Organisms That
Recycle
When plants and animals die, decomposers feed on them.
These organisms break down dead plants and animals into
nutrients in a process called decomposition. Decomposition has two
outcomes. First, decomposers get energy when they feed on
nutrients from dead plants and animals. Second, decomposers
release nutrients such as nitrogen, carbon, and phosphorus.
They put these nutrients back into the soil, where the nutrients can
be used by plants.
Decomposition is an important part of nature. Imagine a food chain
in which a rabbit eats a plant. Then a snake eats the rabbit.
The plant has taken nutrients, such as phosphorus, from the soil to
help it grow. When the rabbit eats the plant, the phosphorus in the
plant is transferred to the rabbit. When the snake eats the rabbit,
the phosphorus is passed to the snake. In this way, phosphorus and
other nutrients travel through food chains. When an organism in a
food chain dies, decomposers break it down. They return
phosphorus and other nutrients to the soil. Then the phosphorus
and other nutrients are available for new plants to use. In this way,
decomposers allow phosphorus and other nutrients to be reused on
Earth.
What would Earth be like without decomposers? First, there would
be no way to break down dead organisms. There would be piles of
dead plants and animals everywhere on Earth. Second, nutrients
would be trapped in dead plants and animals. They would not
return to the soil for plants to use.
There are many types of decomposers.
The main decomposers on Earth are bacteria
and fungi. Fungi are decomposers that often
break down wood. Many dead trees and rotting
logs are full of fungi. Earthworms are a type of
decomposer found in soil. They eat dead leaves
and roots and put waste into the soil.
Earthworm waste is high in nutrients. It makes
the soil good for plant growth. Insects such as
maggots, beetles, ants, and wasps are
decomposers that break down dead animals.
Discovery Education Science
Nutrients pass through
food chains. Decomposers
return these nutrients to
the soil.
Shelf fungi are
responsible for the
decay of dead trees.
Earthworms are beneficial to
farmers because they add
nutrient-rich waste to the
soil.
© 2007 Discovery Communications, LLC