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18-3 Energy Transfer

18-3 Energy Transfer. Producers and Consumers. Objectives. Summarize the role of producers Identify kinds of consumers Explain the role of decomposers Compare food chains and food webs Explain why there are only a few trophic levels in an ecosystem. Producers.

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18-3 Energy Transfer

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  1. 18-3 Energy Transfer Producers and Consumers

  2. Objectives • Summarize the role of producers • Identify kinds of consumers • Explain the role of decomposers • Compare food chains and food webs • Explain why there are only a few trophic levels in an ecosystem

  3. Producers • Autotrophs: make their own energy/food • As producers they make energy that other organisms can use • Photosynthesis: Energy from light • Chemosynthesis: Energy from chemicals

  4. Deep sea ecosystems survive on chemosynthesis

  5. Measuring productivity • Gross primary productivity: Rate that producers catch sun’s energy • Producers store energy in sugars • Biomass: All the organic material • Net primary productivity: how much biomass piles up • GPP minus rate of respiration • Kcal/m2/year • g/m2/year • Where do you think there is high Net PP • What about aquatic environments?

  6. Consumers • Heterotrophs: get energy from outside of themselves • Eat or consume something else

  7. Vore = Eat • Herbivore: eat producers (plants or herbs) • Carnivore: eat other consumers • Carn = flesh • Omnivore: eat everything • Omin = all • Most things are really at least a little bit of an omnivore, even lions • Detrivore: eat waste • Detri = garbage • Decomposers important

  8. Others • Insectivore • Bovivore • Planktavore • Cannibal: happens in nature • Black widows, Mantis : eats the father • Mice will kill the babies if the nest is repeatedly threatened • Many father’s kill the young • Why do this?

  9. Energy flow • When you eat something energy moves into you • Trophic level: where do you fit in the food chain? Who eats you and who do you eat?

  10. Food Webs • There are many trophic relationships • Food webs show the many connections between eater and eaten

  11. Energy transfer • How much does each trophic level store? • Only 10% of the energy makes it up to the next level • Why is so much energy lost? • Some prey escape • You can’t eat everything when you do catch prey • Entropy: energy is always lost • There are only a few trophic levels because energy runs out

  12. How do producers and consumers obtain energy? • Producers: from light or chemicals • Consumers: from eating something else

  13. Name four types of consumers • Herbivore • Carnivore • Detrivore • Insectivore

  14. What important role do decomposers play in an ecosystem? • Decomposers remove wastes preventing them from building up.

  15. How does a food chain differ from a food web? • Food chains are linear (straight) • Food webs are spatial, and show more connections

  16. Give two reasons for the low rate of energy transfer within ecosystems • Some prey escape • You can’t eat everything when you do catch prey • Entropy: energy is always lost

  17. Explain why food chains usually do not exceed three to four levels • There is a low rate of energy transfer • Very little energy gets transferred up • Soon there isn’t enough energy to sustain life

  18. American Pieta

  19. What happens to an ecosystem if all the plants die? What happens if all the decomposers die? • If the plants die then the herbivores die, and then the carnivores die. • If decomposers die then waste will pile up eventually poisoning the ecosystem

  20. What is unreasonable about an ecosystem with 7 levels? • There are to many levels because There is a low rate of energy transfer • Very little energy gets transferred up • Soon there isn’t enough energy to sustain life

  21. Explain why there are more herbivores than carnivores • Herbivores get energy from the largest source of biomass: plants • Carnivores can’t get as much energy by eating other consumers

  22. This Biology Lecture brought to you by Muppet Star Wars

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