A Day in the Life of an Earthworm

Ever Wondered How Earthworms Digest?

Objectives

Explore the anatomy of an earthworm an discover how the earthworm digests its' food.

All About an Earthworm

The scientific name for an earthworm is Lumbricus terrestris. It belongs to the Phylum Annelid which introduced segmented appendages. Earthworms are most commonly found in warm, moist habitats, which is why they like to live under the surface of the soil. Though earthworms don't get much attention they do have an ecological niche or "greater purpose". Earthworms aerate the soil aiding in decomposition. As well as serving as prey to many animals such as snakes, birds, rodents, flatworms, and some insects. Although animals seem to always want to prey on the earthworm, the earthworm has some pretty snazzy adaptations. For one thing earthworms have camouflaged skin that blends in with the soil. They also have moist skin that allows oxygen to pass through, as well as pointed heads to cut through the soil! Humans and earthworms however, seem to have a rocky relationship. Earthworms are often killed by man plowing through their fields, pesticides, chemical fertilizers, and of course used as bait for fisherman.

How does an Earthworm Digest its' Food?

Food in an earthworm literally goes in from one end and out another. The journey the food takes to get there is the interesting part. An earthworm eats the food by using a hand-like mouth . Earthworms usually eat dead grass, leaves, and weeds. They also ingest soil particles to help the lips break up food into small particles. The food particles then travel to the pharynx where food is lubricated by various mucus secretions. The food particles then pass into the esophagus where calcium carbonate is added to help neutralize the acids found after food decays. Food is then temporarily stored in the crop, where it will mix together. The actual digestion then begins in the gizzard. The gizzard will turn and mix the food and soil particles into a thick paste. Glands in the gizzard will add enzymes aiding in the chemical breakdown of the organic material. The mixture is then sent to the intestine that is lined with thousands of finger-like structures filled with small blood vessels that absorb the liquified food. Any soil particles and undigested matter left are passed out through the anus. This waste is called a worm cast which is enriched and neutralized making it a perfect fertilizer. Worms and their digestion help fertilize the soil!

Works Cited


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