These measurements include numbers of species, genetic diversity, chemical diversity, and ecosystem diversity. Biodiversity recovery times after mass extinctions vary, but may be as long as 30 million years.

Biodiversity exists at multiple levels of organization and is measured in different ways depending on the scientific goals of those taking the measurements. The number of described species is estimated to be 1.5 million with about 17,000 new species being described each year.

biodiversity — variety of a biological system, typically conceived as the number of species, but also applying to genes, biochemistry, and ecosystems. extinction — disappearance of a species from Earth; local extinction is the disappearance of a species from a region. genetic diversity — variety of genes in a species or other taxonomic group or ecosystem, the term can refer to allelic diversity or genome-wide diversity. number of described species — estimated to be 1.5 million with about 17,000 new species being described each year.