Earthworms Galore

by: Hannah Katz teacher: Ms. Vu

The Earthworm

The earthworm is from the phylum Annelida. The scientific name is Lumbricina. The earthworm can be found all over the world. Earthworms do not have eyes or ears but they have a mouth and are sensitive to heat, light and touch. This adaptation is important to the survival of the earthworm. In the winter the earthworm travels deep in the soil to avoid the frost. In the hot summer the worm also travels deep into the soil in order to avoid dehydration. During the night an earthworm surfaces to let off their castings. The earthworm is a hermaphrodite. The earthworm eats decaying matter in the soil. They then let off castings which are good for plant growth.

Digestive System

The digestive tract of the earthworm is a straight tube which extends from the worm's mouth to its anus. It is differentiated into a pharynx, gizzard, crop, buccal cavity, intestine, and esophagus. Food enters through the mouth and is brought to the pharynx. The pharynx's muscular walls draw in food. In the pharynx, the pharyngeal glands secrete mucus. Food moves into the esophagus, where calcium is pumped in to maintain proper blood levels. From there the food passes into the crop and gizzard. In the gizzard, strong muscular contractions grind the food with the help of mineral particles ingested along with the food. Once through the gizzard, food continues through the intestine for digestion. The intestine secretes pepsin to digest proteins, cellulase to digest cellulose, lipase to digest fat, and amylase to digest polysaccharides. Instead of being coiled like a mammal's intestine, an earthworm's intestine is long and thin and has many folds running along its length.