1. ECOLOGY The SHORT version BioH Ch 41 1

2. Energy Flow PRODUCERS  Autotrophs  Photosynthesis  Chemosynthesis Energy flows THROUGH an ecosystem 2

3. Consumers  Heterotrophs  Herbivores  Carnivores  Omnivores  Detritivores  Decomposers 3

4. Food Chain Energy relationship between organisms in ecosystem 4

5. Food Web Trophic Levels 5

6. Specific level (relationship) that an organism occupies in a food chain 6

7. Ecological Pyramids Energy Pyramid Shows relative amount of energy available at each trophic level Only 10% of available energy transferred from one trophic level to the next Energy Biomass Pyramid of numbers 7

8. Biomass Pyramid Represents amount of living organic matter at each level 10% transferred between levels 8

9. Pyramid of Numbers Relative number of organisms at each trophic level Only about 10% transferred between levels 9

10. Pyramid of Numbers for oak tree community 10

11. 11

12. Biogeochemical Cycles Biological, geological, & chemical matter recycled through ecosystems WATER CYCLE 12

13. Nutrient Cycles Carbon Cycle  Biological processes (photosynthesis, respiration, decomposition) take up & release carbon  Geochemical processes (erosion, volcanic activity) release CO 2 into the atmosphere  Mixed processes (burial & decomposition of dead organisms converting to petroleum) store carbon underground  Human activities (mining, forestation, burning fossil fuels) release CO 2 into atmosphere 13

14. Nitrogen Cycle  All organisms require nitrogen to build proteins  N 2 is in atmosphere  Nitrogen fixation – bacteria convert N 2 to NH 3 in soil, used as nutrients for producers  Denitrification – bacteria convert NH 3 to N 2 in atmosphere  Used in forming DNA/RNA  Not in atmosphere, just soil and water 14

15. Limiting Factors Primary productivity  Rate at which organic matter is created by producers Limiting factors  Abiotic - ???  Biotic - ??? 15

16. Ecosystem Modeling 16 Through the use of computers, the attempt to model an ecosystem in order to predict what might happen to that ecosystem (or the species within it) if some modification to the ecosystem happens. An example: DDT biological magnification (an increase in the concentration of a substance that occurs in a food chain as a result of: Persistence Food chain energetics Low rate of degradation

17. OVERVIEW 17