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

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

• 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.

The energy flow from one trophic level to the other is know as a food chain

• 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

Most organisms eat more than JUST one organism

• 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

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

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

When a lion eats a zebra, it does not get all of the energy from the zebra.

• 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!

• from grass to sheep, loss is about 90%!

Each level above only gets 10% of the energy from below

• 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)

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)

• 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)

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

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

Shows the numbers of individual organisms at each trophic level in an ecosystem.

• Shows the numbers of individual organisms at each trophic level in an ecosystem.

Biomass is a measure of the total dry mass of organisms in a given area.

• Biomass is a measure of the total dry mass of organisms in a given area.