The Secret Life of a Teenage Earthworm
Where are they?
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
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.