A Worm That's Not a Bookworm

Earthworm Dissection

Lumbricus Terrestris

The Lumbricus terrestris, or earthworm, belongs to the kingdom Animalia under the phylum Annelida. Earthworms are reddish in color and are ringed, a characteristic that defines its place in the Annelida phylum.

Earthworms live in moist soil which contains organic matter. In this soil, the earthworms eats decaying substances. They then leave castings that are beneficial for plant growth. This is part of an earthworm's niche in the ecosystem: it leaves excretion useful for plant growth, breaks down organic matter, and provides a natural means of aeration for the soil as they tunnel through it.

The earthworms are often eaten by many birds and are popular with fisherman who use these creatures as bait.

Earthworms and Farming!

Objectives

  • Learn about the internal and external anatomy of an earthworm
  • Focus on the digestive system of an earthworm and its organs

Dissection of the Earthworm

The Digestive System of the Earthworm

How Does the Earthworm Digest?

The digestive system of the earthworm is a bit different than the human's. Quite different, actually. The earthworm has no jaws or teeth, so it has to use its strong, muscular pharynx to suck in food from the soil. The food then goes through the worm's esophagus to be stored in the crop for a while. Next, the food goes into the gizzard, which contracts and expands to grind up the food. Then the food is digested in the intestine, where enzymes break the food down even further. Lastly, once the food is digested, it is absorbed by the blood in the walls of the intestine (only inorganic matter is excreted as castings).

Want to know more about earthworms?

Works Cited