The term biodiversity - or biological diversity - refers to the immense variety of species on this planet and the complex communities or ecosystems these species form. The result of billions of years of evolution, biodiverse ecosystems are the matrix all species depend on and all are an integral part of.
About 1.75 million different species have been identified on Earth so far. There may actually be some 13 million species, although some estimates range as high as 100 million. Each species plays its role and together they contribute to the formation of the ecosphere that supports all life.
Biodiversity also refers to the genetic differences within species - such as the differences between varieties of crops or breeds of livestock. It also refers to the diversity of ecosystems, such as those that occur in prairies, forests, wetlands, lakes, rivers, and agricultural landscapes. In each ecosystem, living creatures form a community, interacting with one another and with the air, water, and soil.