The many sources of plant proteins might be surprising to students. The following Vegetarian Society website describes some of the high protein vegetarian options: 5. As you discuss the importance of the biogeochemical cycles, you might consider explaining the basic label information provided on a container of plant fertilizer. Typically, plant fertilizers contain various forms of nitrogen and phosphorus, essential chemicals to growth. 6. Challenge students to explain why the areas of greatest primary production are near the equator. Primary production is a consequence of photosynthesis. Regions near the equator receive the highest levels of solar input. 7. A discussion of the movements of water through your local community might help students better relate to the concepts of biogeochemical cycling at a local level. Students could be asked to consider all of the possible inputs of water into your community and the possible routes of exit. 8. The nitrogen-fixing bacteria living in the roots of soybeans add nitrogen to the soil. Corn does not enjoy this same relationship. By rotating corn and soybean crops, corn crops can use some of the nitrogen fixed by the soybean crop in the previous year. Corn and soybean crop rotation has other benefits. Corn is a monocot and soybeans are dicots. Few pests attack corn and soybeans. Thus, crop rotation also helps to control the pest populations characteristic of each type of plant.

Human Resource Use The dynamics of energy flow apply to the human population as much as to other organisms. When humans eat Plants, we are primary consumers Beef or other meat from herbivores, we are secondary consumers Fish like trout or salmon, we are tertiary consumers Student Misconceptions and Concerns 1. Without an understanding of the inefficiency of aerobic metabolism and basic physics, students might not understand how chemical energy in food is lost as heat. Consider expanding upon these explanations in the book. 2. The environmental impact of eating farm animals is little appreciated by most students. This chapter section helps explain the basis for the increased environmental costs associated with a high meat diet. 3. Except for prior classes in science, students are unlikely to have understood biogeochemical cycles. Although some transfers between the biotic and abiotic components may be known, such as the benefits of fertilizing plants, the broader concept of the biosphere as a self-cycling system is not appreciated by most students. Pretesting your students over their knowledge can confirm this expectation or reveal levels of understanding not appreciated. Consider asking your students to explain how carbon, nitrogen, and water cycle through the biosphere. For each substance, create a complete cycle. Teaching Tips 1. Why do food chains and webs typically have only three to five levels? This question is not often considered by students but is addressed directly in this chapter section. This question makes a good discussion before lecturing on the topic of food chains and food webs. 2. The heat generated as a by-product of metabolism is quite evident during strenuous exercise. It is much like the heat produced by a running automobile engine. In both circumstances, heat is a by-product of the fuel burning process. 3. Energy flow through an ecosystem is analogous to the flow of fuel through a car or electricity through a vacuum cleaner. The systems will not work without a steady input. NASA, however, must rely upon some closed systems for its spacecrafts. Students might enjoy investigating the recycling of gases and fluids in these NASA systems. 4. Some students might be interested in eating more proteins and fewer carbohydrates because of some special sort of diet (or fad). Does such a high protein diet require the consumption of more meat? The many sources of plant proteins might be surprising to students. The following Vegetarian Society website describes some of the high protein vegetarian options: 5. As you discuss the importance of the biogeochemical cycles, you might consider explaining the basic label information provided on a container of plant fertilizer. Typically, plant fertilizers contain various forms of nitrogen and phosphorus, essential chemicals to growth. 6. Challenge students to explain why the areas of greatest primary production are near the equator. Primary production is a consequence of photosynthesis. Regions near the equator receive the highest levels of solar input. 7. A discussion of the movements of water through your local community might help students better relate to the concepts of biogeochemical cycling at a local level. Students could be asked to consider all of the possible inputs of water into your community and the possible routes of exit. 8. The nitrogen-fixing bacteria living in the roots of soybeans add nitrogen to the soil. Corn does not enjoy this same relationship. By rotating corn and soybean crops, corn crops can use some of the nitrogen fixed by the soybean crop in the previous year. Corn and soybean crop rotation has other benefits. Corn is a monocot and soybeans are dicots. Few pests attack corn and soybeans. Thus, crop rotation also helps to control the pest populations characteristic of each type of plant.

