Classification
Platyhelminthes are classified as Acoelomates. Acoelomates are flatworms that lack a coelom, although nemerteans have a fluid-filled cavity at their anterior, or head, end, which is used to eject the proboscis rapidly. Diversity Other phylums have a body cavity, a specialized circulatory system, and respiratory system. Platyhelminthes has no body or specialized circulatory and respiratory system which restricts them to having flattened shapes. Life History Platyhelminthes have been around for 550 million years. They have flattened shapes allowing oxygen and nutrients to pass through their bodies by diffusion. Platyhelminthes can't feed because they have a digestive cavity with only one opening both for ingestion and egestion; which doesn't allow it to process food continuously. Platyhelminthes are hermaphroditic which means they each individually produce an egg and sperm. When two mate they exchange sperm so both become fertilized. Both of the flatworms reproduce creating newborns. Ecological Roles Flatworms are parasites that infect the bodies of humans and animals. They feed of the tissue and blood cells within the body. Flatworms cause disease in the body being fatal killing humans and animals. Human Impacts In a variety of cases humans use flatworms for losing weight and becoming healthier. After a person or patient has lost weight they kill the flatworm with medicine. Works Cited http://www.earthlife.net/inverts/platyhelminthes.html http://en.wikipedia.org/wiki/Flatworm |