Earthworm Dissection - Vu - PAP Bio - P.2 - 4/8/14
The objective of this dissection is to learn about the internal and external anatomy of an earthworm (with an emphasis on the digestive system), as well as its role in the ecosystem.
Common earthworms are reddish-gray colored invertebrates, typically only a few inches long. They are thin and cylindrical; their bodies are made up of segments called annuli which are covered in small hairs called setae which help them move and burrow into the soil. Earthworms are hermaphroditic, but choose to mate with each other instead of self-fertilize. Earthworms help keep soil healthy by transporting nutrients into it through their waste. They can also regenerate when their tails are cut off. (This does not mean that two new worms grow from the pieces; the tail only grows back.)
Species: Lumbricus terrestris or Lumbricus rubella
Earthworms live in soil. They originated in Europe, but are also found in North American and western Asia.
Earthworms have many predators, some of which include birds, frogs, and fish.
Earthworms don't really have prey; they get nutrients by eating the soil that they live in.
See an earthworm eat!
setae, segment, clitellum, anus
mouth, pharynx, esophagus, crop, buccal cavity, gizzard, intestine, anus
aortic arches, dorsal blood vessels, ventral blood vessels
Soil enters the earthworm's mouth, where it is then swallowed by the pharynx. It is passed through the esophagus, then into the crop, and then into the gizzard, where it is crushed and then sent into the intestine. Once the food reaches the intestine it is absorbed and transported throughout the rest of the earthworm's body.