ANNELIDS Worms Kingdom- Animalia Phylum- Annelida

Bilateral Symmetry: Each side of the body of the worm is a mirror image of the other side.

Flatworms Flatworms have flattened bodies and are members of the phylum Platyhelminthes. Two flatworms are the planarian and the tapeworm.

Flatworms Flattened body, a digestive system with only ONE opening and a simple nervous system. Example: Planarian ~ less that an 1 inch. ~ live in freshwater. ~ reproduced by mating and laying eggs. ~ can regeneration

Flatworms Planarian

The Planarian Planarians are free-living. They only have one body opening (a mouth). The pharynx connects the mouth and the digestive tract. They can reproduce asexually by dividing in two. They can also regenerate. They can reproduce sexually by producing eggs or sperm.

Roundworms Roundworms belong to the largest phylum of worms, the phylum Nematoda. Many roundworms are parasitic, but most are free-living. Nematodes have two body openings, a mouth and an anus.

Roundworms Roundworms have a round, tube-like body. Most can NOT be seen without a microscope. A shovelful of dirt can contain about 1 million roundworms. ~ digestive system 2 openings ~ a mouth to take in food, the other to expel waste ~ nervous system with a brain ~ reproduces sexually ~ many harm other organisms in which they live and feed

Roundworm Parasites- Hookworm Hookworms use their sharp teeth to burrow into the wall of the small intestine. Humans get hookworm by walking barefoot over dirt or through fields. The best way to prevent hookworm infection is by wearing shoes.

Roundworm Parasites- Ascaris Ascaris is found in the intestines of pigs, horses, and humans. Enter the hosts body in contaminated food or water. Can block the intestines and cause death if left untreated.

Parasite Worms Parasite worms survive by living on or in another animal and feeding on that animal. ~ flatworms and roundworms are parasite worms ~Trichinella which are common roundworms that live in pigs. It can be past on to humans who eat undercooked pork.

Roundworm Parasites- Trichinella Trichinella cause the disease trichinosis. Humans become infected when they eat undercooked pork that has trichinella cysts (young worm with a protective covering). Trichinosis can be prevented by thoroughly cooking pork.

The Tapeworm Tapeworms are parasites. They use hooks and suckers to attach themselves to the intestine of a host organism. Tapeworms don’t have mouths or digestive systems. To reproduce a tapeworm will fertilize eggs in a segment then the segment will break off and be passed out of the host’s body.

On the Lighter Side…

Segmented Worms Segmented worms belong to the Phylum Annelida. Annelid means “little rings” and describes the segments that makeup the body of these worms. Some members of the annelid phylum are… Earthworm Leeches Marine Worms

Roundworm Parasites- Heartworms Heartworms enter the blood of a dog through a mosquito bite. They grow and reproduce in the heart. If left untreated they can block the valves of the heart. Medicine can be given to dogs to prevent heartworm disease.

Setae On the outside of each segment, annelids have little bristle-like structures called setae that help them move. Segmented worms also use the setae to help them stay in the soil if a bird gets a hold of them!

Earthworms Earthworms eat soil. They use their crop for storage and their gizzard to grind the soil. Digested food moves to the intestine where it is broken down and absorbed by the blood. Undigested soil and waste leave the worm through the anus.

The "medicinal leech" feeding on blood from a human arm. Leeches Leeches feed on the blood of animals- including humans. They have two suckers that they use to attach to the animal. It will then cut into the flesh and suck out blood. Leeches produce an anesthetic so that the animal doesn’t feel the bite. For centuries leeches were used for blood letting because of the mistaken belief that bodily disorders and fevers were caused by an excess of blood. Today leeches are used to keep blood flowing to reattach body parts. The "medicinal leech" feeding on blood from a human arm.

Marine Worms Marine worms also have segments with setae. Some marine worms trap food in tentacles. Others build tubes to hide in.