BIOLOGY CONCEPTS & CONNECTIONS Fourth Edition Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Neil A. Campbell Jane B. Reece Lawrence G. Mitchell Martha R. Taylor From PowerPoint ® Lectures for Biology: Concepts & Connections CHAPTER 37 Communities and Ecosystems

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Dining In Apantheles glomeratus (wasp) and catepillar Cabbage white butterfly

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Ichneomon wasp

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings chalcid

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings A community is all the organisms inhabiting a particular area Figure 36.1 Levels of Organization Organism Population Community Ecosystem Biosphere

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings What are the key characteristics that define a community?

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Key characteristics of a Community Species diversity (aka biodiversity) –Species richness + relative abundance Dominant species –Often vegetation, why? Response to disturbances –Grassland fires Trophic structure –Feeding relationships Plants – herbivores - carnivores

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings What are some ways that species can interact in a community?

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings 4 Main types of Interspecific Interactions Competition Predation Herbivory Symbiosis

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Competition and Niches What is a species niche? What are factors that determine a species niche? What are the 2 possible outcomes of competition between species having identical niches?

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 36.2 High tide Chthamalus Balanus Low tide Ocean Competition may occur when a shared resource is limited STRUCTURAL FEATURES OF COMMUNITIES

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 36.3A Eggs Predation leads to diverse adaptations in both predator and prey Eggs How is predation an important factor in evolution? What are some adaptations that could develop in an organism as a result of predation?

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 36.3B

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 36.3C

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 36.3D

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 36.3E

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Predation can maintain diversity in a community Figure 36.4A

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 36.4B

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Herbivory

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Parasitism Commensalism Mutualism Symbiotic relationships help structure communities

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 36.5B

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Disturbance is a prominent feature of most communities Figure 36.6

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Disturbances Small disturbance: tree falls over - can this be beneficial to an ecosystem? How? Large disturbance: fire, drought, overgrazing… - ecological succession - primary (no soil) - secondary (soil remains)

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Talking About Science: Ecologist Frank Gilliam discusses the role of fire in ecosystems Figure 36.7A

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings A food chain is the stepwise flow of energy and nutrients –from plants (producers) –to herbivores (primary consumers) –to carnivores (secondary and higher-level consumers) Trophic structure is a key factor in ecosystem dynamics

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Vocabulary Producers – autotrophs - Photosynthetic or chemosynthetic - Can be bacteria, protist, or plant Consumers - primary, secondary, tertiary, quarternary Detrivores or decomposers - energy from dead material - usually prokaryotic or protist but - all organisms perform decomposition

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 36.9A TROPHIC LEVEL Quaternary consumers Tertiary consumers Carnivore HerbivoreZooplankton PlantPhytoplankton Secondary consumers Primary consumers Producers A TERRESTRIAL FOOD CHAINAN AQUATIC FOOD CHAIN

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 36.9B

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Food chains interconnect, forming food webs

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure Tertiary and secondary consumers Secondary and primary consumers Primary consumers Producers (Plants, algae, phytoplankton) Detritivores (Prokaryotes, fungi, certain animals) Wastes and dead organisms

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 36.8 Chemical cycling (C, N, etc.) Light energy Chemical energy Heat energy Energy flow and chemical cycling are the two fundamental processes in ecosystems ECOSYSTEM STRUCTURE AND DYNAMICS

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Ecosystem questions Do energy and chemicals cycle in the same way through ecosystems? In terms of abiotic and biotic factors: what part to plants play? Decomposers…? Each day, the sun delivers 1019 kcal of solar energy from the sun Q: What happens to most of that energy? Terms: - biomass – amt or mass of living organic material in an ecosystem - primary production – amt of solar energy converted to chemical energy by an ecosystems producers for a given area and during a given time period

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure Tertiary consumers Secondary consumers Primary consumers Producers 10 kcal 100 kcal 1,000 kcal 10,000 kcal 1,000,000 kcal of sunlight Energy supply limits the length of food chains

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Energy Supply and Flow through ecosystems (11) How does energy supply limit the food chain? - grasshopper example - only the chemical energy left over after cellular respiration is converted into grasshopper biomass. -Only this biomass is available to the next energy level Energy pyramid – 10% of energy is available at each trophic level - 1/1000 th of the energy produced by producer is avble to a tertiary consumer How does the amt of energy available to top-level consumers compare to low-level consumers? Why do top-level consumers, like lions, require so much geographic area? Why are production pyramids limited to 4-5 levels?

