生物多样性是生命变化的程度。这可以是指在一个区域的，或生物群系的，或行星范围之内的基因变化，物种变化，或生态系统变化。陆地生物多样性在靠近赤道的低纬度地区往往是最高的，这似乎是由于温暖的气候和高初级生产的结果。海洋生物多样性在西太平洋沿海海岸，和在各大洋中纬度带往往是最高的，在那里海洋表面温度最高。

生物多样性是生物界一个较新的概念。简单来说，是指所有不同种类的生命，生活在一个地球上，其相互交替、影响令地球生态得到平衡。亦可解释为：单位面积内生物种种类的数目，表示生物群落中显示生态地位多样化与基因变异。最后，生物多样性是为维护生态平衡，且有公约。

Biodiversity, a contraction of "biological diversity," generally refers to the variety and variability of life on Earth. One of the most widely used definitions defines it in terms of the variability within species, between species, and between ecosystems. It is a measure of the variety of organisms present in different ecosystems. This can refer to genetic variation, ecosystem variation, or species variation (number of species) within an area, biome, or planet. Terrestrial biodiversity tends to be greater near the equator, which seems to be the result of the warm climate and high primary productivity. Biodiversity is not distributed evenly on Earth. It is richest in the tropics. Marine biodiversity tends to be highest along coasts in the Western Pacific, where sea surface temperature is highest and in the mid-latitudinal band in all oceans. There are latitudinal gradients in species diversity. Biodiversity generally tends to cluster in hotspots, and has been increasing through time, but will be likely to slow in the future.