|MadSci Network: General Biology|
Hello Lisa, I apologize for the delay, but it seems as though the question bounced off a few people before me. Well, the questions were very good, I'm glad to hear of your students being so inquisitive about science and nature. So lets get to the answers... The first question asked was whether or not an earthworm could regrow segments of its body if it got cut into 2 or more pieces. I would have to say no, because a worm has internal organs, a neural cord, and a simplified circulatory system, which means that if we slice them up, important systems to the worm's life functions are stopped and the worm would not survive. An earthworm's organs include a simple heart, a digestive system, and a very simple brain. Next was a question about whether or not they have noses. Earthworms don't actually have noses since they only have one sensory organ, which is the sense of touch. They also wanted to know what earthworms do in the winter. Earthworms need to live in moist soil containing organic matter to provide them with food. They burrow and "eat" large amounts of soil as they go. Once they've eaten the soil, their digestive system takes out things like vegetable remains and nutrients. Earthworms normally live in the upper layers of the soil, but when the winter comes they burrow much deeper to escape the frost. Similiarly, earthworms will burrow deeply into the soil when the weather gets hot so they can avoid drying up (dehydration) and stay cool. Earthworms also like to avoid sunlight and so they sometimes come out at night to feed and shed their skin. They will also surface and come out under unusual conditions like when there are heavy rains since their burrows get flooded. They can also burrow quite fast because of a set of little bristles on the sides of their bodies which enable them to move around. Earthworms actually have one brain as we know it. The question as to whether they have nine of them or not is understandable, because a worm's nervous system consists of a simple brain, a neural cord, and a bunch of segments of nerves all along their body called ganglia, which are classified as somewhat similiar to the brain material. Some cool facts for them: ---There are over 1000 different kinds of earthworms. ---Earthworms are generally uniform in color, pale red, but can also vary from dull pink to dark brown. ---Many types of earthworms grow to only a few centimeters long, but some tropical types can grow to as long as 11 feet! ---Some types can live for ten years or longer. I hope this helped you out Lisa. If your students would like to send us questions directly, they should definitely be encouraged. We have alot of good people who can answer their questions in a way that they can understand. Tye Morancy
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