Earthworm

From CreationWiki, the encyclopedia of creation science

Earthworm

Scientific Classification
Kingdom: Animalia Phylum: Annelida Class: Clitellata Order: Haplotaxida Suborder: Lumbricina
Families
Acanthodrilidae Ailoscolecidae Alluroididae Almidae Biwadrilidae Eudrilidae Exxidae Glossoscolecidae Lumbricidae Lutodrilidae Megascolecidae Microchaetidae Ocnerodrilidae Octochaetidae Sparganophilidae

Earthworms, as their name implies, live in earthen matter. There are over 3000 species, which belong to the phylum annelida along with the leech.

Earthworms are extremely beneficial in the production of organic-rich top soils. As they digest organic matter they discard waste known as worm casting, which are used by farmers and gardeners to improve top soil quality. As the worm pushes its way through soil it also creates passages allowing oxygen and water to reach deep into the soil.

Overall, earthworms provide a positive impact on the lives of humans who grow fruits and grains, by generating soil aeration, drainage, and fertilization.

Anatomy

Anatomy of the earthworm.

The most complex part of the earthworm is the segments. Usually earthworms are divided into 95~200 segments. Some of the segments have different functions. One intriguing aspect of the worms is that they have five pairs of hearts distributed through these segments. The Earthworm's first segment(head part) consists of a mouth sac. The mouth sac is used to protect the mouth as the worm moves through cracks in the soil. The earthworms use setae to shift their position by extension and contraction. Earthworms can dig through soil easily with their smoothly rounded body shape, and they also release a lubricating liquid that helps them to move. Earthworms eat organic soil material commonly considered garbage by humans. The soil enters the earthworm's mouth and is mixed by the creature's muscles while being simultaneously broken down to small components by digestive fluids. Anything not converted into energy is released out the tail in the form of "worm castings."[1]

Reproduction

Mate free earthworms.

Earthworms are hermaphroditic which means they have both female and male reproductive organs. During mating, two earthworms bind together, and exchange sperms. They then separate, and after a time each forms a cocoon around the clitellum band, where the fertilized eggs are laid. When the cocoon is ready, the adult worm backs out of it and the ends of the cocoon seal to provide an incubator for the developing baby earthworms. Small earthworms usually come out the cocoon after 2~4 weeks, after 60~90 days reproductive parts of the earthworm develop, and growth is completed after about 1 year. Earthworm reproduction is miraculous. [2]

Ecology

Whether an earthworm can survive in the soil is largely dependent on the pH level, with many preferring neutral or slight acidity. Earthworms are divided into perennial and annual types. Perennials are known to live 9-10 years. Annual worms have very specific life cycles, hatching around March-April and growing until August-September, after which they go on to produce eggs. These are also susceptible to cold and will die with a significant enough drop in temperature. During the day, annual worms live underground, but during the night they will expose parts of their bodies above ground in order to eat biodegradable surface waste. Sometimes, the worms will draw portions of these meals into their tunnels.[3] Rainfall causes earthworm deaths through asphyxiation, but can also kill by creating a situation which leads to UV exposure. As water floods the worm tunnels, the worms move above ground, where they become paralyzed from the ultraviolet light, dehydrate, and die.[4] The earthworms also have many predators, from birds to moles, though farmers generally see the worms as beneficial to the soil, particularly in organic farming. Some businesses operate by raising worms and selling them to farmers, as well as to fishermen.[5]