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When you have finished this page, go to the Earthworms Quiz.
Earthworms are the most highly developed worms. They are divided into segments or parts. They are found in salt and fresh water as well as in the soil. Earthworms are helpful to man as bait for fishing and more importantly, because they loosen the soil for roots to grow.
There are 2700 species of earthworms. Earthworms have many enemies including animals that eat them and man who uses them.
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System
Type
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Earthworms
System
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| Muscular-Skeletal | A earthworm does not have a skeleton. It has bristles on each segment called setae that help the earthworm move. Earthworms have no limbs. The earthworm has two sets of muscles; one that makes it long and thin and one that makes it fat. |
| Digestion | A earthworm has a digestive system. It eats dirt, digesting the plant and animal matter in the dirt and then eliminates the rest. It has an esophagus for the food to go down, a crop to store the food in, a gizzard that grinds the food down, intestines for the food to pass through and take out nutrients and an anus for the food to come out. |
| Nervous | A earthworm has a nervous system with a simple brain and nerve cord. |
| Circulation | A earthworm has blood and blood vessels with multiple (5) hearts. Click here for earthworm heartbeat movie: Earthworm heartbeat movie |
| Respiration | A earthworm has no respiratory organ. It takes in oxygen directly through its skin and gives off carbon dioxide. Its skin is always moist. |
| Reproduction | A earthworm has both sperm and eggs within its body and reproduces sexually. However, the eggs must be fertilized by the sperm of another worm. An earthworm lays a batch of eggs at one time. They do not spend time raising their young once they are hatched. Click here to see a movie of an earthworm giving birth. Earthworm Birth |
| Excretion | A earthworm's wastes help to fertilize the soil. It gets rid of its wastes through tubes called nephridin that lead to pores that allow the wastes out. |
| Symmetry | A earthworm has bilateral symmetry. |
| Coloration | A earthworm is generally earthtones such as brown, tan, etc.. It can be up to eight feet in length! |
