1. Copyright © 2009 Pearson Education, Inc. Basic Ecology Populations, Communities and Ecosystems

2. Copyright © 2009 Pearson Education, Inc. 37.1 A community includes all the organisms inhabiting a particular area  Biological community –All the different species of populations living close enough together for potential interaction  Boundaries of the community vary with research questions –Can be a pond –Can be the intestinal microbes of a pond organism

3. Copyright © 2009 Pearson Education, Inc. 37.3 Competition may occur when a shared resource is limited  Ecological niche –An organism’s role or job in the community such as the biotic and abiotic resources it consumes and where it fits in on the food web.  Competition lowers the carrying capacity of competing populations

4. Copyright © 2009 Pearson Education, Inc. 37.8 Trophic structure is a key factor in community dynamics  Trophic structure –A pattern of feeding relationships consisting of several different levels  Food chain –Sequence of food transfer up the trophic levels

5. Copyright © 2009 Pearson Education, Inc.  Producers –Support all other trophic levels –Autotrophs –Photosynthetic producers –Plants on land –Cyanobacteria in water –Protists such as plankton (aka sponge bob) 37.8 Trophic structure is a key factor in community dynamics

6. Copyright © 2009 Pearson Education, Inc.  Consumers –Heterotrophs –Primary consumers –Secondary consumers –Tertiary consumers –Quaternary consumers  Detritivores and decomposers –Derive energy from dead matter and wastes 37.8 Trophic structure is a key factor in community dynamics

7. Plant A terrestrial food chain Producers Phytoplankton An aquatic food chain

8. Plant A terrestrial food chain Producers Phytoplankton An aquatic food chain Primary consumers Grasshopper Zooplankton

9. Plant A terrestrial food chain Producers Phytoplankton An aquatic food chain Primary consumers Grasshopper Zooplankton Secondary consumers Mouse Herring

10. Plant A terrestrial food chain Producers Phytoplankton An aquatic food chain Primary consumers Grasshopper Zooplankton Secondary consumers Mouse Herring Snake Tuna Tertiary consumers

11. Plant A terrestrial food chain Producers Phytoplankton An aquatic food chain Primary consumers Grasshopper Zooplankton Secondary consumers Mouse Herring Snake Tuna Tertiary consumers Hawk Killer whale Quaternary consumers Trophic level

12. Copyright © 2009 Pearson Education, Inc. 37.9 Food chains interconnect, forming food webs  Food web –A network of interconnecting food chains

13. Producers (plants) Primary consumers Secondary and primary consumers Tertiary and secondary consumers Quaternary, tertiary, and secondary consumers

14. Copyright © 2009 Pearson Education, Inc. ECOSYSTEM STRUCTURE AND DYNAMICS

15. Copyright © 2009 Pearson Education, Inc. 37.14 Ecosystem ecology emphasizes energy flow and chemical cycling  Ecosystem –All the organisms in a community as well as the abiotic environment  Components of ecosystems –Energy flow –Passage of energy through the ecosystem –Chemical cycling –Transfer of materials within the ecosystem

16. Copyright © 2009 Pearson Education, Inc. 37.15 Primary production sets the energy budget for ecosystems  Primary production –The amount of solar energy converted to chemical energy –Carried out by producers –Produces biomass –Amount of living organic material in an ecosystem

17. Open ocean Estuary Algal beds and coral reefs Desert and semidesert scrub Tundra Temperate grassland Cultivated land Boreal forest (taiga) Savanna Temperate deciduous forest Tropical rain forest 0 500 Average net primary productivity (g/m 2 /yr) 1,000 1,500 2,5002,000

18. Copyright © 2009 Pearson Education, Inc. 37.16 Energy supply limits the length of food chains  A pyramid of production –Illustrates the cumulative loss of energy transfer in a food chain

19. 1,000,000 kcal of sunlight 10 kcal 100 kcal 1,000 kcal 10,000 kcal Producers Primary consumers Secondary consumers Tertiary consumers

20. Copyright © 2009 Pearson Education, Inc. 37.17 CONNECTION: A production pyramid explains why meat is a luxury for humans  The dynamics of energy flow apply to the human population

21. Producers Primary consumers Secondary consumers Human meat-eaters Cattle Corn Human vegetarians Trophic level

22. Copyright © 2009 Pearson Education, Inc. 37.19 The carbon cycle depends on photosynthesis and respiration  Carbon is the major ingredient of all organic molecules  The return of CO 2 to the atmosphere by respiration closely balances its removal by photosynthesis  The carbon cycle is affected by burning wood and fossil fuels

