Unearthing a Dissection
As a decomposer, it has a huge influence.
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 esophagus 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).
2.) Toy, Andrew. "The Anatomy of an Earthworm (Lumbricus Terrestris)." Earthworm - Circulatory System. N.p., n.d. Web. 7 Apr. 2014.
3.) "Lecture 2." Lecture 2. N.p., n.d. Web. 07 Apr. 2014.
4.) "Earthworm Labeling Answer Key." Earthworm Labeling Answer Key. Biology Corner, n.d. Web. 07 Apr. 2014.