Let's Get the Dirt on Earthworms

By Grace and Alya

This is the story of Eric the Earthworm, but first you'll need some background information on earthworms first.

Habitat

By having a specific niche, earthworms make use of conditions that are best suited to their survival. Although all earthworms have common characteristics, features like size, skin color, and quickness of movement reflect which niche different species occupy.


Earthworms live anywhere there is moist soil and dead plant material. They are most abundant in rainy forest areas, but can be found in many habitats on land and in freshwater. But at the end of the day, earthworm species need moist soil conditions to survive.


Most earthworms species live in the top meter of soil, and spend most of their time just below the surface where there is plenty of decomposing plant material. Some species emerge onto the surface at night when it is damp enough, but they’ll go deeper to avoid droughts or winter freezes. Others never even come to the surface, and spend their whole lives meters below the surface. Worm tunnels have been found to go at least 5 meters below the surface!

Adaptations of the Earthworm

    • One of the many adaptations an earthworm has is it's setae. 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.

    • Setae are tiny, bristle-like hairs that extend from most parts of the earthworm’s body. When retracted, the setae allow the earthworm to move freely through the soil.

    • An earthworm has no antennae fins, arms, or legs! They just have a streamlined shape. It’s an adaptation to living in narrow burrows underground. It supports their need to move easily through the soil.

    • 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.

    • Many worms survive when they lose posterior segments; some even regenerate the lost segments. The main use for the segments is locomotion. When an earthworm wants to move forward, it squeezes the muscles encircling his front segments to lengthen that portion of his body. It releases those muscles and contracts some in his middle section, lengthening it temporarily, followed by muscles in his rear segments.



    • 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.


    • 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.

    Lifestyle

    Seeing

    Worms have no eyes. They have light receptors, which help them tell between light and dark.

    Hearing

    Earthworms have no ears, but their bodies can sense the vibrations of animals moving nearby.

    Thinking and Feeling

    Worms have a brain that connects with nerves from their skin and muscles. Their nerves can detect light, vibrations, and even some tastes, where their muscles of make movements in response.

    How Do They Really Breathe?

    Worms breathe in oxygen and let out carbon dioxide, like humans. Since they don't have lungs like us, they breathe through their skin. Air dissolves on the mucus of their skin, meaning they have to stay moist in order to breathe. If they dry out, it just leads to suffocating.

    Process of Eating

    Worms do not have teeth, but their mouths are muscular and strong. 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 swallow pieces of dirt and decaying leaves, and the food passes through the pharynx, the esophagus, and into the crop, which stores food temporarily. The worm's stomach, gizzard, is very muscular and grinds up the food, moving into the intestine. In the intestine, food is broken down into usable chemicals which are absorbed into the bloodstream.

    Heart

    Worms don't have just one heart. They have FIVE! But their hearts and circulatory system aren't as complicated as ours.

    Moving Around

    Worms have two kinds of muscles beneath their skin. The outer layer of muscles are circular muscles, which decrease the diameter but stretch the length of the earthworm's 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 called setae. To move forward, this is what a worm does:

    • First it grips the soil with some of its back setae so its back part can't move.

    • Then it squeezes its circular muscles, which makes its body get longer. Since the back of the body is gripping the soil, the front part of the body moves forward.

    • Then the front setae grip the soil and the back setae let go.

    • Then the worm squeezes its longitudinal muscles, which makes its body shorter. The back part moves forward.

    Fun Facts About Earthworms!

    • A worm has no arms, legs or eyes.


    • In one acre of land, there can be more than a million earthworms.


    • The largest earthworm ever found was in South Africa and measured 22 feet from its nose to the tip of its tail.


    • Worms are cold-blooded animals.


    • Baby worms are not born. They hatch from cocoons smaller than a grain of rice.


    • They move away from light and will become paralyzed if exposed to light for too long.


    • If a worm’s skin dries out, it will die.


    • Worms can eat their weight each day.

    The Story of Eric the Earthworm

    It was a dark night. Not too hot, and not too cold, the perfect weather for an earthworm like Eric and his friends. "Hey Eric, do you wanna go hang out and feel some vibrations?" Efe said to Eric. "Dude of course, lets go get Ernie and go feel those vibrations together!" The three of them dug their way through the soil. It wasn’t long until they felt the sounds of their arch nemesis, the mole. “Hide! the moles will eat you alive!” Efe communicated, trying to warn the others. Together, they burrowed deeper into the soil, and stopped in a spot that they thought would be safe, using their setae. “I am so happy we have these small body diameters! This way, we don’t undermine soil!” They waited until the moles were gone, and decided to go eat some food. They found a nice pile of leaves and ate until they couldn't eat anymore. “Hmmm” Ernie thought, lets just call this a day and go home, it is getting pretty bright. We should get back before we dry out.” Knowing that Ernie was the smartest of the three worms, Eric and Efe listened to his advice, and headed home, ending their adventures. Ernie was a little bit ahead of Efe and Eric, when they suddenly heard his loud scream. When Efe and Eric squirmed quickly to check it out, they saw a huge mole eating him away. Eric almost screamed like his usual girl scream, but Efe stopped him and told him they had to get out of their before the mole spotted them. Even though they were struck by the horrible sight, they survived and lived their life as the usual, watching the two-leg’s pokemon on their TV day and night.