Trophic Levels

Producers

Primary Consumers

Secondary Consumers

Tertiary Consumers

Decomposers

Kinds of consumers

• ____________ consumer who eats producers.

• ______________ consumer who eats only other consumers

• _______________consumer who eats producers and consumers

• _______________ consumer who breaks down dead organisms

Energy Transfers

• When one organism eats another, energy is transferred

• Food __________show the flow of energy from 1 organism to another (just one way flow)

• Food __________ are more complicated: each organism eats more than 1 thing and is eaten by more than 1 thing

Energy Transfer

Law of 10% Activity

1. Relate and describe the amount of energy you have available to you in comparison to other trophic levels at your table.

2. Why doesn’t all of the energy transfer to the next trophic level?

3. Why can’t a food chain have 10 links?

4. Which organism in the food chain is going to have to eat the most food to meet their energy needs? What does this mean for survival?

Law of 10%

10% of usable energy passed on

Waste Heat (due to cellular respiration)

Unusable energy

Trophic Levels

Energy Pyramid

• Why are there more producers than herbivores?

• Why are there more herbivores than carnivores?

• Why can’t there be too many links in a food chain?

• Why do top carnivores need such a large territory?

Energy Flow and Eating Habits

• Meat eating (higher on the trophic pyramid) uses more energy than eating veggies

• 90% of the grain that we grow is used to feed livestock

• 100 kg of grain can feed:– 10 kg of cow and 1 kg of steak eating people– 10 kg of grain eating people (10x more)

What can pass through a food web?

• Energy

• Mineral nutrients (carbon, nitrogen, phosphorus) (more on this soon)

• Bad Stuff– any toxins or poisons that are fat stored

can be passed along a food chain

Biological Magnification

BIOMAGNIFICATION

• If each little fish eats a little DDT, but

• Each medium fish eats 10 little fish (or more)

-10X DDT (or more)

• Each larger fish eats 10 medium fish (or more)

-_____X DDT (or more)

• Each huge fish eats 10 larger fish (or more)

-______X DDT (or more)

• Each level along the food chain, the poison gets more and more concentrated