What Are Characteristics Of Phylum Platyhelminthes?

This is a phylum of invertebrates. Its members are tripoblastic animals because their body is composed of three layers of cells. An outer ectoderm layer, a middle mesoderm layer and an inner endoderm layer. They are also known as flat worms because their bodies are thin, flattened and tape like. Some are free living but some are parasites. Parasites live in liver, stomach and intestine of other animals. They attach themselves to the walls of intestine of their hosts sucker and suck blood and food. Tape worms suck food from intestine and sometimes grows up to 40 feet in length. Mouth is present and anus is absent in them. Blood vascular system is absent in them. Most of them are bi-sexual.

Their common examples are Liver fluke, Tape worm and Planaria. For an example we discuss Liver fluke. It is a parasite. It has a leaf like structure. It lives in lungs, liver, stomach and intestines of its host. At the interior end of the body an oral sucker is present around the mouth. A sucker is also present at ventral side of the body by which it firmly attaches itself to the body for its host. It sucks food through oral sucker. The tissues of the body parts from where it sucks food are damaged producing ulcer or wounds. It has two parts of its life cycle. One of its parts is passed in man, sheep or goat and the other in the body of a snail. This parasite has two hosts one is man, sheep or goat and the other is snail.

Phylum Platyhelminthes come under non-vertebrate division. Platy means flat and helminthes means worms. These are also known as flatworms. There body is flat from both sides. They live as parasitic life. They have well developed suckers, hookers and other organized organs for parasitic mode of life. It is their adaptation that has made them able to pass life as parasite. They have degraded digestive system. They have well developed reproductive systems. Their body is well modified as a parasite. They also have complicated life cycles. They are multi-cellular and have a lot of cells in their body. They are triploblastic animals.
They have three classes all in all. All of them are flat in shape. They have degenerated eyes. They live in the body of host for long times. They are dioecious so they could produce more and more eggs to make colossal populations. This phylum is well known for parasites. They cause stomach diseases in human beings and other organisms. We may get them from the dust and dirt. Scientists have studied them deeply this is why today we have a lot of details with us. Hope you will get some more from biology books.

1-have no skeleton
digestive system is totally absent in tubellarian worms and tape worms but in termatoda it consist of mouth , pharynex and blind intestine
3- respiratry and circulautry system are absent
4- nervous system is premitive

Some characteristics are symmetry ,asexual and sexual production, live nearly everywhere, invertebrates, heterotrophs, From Kenneth Vaser

Phylum Platyhelminthes:
These phylums are called triloblastic because their body contains three layers of cells named as ectoderm, mesoderm and endoderm. They are also called flat worm because of their thin, fine and flexible body. Some of them live independently but most of them are parasites.

Parasites live in stomach, liver and intestines of other animals and stick to their walls with the help of sucker in order to get food and blood. Their most common examples are Liver fluke, tape worm and Planaria.

Liver fluke is one of the parasites. They shape look likes a leaf. It lives in lungs, stomach and intestines. An oral sucker is present around its mouth and on ventral side with the help of which it sticks itself to the host and sucks food with the oral suckers. The place where it sucks the tissues become damaged and wounded. Due to its blood sucking the body of animal becomes blood-deficient.
Tape worm is also a parasite. Its body is also lengthy, flexible and consists of pieces. The head is relatively large called scolex and contain suckers and a hook. This organism sticks it self into intestines of the animals. They have no eyes and body does not move New and new pieces form from the back of the head.

The head region has two eyes which are sensitive to lght and a...ganglion which is the equivalent of a very primitiv brain.

1- free living or parasitic worms
2-acoelomate .absence of true coelom
3-presence of great variety of adhesive secretions ,organs of attachment and adhesive hooks and suckers
4-body dorso-ventrally flattered and bilaterally symmetrical
5-body is covered with a cellular syncytial ,one layered partly ciliated epiderms ,while is parasitic

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