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Earthworm Ecology
Earthworm Ecology An earthworm is a term for some of the largest members of the class or subclass Oligochaeta which is part of the phylum Annelida. The body of the earthworm is basically a tube made of muscle that encloses another tube which is the digestive system. The body is annular which means that it is composed of segments. These segments are more specialized towards the front of the earthworm. The circulatory system of the earthworm is a simple affair with two major blood vessels extending through their bodies. The ventral blood vessel carries blood to the posterior end and the dorsal vessel which is contractile carries blood to the anterior end. The typical earthworm has five aortic arches which serve as its hearts. The blood is distributed by capillaries on the body wall and into the organs. Earthworms move by means of rhythmic muscular contractions. These muscular contractions alternately lengthen and shorten the worm’s body. When the worm’s body lengthens the forward part is anchored to the surrounding soil by setae which are tiny claw like bristles. When the body shortens the unanchored part is pulled forward. This whole process is facilitated by with the secretion of lubricating mucus. When earthworms tunnel through the soil and create their tiny tunnels the effect is much the same as plowing the soil. These tunnels can provide channels for air and water to pass through more easily. This tunneling allows air and water carrying nutrients to circulate more freely. This process is important because much as we do soil microorganisms and plant roots need air and water. Unplowed soil becomes compact and air and water cannot circulate. Plant roots also need plowed soil for optimal penetration. Additionally earthworm droppings which are called castings are rich in nitrogen, calcium, magnesium, and phosphorus which are necessary nutrients for a healthy, thriving ecosystem. Studies have also shown that every year on an acre of average cultivated land 16,000 pounds of soil pass through the digestive systems of earthworms and end up above the soil. On really wormy land the volume can even reach 30,000 pounds per year. In forests ecosystems some species of earthworms can consume all kinds of organic waste on the surface in as little as several weeks. Incorporation and consumption of surface waste by earthworms is theorized to be an important function of earthworms in no- tillage agricultural ecosystems like forests.
Define Ecology
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