Eating meat of any kind is expensive economically and environmentally.
The two energy pyramids that follow compare the amount of food available to humans if we are strictly either: Vegetarians or Carnivores Eating meat of any kind is expensive economically and environmentally. Student Misconceptions and Concerns 1. Without an understanding of the inefficiency of aerobic metabolism and basic physics, students might not understand how chemical energy in food is lost as heat. Consider expanding upon these explanations in the book. 2. The environmental impact of eating farm animals is little appreciated by most students. This chapter section helps explain the basis for the increased environmental costs associated with a high meat diet. 3. Except for prior classes in science, students are unlikely to have understood biogeochemical cycles. Although some transfers between the biotic and abiotic components may be known, such as the benefits of fertilizing plants, the broader concept of the biosphere as a self-cycling system is not appreciated by most students. Pretesting your students over their knowledge can confirm this expectation or reveal levels of understanding not appreciated. Consider asking your students to explain how carbon, nitrogen, and water cycle through the biosphere. For each substance, create a complete cycle. Teaching Tips 1. Why do food chains and webs typically have only three to five levels? This question is not often considered by students but is addressed directly in this chapter section. This question makes a good discussion before lecturing on the topic of food chains and food webs. 2. The heat generated as a by-product of metabolism is quite evident during strenuous exercise. It is much like the heat produced by a running automobile engine. In both circumstances, heat is a by-product of the fuel burning process. 3. Energy flow through an ecosystem is analogous to the flow of fuel through a car or electricity through a vacuum cleaner. The systems will not work without a steady input. NASA, however, must rely upon some closed systems for its spacecrafts. Students might enjoy investigating the recycling of gases and fluids in these NASA systems. 4. Some students might be interested in eating more proteins and fewer carbohydrates because of some special sort of diet (or fad). Does such a high protein diet require the consumption of more meat? The many sources of plant proteins might be surprising to students. The following Vegetarian Society website describes some of the high protein vegetarian options: 5. As you discuss the importance of the biogeochemical cycles, you might consider explaining the basic label information provided on a container of plant fertilizer. Typically, plant fertilizers contain various forms of nitrogen and phosphorus, essential chemicals to growth. 6. Challenge students to explain why the areas of greatest primary production are near the equator. Primary production is a consequence of photosynthesis. Pegions near the equator receive the highest levels of solar input. 7. A disCussion of the movementc of water through your local communIty might help students better relate tm the concepts of biogeochemical cycling at a local level. Studants could be asked to consider all of the possible inputs of water into your community and the possible routes of exit. 8. The nitrogen-fixing bacteria living in th% roots of 3oybeanS add nitrogen to the soil. Corn does not enjoy this same relationship. By rotating corn and soybean crops, corn crops can use some of the nitrogen fixed by the soybean crop in the previous year. Corn and soybean crop rotation has other benefits. Corn is a monocot and soybeans are dicots. Few pests attack corn and soybeans. Thus, crop rotation also helps to control the pest populations characteristic of each type of plant.

Secondary consumers Primary consumers Producers
Trophic level Secondary consumers Human meat-eaters Primary consumers Human vegetarians Cattle Corn Corn Producers Figure Food energy available to the human population at different trophic levels.

animation Energy flow

Concept Check The caterpillar is a primary consumer in a food chain. How much of the energy captured by the plant and then eaten by the caterpillar is transferred to the next trophic level—the secondary consumer (bird)? Less than 5% About 15% About 50 % 100% Answer: 2

Answer The caterpillar is a primary consumer in a food chain. How much of the energy captured by the plant and then eaten by the caterpillar is transferred to the next trophic level—the secondary consumer (bird)? About 15%

Chemical Cycling in Ecosystems
Life depends on the recycling of chemicals. Nutrients are acquired and waste products are released by living organisms. At death, decomposers return the complex molecules of an organism to the environment. The pool of inorganic nutrients is used by plants and other producers to build new organic matter. Student Misconceptions and Concerns 1. Without an understanding of the inefficiency of aerobic metabolism and basic physics, students might not understand how chemical energy in food is lost as heat. Consider expanding upon these explanations in the book. 2. The environmental impact of eating farm animals is little appreciated by most students. This chapter section helps explain the basis for the increased environmental costs associated with a high meat diet. 3. Except for prior classes in science, students are unlikely to have understood biogeochemical cycles. Although some transfers between the biotic and abiotic components may be known, such as the benefits of fertilizing plants, the broader concept of the biosphere as a self-cycling system is not appreciated by most students. Pretesting your students over their knowledge can confirm this expectation or reveal levels of understanding not appreciated. Consider asking your students to explain how carbon, nitrogen, and water cycle through the biosphere. For each substance, create a complete cycle. Teaching Tips 1. Why do food chains and webs typically have only three to five levels? This question is not often considered by students but is addressed directly in this chapter section. This question makes a good discussion before lecturing on the topic of food chains and food webs. 2. The heat generated as a by-product of metabolism is quite evident during strenuous exercise. It is much like the heat produced by a running automobile engine. In both circumstances, heat is a by-product of the fuel burning process. 3. Energy flow through an ecosystem is analogous to the flow of fuel through a car or electricity through a vacuum cleaner. The systems will not work without a steady input. NASA, however, must rely upon some closed systems for its spacecrafts. Students might enjoy investigating the recycling of gases and fluids in these NASA systems. 4. Some students might be interested in eating more proteins and fewer carbohydrates because of some special sort of diet (or fad). Does such a high protein diet require the consumption of more meat? The many sources of plant proteins might be surprising to students. The following Vegetarian Society website describes some of the high protein vegetarian options: 5. As you discuss the importance of the biogeochemical cycles, you might consider explaining the basic label information provided on a container of plant fertilizer. Typically, plant fertilizers contain various forms of nitrogen and phosphorus, essential chemicals to growth. 6. Challenge students to explain why the areas of greatest primary production are near the equator. Primary production is a consequence of photosynthesis. Regions near the equator receive the highest levels of solar input. 7. A discussion of the movements of water through your local community might help students better relate to the concepts of biogeochemical cycling at a local level. Students could be asked to consider all of the possible inputs of water into your community and the possible routes of exit. 8. The nitrogen-fixing bacteria living in the roots of soybeans add nitrogen to the soil. Corn does not enjoy this same relationship. By rotating corn and soybean crops, corn crops can use some of the nitrogen fixed by the soybean crop in the previous year. Corn and soybean crop rotation has other benefits. Corn is a monocot and soybeans are dicots. Few pests attack corn and soybeans. Thus, crop rotation also helps to control the pest populations characteristic of each type of plant.

