Worms


Body Structure


worm.jpg The body of the worm is cylindrical except for being a little flat on the top. The belly side may be used in movement. Matured worms have a band called the clitellum which makes the egg capsule. Every worm has the same building plan, "A tube within a tube." The inner tube is the digestive track. The outer tube, the body wall, is made out of two layers of muscle. The fluid filled sack between the two tubes has inside of it a circulatory system, a nervous system, kidneys, and its reproductive organs. The worm is a very well organized animal! It has no arms, legs, or eyes.
Body Parts:
Pharynx: (throat) used to be pushed out of the mouth and grab food.
Esophagus: The tube that carries the food down towards the crop.
Crop: The crop is the storage area for the worms food. Once the food leaves the crop, it heads to the gizzard.
Gizzard: this is where the worm grinds up his food. He may even use rocks that he has swallowed to help with the grinding. These muscles work kind of like teeth.
Intestine: Once the food is all ground up, it moves down to the intestine where the digestive juices break it down even more.
Bloodstream: Now that the leaf is digested, some parts of it will move into the worms blood stream.
Anus: Whatever is leftover from the leaf comes out the anus as castings or worm droppings.

Obtaining Food


Red_Worms.jpg
Our Composting Friends
Most worms obtain their food from their hosts. Worms eat all sorts of things, they eat corn, left over food, they eat pasta salad, they do not eat kinds of ice cream, and they also eat apples. They love eating through the apple in a tube like motion. The mouths of worm are very small. Sometimes the food they eat is too big for their mouth, so they moisten it and then suck it in through their mouth. Worms eat dirt and sand that contain organic material for nutrients. It all depends on where the worm lives. The depth of the soil determines what foods a earth worm eats. Worms that live at the surface eat decaying plants and leaves that are decaying. They return the nutrients to the soil. Earthworms can eat their own body weight in 24 hours and create the same amount of castings. Castings are rich in nutrients and they are returned to the soil from the worms. They also eat algae, bacteria, and parasites. They keep a balanced level of bacteria and parasites by eating them. Most of the organic material in the soil is eaten and recycled by earthworms.


Reproduction


The two worms line up with their heads facing opposite directions. The worms release slime which covers both worms. They are now enclosed in a slime tube. The worms next release a sperm. The sperm is carried to the other worm. This is how the eggs of the worms becomes fertilized. Later, once the eggs in the egg tube are ready, the saddle on the worm begins to slide up the worms body. The saddle reaches the egg tube and six eggs fall in. The saddle goes over the worms head and the ends close up to form into a cocoon. The cocoon protects the eggs until they are ready to hatch.

Movement


Worms differ in their abilities to move on their own. Many have bodies with no major muscles, and can't move on their own. They must be moved by forces or other animals in their environment. Many other species have bodies with major muscles and can move on their own; they're a type of muscular hydrostat. Some like segmented worms contract and then push their body through the soil. One of these worms is the earth worm. By using it's segments it can go in the ground very deep.

Adaptations


Worms are commonly found in wet or damp conditions like soil and water. To hide from there enemies, worms are found in logs, rocks or even in burrows of other animals that are friends. To keep fed, they are found in sacks of grains which the farmers hate. They are also very slimey so they can get away from there predtitors.

Importance to Humans


wormsAtWork.gif Our soil depends on earthworms and our plants depend on soil. We depend on plants to give us food and oxygen. They break down and compost dead materials and recycle them back to the soil. The break down inorganic materials and aerate the soil. In return they give back fertile, clean soil. They naturally "clean up" and recycle the soil. As they crawl they create pathways in the soil that help the soil take in water and air. The more water and air soil has the more likely a plant growing there is to survive. Earthworm castings are very rich in nutrients and are rich with calcium, nitrogen, and potassium. It is proven that earthworms increase crop growth. They help plants grow which produce oxygen for us. They eat dead materials and soil. They can digest their own weight in material in one day. They are used for composting and they make worm castings which is used for gardening.

Phylums


Nematoda

They were originally name nematoidea in 1808. They were again renamed in 1837, then renamed again to nematoda in 1861. They are also known as roundworms and are found in Antarctica and ocean trenches.

Platyhelminthes

They are found in marine, freshwater,and even damp terrestrial environments. They are the largest acoelomates. The body is ribbon-shaped and it is the simplest animal with organs. They can range in sizes from microscopic to over 20m long. Platyhelminthes are very well known as "flatworms" because of their paper-thin bodies. They also have a spongy structure!

Annelida

Their bodies and coelom give them evolutionary advantages over other worms. The coelom in their body is divided into a sequence of compartments by walls called septa. They can be found in most wet environments and many terrestrial, freshwater, and especially marine species. As well as some which are parasitic or mutualistic.

Sources:

http://www.urbanext.uiuc.edu/worms/anatomy/anatomy9.html
http://www.infoplease.info/ce6/sci/A0839338.html
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