1. Energy Flow in Ecosystems Chapter 3

2. Life Depends on the Sun Plants, algae, and some bacteria –Photosynthesis –Convert solar energy from sun into food Glucose –Producers Organisms that make their own food –Autotrophs

3. Life Depends on the Sun An exception –Deep-ocean ecosystems Too deep for sunlight to reach Primary producer? –Chemoautotrophs »Uses simple chemicals to make energy »Sulfur compunds

4. Who Eats What Herbivores –Consumers that eat only producers Plant eaters Carnivores –Consumers that eat only other consumers Meat eaters Omnivores –Eat both produces and consumers

5. Who Eats What Decomposers –Consumers that get their food by breaking down dead organisms Causes them to “rot” –Nutrients returns to the soil, water, or air

6. Cellular Respiration The process that organisms use to break down chemical energy –Photosynthesis 6 H2O + 6CO2 (+ light)  glucose + 6O2 –Respiration Glucose + 6O2  6 H2O + 6CO2 + energy

7. Energy Transfer Food chain –Sequence where energy is transferred from one organism to the next Linear Most – 4 or 5 links, max

8. Energy Transfer Food webs –All of the energy transfers in an ecosystem Made up multiple food chains More accurate representation

9. Energy Transfer Energy pyramid –Each layer represents a trophic level –Lower level = more energy Primary, secondary, tertiary consumers

10. Loss of Energy Loss of energy affects and shapes the ecosystem –Primary producers store 1,000 times more energy then the primary consumer Not enough energy to support more higher level organisms Limits the number of trophic levels

11. The Cycling of Materials All materials in an ecosystem are recycled –Biogeochemical cycles Chemicals cycle through the biological and geological worlds –Reservoirs – large amounts of chemical for long amounts of time –Exchange pools – area where chemical is held for short period of time »Residence time

12. Water Cycle Energy is supplied by the sun Evaporation or Transpiration –Body of water or treetop Clouds –Solar energy makes weather Condensation + gravity = rain Groundwater, ice, or runoff

14. Carbon Cycle Carbon is cycled in the environment through: –Photosynthesis 6 H2O + 6CO2 (+ light)  glucose + 6O2 –Respiration Glucose + 6O2  6 H2O + 6CO2 + energy –Consumers eating producers

15. Carbon Cycle CO 2 stored mainly in ocean and rock –Easily dissolves into seawater May precipitate out and become calcium carbonate (limestone) May be used by plants –Released by plant –Eaten by heterotroph –Remain with dead plant »Taken up by decomposers »Become fossil fuel

16. Humans’ Affect on Carbon Cycle Forms of stored carbon: –Coal –Oil –Natural gas Burning these releases additional carbon into the atmosphere –Raises average concentration »Global warming

18. Nitrogen Cycle Nitrogen is needed by organisms to build proteins –Very abundant ~ 78% of atmosphere Needs to be “fixed” into a useable form by nitrogen-fixing bacteria Also produces excess nitrogen that is left in the soil for use by plants that do not have nitrogen-fixing bacteria

19. Nitrogen Cycle Bacteria and fungi break down wastes and dead organisms –Return nitrogen to the soil in the form of ammonia Other bacteria turn this back into a nitrogen gas

22. Ecosystem Change Succession –Regular pattern of changes over time in the types of species in a community Resulting stable community – climax community –Secondary succession Occurs where an ecosystem previously existed

24. Ecosystem Change Pioneer species –Plants that are the first to colonize a newly available area Grow rapidly and produce many seeds Primary succession –Occurs where no ecosystem existed before Begins where there is no soil –Slow process