Wiggling Inside an Earthworm

Earthworm Dissection Lab

Cecilia Compean




- Describe the appearance of various organs found in the earthworm.

- Name the organs that make up various system in the earthworm.

Background Information

The earthworm, Lumbricus terrestris, is a memeber 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. One of the main predators of the earthworms are birds.

Earthworm Circulatory System

The earthworm like many more complex organisms has a closed circulatory system, meaning that its blood is confined to blood vessels and its blood is recirculated so it gets maximum use. An earthworm has neither lungs nor gills but uses its body's great surface area to absorb oxygen from the soil. The oxygen is taken in by the dorsal blood vessel and travels to the five aortic arches (hearts) by the esophogus where it is pumped to the lower, ventral blood vessel. The ventral blood vessel pumps the blood to all segments and organs in need of oxygen. In each segment, there is a small blood vessel that sends the blood from the ventral blood vessel back to the dorsal blood vessel, thus completing the loop (Musurca).

Other Info

-There are approximately 2,700 kinds of earthworms

-The largest earthworm was found in South Africa and measured about 22ft

-Charles Darwin spent 39 years studying earthworms

-Worms are cold-blooded animals