The General Scheme of Chemical Cycling
Biogeochemical cycles involve Biotic components Abiotic components from an abiotic reservoir where a chemical accumulates or is stockpiled outside of living organisms Student Misconceptions and Concerns 1. Without an understanding of the inefficiency of aerobic metabolism and basic physics, students might not understand how chemical energy in food is lost as heat. Consider expanding upon these explanations in the book. 2. The environmental impact of eating farm animals is little appreciated by most students. This chapter section helps explain the basis for the increased environmental costs associated with a high meat diet. 3. Except for prior classes in science, students are unlikely to have understood biogeochemical cycles. Although some transfers between the biotic and abiotic components may be known, such as the benefits of fertilizing plants, the broader concept of the biosphere as a self-cycling system is not appreciated by most students. Pretesting your students over their knowledge can confirm this expectation or reveal levels of understanding not appreciated. Consider asking your students to explain how carbon, nitrogen, and water cycle through the biosphere. For each substance, create a complete cycle. Teaching Tips 1. Why do food chains and webs typically have only three to five levels? This question is not often considered by students but is addressed directly in this chapter section. This question makes a good discussion before lecturing on the topic of food chains and food webs. 2. The heat generated as a by-product of metabolism is quite evident during strenuous exercise. It is much like the heat produced by a running automobile engine. In both circumstances, heat is a by-product of the fuel burning process. 3. Energy flow through an ecosystem is analogous to the flow of fuel through a car or electricity through a vacuum cleaner. The systems will not work without a steady input. NASA, however, must rely upon some closed systems for its spacecrafts. Students might enjoy investigating the recycling of gases and fluids in these NASA systems. 4. Some students might be interested in eating more proteins and fewer carbohydrates because of some special sort of diet (or fad). Does such a high protein diet require the consumption of more meat? The many sources of plant proteins might be surprising to students. The following Vegetarian Society website describes some of the high protein vegetarian options: 5. As you discuss the importance of the biogeochemical cycles, you might consider explaining the basic label information provided on a container of plant fertilizer. Typically, plant fertilizers contain various forms of nitrogen and phosphorus, essential chemicals to growth. 6. Challenge students to explain why the areas of greatest primary production are near the equator. Primary production is a consequence of photosynthesis. Regions near the equator receive the highest levels of solar input. 7. A discussion of the movements of water through your local community might help students better relate to the concepts of biogeochemical cycling at a local level. Students could be asked to consider all of the possible inputs of water into your community and the possible routes of exit. 8. The nitrogen-fixing bacteria living in the roots of soybeans add nitrogen to the soil. Corn does not enjoy this same relationship. By rotating corn and soybean crops, corn crops can use some of the nitrogen fixed by the soybean crop in the previous year. Corn and soybean crop rotation has other benefits. Corn is a monocot and soybeans are dicots. Few pests attack corn and soybeans. Thus, crop rotation also helps to control the pest populations characteristic of each type of plant.

Consumers Producers Decomposers Nutrients available to producers
3 2 Producers Decomposers 1 Nutrients available to producers 4 Figure A general model of biogeochemical cycling of nutrients. Abiotic reservoir Geologic processes

