Population and Community Ecology

Population & Community Ecology Learning Targets Explain how nature exists at several levels of complexity Discuss the characteristics of populations Contrast the effects of density-dependent and density-independent factors on population growth Explain the exponential growth model of populations, which produces a J-shaped curve Describe how the logistic growth model incorporates a carrying capacity and produces and S-shaped curve Compare the reproductive strategies and survivorship curves of different species Explain the dynamics that occur in metapopulations Identify and discuss species interactions that cause negative, neutral or positive effects on one or both species Explain the role of keystone species Explain the processes of primary and secondary succession Explain the process of aquatic succession Describe the factors that determine the species richness of a community

New England Forests Come Full Circle Deforestation peaked in the 1800s due to agriculture. Plants started to return such as goldenrod. Eventually they were replaced with tree species. Species interactions can alter species abundance. Populations can increase and decrease dramatically over time. Human activity can alter the distribution and diversity of species within an ecosystem

Case Study: New England Forests

Levels of Complexity in Nature Species: most specific. P???: same species found in the same area at the same time (can evolve). C???: All the populations of organisms in the same area. E??: all living and non-living components within an area. B??: where live can exist.

Levels of Complexity in Nature Species: most specific. Population: same species found in the same area at the same time (can evolve). Community: All the populations of organisms in the same area. Ecosystem: all living and non-living components within an area. Biosphere: where live can exisit.

Ecosystem: all living and non-living components within an area. Biosphere: where live can exist.

Population Ecology Population Ecology: the study of factors that cause populations to increase or decrease. Which two factors control increases? Which two factors control decreases?

Population Ecology Population Ecology: the study of factors that cause populations to increase or decrease.

Population Characteristics Population Size (N): total number of individuals within a defined area in a given time. Population ?????: number of individuals per unit area.

Population Characteristics Population Size (N): total number of individuals within a defined area in a given time. Population Density: number of individuals per unit area.

Name this type of distribution? Population Distribution: how individuals are distributed with respect to one another. Name this type of distribution?

Population Distribution: how individuals are distributed with respect to one another.

Name this type of distribution?

Name this type of distribution?

Population Sex Ratio: the ratio between males and females. Population Age Structure: how many individuals fit into particular age categories.

Factors That Influence Population Size Name this concept Density –Dependent Factors: influence an individual’s probability of survival and reproduction in a manner that depends on the size of the population. Example: food available

Factors That Influence Population Size Density –Dependent Factors: influence an individual’s probability of survival and reproduction in a manner that depends on the size of the population. Example: food available

L??? Resource: a resource that a population cannot live without and which occurs in quantities lower than the population would require to increase in size. ???? (K): the limit of how many organisms an environment can contain.

Limiting Resource: a resource that a population cannot live without and which occurs in quantities lower than the population would require to increase in size. Carrying Capacity (K): the limit of how many organisms an environment can contain.

Density-Independent Factors: Have the same effect on an individual’s probability of survival and amount of reproduction at any population size. Examples: hurricanes, floods, fires, etc. Name this concept

Examples: hurricanes, floods, fires, etc. Density-Independent Factors: Have the same effect on an individual’s probability of survival and amount of reproduction at any population size. Examples: hurricanes, floods, fires, etc. Population Ecology Video Reviews https://www.youtube.com/watch?v=PQ-CQ3CQE3g (Bozeman) https://www.youtube.com/watch?v=6IS_M6CX7FE (Khan) https://www.youtube.com/watch?v=RBOsqmBQBQk (Crash)

Growth Models Represent Population Changes Exponential Growth Model When populations are not limited by resources, their growth can be very rapid. Creates a “?” shape curve. Illustrates density dependent OR? independent growth pattern.

Growth Models Represent Population Changes Exponential Growth Model When populations are not limited by resources, their growth can be very rapid. Creates a “J” shape curve. Illustrates density independent growth pattern.

?? What’s the rest of the equation that represents this graph?

The Logistic Growth Model Initial growth is exponential but slows as the population approaches the carrying capacity of the environment (K). Creates an “?” shaped curve. Density dependent type of growth.

The Logistic Growth Model Initial growth is exponential but slows as the population approaches the carrying capacity of the environment (K). Creates an “S” shaped curve. Density dependent type of growth.

What does this line represent?

p. 199 25 reindeer introduced to St. Paul Island, Alaska in 1910 Animals exhausted the food supply p. 199 25 reindeer introduced to St. Paul Island, Alaska in 1910

p. 199; Population oscillations- overshoots and die-offs around carrying capacity

Variations Overshoots Die offs

Hare and Lynx Cyclic pattern The lynx population peaks 1 or 2 years after the hare population peaks. Isle Royale, Michigan Wolves and moose Wolf population declined drastically due to a virus. Overpopulation of moose then they ran out of food and their population declined.

