The variety of flora and fauna in a particular habitat or the globe is called biodiversity. Basically, it is a way to measure the differences and variations among the organisms at genetic, species and ecological level. Biodiversity is higher at tropical region compared to the temperate and polar regions.

Vertebrates are further divided in to groups as fishes, amphibians, reptiles, birds and mammals. Fishes are the aquatic vertebrates found in marine as well as fresh water habitat. They are the most diverse group among vertebrates comprising nearly 50% of all vertebrates. Birds form the second highest diverse group in vertebrates. Reptiles rank third in terms of diversity. Amphibians come on the second last position and lastly, are the mammals in the extent of global diversity.