school energy&environment

What is biodiversity?

The Earth is populated by an incredible number of different living creatures. The term that is used to define this “crowd” of organisms that populate every corner of the Planet, and that have adapted even to the most extreme environments, is biodiversity or biological diversity. Biodiversity measures the variety of animal and vegetable species in the biosphere and is the result of long evolutive processes. The elements that make up biodiversity can be subdivided into three different levels:

• Genetic level
• Species level
• Ecosystem level

Genetic biodiversity
Genetic diversity refers to the differences in the genetic heritage of a species. The morphological characteristics, i.e. the visible characteristics of living organisms, such as for example the colour of the eyes and fur of a cat, which are examples of variety, from a genes level, in each single species.
Species biodiversity
However when we speak of biodiversity, we generally refer to the species biodiversity, i.e. the diversity of the different species in a determined environment, where by species we mean a group of organisms that can be crossed with one another giving life to prolific offspring.
Species biodiversity can be measured through the number of species in a particular area (richness of species), the number of units in each species in a place (abundance of a species) and through the evolutive relationship of the different species (taxonomic diversity). For example, a man and a chimpanzee have 98% of common genes, but as we all well know, their characteristics make them very discernible one from the other. Some areas of the Planet have greater richness of species than others: at the equator, for example there is the largest number of species, that decreases nearer to the Poles. In the ocean there are many more different species near the coastlines than in the abysses.
Ecosystem biodiversity
The variety of environments in a determined natural area is the expression of biodiversity in the ecosystem, in other words, consider the differences there are, for example, between a temperate forest in South America and a mangrove forest at the Equator.