Friday, February 22, 2008

Unit 1. Living and non-living

LIVING AND NON- LIVING THINGS

DISCOVERING CHARACTERISTICS OF LIVING THINGS:
Living things are sensitive to their environment. Non-living objects are not. For example, let us suppose that a grain of sand and a seed lie side by side in the ground. Let's now suppose that the earth becomes warmed by the Sun and moistened by the rain. The seed will respond by sprouting and in time will become a plant or a tree. The grain of sand however, remains the same. It may have moved a bit by wind or rain, but it hasn't changed in appearance in any way. The seed, unlike the grain of sand has reacted to the environment by growing.
Living things also respond to internal changes. For example, you quickly pull your hand away from a hot iron because of an impulse or feeling.
Living things are able to reproduce. People, snakes, insects, fish, or any other organisms have young which in time develop into adults. Trees produce seeds which will grow into an adult tree. Non-living things do not have this ability. Viruses cannot reproduce on their own and therefore are not living organisms.
http://msnucleus.org/membership/html/k-6/lc/organ/1/lco1_2a.html