important biogeochemical cycles 1. Carbon 2. Phosphorus 3. Nitrogen
Student Misconceptions and Concerns 1. Without an understanding of the inefficiency of aerobic metabolism and basic physics, students might not understand how chemical energy in food is lost as heat. Consider expanding upon these explanations in the book. 2. The environmental impact of eating farm animals is little appreciated by most students. This chapter section helps explain the basis for the increased environmental costs associated with a high meat diet. 3. Except for prior classes in science, students are unlikely to have understood biogeochemical cycles. Although some transfers between the biotic and abiotic components may be known, such as the benefits of fertilizing plants, the broader concept of the biosphere as a self-cycling system is not appreciated by most students. Pretesting your students over their knowledge can confirm this expectation or reveal levels of understanding not appreciated. Consider asking your students to explain how carbon, nitrogen, and water cycle through the biosphere. For each substance, create a complete cycle. Teaching Tips 1. Why do food chains and webs typically have only three to five levels? This question is not often considered by students but is addressed directly in this chapter section. This question makes a good discussion before lecturing on the topic of food chains and food webs. 2. The heat generated as a by-product of metabolism is quite evident during strenuous exercise. It is much like the heat produced by a running automobile engine. In both circumstances, heat is a by-product of the fuel burning process. 3. Energy flow through an ecosystem is analogous to the flow of fuel through a car or electricity through a vacuum cleaner. The systems will not work without a steady input. NASA, however, must rely upon some closed systems for its spacecrafts. Students might enjoy investigating the recycling of gases and fluids in these NASA systems. 4. Some students might be interested in eating more proteins and fewer carbohydrates because of some special sort of diet (or fad). Does such a high protein diet require the consumption of more meat? The many sources of plant proteins might be surprising to students. The following Vegetarian Society website describes some of the high protein vegetarian options: 5. As you discuss the importance of the biogeochemical cycles, you might consider explaining the basic label information provided on a container of plant fertilizer. Typically, plant fertilizers contain various forms of nitrogen and phosphorus, essential chemicals to growth. 6. Challenge students to explain why the areas of greatest primary production are near the equator. Primary production is a consequence of photosynthesis. Regions near the equator receive the highest levels of solar input. 7. A discussion of the movements of water through your local community might help students better relate to the concepts of biogeochemical cycling at a local level. Students could be asked to consider all of the possible inputs of water into your community and the possible routes of exit. 8. The nitrogen-fixing bacteria living in the roots of soybeans add nitrogen to the soil. Corn does not enjoy this same relationship. By rotating corn and soybean crops, corn crops can use some of the nitrogen fixed by the soybean crop in the previous year. Corn and soybean crop rotation has other benefits. Corn is a monocot and soybeans are dicots. Few pests attack corn and soybeans. Thus, crop rotation also helps to control the pest populations characteristic of each type of plant.

Blast Animation: Carbon Cycle
1. The Carbon Cycle The cycling of carbon between the biotic and abiotic worlds is accomplished mainly by the reciprocal metabolic processes of a. Photosynthesis – takes in CO2 b. Cellular respiration – releases CO2 c. Burning of fossil fuels and volcanic eruptions- releases CO2 Student Misconceptions and Concerns 1. Without an understanding of the inefficiency of aerobic metabolism and basic physics, students might not understand how chemical energy in food is lost as heat. Consider expanding upon these explanations in the book. 2. The environmental impact of eating farm animals is little appreciated by most students. This chapter section helps explain the basis for the increased environmental costs associated with a high meat diet. 3. Except for prior classes in science, students are unlikely to have understood biogeochemical cycles. Although some transfers between the biotic and abiotic components may be known, such as the benefits of fertilizing plants, the broader concept of the biosphere as a self-cycling system is not appreciated by most students. Pretesting your students over their knowledge can confirm this expectation or reveal levels of understanding not appreciated. Consider asking your students to explain how carbon, nitrogen, and water cycle through the biosphere. For each substance, create a complete cycle. Teaching Tips 1. Why do food chains and webs typically have only three to five levels? This question is not often considered by students but is addressed directly in this chapter section. This question makes a good discussion before lecturing on the topic of food chains and food webs. 2. The heat generated as a by-product of metabolism is quite evident during strenuous exercise. It is much like the heat produced by a running automobile engine. In both circumstances, heat is a by-product of the fuel burning process. 3. Energy flow through an ecosystem is analogous to the flow of fuel through a car or electricity through a vacuum cleaner. The systems will not work without a steady input. NASA, however, must rely upon some closed systems for its spacecrafts. Students might enjoy investigating the recycling of gases and fluids in these NASA systems. 4. Some students might be interested in eating more proteins and fewer carbohydrates because of some special sort of diet (or fad). Does such a high protein diet require the consumption of more meat? The many sources of plant proteins might be surprising to students. The following Vegetarian Society website describes some of the high protein vegetarian options: 5. As you discuss the importance of the biogeochemical cycles, you might consider explaining the basic label information provided on a container of plant fertilizer. Typically, plant fertilizers contain various forms of nitrogen and phosphorus, essential chemicals to growth. 6. Challenge students to explain why the areas of greatest primary production are near the equator. Primary production is a consequence of photosynthesis. Regions near the equator receive the highest levels of solar input. 7. A discussion of the movements of water through your local community might help students better relate to the concepts of biogeochemical cycling at a local level. Students could be asked to consider all of the possible inputs of water into your community and the possible routes of exit. 8. The nitrogen-fixing bacteria living in the roots of soybeans add nitrogen to the soil. Corn does not enjoy this same relationship. By rotating corn and soybean crops, corn crops can use some of the nitrogen fixed by the soybean crop in the previous year. Corn and soybean crop rotation has other benefits. Corn is a monocot and soybeans are dicots. Few pests attack corn and soybeans. Thus, crop rotation also helps to control the pest populations characteristic of each type of plant. Blast Animation: Carbon Cycle

