Definition of Evolution

Evolution: The continuing process of change, especially in reference to natural selection.

Charles Darwin (1809-82) noted that successful species produce more offspring in each generation than are needed to replace the adults who die. Not all offspring survive. Some creatures or plants struggle to survive. Many things affect an individual's chances of survival, including its ability to obtain enough food and avoid being killed. Sometimes there are differences which may make it easier for an individual to survive long enough to reproduce. The species would thus have changed or evolved to favor traits that favor survival and reproduction. Darwin called this process "natural selection", as explained in his book "On the Origin of Species" in 1859.