1. Food and energy cycles CP Biology - ECOLOGY

2. Energy flow AAAAn ecosystems energy budget is determined by the amount of photosynthetic activity of the producers PPPProducers use light energy to synthesize organic molecules which are then used to make ATP in cellular respiration CCCConsumers obtain energy from organic molecules produced in lower trophic levels

3.  Consumers use food energy for:  Cell respiration  Maintaining life processes (homeostasis, growth, development, etc)  Some is lost in waste products and as heat  Energy has to constantly be added to and ecosystem

4. An overview of ecosystem dynamics

5. Organismal ecology  Organisms can be put into 1 of 2 groups based on the costs and benefits of maintaining homeostasis  Regulators expend energy in response to changing environmental conditions; the energy costs cannot exceed the benefits of regulating their internal environment  Conformers allow their internal conditions to vary with the external environment  The principle of allocation says that organisms have a limited amount of energy to spend on all life functions; the energy spent on one can’t be spent on the others.

6. Regulators and conformers

7. The relationship between body temperature and ambient (environmental) temperature in an ectotherm and an endotherm

8. Primary productivity  Gross primary productivity (GPP): The amount of light energy converted to chemical energy by autotrophs in an ecosystem; some is stored by plant, some is used for life processes  Net primary productivity (NPP): the amount of chemical energy available to consumers; also called biomass

9. Figure 54.3 Primary production of different ecosystems

10. Figure 54.4 Regional annual net primary production for Earth

11. Secondary productivity  Rate at which consumers convert the chemical energy in the food they eat to their own biomass  Consumers use energy for life functions but cannot completely digest the food so only about 10% of the energy consumed is available to the next trophic level  Pictured in a pyramid

12. Figure 54.10 Energy partitioning within a link of the food chain

13. Types of pyramids  Pyramid of productivity (at trophic levels)  Biomass pyramid  Pyramid of numbers (individuals)  All are similar in that the bases are wide (lots of producers) and narrow greatly at the top (few top level consumers) and only have 3-5 trophic levels

14. An idealized pyramid of net production

15. A pyramid of numbers

16. Biogeochemical cycles  Global recycling: gaseous elements are recycled in the atmosphere (oxygen, nitrogen, carbon, sulfur)  Local recycling: elements that are solid are recycled in the soil (phosphorous, potassium, calcium, trace elements)  Matter is recycled, energy is not

17. A general model of nutrient cycling

18. U.S. map profiling pH averages for precipitation in 1999

19. Figure 54.25 Biological magnification of DDT in a food chain