Safari Ltd Life Cycle of a Worm
The nearly featureless brownish-red worms can be anywhere from 1-14 inches long, depending primarily on the environment. Their bodies consist of ringed segments called annuli which are covered with tiny bristles called setae. The translation of their Phylum name means ‘little rings’. The setae allow the worm to burrow through loose or wet soil, even though they have little strength. Worms have surprisingly complex systems, which is why they are often used in biology classes. They have five aortic arches, which are essentially hearts. They also have a complete digestive system, including an esophagus, gizzard, and intestines. They do, however, lack lungs and absorb oxygen through their skin. While popular myth holds that a worm can be cut into segments and those pieces will regenerate new worms, that is not the case. There are some studies into how much a worm can restore some minimal loss, but there is no real consensus on this ability.