Biodiversity is that the variety and variability of life on Earth. Biodiversity is usually a measure of variation at the genetic, species, and ecosystem level. Terrestrial biodiversity is typically greater near the equator, which is that the results of the nice and cozy climate and high primary productivity. Biodiversity isn't distributed evenly on Earth, and is richest within the tropics. These tropical forest ecosystems cover but 10 percent of surface and contain about 90 percent of the world's species. Marine biodiversity is typically highest along coasts within the Western Pacific, where sea surface temperature is highest, and within the mid-latitudinal band altogether oceans. There are latitudinal gradients in species diversity.