Earthworms have survived for millions of years due to their ability to adapt to the environment. Kids enjoy learning about adaptations of earthworms and the important role they play in the environment through conducting studies and experiments. Earthworms have adapted their physical bodies to move through the soil to break down organic materials and become the earth's most important recyclers. Once students learn that earthworms are an essential part of soil decomposition and the growth of healthy food crops, they gain a new respect for them.
Learning about earthworms and their contribution and adaptation to our ecosystem enlightens students. Start by studying an actual earthworm. See if the students can tell the head from the tail. Go over the anatomy of an earthworm and discuss why it moves the way it does. Have the students watch how the earthworms move and burrow into the dirt. An important adaptation that allows earthworms to move is the setae. Setae are microscopic bristles covering the worm body, which enable them to grip the soil and move through it quickly.
Building an earthworm habitat is an excellent way of teaching students about adaptations of earthworms. An earthworm habitat can be made out of any clear container, such as an aquarium or a large glass or plastic jar. Put some gravel in the bottom of the container, then fill it with potting soil almost to the top. Place some worms on the dirt and watch them tunnel their way down. Put a layer of dry leaves over the dirt and cover that with several wet kitchen towels. Tape heavy black construction paper all the way around the outside of the aquarium. Earthworms are sensitive to light and do not go to the top of the aquarium to decompose the leaves if it is not dark. After three days, unwrap the aquarium and be amazed at the tunnels the worms made. Remove the wet towels to reveal the decomposed leaves.
Sensitivity to Light, Touch and Temperature
Earthworms do not have eyes or ears, so they adapted sensitivities to light, temperature and touch. Earthworms need to move deep into the soil during the day so they can stay cool and moist. At night, they move to the surface to remove their castings. Castings are the excrement from the worm's digestive system. Earthworms can sense light and cooler temperatures deep in the soil and know when it is safe to move to the surface. Finding an earthworm at the surface of the soil is easiest at night or very early in the morning. To teach the students about earthworm sensitivity to temperature, light and touch, have the students conduct experiments using different types of stimuli such as a flashlight or droplets of water.
Make a Compost Bin
Worms are our most important recyclers. An earthworms diet is made up of old and decaying organic matter. Students can put to use their knowledge of earthworms and build a school compost bin. Students can throw their organic trash such as orange peels, apple cores and carrot sticks in the compost bin and watch the worms turn the matter into soil. Use the soil to plant seeds to take home for a garden.