Tuesday 29 May 2012

CHARACTERS OF LIVING THINGS


Characteristics of Living Beings

1. Growth: All living organisms grow in size and number. Some non-living things also grow. For example mountains develop over a period of time. But growth of non-living things is a result of accumulation of substances from outside. On the other hand growth of living beings comes from inside. A continuous process of cell division makes this growth possible. Most of the plants show growth in size throughout their life. But animals grow to a certain limit. After this the cell division facilitates repair in the organism. The growth from inside is also called organic growth.
2. Reproduction: All living beings reproduce their progeny. Progeny are more or less similar to their parents. Reproduction can be sexual or asexual. Most of the unicellular and less complex organisms reproduce by asexual methods. Multicellular and complex organisms reproduce by sexual methods. Reproduction by sexual method involves formation of male and female gametes and fusion of those gametes results in formation of zygotes, which ultimately give birth to the new progeny.
3. Metabolism: All living organisms are made of chemicals. These chemicals are constantly undergoing some change inside the body of a living organism. The process of this constant change is called metabolism. Metabolism can be classified in two types:
(a) Anabolism: The process which results in synthesis of something is called anabolism. Photosynthesis is a good example of anabolism as it involves synthesis of carbohydrates.
(b) Catabolism: The process which results in breaking down of a compound is called catabolism. Respiration is a good example of catabolism as it involves breaking down of carbohydrates into carbon-dioxide and water.
4. Response to Outside Stimuli: All living organisms show a response to outside stimulus. These stimuli can be light, heat, other organisms or chemicals. For example all green plants grow in the direction from which sunlight comes. All animals are sensitive to heat.

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