Food Chains
and Food Webs in an
Ecosystem
Cornell Notes pg. 151
What is a
Food Chain?
 Shows
transfer of
energy as
organisms feed.
 Producer
->
Consumer(s) ->
Decomposer
What is a
Food Web?
 Shows
multiple food
chains of what is
eating what.
What is a
Predator?
a
consumer that kills
and eats all or part of
another consumer
What are
Prey?
 consumers
that are
killed and eaten by
another consumer
Food Production and Energy Efficiency
At each stage in a food chain, less material and less energy are contained in the biomass of
the organisms.
Long food chains are therefore inefficient.
If a farmer has one hectare of land, he could either use the land to grow food for cows,
which would then be fed to humans, or use the land to grow corn to feed humans directly.
It would be more efficient to grow corn for humans, because less energy is wasted in the
shorter food chain. In fact, ten times as many people could be fed from the same area of
land.
Shorter food chains are more efficient for food production.