Template:Cover abstract/Common descent
Common descent is the theory that all living organisms on Earth descended from a common ancestor. Biologists have evidence that all life developed from a common ancestor that lived just under 4 billion years ago, and the concept is accepted by virtually all scientists working in the field. The structures and functions of all living organisms are encoded in the same basic nucleic molecules, DNA and RNA. Similarities in amino acid sequences between various organisms also suggest common descent, and the fossil record also shows cases in which one plant or animal type evolved into different types over time.
Creationists reject common descent as it implies an evolutionary model. Young Earth creationists, as Biblical literalists, reject it outright, believing that life was created within a few days less than ten thousand years ago. Intelligent design proponents may accept some aspects of common descent, as long as they are allowed to claim that the "designer" mucked with the genes and mutations along the way, but usually just claim "we don't know" what happened. Cdesign proponentsists probably believe a muddled overlap of these positions.
