1. Intro to Ecosystems Chapter 55

2. Ecosystems All abiotic factors & species

3. Ecosystems Processes in the ecosystems 1. Energy Comes from sun Photosynthesis(chemical energy) 2. Biogeochemical cycles(nutrients) Chemicals that move through ecosystems Mostly found in nonliving reservoirs

4. Ecosystems Photosynthesis Decomposition & respiration return elements to abiotic forms Elements are recycled Energy is released as heat Sun continuously supplies energy Evaporation & precipitation circulate elements

5. Trophic levels Energy flow through the ecosystem Autotrophs: primary producers Heterotrophs: consumers Primary consumers: herbivores Secondary consumers: carnivores Decomposers: break down organic matter Detritivore: live on refuse of ecosystem

6. Trophic levels “trophos” means feeder All levels feed on another Food chain Represents these levels Food web: More complex relationships between levels

7. Food chain

9. Food web

10. Energy flow Primary productivity: Amount of energy produced by photosynthesis (organic matter) in a community Biomass: Total mass of organisms in an ecosystem Rainforests or wet lands have a high productivity

11. Energy flow Secondary productivity Rate of biomass of heterotrophs Less than primary due to 1. Not all plants are consumed by herbivores 2. Some energy of herbivores is passed as waste 3. Some energy is lost as heat

12. Energy flow

13. Gross primary production (GPP) Amount light energy converted to chemical energy over time Net primary production (NPP) GPP less the amount of energy for plant cellular respiration (R) NPP= GPP-R

14. Energy flow Net primary production (kg carbon/m 2 ·yr) 0 1 2 3 ·

15. Energy flow in food chains Ecological pyramids Relationship of energy, biomass or numbers in an ecosystem The limit is based on amount of sunlight and nutrients available

16. Ecological pyramids

20. Water cycle Oceans cover ¾ of earth’s surface Sun powers evaporation of water from oceans 90% of water in atmosphere over land comes from plant transpiration Most falls over the ocean as rain 2% is frozen in ice Water supplies the hydrogen in ATP formation

21. Water cycle

22. Carbon cycle Photosynthesis uses up about 10% of atmospheric CO 2 Respiration replaces CO 2 in the air Most CO 2 is in fossil fuels, coals, gas Use of these is increasing CO 2 in the atmosphere

23. Carbon cycle

24. Nitrogen cycle Prokayotes “fix” nitrogen to usable form Nitrogen is being added to the system by fertilizers

25. Nitrogen cycle

26. Phosphorus cycle Exist in mineral form (not atmosphere) Need for ATP, phospholipids, DNA, RNA Fertilizers adding a lot

27. Phosphorus cycle

28. Ecosystem stabilization More diverse species (species richness) 1. Ecosystem productivity 2. Spatial heterogencity More habitat variation (soils, topography) allows more areas for animals to live 3. Climate More stable the weather the greater the species

29. Biodiversity hotspots

30. Biodiversity

31. Problems Pollution Rhine river (Mercury, pesticides 1986) DDT (chlorinated hydrocarbons) Absorbed in animal fats Biological magnification: Become more concentrated in food chain

32. DDT

33. Acid rain Sulfur dioxide Forms sulfuric acid when comes with rain Lowers pH Kills wildlife

34. Acid rain

35. Farming

36. Ozone layer Protects against UV Thinning 1975 Chloroflurocarbons (CFC’s) Increased melanoma

37. Ozone

39. Greenhouse effect Increased carbon dioxide & other gases Reflects heat from earth Keeping it in the atmosphere Global warming

40. Greenhouse effect

41. Effect of warming Plants/animals further north Migratory changes Species have problems adapting Increasing sea level Retreating glaciers More severe weather changes

42. Logging