Biology Trophic Levels, Biomagnification, and Populations

• trophic levels
• biomagnification
• populations

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Trophic Levels

There are 5 major trophic levels: primary producers, primary consumers, secondary consumers, tertiary consumers, and quaternary consumers.

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%%Primary Producers%%

“%%Autotrophs%%” - make their own food through either %%photosynthesis%% or %%chemosynthesis%%

Et: trees, bacteria, algae

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%%Primary Consumers%%

“%%Heterotrophs%%” - strictly herbivores that eat primary producers

Et: krill, shrimp, zooplankton

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%%Secondary Consumers%%

“Heterotrophs” - omnivores or carnivores that eat primary producers and/or primary consumers

Et: whales, cod, menhaden

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%%Tertiary Consumers%%

“Heterotrophs” - omnivores or carnivores that eat any organism below on the food web

Et: sharks, dolphins, ocean sunfish

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%%Quarternary Consumers%%

“Heterotrophs” - apex predators; omnivores or carnivores that eat any organism below on the food web

Et: orcas

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Clean-up Crew

• %%detritivores%%: animals that break down and feed on dead material (lobsters, crabs)
• %%decomposers%%: animals that break down organic material (fungi, worms)
• %%scavengers%%: animals that feed on the carcasses of dead organisms (vultures, seagulls)

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%%Biomagnification%%

Biomagnification is the concentration of toxins in an organism’s tissue as a result of consuming other organisms with a lower toxin concentration.

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%%10% Rule%%

Only 10% of the energy produced by a trophic level is used by the next level up. The amount of energy reduces as you move up the food web. The other 90% is lost through heat, metabolism, response to stimuli, reproduction, etc.

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%%Biomass%%

The amount of living tissue in a trophic level.

Populations

%%Population Density%%

The number of living organisms per unit area.

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%%Exponential Growth%%

The ability of a population to grow and thrive rapidly.

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%%Logistic Growth%%

When a population slows and stops.

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%%Carrying Capacity%%

The limit at which an environment Is able to sustain a population of organisms.

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%%Limiting Factor%%

A factor that controls the growth of a population.

Et: predation, competition, disease