An Earthworm's Guide to Surviving
By. Varenya S. & Brinda B. - Mrs. Stokes - Period 5
Earthworm Background Information
Suborder: Lumbricina & Moniligastrida
The basic shape of earthworms is a cylindrical tube. Their bodies are divided into segments. Earthworms have bilateral symmetry. Adults have a swelling called the clitellum. The topside of earthworms is called the dorsal; the bottom side is the ventral. The periproct is the last segment of an earthworm's body. Each segment (except the first and last) have tiny, bristlelike structures called setae. Setae help the earthworm sense the environment. The epidermis is the skin of the earthworm. It is also the outer layer.
Earthworms have no eyes. They use light receptors to tell whether they are in light or in dark.
Though earthworms don't have ears, their bodies can sense the vibrations of animals nearby.
Thinking & Feeling
Worms have a brain that connects with nerves from their skin and muscles. Their nerves can detect light, vibrations, and even some tastes, and the muscles of their bodies make movements in response.
Though they don't have lungs, earthworms breathe in and out just like us. They breathe using their skin! Air dissolves on the mucus of their skin, so they have to stay moist to breathe. If worms dry out, they suffocate. Acccording to www. learner.org, "As fresh air is taken in through the skin, oxygen is drawn into the worm's circulatory system, and the worm's hearts pump the oxygenated blood to the head area. The movements of the worm's body make the blood flow back to the back end of the body, and the hearts pump the blood forward again. Carbon dioxide dissolves out of the blood back to the skin. "
Worms may not have teeth, but their mouths are muscular and strong. The mouth of the worm is behind their prostomium. Worms swallow pieces of dirt and decaying leaves, and the food passes through the pharynx, the esophagus, and into the crop, which stores food temporarily. The worm's stomach is very muscular. It grinds up the food, which then moves into the intestine. In the intestine, food is broken down into usable chemicals which are absorbed into the bloodstream. Leftover soil particles and undigested organic matter pass out of the worm through the rectum and anus in the form of castings (basically worm poop). Casting is dark, moist, soil-colored, and very rich in nutrients. That's why farmers and gardeners like to have lots of worms in their soil.
Earthworms have setae, which provides them with some grip to move through soil.
Earthworms have a stream-lined body. This streamlined shape is an adaptation to living in narrow burrows underground and the need to move easily through the soil.
An earthworm has circular muscles that surround each body segment. It also has longitudinal muscles that run the length of its body. These two groups of muscles work together to help the earthworm move.
Earthworms have adapted to become more sensitive. They can't see or hear, but they can sense a predator's movement. They are also sensitive to light.
Earthworms secrete mucus (coelomic fluid) that helps them move through soil easily.
The main habitat of earthworms is in soil. The brandling worm "Eisenia fetida" lives in decaying plant matter and manure. "Arctiostrotus vancouverensis" is generally found in decaying conifer logs. "Aporrectodea limicola", "Sparganophilus", and several others are found in mud in streams. Some species are arboreal, some aquatic and some are salt-water tolerant. Some are littoral (living on the sea-shore). " Pontodrilus litoralis", for example, is littoral.
What is Their Niche?
Earthworms are beneficial creatures. They improve soil wherever they go by providing a natural means of aeration. As they move through the ground, they create tunnels. Air and water then pass through these tunnels to the roots of plants. They break down organic matter such as leaves and litter and excrete nitrogen-rich waste that fertilizes the soil. Basically, it aerates the soil which aids in decomposition. It also uses partially decomposed soil as a food source, furthering the decomposition.
Now's the Time to Test Your Skills!
Hi, there! Emily the earthworm here. I hope you were paying attention to the information above because I have a quiz for you!