Trophic Levels, Energy transfer and Pyramids

Trophic Levels – is the position an organism occupies in a food chain Trophic Levels – is the position an organism occupies in a food chain. It refers to food or feeding.

Food Chain

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

Trophic Levels (feeding levels) 3 2 1

Food webs are multiple food chains.

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

Food webs

1st 2nd producer Grass Mouse Primary consumer Grasshopper Frog Owl Energy Level Producer, primary consumer, secondary consumer, tertiary consumer? Grass Mouse Grasshopper Frog Owl Hawk 1st producer 2nd Primary consumer

Secondary and tertiary consumer Energy Level Producer, primary consumer, secondary consumer, tertiary consumer Grass 1st Producer Mouse 2nd Primary consumer Grasshopper Frog 3rd Secondary consumer Owl 3rd and 4th Secondary and tertiary consumer Hawk

Energy lost from chain “link” to “link” is significant! Transfer of Energy Energy lost from chain “link” to “link” is significant!

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

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

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)

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

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

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?