3. Energy Flow and Chemical Cycles

4. Objectives Discuss energy flow through different ecosystems Trace cycles of Carbon, Nitrogen, and water

5. Ecosystem All the energetic interactions and material cycling that link organisms in a community with one another and with their environment

6. Energy and Production

7. Laws of Thermodynamics Energy is not created or destroyed. It changes form and place When energy changes form some of it is lost as entropy (heat)

8. Production Primary Production = energy accumulated by plants Gross Primary Production = total photosynthesis Net Primary Production = energy remaining after Respiration and stored as organic matter. NPP=GPP-R Standing crop biomass = accumulated organic matter on a given are at a given time

9. Difference in productivity Species efficiency Efficiency = NPP/GPP Corn.85 Deciduous trees.42 Prairie grass.66 Physical environment –Water –Heat

10. Secondary Production Animals Energy, once consumed goes to maintenance, and waste. Little is left for production. 10% rule.

11. Homeotherms High assimilation, high metabolism, thus low production efficiency

12. Poikilotherms Low metabolism, low assimilation, thus even lower production efficiency

13. Food Chains and Food Webs

14. Definitions Food Chain– series of steps by which energy stored in plants is passed through an ecosystem Fig. 5.14

15. Definitions Food web – several interrelated food chains Fig. 5.15

16. Components Producers – plants Herbivores – convert plant tissue into animal tissue Carnivores – eat other animals, levels Omnivores – eats both plants and animals

17. Components Scavengers – animals that eat dead plant and animal matter Saprophytes – plant and fungi that absorb dead material Decomposers – everything is a decomposer

18. Another way of viewing energy relationships (Heterotrophs) Biophages – use living matter Saprophages – use nonliving matter

19. Two Major Food Chains Grazing food chain – energy flows through the biophages Detrital food chain – energy flows through the saprophages. Fig. 23.3 Fig. 23.4 Fig. 23.5

20. Chemical Cycles

21. Water cycle Fig. 16.3

22. Water Cycle

23. Carbon Cycle Fig 5.16

24. Carbon Cycle

25. Nitrogen cycle Fig. 5.17

26. Nitrogen cycle

27. The End Have a good weekend!