Biodiversity is the variety and variability of life on Earth. Biodiversity is typically a measure of variation at the genetic, species, and ecosystem level. Terrestrial biodiversity is usually greater near the equator, which is the result of the warm climate and high primary productivity.
Biodiversity is the diversity and diversity of life on Earth. Biodiversity is a measure of variation in genetic, species and ecosystem levels. Terrestrial biodiversity is the greater near-equator, which results in a warmer climate and higher primary productivity. Biodiversity is not evenly distributed on Earth and is the richest in the tropics. These tropical forest ecosystems cover less than 10% of the Earth's surface and contain about 90% of the world's species. Marine biodiversity is the highest along the western Pacific, where the temperature of the sea surface is the highest, and in the mid-latitudinal band of all the oceans. There are latitudinal gradients in the diversity of species.
Rapid environmental changes usually cause massive extinctions. It is estimated that over 99.9% of all species have ever lived on Earth, or more than five billion species. Estimates of the number of current Earth species ranging from 10 million to 14 years, of which about 1.2 million have been documented and over 86% have not yet been described. More recently, in May 2016, scientists reported that 1 trillion species are present on Earth, with only one thousandth of a thousand described. The total amount of related DNA base pairs on Earth is estimated at 5.0 x 1037 and weighs 50 billion tonnes. In comparison, the biosphere of total mass has been estimated at 4 TtC (billions of tonnes of carbon).