CO2 in atmosphere 5 Burning 3 Photosynthesis Cellular respiration 1
Plants, algae, cyanobacteria Higher-level consumers 2 Wood and fossil fuels Primary consumers Decomposition Figure The carbon cycle. Wastes; death Plant litter; death 4 Decomposers (soil microbes) Detritus

animation Carbon cycle

2. phosphorus cycle Organisms require phosphorus for nucleic acids, phospholipids, and ATP a. Plants absorb phosphate ions in the soil and build them into organic compounds b. Phosphates are returned to the soil by decomposers Student Misconceptions and Concerns 1. Students are unlikely to have any prior knowledge of biogeochemical cycles. Although some transfers between the biotic and abiotic components of ecosystems, such as the use of fertilizer on plants, may be known to them, the broader fact that the biosphere is a self-cycling system is not appreciated by most students. Before you lecture, consider asking your students to explain how carbon, phosphorus, and nitrogen cycle through the atmosphere. Pre testing your students on their knowledge can confirm both what they understand and what they may need explained to them in more detail. Teaching Tips 1. As you discuss the importance of the biogeochemical cycles, consider explaining the basic label information provided on a container of plant fertilizer. Typically, plant fertilizers contain various forms of nitrogen and phosphorus, which are essential chemicals for growth. 2. Discussing the movements of water through your local community can help students better understand the concept of biogeochemical cycling. You may want to ask students to consider all of the possible inputs of water into your community as well as the possible routes of exit. 3. As noted in Module 37.20, phosphate contamination of aquatic systems typically leads to increased algal growth and potentially disastrous fish kills. Copyright © 2009 Pearson Education, Inc.

6 3 1 2 5 4 Uplifting of rock Weathering of rock Phosphates in rock
Animals Runoff Plants 1 Assimilation 2 Figure The phosphorus cycle. Phosphates in soil (inorganic) Detritus Phosphates in solution 5 Precipitated (solid) phosphates Decomposition Decomposers in soil Rock 4

2. The Nitrogen Cycle Nitrogen is
An ingredient of proteins and nucleic acids Essential to the structure and functioning of all organisms Nitrogen has two abiotic reservoirs: The atmosphere The soil Student Misconceptions and Concerns 1. Without an understanding of the inefficiency of aerobic metabolism and basic physics, students might not understand how chemical energy in food is lost as heat. Consider expanding upon these explanations in the book. 2. The environmental impact of eating farm animals is little appreciated by most students. This chapter section helps explain the basis for the increased environmental costs associated with a high meat diet. 3. Except for prior classes in science, students are unlikely to have understood biogeochemical cycles. Although some transfers between the biotic and abiotic components may be known, such as the benefits of fertilizing plants, the broader concept of the biosphere as a self-cycling system is not appreciated by most students. Pretesting your students over their knowledge can confirm this expectation or reveal levels of understanding not appreciated. Consider asking your students to explain how carbon, nitrogen, and water cycle through the biosphere. For each substance, create a complete cycle. Teaching Tips 1. Why do food chains and webs typically have only three to five levels? This question is not often considered by students but is addressed directly in this chapter section. This question makes a good discussion before lecturing on the topic of food chains and food webs. 2. The heat generated as a by-product of metabolism is quite evident during strenuous exercise. It is much like the heat produced by a running automobile engine. In both circumstances, heat is a by-product of the fuel burning process. 3. Energy flow through an ecosystem is analogous to the flow of fuel through a car or electricity through a vacuum cleaner. The systems will not work without a steady input. NASA, however, must rely upon some closed systems for its spacecrafts. Students might enjoy investigating the recycling of gases and fluids in these NASA systems. 4. Some students might be interested in eating more proteins and fewer carbohydrates because of some special sort of diet (or fad). Does such a high protein diet require the consumption of more meat? The many sources of plant proteins might be surprising to students. The following Vegetarian Society website describes some of the high protein vegetarian options: 5. As you discuss the importance of the biogeochemical cycles, you might consider explaining the basic label information provided on a container of plant fertilizer. Typically, plant fertilizers contain various forms of nitrogen and phosphorus, essential chemicals to growth. 6. Challenge students to explain why the areas of greatest primary production are near the equator. Primary production is a consequence of photosynthesis. Regions near the equator receive the highest levels of solar input. 7. A discussion of the movements of water through your local community might help students better relate to the concepts of biogeochemical cycling at a local level. Students could be asked to consider all of the possible inputs of water into your community and the possible routes of exit. 8. The nitrogen-fixing bacteria living in the roots of soybeans add nitrogen to the soil. Corn does not enjoy this same relationship. By rotating corn and soybean crops, corn crops can use some of the nitrogen fixed by the soybean crop in the previous year. Corn and soybean crop rotation has other benefits. Corn is a monocot and soybeans are dicots. Few pests attack corn and soybeans. Thus, crop rotation also helps to control the pest populations characteristic of each type of plant.

