The Value of Biodiversity

Why is biodiversity important?

Biological diversity, or biodiversity, is the total of all the genetically based variation in all organisms in the biosphere. To biologists, biodiversity is precious, worth preserving for its own sake. But what kinds of biodiversity exist, and what value do they offer society?

Types of Biodiversity Biodiversity exists on three levels: ecosystem diversity, species diversity, and genetic diversity. Ecosystem diversity refers to the variety of habitats, communities, and ecological processes in the biosphere. The number of different species in the biosphere, or in a particular area, is called species diversity. To date, biologists have identified and named more than 1.8 million species, and they estimate that at least 30 million more are yet be discovered. Much of this diversity exists among single-celled organisms. But new species of vertebrates, like the snake in Figure 6–13, are still being found.

Genetic diversity can refer to the sum total of all different forms of genetic information carried by a particular species, or by all organisms on Earth. Within each species, genetic diversity refers to the total of all different forms of genes present in that species. In many ways, genetic diversity is the most basic kind of biodiversity. It is also the hardest kind to see and appreciate. Yet, genetic diversity is vitally important to the survival and evolution of species in a changing world.

FIGURE 6–13 A New Species This tiny snake, native to the island of Barbados, is one of many recently discovered species. Photos of the snake were released in 2008. Infer Why are you more likely to discover a new vertebrate species in a tropical area than in a desert?