HiSET Science: Energy Flow in the Environment

Energy Flow in the Environment

Using Trophic Levels with an Energy Pyramid
Energy flow through an ecosystem can be tracked through an energy pyramid.

An energy pyramid shows how energy is transferred from one trophic level to another.
Producers always form the base of an energy pyramid, and the consumers form successive levels above the producers.
Producers only store about 1% of the solar energy they receive. Then, each successive level only uses about 10% of the energy of the previous level. That means that primary consumers use about 10% of the energy used by primary producers, such as grasses and trees.
Next, secondary consumers use 10% of primary consumers' 10%, or 1% overall. This continues up for as many trophic levels as exist in a particular ecosystem.


Food Web

An ecosystem can be illustrated by a food web.
Energy moves through the food web in the direction of the arrows.
In the food web, producers such as grass, trees, and shrubs use energy from the sun to produce food through photosynthesis.
Herbivores or primary consumers such as squirrels, grasshoppers, and rabbits obtain energy by eating the producers.
Secondary consumers, which are carnivores such as snakes and shrews, obtain energy by eating the primary consumers.
Tertiary consumers, which are carnivores such as hawks and mountain lions, obtain energy by eating the secondary consumers.

Note that the hawk and the mountain lion can also be considered quaternary consumers in this food web if a different food chain within the web is followed.