What is biodiversity?
Biodiversity describes the variety and variability of all living things on Earth. Find out more about biodiversity and why it matters to all of us.
Definition of biodiversity
Biological diversity, or biodiversity for short, is a word used to describe the variety and variability of all living things on Earth. The biodiversity of the planet is therefore made up of all the living organisms, from the smallest bacteria to the mighty giant redwood tree and includes humans too!
For example, the biodiversity of a woodland includes the trees, the plants and fungi that grow on and under the trees and in the soil, the insects, the birds, the mammals and any other living things that make woodlands their home. The biodiversity of a garden pond includes water plants, algae, fish, and all the insects, invertebrates and microorganisms in the water and the mud at the bottom.
Low biodiversity vs. high biodiversity
Areas that are low in biodiversity support only a small number of different species, even though individual species may occur in large numbers. For example, a polluted lake may be low in biodiversity, only containing a few species, but there may be thousands of algal cells covering the water surface, or large numbers of breeding midges.
However, some areas of the planet are naturally low in biodiversity, for example deserts and mountain tops. Such regions can contain unique biodiversity, and these organisms are usually specially adapted to their local environmental conditions. So, even areas of low biodiversity can be important.
Areas that are high in biodiversity support many species and offer lots of variability too. For example, the Amazon rainforest is one of the most diverse natural areas on the planet and can contain many thousands of species of plants, animals and microorganisms in just one hectare.
Plants found nowhere else on Earth
Plants found in some regions of the world are described as endemic, meaning they do not occur anywhere else. Madagascar is one example of a region containing many endemic plants.
The world’s fourth largest island, Madagascar, is recognised as one of the world’s top ten hotspots for biodiversity. It is estimated that there are about 10,000 plant species on the island. Of these, 80% or more occur nowhere else on Earth. Man arrived in Madagascar just 2,000 years ago, and since then has cleared much of the island’s forest. The uniqueness of plant life in Madagascar makes the region a priority for international conservation efforts.
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