Earthworms Essay

This essay has a total of 431 words and 3 pages.



Earthworms are classified as Annelida. Annelida mean little rings which refers to the many segments in their body.
The structure of an earthworm’s body is made up of more than one hundred segments
separated by partitions that divide the coelum. All segments are identical except by the
anterior and posterior ends. The anterior segments reflect the cephalization that is an
adaption of burrowing. The head of the earthworm contains the sense organs. The muscle
lines that make up the interior body wall are circular and longitudinal. Earthworms move
by anchoring some segments by their setae and contracts the circular muscles in front of
those segments, producing fluid pressure in the anterior coelom cavities. The anterior
setae grip the ground, the longitudinal muscles contract pulling the posterior along.

Earthworms burrow and feed on soil and organic matter at the same time. They digest the
organic matter and eliminate wastes and undigested matter as dirt and feces called
castings. Earthworms are good for the soil because they sucked up soil into the by the
muscular pharynx. The soil then passes through a tubelike esophagus to a temporary
storage called a crop, and from there to the gizzard. The gizzard walls grind the soil,
releasing and breaking up organic matter.

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