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure Secondary consumers Primary consumers Producers Human vegetarians Corn Human meat-eaters Cattle Corn TROPHIC LEVEL Connection: A production pyramid explains why meat is a luxury for humans

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Meat Consumption Are we always consumers at the “ top of the food chain ” ? Ecologically speaking, what does producing meat for human consumption entail? Why is there such a step-down in energy available to humans when we consumer beef as opposed to corn?

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Ecosystems require daily infusions of energy –The sun supplies the Earth with energy –But there are no extraterrestrial sources of water or other chemical nutrients Nutrients must be recycled between organisms and abiotic reservoirs –Abiotic reservoirs are parts of the ecosystem where a chemical accumulates Chemicals are recycled between organic matter and abiotic reservoirs

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings There are four main abiotic reservoirs –Water cycle –Carbon cycle –Nitrogen cycle –Phosphorus cycle

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Heat from the sun drives the global water cycle –Precipitation –Evaporation –Transpiration Water moves through the biosphere in a global cycle

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure Solar heat Precipitation over the sea (283) Net movement of water vapor by wind (36) Flow of water from land to sea (36) Water vapor over the sea Oceans Evaporation from the sea (319) Evaporation and transpiration (59) Water vapor over the land Precipitation over the land (95) Surface water and groundwater

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Carbon is taken from the atmosphere by photosynthesis –It is used to make organic molecules –It is returned to the atmosphere by cellular respiration The carbon cycle depends on photosynthesis and respiration

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure CO 2 in atmosphere Cellular respiration Higher-level consumers Primary consumers Plants, algae, cyanobacteria Photosynthesis Wood and fossil fuels Detritivores (soil microbes and others) Detritus Decomposition Burning

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Nitrogen is plentiful in the atmosphere as N 2 –But plants cannot use N 2 Various bacteria in soil (and legume root nodules) convert N 2 to nitrogen compounds that plants can use –Ammonium (NH 4 + ) and nitrate (NO 3 – ) The nitrogen cycle relies heavily on bacteria

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure Nitrogen (N 2 ) in atmosphere Amino acids and proteins in plants and animals Assimilation by plants Denitrifying bacteria Nitrates (NO 3 – ) Nitrifying bacteria Detritus Detritivores Decomposition Ammonium (NH 4 + ) Nitrogen fixation Nitrogen-fixing bacteria in soil Nitrogen-fixing bacteria in root nodules of legumes Nitrogen fixation

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Phosphates (compounds containing PO 4 3- ) and other minerals are added to the soil by the gradual weathering of rock Consumers obtain phosphorus in organic form from plants Phosphates are returned to the soil through excretion by animals and the actions of decomposers The phosphorus cycle depends on the weathering of rock

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure Uplifting of rock Phosphates in solution Weathering of rock Phosphates in rock Phosphates in organic compounds Detritus Detritivores in soil Phosphates in soil (inorganic) RockPrecipitated (solid) phosphates Plants Animals Decomposition Runoff

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Experimental studies have been performed to determine chemical cycling in ecosystems A study to monitor nutrient dynamics has been ongoing in the Hubbard Brook Experimental Forest since 1963 Connection: Ecosystem alteration can upset chemical cycling ECOSYSTEM ALTERATION

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Dams were built across streams at the bottom of each watershed to monitor water and nutrient losses Figure 36.18A

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings In 1966, one of the valleys was completely logged –It was then sprayed with herbicides for 3 years to prevent plant regrowth –All the original plant material was left in place to decompose Figure 36.18B

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Researchers found that the total removal of vegetation can increase the runoff of water and loss of soil nutrients Figure 36.18C

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Eutrophication is a process in which nutrient runoff from agricultural lands or livestock operations causes photosynthetic organisms in ponds and lakes to multiply rapidly –The result is algal bloom Talking About Science: David Schindler talks about the effects of nutrients on freshwater ecosystems

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Algal bloom can cause a pond or lake to lose much of its species diversity –Human-caused eutrophication wiped out fisheries in Lake Erie in the 1950s and 1960s Figure 36.19B

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Dr. David Schindler is an ecologist who worked at the Experimental Lakes Project in northern Ontario –He performed several classic experiments on eutrophication that led to the ban on phosphates in detergents Figure 36.19A

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings According to Dr. Schindler, there are three serious threats to freshwater ecosystems –Acid precipitation –Climate warming –Changes in land use