Blast Animation: Nitrogen Cycle
nitrogen fixation converts gaseous N2 to ammonia and nitrates, which can be used by plants. Most of the nitrogen available in natural ecosystems comes from biological fixation performed by two types of nitrogen-fixing bacteria. decomposition- bacteria and fungi return N to the soil Student Misconceptions and Concerns 1. Without an understanding of the inefficiency of aerobic metabolism and basic physics, students might not understand how chemical energy in food is lost as heat. Consider expanding upon these explanations in the book. 2. The environmental impact of eating farm animals is little appreciated by most students. This chapter section helps explain the basis for the increased environmental costs associated with a high meat diet. 3. Except for prior classes in science, students are unlikely to have understood biogeochemical cycles. Although some transfers between the biotic and abiotic components may be known, such as the benefits of fertilizing plants, the broader concept of the biosphere as a self-cycling system is not appreciated by most students. Pretesting your students over their knowledge can confirm this expectation or reveal levels of understanding not appreciated. Consider asking your students to explain how carbon, nitrogen, and water cycle through the biosphere. For each substance, create a complete cycle. Teaching Tips 1. Why do food chains and webs typically have only three to five levels? This question is not often considered by students but is addressed directly in this chapter section. This question makes a good discussion before lecturing on the topic of food chains and food webs. 2. The heat generated as a by-product of metabolism is quite evident during strenuous exercise. It is much like the heat produced by a running automobile engine. In both circumstances, heat is a by-product of the fuel burning process. 3. Energy flow through an ecosystem is analogous to the flow of fuel through a car or electricity through a vacuum cleaner. The systems will not work without a steady input. NASA, however, must rely upon some closed systems for its spacecrafts. Students might enjoy investigating the recycling of gases and fluids in these NASA systems. 4. Some students might be interested in eating more proteins and fewer carbohydrates because of some special sort of diet (or fad). Does such a high protein diet require the consumption of more meat? The many sources of plant proteins might be surprising to students. The following Vegetarian Society website describes some of the high protein vegetarian options: 5. As you discuss the importance of the biogeochemical cycles, you might consider explaining the basic label information provided on a container of plant fertilizer. Typically, plant fertilizers contain various forms of nitrogen and phosphorus, essential chemicals to growth. 6. Challenge students to explain why the areas of greatest primary production are near the equator. Primary production is a consequence of photosynthesis. Regions near the equator receive the highest levels of solar input. 7. A discussion of the movements of water through your local community might help students better relate to the concepts of biogeochemical cycling at a local level. Students could be asked to consider all of the possible inputs of water into your community and the possible routes of exit. 8. The nitrogen-fixing bacteria living in the roots of soybeans add nitrogen to the soil. Corn does not enjoy this same relationship. By rotating corn and soybean crops, corn crops can use some of the nitrogen fixed by the soybean crop in the previous year. Corn and soybean crop rotation has other benefits. Corn is a monocot and soybeans are dicots. Few pests attack corn and soybeans. Thus, crop rotation also helps to control the pest populations characteristic of each type of plant. Blast Animation: Nitrogen Cycle

Nitrogen (N2) in atmosphere
8 Plant Animal 6 Organic compounds Organic compounds Assimilation by plants Nitrogen fixation 1 5 Death; wastes Denitrifiers 3 Nitrogen-fixing bacteria in root nodules Nitrates in soil (NO3–) Detritus Figure The nitrogen cycle. Free-living nitrogen-fixing bacteria and cyanobacteria Decomposers Nitrifying bacteria 4 7 Decomposition Nitrogen fixation Ammonium (NH4+) in soil 2

