Wacky Worms

The Secret Life of a Teenage Earthworm

Where are they?

Earthworms and their aquatic relatives are found all over the world. There are several thousand species! Most live in muck and mud around freshwater, but some live under the sea, and many live in the soil on land. Earthworms and their relatives live anywhere there is moist soil and dead plant material. Earthworms are mostly found in rainy forest areas, but can be found in many habitats on land and in freshwater. In summary, they can be found in moist climates.

Earthworms Adapting

Earthworms n their habitat

Structural Adapations

Each segment on an earthworm’s body has a number of bristly hairs, called setae. These hairs provide some grip to help the earthworm move through the soil. An earthworm has a body with no antennae, fins, arms or legs. This shape is an adaptation to living in narrow burrows underground and the need to move easily through the soil. An earthworm has circular muscles that surround each body segment. It also has longitudinal muscles that run the length of its body. These two groups of muscles work together to help the earthworm move. In order to get food into its mouth, an earthworm pushes its pharynx out of its mouth to grasp hold of its food. It then pulls the food back into its mouth and wets it with saliva.

Physiological Adaptations of Earthworms

Many earthworms secrete a mucus that helps them to move more easily through the soil. In some burrowing species, the mucus forms a cement-like substance that lines their burrows to help keep the walls from collapsing in. When the environmental conditions in an earthworm’s habitat change, for example, the soil becomes too hot or too dry, many earthworms become inactive in a process called aestivatio. They move deeper into the soil, coil into a tight ball, excrete a protective mucus and lower their metabolic rate in order to reduce water loss. They will remain like this until conditions become favorable again.

Behavioural Adaptations of Earthworms

Earthworms cannot see or hear but they are sensitive to vibrations. Birds looking for food or humans collecting earthworms for bait stamp on or vibrate the ground in some manner, causing earthworms to move to the surface. Perhaps this is to escape from moles, whose primary food is earthworms. Earthworms are sensitive to light. Most species spend their days in their burrows or in the soil or leaf litter. In general, you usually find them on the surface at night. Earthworms lose moisture through their skin. They move out of their burrows to migrate or reproduce when the ground is wet with dew – one reason why we may see them in the early morning.

Summary of Adaptions

Earthworms have different ways to adapt to their environment. Their skin camouflages them and helps them to blend in with the soil, while their skin stays moist so that oxygen can get through to them. They can adjust their bodies so that only a certain amount of liquid is leaving their body at a time. Their pointed heads can shovel through soil and in the winter they sleep only coming out when things are thawed and warm once more. They don't have a backbone so they are able to move their body as many positions as they like, due to their environment. Each segment of an earthworm contains bristly hairs that aid in movement.

The Amazing World Of Earthworms In The UK - Springwatch - BBC Two

Living the Worm Life

The Challenging Life

Earthworms have no eyes, but they do have light receptors and can tell when they are in the dark. Earthworms have no ears, but their bodies can sense the vibrations of animals moving nearby. Worms breathe air in and carbon dioxide out through their skin. Worms do not have teeth, but their mouths are muscular and strong. Night crawlers can pull leaves into their burrows using their strong mouths. The front end of the worm, its prostomium, is pointed and firm, making it easy for worms to push their way into crevices as they eat their way through their burrows. Worms don't have kidneys, but they have nephridia to filter out the dead cells and other wastes that are in the blood. Worms don't have just one heart. They have FIVE! But their hearts and circulatory system aren't as complicated as ours -- maybe because their blood doesn't have to go to so many body parts. Worms have two kinds of muscles beneath their skin. The outer layer of muscles are circular muscles, which decrease the diameter of the worm but stretch the length of the body when contracted. The inner layer of muscles are longitudinal, which shorten but widen the body when contracted. Every segment of a worm's body (except the first and last) has four pairs of tiny, stiff hair called setae.

Reproduction and Lifestyle of Earthworms

The Earthworm

Fun Fact

If an earthworm's brain is removed, changes in its general behavior are hardly noticeable.