By Majela Fonseca & Franco Figueroa

FLATWORMS

The flatworms are scientifically known as Platyhelminthes or Plathelminthes. From the worms group, flatworms are the simplest. They are free living or parasitic. The three main types are: Tapeworms, flukes, planerians.

Introduction

They are made of three layers.They are soft-bodied invertebrate animals. They don’t have a body cavity. They get rid of waste through the same

opening it takes food in because it has a combination digestive/excretory.

They have a bilateral symmetry.They also have a simple nervous system with

two nerve cords running down either side. They don’t have a respiratory system but they

take in oxygen.

Morphology

Most Flatworms have both female and male reproductive organs.

During sexual reproduction, two worms join and deliver sperm to each other.

Then, the eggs are laidIn asexual reproduction, fission occurs.The organ splits in two, and each half become

a grown organism.

Life Cycle

They have three main types: Turbellarians, Flukes, and Tapeworms.

Turbellarians are free-living flatworms, and live in fresh or marine water.

Flukes are parasitic flatworms and infect the internal organs.

Tapeworms are parasitic worms that live in the intestines of their host. They are long and flat. They are adapted to life inside the intestines.

Groups of Flatworms

The planarian Endeavouria Sepetemlineata, a non-parasitic flatworm, is used to control the giant African land snail.

Human Uses

More than half of flatworms’ species are parasitic.

Some of them cause severe diseases to human and affect their livestock.

It causes Schistosomiasis, also know as snail fever. It is one of the most dangerous parasitic diseases in tropical countries, after Malaria.

 This diseases have a low mortality rate, but usually are chronic illness that affect internal organs.

It also causes losses of stocks in fish farms.

Effect of Humans