Calculating Energy Transfer in Food Webs and Pyramids

Energy Transfer and Energy Pyramids

What is an energy pyramid? Ecological Pyramid is not the same.....

• Ecological pyramids are visual representations of energy flow, biomass accumulation, and number of individuals at different trophic levels.

• The energy pyramid is used in energy transfer from one organism to another along the food chain. The energy decreases as you move from the bottom to the top of the energy pyramid.

Multiple Choice

In an energy pyramid, The energy increases as you move from the bottom to the top of the energy pyramid.

• True

• False

10% Rule

90% of the energy entering each step of the pyramid is used up by the consumers, only 10% of the energy get stored. So, when the next level on the pyramid eats them, that 10% gets passed down to them.

Multiple Choice

If there are 50,000 Joules of Energy available at the producers level, how much will available in secondary consumer trophic level?

• 5000 Joules

• 5 Joules

• 50 Joules

• 500 Joules

Food Chain

The food chain describes who eats whom in the wild. Every living thing—from one-celled algae to giant blue whales—needs food to survive. Each food chain is a possible pathway that energy and nutrients can follow through the ecosystem.

For example, grass produces its own food from sunlight. A rabbit eats the grass. A fox eats the rabbit.

Multiple Choice

A mosquito larva eats the algae, therefore the mosquito larva is a

• primary consumer

• producer

• secondary consumer

• autotroph

• tertiary consumer

Food Web

Different habitats and ecosystems provide many possible food chains that make up a food web.

In a grassland ecosystem, a grasshopper might eat grass, a producer. The grasshopper might get eaten by a rat, which in turn is consumed by a snake. Finally, a hawk—an apex predator—swoops down and snatches up the snake.

Multiple Choice

A scorpion eats grasshoppers and the grasshopper eats plants. What is the scorpion?

• producer

• primary consumer

• secondary consumer

• tertiary consumer