What caption goes here? What caption goes here?

https://www.youtube.com/watch?v=PdwnfPurXcs

Reproductive Strategies and Survivorship Curves ?-Selected Species (large mammals, most birds) Few number of offspring Long life span Long time to reproductive age Size of offspring is large Parental care present Slow population growth rate Density dependent Stable, near carrying capacity

Reproductive Strategies and Survivorship Curves K-Selected Species (large mammals, most birds) Few number of offspring Long life span Long time to reproductive age Size of offspring is large Parental care present Slow population growth rate Density dependent Stable, near carrying capacity

Reproductive Strategies and Survivorship Curves K-Selected Species (large mammals, most birds) Name 4 characteristics

r -Selected Species (mice, fishes, insects, weeds) Name 4 characteristics

r -Selected Species (mice, fishes, insects, weeds) Short life span Short time to reproductive maturity Many reproductive events Many offspring Small size of offspring No parental care Fast population growth rate Density independent growth Variable population dynamics

https://www.youtube.com/watch?v=oNgBJSUVwSg

Survivorship Curves Type 1?2? Or 3?: K-selected species. High survival rates throughout most of their lives. Die off as they get old (humans, whales, elephants). Type 1?2?3?: R-selected species. Low survivorship at younger age, few reach adulthood (mice, weeds, frogs, fungi). Type 1?2?3?: Constant decline in survivorship throughout their lives (squirrels, corals).

Survivorship Curves Type 1: K-selected species. High survival rates throughout most of their lives. Die off as they get old (humans, whales, elephants). Type 3: R-selected species. Low survivorship at younger age, few reach adulthood (mice, weeds, frogs, fungi). Type 2: Constant decline in survivorship throughout their lives (squirrels, corals).

A??? B??? C???

Name this term A group of spatially distinct populations that are connected by occasional movements of individuals between them. Corridors: strip of habitat in which organisms can travel to one population to another. Growing due to human intervention. Maintain corridors is an important part to preserving biodiversity

Metapopulations A group of spatially distinct populations that are connected by occasional movements of individuals between them. Corridors: strip of habitat in which organisms can travel to one population to another. Growing due to human intervention. Maintain corridors is an important part to preserving biodiversity

Example: Cougars (mountain lions, pumas) Once lived throughout North America. Population decreased due to habitat destruction and overhunting. Now found in remote mountain ranges. Each area is considered a population. Corridors provide “connectedness”. Important part of each population’s persistence. Small populations subject to extinction and density independent factors (winters, hurricanes).

https://www.youtube.com/watch?v=oRw3Zw23ZAs https://www.youtube.com/watch?v=UIcqhYezm08

Community Ecology: Interactions Between Species Competition Predation Symbiotic Relationships

Competition The struggle of individuals to obtain a limiting resource. ?????????? Principle Two species competing for the same limiting resource cannot coexist. Resource P????????????? Two species divide a resource based on differences in the species’ behavior or morphology.

Competition The struggle of individuals to obtain a limiting resource. Competitive Exclusion Principal Two species competing for the same limiting resource cannot coexist. Resource Partitioning Two species divide a resource based on differences in the species’ behavior or morphology.

Competition for limiting resource; Gause grew 2 species of paramecium- separately- then together- demonstrate that two species competing for same limiting resource cannot coesist

3 Types of Resource Partitioning Name this word for different time periods Name this word for area Name this word for structure or change

3 Types of Resource Partitioning Temporal Spatial Morphological

https://www.youtube.com/watch?v=0w5-UfEi470

Name this common word…P? The use of one species as a resource of another species.

Predation The use of one species as a resource of another species.

True Predators Kill their prey and consume it.

Name this term Consume plants as prey. Typically do not kill the plant.

Herbivores Consume plants as prey. Typically do not kill the plant.

S??? Relationship A close relationship between two species.

Symbiotic Relationship A close relationship between two species.

1. Parasites Define Rarely OR Often? kill the host. Parasites that cause disease are called p?. include viruses, bacteria, fungi, protists and wormlike organisms called helminths.

1. Parasites Live on or in the organism they consume, the host. Rarely kill the host. Parasites that cause disease are called pathogens. Pathogens include viruses, bacteria, fungi, protists and wormlike organisms called helminths.

Parasitoids Lay eggs inside other organisms. Wasps and flies.

2. Name this relationship term? Both species benefit. Examples: Plants and pollinators. Acacia trees and ants. Algae and fungus (lichen). Algae and coral.

2. Mutualism Both species benefit. Examples: Plants and pollinators. Acacia trees and ants. Algae and fungus (lichen). Algae and coral.

Acacia trees and Pseudomyrmex ants- thorns for nest sites; food in form of nectar; ants protect trees https://www.youtube.com/watch?v=Xm2qdxVVRm4

Lichens- British soldiers- fungus and alga- fungus provides nutrients and alga provides carbohydrates through photosynthesis

3. Name this relationship One species benefits and the other is neither harmed nor helped. Examples: Barnacles on whales. Birds perching on trees. Fish using coral reefs in order to hide from predators.

3. Commensalism One species benefits and the other is neither harmed nor helped. Examples: Barnacles on whales. Birds perching on trees. Fish using coral reefs in order to hide from predators.

Name this concept/species Plays a role in its community that is far more important than its relative abundance might suggest. The most abundant species or the major energy producers are NOT keystone species. They typically exist in LOW numbers. Example: Sea stars and mussels. Example of predator-mediated competition.

