The theory of evolution by natural selection, first formulated in Darwin's book "On the Origin of Species" in 1859. The theory has two main points, said Brian Richmond, curator of human origins at the American Museum of Natural History in New York City. "All life on Earth is connected and related to each other," and this diversity of life is a product of "modifications of populations by natural selection, where some traits were favored in and environment over others," he said.
