Earthworm Dissection Lab

by: Deborah Adane Vu-PAP Bio-2

Lumbricus Terrestris

The earthworm is a member of the phylum Annelida. An earthworm is well-adapted to a life of burrowing through the soil. Its streamlined shape helps it move through the soil. The mucus coating also helps oxygen pass through the earthworm's skin while it is in the air or underwater. The earthworm moves through the soil by sucking the osil in its path into its mouth with the aid of its muscular pharynx. As material passes through the tube-like digestive system, sad grains in the gizzard help grind the food, which is then digested and absorbed in the intestine.

Today's Obectives

Students will be learning about the external and internal anatomy of an earthworm. Students will focus on the organs, structures, and functions of the digestive system.

Digestive System

The digestive system consists of the pharynx, the esophagus, the crop, the intestine and the gizzard. Food such as soil enters the earthworm’s mouth where it is swallowed by the pharynx. Then the soil passes through the esophagus, which has calciferous glands that release calcium carbonate to rid the earthworm’s body of excess calcium. After it passes through the esophagus, the food moves into the crop where it is stored and then eventually moves into the gizzard. The gizzard uses stones that the earthworm eats to grind the food completely. The food moves into the intestines as gland cells in the intestine release fluids to aid in the digestive process. The intestinal wall contains blood vessels where the digested food is absorbed and transported to the rest of the body.