1. Albia Dugger Miami Dade College Cecie Starr Christine Evers Lisa Starr www.cengage.com/biology/starr Chapter 42 Ecosystems (Sections 42.1 - 42.6)

2. 42.1 Eutrophication of a lake means an there are far too many nutrients in the lake.

3. 42.2 The Nature of Ecosystems COPY THIS: In ecosystems, communities and their environment interact through a one-way flow of energy and a cycling of nutrients Nutrients taken up by producers are returned to the environment by decomposers, then taken up again

4. Energy Flows, Nutrients Cycle Light energy that enters the system returns to the environment as heat Nutrients are continually recycled

5. ANIMATION: One-way energy flow and materials cycling To play movie you must be in Slide Show Mode PC Users: Please wait for content to load, then click to play Mac Users: CLICK HERECLICK HERE

6. Primary Producers and Production An ecosystem runs on energy captured by primary producers primary producer (autotroph) An organism that obtains energy and nutrients from inorganic sources to build organic compounds primary production Rate at which producers capture and store energy Varies by ecosystem, season, and nutrient availability

7. The Roles of Consumers Consumers are described by their diets: Herbivores (plants) Carnivores (animal flesh) Parasites (tissues of a living host) Omnivores (plants and animals) Detritivores (detritus) Decomposers (waste and remains)

8. Key Terms consumer Organism that obtains energy and carbon by feeding on tissues, wastes, or remains of other organisms detritivore Consumer that feed on small bits of organic material, such as earthworms decomposer Organism that feeds on biological remains and breaks organic material down into its inorganic subunits. Feed by diffusion, no “mouth”. Bacteria and Fungi.

9. Energy Flow and Nutrient Cycling Heat energy is not recycled: Energy captured by producers is converted to bond energy in organic molecules, and released by metabolic reactions that give off heat Nutrients are recycled: Producers take up inorganic molecules (nutrients) from the environment to form organic molecules Decomposers break down organic molecules and return nutrients to the environment

10. ANIMATION: The role of organisms in an ecosystem To play movie you must be in Slide Show Mode PC Users: Please wait for content to load, then click to play Mac Users: CLICK HERECLICK HERE

11. ANIMATION: Food chain To play movie you must be in Slide Show Mode PC Users: Please wait for content to load, then click to play Mac Users: CLICK HERECLICK HERE

12. 42.3 Food Chains Food chains describe how energy and materials are transferred from one organism to another food chain Description of who eats whom in one path of energy in an ecosystem – transfer of energy to higher trophic levels trophic level Position of an organism in a food chain

13. A Food Chain First trophic level (primary producer): Autotroph (grass) converts light to chemical energy Second trophic level (primary consumer): Grasshopper eats grass Third trophic level (second-level consumer): Bird eats grasshopper Fourth trophic level (third-level consumer): Coyote eats bird

14. Fig. 42.3, p. 711 First Trophic Level Primary producer Second Trophic Level Primary consumer Third Trophic Level Second-level consumer Fourth Trophic Level Third-level consumer big bluestem grass grasshopper coyote sparrow A Food Chain

15. Food Chain Limits Energy captured by producers usually passes through no more than four or five trophic levels The length of food chains is restricted by the inefficiency of energy transfers Only 5-30% of energy in an organism at one trophic level ends up in tissues of an organism at the next trophic level

16. 42.4 Food Webs Food chains of an ecosystem cross-connect as a food web Food web structure reflects environmental constraints and the inefficiency of energy transfers among trophic levels food web Set of cross-connecting food chains

17. ANIMATION: Food webs To play movie you must be in Slide Show Mode PC Users: Please wait for content to load, then click to play Mac Users: CLICK HERECLICK HERE

18. ANIMATION: Rainforest food web To play movie you must be in Slide Show Mode PC Users: Please wait for content to load, then click to play Mac Users: CLICK HERECLICK HERE

19. 42.5 Ecological Pyramids Ecological pyramid diagrams illustrate the inefficiency of transfers between trophic levels A biomass pyramid shows amounts of organic material in bodies of organisms at each trophic level at a specific time An energy pyramid shows energy flow through each trophic level in a given interval

20. Florida Aquatic Ecosystem

21. Fig. 42.6, p. 713 Florida Aquatic Ecosystem

22. Fig. 42.6a, p. 713 A Biomass pyramid (grams per square meter) 809 detritivores (crayfish) and decomposers (bacteria) top carnivores (gar and bass) 1.5 11 37 5 carnivores (smaller fishes, invertebrates) herbivores (plant-eating fishes, invertebrates, turtles) producers (algae and aquatic plants) Florida Aquatic Ecosystem

23. Fig. 42.6a, p. 713 detritivores (crayfish) and decomposers (bacteria) 5 A Biomass pyramid (grams per square meter) 809 producers (algae and aquatic plants) 11 carnivores (smaller fishes, invertebrates) top carnivores (gar and bass) 1.5 37 herbivores (plant-eating fishes, invertebrates, turtles) Stepped Art Florida Aquatic Ecosystem

24. Fig. 42.6b, p. 713 Florida Aquatic Ecosystem

25. Fig. 42.6b, p. 713 detritivores + decomposers = 5,060 21 carnivores 3,368 383 top carnivores 20,810 producers herbivores B Energy flow pyramid (kilocalories per square meter per year) Florida Aquatic Ecosystem

26. Fig. 42.6b, p. 713 detritivores + decomposers = 5,060 20,810 producers B Energy flow pyramid (kilocalories per square meter per year) 21 top carnivores carnivores 383 3,368 herbivores Stepped Art Florida Aquatic Ecosystem

27. Food and Energy Feeding a population of meat-eaters requires far greater crop production than sustaining a population of vegetarians A person who eats a plant food gets most of the calories in that food When plant food is used to grow livestock, only a small percentage of the plant’s calories ends up in meat

28. Key Concepts Organization of Ecosystems A one-way flow of energy and the cycling of raw materials among species maintain an ecosystem Nutrients and energy are transferred in a stepwise fashion through food chains that interconnect as complex food webs

29. ANIMATION: Energy flow at Silver Springs To play movie you must be in Slide Show Mode PC Users: Please wait for content to load, then click to play Mac Users: CLICK HERECLICK HERE

30. 42.6 Biogeochemical Cycles Elements essential to life move between a community and its environment in a biogeochemical cycle biogeochemical cycle A nutrient moves between environmental reservoirs and in and out of food webs Chemical and geologic processes move elements to, from, and among environmental reservoirs (rocks, sediments, water, atmosphere)

31. Biogeochemical Cycles

32. Key Concepts Biogeochemical Cycles In a biogeochemical cycle, a nutrient moves relatively slowly among its environmental reservoirs The reservoirs may include air, water, and rocks (gas, liquid, solid) Nutrients moves more quickly into, through, and out of food webs