Worms are long, wriggling, tube-like animals. Annelids are worms such as the earthworm whose bodies are divided into segments.
There are 15,000 species of annelid. Most live underground in tunnels, or in the sea.
The world’s largest earthworm is the giant earthworm of South Africa, which can grow to as long as 6.5 m when fully extended.
Earthworms spend their lives burrowing through soil. Soil goes in the mouth end, passes through the gut and comes out at the tail end.
An earthworm is both male and female (hermaphrodite), and after two earthworms mate, both develop eggs.
Plants would not grow half as well without earthworms to aerate the soil as they burrow in it, mix up the layers and make it more fertile with their droppings.
Over half the annelid species are marine (sea) bristleworms, such as ragworms and lugworms. They are named because they are covered in bristles, which they use to paddle over the seabed or dig into the mud.
The sea mouse is a mouse-shaped bristleworm with furry hairs.
Flatworms look like ribbons or as though an annelid worm has been ironed flat. Their bodies do not have proper segments. Of the thousands of flatworm species, many live in the sea or in pond algae.
Flukes are flatworms that live as parasites inside other animals. Diseases like bilharzia are caused by flukes.
Tapeworms are parasitic flatworms that live inside their host’s gut and eat their food.