The earthworm is a very important part of the animal system because it contributes to healthy soil. It does this by borrowing through the soil to help keep it aerated and because the worms waste is full of nutrients.
The respiratory system of the worm is very different from that of our own because the worms have no lungs. The worm breathes by diffusion occurring between the skin and the air. In order for this to occur the skin of the worm must always remain moist. This is why the worm must stay in the soil during the night and only traveling on the ground in the night when it is cooler and their skin is less likely to dry up. This is why in the morning you might see a dried up worm on the sidewalk, because he tried to travel to far away from soil during the night and his skin dried up in the sun. |