Facts On Earthworms -Erica Chen

Vu - PreAP Biology - April 6, 2014 - Period 3

Objective: Students will be learning the anatomy of an earthworm specifically the organs, functions, and interactions of the earthworm’s digestive system.


Earthworms belong to phylum Annelids. In Latin, Annelida means "little rings". They live in areas of moist soils that contain organic matter where they eat decaying matters. Its predators are arthropods, birds, and mammals. Earthworms ecological niche is to provide channels for root growth, increase water and air infiltration, break down organic matter and release nutrients.



  • Setae are bristly hairs that provides grip to help earthworm move through soil
  • Earthworm's streamlined body with no antennae, fin, arms or legs helps them live in narrow burrows underground and makes moving easier
  • Earthworm has circular muscle that surround each body segment. It also has longitudinal muscles that run the lengths of its body. Those muscle also helps with movement.


  • Mucus or coelomic fluid helps them move smoothly through soil
  • When environmental condition is not favorable, earthworms can become inactive in a process called aestivation


  • Earthworms react to vibration. When they feel predator, they will move away.
  • Earthworms are sensitive toward light and are usually seen on soil surface at night
  • Earthworms lose moisture through their skin so they move out of their burrow to migrate and reproduce when the ground is wet with dew. This is one reason why they can be seen in the early morning.


Kingdom: Animalia

Phylum: Annelida

Class: Clitellata

Order: Haplotaxida

Family: Lambricicdae

Genus: Lumbricus

Species: Terrestris

Evolutionary History and Relationships

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Lab Dissection

Earthworm Anatomy

Digestive System

The digestive tract of the earthworm is a long, straight tube. The mouth leads into a strong, muscular pharynx, which acts like a suction cup, helping the mouth to draw in organic matter. The narrow section of the digestive tract posterior to the pharynx, the esophagus, leads to the crop, where food is stored. In the gizzard, which is thick, muscular walls lined with protective cuticles, the food is ground up with the help of the ever-present soil particles. The rest of the digestive tract is made up of a long intestine.

Digestive System Interaction

Earthworm Digestive & Circulatory Systems

Interesting Fun Facts

  • A worm has no arms, legs or eyes.

  • There are approximately 2,700 different kinds of worms

  • In one acre of land, there can be more than a million earthworms

  • The largest earthworm ever found was in South Africa and was measured 22 feet.

  • Charles Darwin spent 39 years studying earthworms

  • Worms are cold-blooded animals

  • Earthworms have the ability to replace or replicate lost segments.

  • Baby worms hatch from cocoons smaller than a grain of rice

  • Even though worms don't have eyes, they can sense light

  • If a worm's skin dries out, it will die

  • Worms are hermaphrodites. Each worm has both male and female organs.

  • Worms can eat their weight each day