Trophic Levels, Energy transfer and Pyramids

1. Trophic Levels, Energy transfer and Pyramids

2. Vocabulary • Trophic Levels – is the position an organism occupies in a food chain. It refers to food or feeding. • Apex predator – top level predators with few or no predators of their own.

3. Food Chain

4. Food Chains • The energy flow from one trophic level to the other is know as a food chain • Producers are at the first TROPHIC LEVEL • Primary Consumers are the SECOND TROPHIC LEVEL • Secondary consumers are at the THIRD TROPHIC LEVEL

5. Trophic Levels (feeding levels) 3 2 1

6. Food Web • Most organisms eat more than JUST one organism • When more organisms are involved it is know as a FOOD WEB • Food webs are more complex and involve lots of organisms

7. Food Webs Food webs show ALTERNATIVE PATHWAYS other possible pathways through which an organism can obtain energy

8. Food webs

12. Transfer of Energy • When a lion eats a zebra, it does not get all of the energy from the zebra. • Energy lost is usually in form of heat • Energy lost from chain “link” to “link” is significant!

13. from grass to sheep, loss is about 90%! HEAT 90% HEAT 90% 100% Energy Available 10% Original Energy! 1% Original Energy!

14. Energy lost from one trophic level (energy level) to the next level can be represented by a pyramid 4⁰CONSUMERS 3 CONSUMERS 2 CONSUMERS 1 CONSUMERS PRODUCERS

15. Each level above only gets 10% of the energy from below • Ex: 10,000 J of producers (plants) only give 10% of energy to primary consumers • 1,000 J to primary consumers (snails, minnows, dragonflies) • 100 J to secondary consumers (small fish) • 10 J to tertiary consumers (big fish) • 1 J to quaternary consumers (fish hawk)

16. ENERGY PYRAMID 1 J 10 J 100 J 1,000 J 10,000 J

17. Energy Pyramid

20. Three hundred trout are needed to support one man for a year. The trout, in turn, must consume 90,000 frogs, that must consume 27 million grasshoppers that live off of 1,000 tons of grass. -- G. Tyler Miller, Jr., American Chemist (1971)

21. Usually no more than 5 trophic levels since 6th level would have very little energy to keep it alive

22. Ecological Pyramid • Which level has the most energy? • Which level has the most organisms? • Which level has the least organisms? • Which level has the least energy?

23. 5 tertiary consumers secondary consumers 5000 primary consumers 500,000 producers 5,000,000 producers 5,000,000 Pyramid of Numbers • Shows the numbers of individual organisms at each trophic level in an ecosystem. • A vast number of producers are required to support even a few top level consumers.

24. tertiary consumers 75 g/m2 150g/m2 secondary consumers primary consumers 675g/m2 2000g/m2 2000g/m2 producers producers Biomass pyramid • Biomass is a measure of the total dry mass of organisms in a given area.