Keystone Species Plays a role in its community that is far more important than its relative abundance might suggest. The most abundant species or the major energy producers are NOT keystone species. They typically exist in LOW numbers. Example: Sea stars and mussels. Example of predator-mediated competition.

https://www.youtube.com/watch?v=_IWw8Ruz8Uo https://www.youtube.com/watch?v=hRGg5it5FMI

Ecosystem Engineers Create or maintain a habitat for other species. Example: Beaver

Changes in an Ecosystem Ecological ????: the predictable replacement of one group of species by another group of species over time.

Changes in an Ecosystem Ecological Succession: the predictable replacement of one group of species by another group of species over time.

P??? Succession Occurs on surfaces devoid of soil. Results in trees and shrubs. Bare rock is colonized by lichens and mosses-- They break down the rock with acids--- The rock turns into soil---Grasses and shrubs colonize. Usually occurs on lava!

Primary Succession Occurs on surfaces devoid of soil. Results in trees and shrubs. Bare rock is colonized by lichens and mosses-- They break down the rock with acids--- The rock turns into soil---Grasses and shrubs colonize. Usually occurs on lava!

Secondary Succession Happens in disturbed areas that have not lost their soil. Happens after an event that removes vegetation but not the soil. P????? Species: able to colonize new areas rapidly and grow well in full sunshine. Ends with a climax stage or climax forest.

Secondary Succession Happens in disturbed areas that have not lost their soil. Happens after an event that removes vegetation but not the soil. Pioneer Species: able to colonize new areas rapidly and grow well in full sunshine. Ends with a climax stage or climax forest.

Aquatic Succession Happens near the ocean shore or in ponds or small lakes.

Species Richness of a Community is Influenced by Many Factors Declines as we move from the equator toward the North or South Pole. 2. T? The longer it has been around the more opportunity for speciation.

Species Richness of a Community is Influenced by Many Factors 1. Latitude Declines as we move from the equator toward the North or South Pole. 2. Time The longer it has been around the more opportunity for speciation.

Habitat Size and Distance: The Theory of Island Biogeography 3. Larger or smaller? habitats typically contain more species. 4. The farther or?? closer “islands” are to other natural areas the greater the species richness. Islands can be considered on land masses as well such as National Parks!

Habitat Size and Distance: The Theory of Island Biogeography 3. Larger habitats typically contain more species. 4. The closer “islands” are to other natural areas the greater the species richness. Islands can be considered on land masses as well such as National Parks!

Black-footed ferret- once critically endangered; rebounding because of conservation efforts

Learning Check for Ch. 6 Community Ecology A trophic cascade is the effect of ___ on ___ flooding; terrestrial ecosystem Detritivores; decomposers Producers; first=-level consumers Top predators; one another Tertiary consumers; the abundance of primary consumers

Learning Check for Ch. 6 Community Ecology A trophic cascade is the effect of ___ on ___ flooding; terrestrial ecosystem Detritivores; decomposers Producers; first=-level consumers Top predators; one another Tertiary consumers; the abundance of primary consumers

Learning Check for Ch. 6 Community Ecology The Hawaiian honeycreeper’s specific biotic interactions, including the abiotic factors in its high-altitude forest environment, are collectively referred to as its Trophic level Consumption rate Habitat Symbiotic placement Ecological niche

Learning Check for Ch. 6 Community Ecology The Hawaiian honeycreeper’s specific biotic interactions, including the abiotic factors in its high-altitude forest environment, are collectively referred to as its Trophic level Consumption rate Habitat Symbiotic placement Ecological niche

Learning Check for Ch. 6 Community Ecology A keystone species Is most often dominant in numbers in their ecosystem When removed, causes the removal of a trophic level in the ecosystem Is most likely a top predator Is most likely to be a producer on which all species ultimately depend Feeds upon a variety of species in several different trophic levels

Learning Check for Ch. 6 Community Ecology A keystone species Is most often dominant in numbers in their ecosystem When removed, causes the removal of a trophic level in the ecosystem Is most likely a top predator Is most likely to be a producer on which all species ultimately depend Feeds upon a variety of species in several different trophic levels

Learning Check for Ch. 6 Community Ecology The level of ecological organization described by ecologists when studying multiple interacting species that live in the same area is The habitat Energy flow The population The community The ecosystem

Learning Check for Ch. 6 Community Ecology The level of ecological organization described by ecologists when studying multiple interacting species that live in the same area is The habitat Energy flow The population The community The ecosystem

Learning Check for Ch. 6 Community Ecology Characteristics that contribute to the vulnerability of a species becoming endangered include which of the following? Having low genetic diversity Having a generalist habitat Being a keystone species Being r-selected (A) I only (B) II only (C)III only (D) III and IV only (E)I and IV only

Learning Check for Ch. 6 Community Ecology Characteristics that contribute to the vulnerability of a species becoming endangered include which of the following? Having low genetic diversity Having a generalist habitat Being a keystone species Being r-selected (A) I only (B) II only (C)III only (D) III and IV only (E)I and IV only