Biodiversity: Diversity of Plants and Animals

Each organism in this world, whether it is a plant, an animal or a microorganisms ( viruses, bacteria, unicellular eukaryotes ), is unique in itself. This uniqueness of individuals forms the basis of the diversity among the living organisms.

The term “biodiversity” is a concise form of “Biological Diversity”. It was coined by Walter G. Rosen in 1986. Biodiversity refers to the diverse or varied forms of living beings which differ from one another in external appearance, size, colour pattern, internal structure, nutrition, behaviour, habitat, etc. Currently there are 1.7 to 1.8 million organisms, all of which are different from one another. They range in size from microorganisms bacteria, hardly a few micrometres in size, to blue whales ( about 30m in length ) and Redwood trees ( Sequoia ) of California ( about 100m in height ). Some pine trees (e.g., Pinus ) live for thousands of years while many insects such as mosquitoes have a life span of a few days. The diversity extends to habitat, habits, nutrition, forms, etc., of different organisms.

This bewildering variety of life around us has evolved on the earth over millions of years. However, we do not have more than a tiny fraction of this time to try and understand all these living organisms, so we cannot look at them one by one. instead, we look for similarities among the organisms which will allow us to put them into different classes and then study different classes or groups as a whole.