Common descent
shared ancestry of organisms from different species / From Wikipedia, the free encyclopedia
In evolutionary biology, a group of organisms have common descent if they have a common ancestor. There is strong support for the theory that all living organisms on Earth are descended from a common ancestor.[1][2]
Charles Darwin proposed the theory of universal common descent through an evolutionary process in On the Origin of Species, saying, "There is a grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one".[3]p490
The last universal ancestor (LUA) (or last universal common ancestor, LUCA), is the most recent common ancestor of all currently living organisms.[1] It is believed to have appeared about 3.9 billion years ago.[4][5]