Nutrient Pollution The growth of algae and cyanobacteria in aquatic ecosystems is limited by low nutrient levels, especially of phosphorus and nitrogen. Nutrient pollution occurs when human activities add excess amounts of these chemicals to aquatic ecosystems. Student Misconceptions and Concerns 1. Without an understanding of the inefficiency of aerobic metabolism and basic physics, students might not understand how chemical energy in food is lost as heat. Consider expanding upon these explanations in the book. 2. The environmental impact of eating farm animals is little appreciated by most students. This chapter section helps explain the basis for the increased environmental costs associated with a high meat diet. 3. Except for prior classes in science, students are unlikely to have understood biogeochemical cycles. Although some transfers between the biotic and abiotic components may be known, such as the benefits of fertilizing plants, the broader concept of the biosphere as a self-cycling system is not appreciated by most students. Pretesting your students over their knowledge can confirm this expectation or reveal levels of understanding not appreciated. Consider asking your students to explain how carbon, nitrogen, and water cycle through the biosphere. For each substance, create a complete cycle. Teaching Tips 1. Why do food chains and webs typically have only three to five levels? This question is not often considered by students but is addressed directly in this chapter section. This question makes a good discussion before lecturing on the topic of food chains and food webs. 2. The heat generated as a by-product of metabolism is quite evident during strenuous exercise. It is much like the heat produced by a running automobile engine. In both circumstances, heat is a by-product of the fuel burning process. 3. Energy flow through an ecosystem is analogous to the flow of fuel through a car or electricity through a vacuum cleaner. The systems will not work without a steady input. NASA, however, must rely upon some closed systems for its spacecrafts. Students might enjoy investigating the recycling of gases and fluids in these NASA systems. 4. Some students might be interested in eating more proteins and fewer carbohydrates because of some special sort of diet (or fad). Does such a high protein diet require the consumption of more meat? The many sources of plant proteins might be surprising to students. The following Vegetarian Society website describes some of the high protein vegetarian options: 5. As you discuss the importance of the biogeochemical cycles, you might consider explaining the basic label information provided on a container of plant fertilizer. Typically, plant fertilizers contain various forms of nitrogen and phosphorus, essential chemicals to growth. 6. Challenge students to explain why the areas of greatest primary production are near the equator. Primary production is a consequence of photosynthesis. Regions near the equator receive the highest levels of solar input. 7. A discussion of the movements of water through your local community might help students better relate to the concepts of biogeochemical cycling at a local level. Students could be asked to consider all of the possible inputs of water into your community and the possible routes of exit. 8. The nitrogen-fixing bacteria living in the roots of soybeans add nitrogen to the soil. Corn does not enjoy this same relationship. By rotating corn and soybean crops, corn crops can use some of the nitrogen fixed by the soybean crop in the previous year. Corn and soybean crop rotation has other benefits. Corn is a monocot and soybeans are dicots. Few pests attack corn and soybeans. Thus, crop rotation also helps to control the pest populations characteristic of each type of plant.

Algal growth as a result of phosphate pollution
Figure Algal growth resulting from nutrient pollution Algal growth as a result of phosphate pollution Figure 20.35

Nitrogen runoff from Midwestern farm fields has been linked to an annual summer dead zone in the Gulf of Mexico. Bacteria feed on algae blooms in these areas and deplete the supply of oxygen. Student Misconceptions and Concerns 1. Without an understanding of the inefficiency of aerobic metabolism and basic physics, students might not understand how chemical energy in food is lost as heat. Consider expanding upon these explanations in the book. 2. The environmental impact of eating farm animals is little appreciated by most students. This chapter section helps explain the basis for the increased environmental costs associated with a high meat diet. 3. Except for prior classes in science, students are unlikely to have understood biogeochemical cycles. Although some transfers between the biotic and abiotic components may be known, such as the benefits of fertilizing plants, the broader concept of the biosphere as a self-cycling system is not appreciated by most students. Pretesting your students over their knowledge can confirm this expectation or reveal levels of understanding not appreciated. Consider asking your students to explain how carbon, nitrogen, and water cycle through the biosphere. For each substance, create a complete cycle. Teaching Tips 1. Why do food chains and webs typically have only three to five levels? This question is not often considered by students but is addressed directly in this chapter section. This question makes a good discussion before lecturing on the topic of food chains and food webs. 2. The heat generated as a by-product of metabolism is quite evident during strenuous exercise. It is much like the heat produced by a running automobile engine. In both circumstances, heat is a by-product of the fuel burning process. 3. Energy flow through an ecosystem is analogous to the flow of fuel through a car or electricity through a vacuum cleaner. The systems will not work without a steady input. NASA, however, must rely upon some closed systems for its spacecrafts. Students might enjoy investigating the recycling of gases and fluids in these NASA systems. 4. Some students might be interested in eating more proteins and fewer carbohydrates because of some special sort of diet (or fad). Does such a high protein diet require the consumption of more meat? The many sources of plant proteins might be surprising to students. The following Vegetarian Society website describes some of the high protein vegetarian options: 5. As you discuss the importance of the biogeochemical cycles, you might consider explaining the basic label information provided on a container of plant fertilizer. Typically, plant fertilizers contain various forms of nitrogen and phosphorus, essential chemicals to growth. 6. Challenge students to explain why the areas of greatest primary production are near the equator. Primary production is a consequence of photosynthesis. Regions near the equator receive the highest levels of solar input. 7. A discussion of the movements of water through your local community might help students better relate to the concepts of biogeochemical cycling at a local level. Students could be asked to consider all of the possible inputs of water into your community and the possible routes of exit. 8. The nitrogen-fixing bacteria living in the roots of soybeans add nitrogen to the soil. Corn does not enjoy this same relationship. By rotating corn and soybean crops, corn crops can use some of the nitrogen fixed by the soybean crop in the previous year. Corn and soybean crop rotation has other benefits. Corn is a monocot and soybeans are dicots. Few pests attack corn and soybeans. Thus, crop rotation also helps to control the pest populations characteristic of each type of plant.

