Earthworms

Earthworms are an organism which has been able to survive for millions of years due to the fact that they have been able to adapt to their surroundings in order to survive. Adaptation is an alternation or adjustment by which a species or individual improves its condition in relationship to its environment. Earthworms have adapted in many ways over the pass generations in order to improve reproduction, to get food and to improve their defenses.
Earthworms live in moist soil which contains organic matter. Earthworms do not have eyes or ears but they have a mouth and are sensitive to heat, light and touch. This adaptation is important to the survival of the earthworm. In the winter the earthworm travels deep in the soil to avoid the frost. In the hot summer the worm also travels deep into the soil in order to avoid dehydration. During the night an earthworm surfaces to let off their castings.
The earthworm moves by stretching it’s front section through the soil and then pulling it’s hind section up. The earthworm has two kinds of muscles that it uses to move. The circular muscles surround the worm’s body and can make the body shrink or spread out. The longitudinal muscles run along the length of the body and can shorten or lengthen the worm. An important adaptation for the movement of the worm are the setae. These are tiny bristles which cover the body of the worm and enable the worm to grip the soil as it passes through. This really helps the worm moves through the soil quickly without slipping.
The earthworm is a hermaphrodite. This means the earthworm contains both male and female reproductive organs. The eggs which contain yolk are buried in the earth in capsules formed from secretions of the clitellum. The clitellum is the thickened section of the body near the front end. The capsules protect the young until they hatch as worms. The fact that the earthworm is a hermaphrodite means the earthworm can easily reproduce which is an excellent adaptation. Another