Daniel Stewart Biology Pre-AP Vu Period 4

How Much Do You Know The Earthworm?

The earthworm, Lumbricus terrestris, is a member of the phylum Annelida. An earthworm is quite 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 eathworm moves through the soil by sucking the soil in its path into its mouth with the aid of its muscular pharynx. As material passes through the tube-like digestive system, sand grains in the gizzard help grind the food which is then digested and absorbed in the intestine.

The Digestive System

The digestive system of the earthworm is very strait and simple. Soil enters the mouth where it is swallowed by the pharynx. The food travels down the esophogus where it is stored in the crop. It is then sent to the gizzard where stones crush the food into managable sized portions. The intestinal wall is lined with blood vessels where the digested food is absorbed and transported to different parts of the body

Interesting Facts

  • Usually grows up to 14 inches
  • Up to 11.2 grams
  • Contrary to common belief, if one cuts a earthworm in half, the two halves will not grow
  • Can dig up to 6.5 feet deep
  • The setae which covers the entire earthworm allows the earthworm to move and burrow