1. ECOSYSTEMS

2. Energy: How does energy move through the ecosystem, does it cycle or flow? It flows, energy cannot be re-cycled once it is lost as heat. What is a trophic level? A feeding level What is the trophic level that supports all others? Primary producers.

3. What is missing from this food chain? detritivores

4. In what way is this food web more realistic than the food chain? The food web incorporates consumers that feed at multiple trophic levels

5. Primary Producers Who are the primary producers of most terrestrial ecosystems? Plants Who are the primary producers of most aquatic ecosystems? Microscopic algae and bacteria (phytoplankton), and multicellular algae and aquatic plants. Who are the primary producers of the deep sea floor? Chemoautotrophic bacteria

6. Consumers Herbivores - primary consumers Carnivores - secondary consumers Omnivores - can feed at multiple trophic levels

7. Decomposers What organisms are decomposers in most ecosystems? Fungi and Bacteria What do the decomposers do? They convert organic material from all trophic levels to inorganic compounds that can be used by the autotrophs.

8. Primary Productivity The energy budget of an ecosystem depends on its primary productivity. What is primary productivity? The amount of light energy converted to chemical energy by the producers GPP = total productivity NPP = GPP - Rs NPP results from the photosynthetic yield minus whatever is used for respiration.

9. Net Primary Productivity Why is NPP a more useful measurement than GPP? NPP measures how much energy is available to the consumers in the ecosystem. What is biomass? The dry weight of organic material. Primary productivity is the rate at which organisms synthesize new biomass.

10. How is it that the open ocean has low productivity yet accounts for most of the Earth’s total productivity?

11. Limiting Factors What sort of factors will limit productivity? Light intensity Water Inorganic nutrients such as nitrogen and phosphorus. CO 2

12. Energy Partitioning Within the Food Chain What does this number represent?

13. Energy Partitioning Within the Food Chain The energy available for the next trophic level.

14. Ecological Effeciency How much of energy is actually available to the next trophic level? Usually around 10% is available Why is it that we don’t see 6th order consumers? There is not enough energy available to support consumers at this level.

15. Which has more energy, a quarter pound of peas or a quarter pound of hamburger?

16. How can the producers in the English Channel support the producers in this ecosystem?

17. How many individuals are supported at the top level of this ecosystem?

18. Chemical Cycling

23. What does the loss of nitrates from the deforested ecosystem tell you about the water, and about how nitrates are normally maintained in the ecosystem?

24. What is going on in this picture?

25. How We Threaten Biodiversity….

26. Three levels of biodiversity Genetic diversity Species diversity Ecosystem diversity

27. Nearly Extinct

28. Major Threats to biodiversity Habitat destruction –Tropical rain forests cleared (98% of Mexico's and Central America's have been cleared) –Coral reefs 40 – 50 % could be lost over the next 30 years

29. Introduced Species

30. Overexploitation

31. Disruption of interactions

32. Extinction Vortex

33. Case Study

34. Conflicting demands Demands of developers, farmers and recreationsits… Demands for conservationists Who should have the power..?

35. Importance of Corridors Edge communities have special characteristics Conservationists have moved to develop corridors to link destroyed edges and fragmented communities

36. Artificial corridor in Banff

37. Protected Areas Look for biodiversity hot spots..

38. Biophilia What is biophilia? Do we all have it? How does it affect us?

39. Concept Check 1.How does energy move through the ecosystem? In what way is this different from the way nutrients move? 2.What are some limiting factors that effect productivity? 3.What is the difference between NPP and GPP? 4.Why don’t food chains usually go higher than 5 trophic levels? 5.What is biological magnification? 6.What type of organism is fixes nitrogen and releases it as well? 7.How do plants and animals assimilate and release carbon? 8.What is the effect of increased CO 2 on an ecosystem? 9.What causes ozone depletion? Why is this a problem?