Figure 20.36 Mississippi River G u l f o M e x i co
Light blue lines represent rivers draining into the Mississippi River (shown in dark blue) Figure The Gulf of Mexico dead zone G u l f o M e x i co G u l f o M e x i co Summer Winter Figure 20.36

animation Nitrogen cycle

Concept Check nitrogen
Concept Check Matter that makes up life is recycled and reused. Which of the following is not recycled primarily through the atmosphere (rapid) but instead is cycled through the rock cycle (slow by rock formation and weathering). nitrogen carbon water phosphorus Answer: 4

Answer Matter that makes up life is recycled and reused. Which of the following is not recycled primarily through the atmosphere (rapid) but instead is cycled through the rock cycle (slow by rock formation and weathering). phosphorus

Thinking Like a Scientist
Thinking Like a Scientist This figure plots the loss of nitrate from a deforested watershed on the Hubbard Brook study site. After the tree cutting was complete about how much more nitrate left the watershed during runoff? The runoff had 3 times the normal nitrate. The runoff had 15 times the normal nitrate. The runoff had 60 times the normal nitrate. Answer: 3

Answer This figure plots the loss of nitrate from a deforested watershed on the Hubbard Brook study site. After the tree cutting was complete about how much more nitrate left the watershed during runoff? The runoff had 60 times the normal nitrate.

Thinking Like a Scientist How long after tree cutting did it take for the nitrate levels to spike? 8 months 12 months 24 months Answer: 1

Answer How long after tree cutting did it take for the nitrate levels to spike? 8 months.

Thinking Like a Scientist Snow is a source of nitrate. Based on this plot during what season do nitrate levels usually peak in the runoff? (Assume that the vertical white grid lines mark the beginning of the year.) Winter. Spring. Fall. Answer: 2

Answer Snow is a source of nitrate. Based on this plot during what season do nitrate levels usually peak in the runoff? (Assume that the vertical white grid lines mark the beginning of the year.) Spring.

Biome Major biomes of north america 1. Desert 2. Grasslands
3. Deciduous forests 4. Coniferous forests 5. Tundra

Deserts Figure 18.5 Examples of three low-moisture biomes in the United States. (A) The Sonoran Desert in Arizona. (B) Tallgrass prairie in Kansas. (C) Chaparral in California. Fig. 18-5a, p. 365

Grasslands Figure 18.5 Examples of three low-moisture biomes in the United States. (A) The Sonoran Desert in Arizona. (B) Tallgrass prairie in Kansas. (C) Chaparral in California. Fig. 18-5b, p. 365

Figure 18.6 Broadleaf forests. (A) Tropical rain forest in Southeast Asia. (B) Temperate deciduous forest in New England. Fig. 18-6, p. 366

Coniferous forests Figure 18.7
Coniferous forest. Aerial view of Siberian taiga. Fig. 18-7, p. 366

Figure 18.8 Arctic tundra. Soil just below the surface remains frozen even during the summer. Fig. 18-8, p. 367

Strongly A B C D E Strongly
Science and Society During the summer of 2003 the entire western U.S. seemed to experience large forest fires. One of the fires was in fact the result of a controlled “burn” getting out of control. The controlled burn is a management technique that seeks to remove the accumulated litter in forest so that fires will not burn out of control. Fire is a part of the western forest’s ecosystem. The U.S. Forest service has implemented a number of forest clean up plans—including increasing timber harvest. However, people continue to build homes in ecosystems where fire is to be expected. Should development be limited in fire prone areas? Disagree Agree Strongly A B C D E Strongly

Science and Society Travelers into and out of our country are asked about agricultural products. “Are you bringing into the country fruits or vegetables purchased abroad?” Of course, the primary reason is to prevent exotic pest species from entering our ecosystems. As a traveling citizen do you take precautions to minimize the possibility that you could accidentally bring foreign organisms into the U.S.? Disagree Agree Strongly A B C D E Strongly

Science and Society The tall grass prairies of eastern Kansas are the largest remaining tract of the tall-grass prairie ecosystem. Each spring to recycle nutrients and to control brush, ranchers burn large areas of the tall-grass prairie. This has been done for more than a hundred years and the Native Americans also burned the prairie to attract bison. Recently, the EPA issued a document that suggested that range burning could be contributing to high ozone levels in nearby urban areas and suggested that the ranchers curtail their burning. Do you agree that urban ozone levels should take precedent over range management of an endangered ecosystem? Disagree Agree Strongly A B C D E Strongly

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