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

24. Copyright © 2009 Pearson Education, Inc. 37.21 The nitrogen cycle depends on bacteria  Nitrogen is an essential component of proteins and nucleic acids  Nitrogen has two abiotic reservoirs –Air –Soil  Nitrogen fixation converts N 2 to nitrogen used by plants –Carried out by some bacteria and cyanobacteria

25. Nitrogen (N 2 ) in atmosphere 8 Plant Animal Assimilation by plants Organic compounds Organic compounds Death; wastes Denitrifiers Nitrates in soil (NO 3 – ) Detritus Decomposers Decomposition Nitrifying bacteria Ammonium (NH 4 + ) in soil Nitrogen fixation Nitrogen fixation Nitrogen-fixing bacteria in root nodules Free-living nitrogen-fixing bacteria and cyanobacteria 6 1 2 7 4 3 5

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

27. Copyright © 2009 Pearson Education, Inc. PowerPoint Lectures for Biology: Concepts & Connections, Sixth Edition Campbell, Reece, Taylor, Simon, and Dickey Fig. 36-3b Percentage of maximum life span Percentage of survivors (log scale) 0 50100 0.1 1 10 100 III II I

28. Copyright © 2009 Pearson Education, Inc. PowerPoint Lectures for Biology: Concepts & Connections, Sixth Edition Campbell, Reece, Taylor, Simon, and Dickey Fig. 36-4a Time (months) Population size (N) 0 1 23 4 567 89 10 1112 0 50 100 150 200 250 300 350 400 450 500

29. Copyright © 2009 Pearson Education, Inc. PowerPoint Lectures for Biology: Concepts & Connections, Sixth Edition Campbell, Reece, Taylor, Simon, and Dickey Fig. 36-4b Year Breeding male fur seals (thousands) 1915 1925 19351945 0 2 4 6 8 10

30. Copyright © 2009 Pearson Education, Inc. PowerPoint Lectures for Biology: Concepts & Connections, Sixth Edition Campbell, Reece, Taylor, Simon, and Dickey Fig. 36-6 Lynx Snowshoe hare Lynx population size (thousands) Hare population size (thousands) Year 1850187519001925 0 40 80 120 160 0 3 6 9

31. Copyright © 2009 Pearson Education, Inc. PowerPoint Lectures for Biology: Concepts & Connections, Sixth Edition Campbell, Reece, Taylor, Simon, and Dickey Fig. 36-9a 1500 Year Population increase Total population size Total population (in billions) 15501600 1650 1700175018001850190019502000 2050 0 2 4 6 8 10 20 40 60 80 100 Annual increase (in millions)

32. Copyright © 2009 Pearson Education, Inc. PowerPoint Lectures for Biology: Concepts & Connections, Sixth Edition Campbell, Reece, Taylor, Simon, and Dickey Fig. 36-9b Year Birth rate Death rate Rate of increase (r) 1900 1950 1925 19752000 20252050 0 10 20 30 40 50 Birth or death rate per 1,000 population

33. Copyright © 2009 Pearson Education, Inc. PowerPoint Lectures for Biology: Concepts & Connections, Sixth Edition Campbell, Reece, Taylor, Simon, and Dickey Fig. 36-UN3 Time Birth or death rate IIIIVI II

34. Copyright © 2009 Pearson Education, Inc. PowerPoint Lectures for Biology: Concepts & Connections, Sixth Edition Campbell, Reece, Taylor, Simon, and Dickey 0 1234 554 321 0 1234 554 321 Fig. 36-9c 1980 Age Male Female 80+ 75-79 70-74 65-69 60-64 55-59 50-54 45-49 40-44 35-39 30-34 25-29 20-24 15-19 10-14 5-9 0-4 Population in millions Total population size = 68,347,479 Population in millions Total population size = 106,202,903 FemaleMale 2005 2030 Female Male Population in millions Total population size = 135,172,155 0 1234 554 321

35. Copyright © 2009 Pearson Education, Inc. PowerPoint Lectures for Biology: Concepts & Connections, Sixth Edition Campbell, Reece, Taylor, Simon, and Dickey Fig. 36-UN2 G = rN (K  N)(K  N) K