The lineage leading to the human species emerged from an ancestry among the apes, almost certainly in Africa around five million years ago. Fossils usually attributed to the genus Homo itself date from the late Pliocene, perhaps two million years ago, and anatomically modern humans appeared some 100,000 years or more before present.
Agriculture developed independently in several regions around 10,500 years ago, in association with increased population density. The global human population continued to grow only slowly until the nineteenth century, when revolutionary developments in agriculture, industry and public health triggered an exponential rise that has continued to the present day.
Agriculture is a means to channel Earth's resources into production of human bodies. Humans have converted large areas of terrestrial habitat and use more than one third of net primary production on land. They are strongly implicated in the extinction of many large terrestrial mammal and bird species in prehistory, and are responsible for habitat change and exploitation that have caused the decline and extinction of many species in recent times.