According to the overwhelming scientific consensus, all living organisms on Earth share a common ancestor. This idea is a fundamental concept in the field of biology and is supported by a large body of evidence from various disciplines, including genetics, paleontology, and comparative anatomy.
The theory of common descent proposes that all organisms, from bacteria to plants, animals, and humans, trace their ancestry back to a single common ancestor that lived billions of years ago. This common ancestor is believed to have given rise to diverse forms of life through the process of evolution by natural selection.
The evidence for common descent is extensive. One of the key lines of evidence comes from the study of DNA and genetic information. By comparing the genetic sequences of different organisms, scientists have found striking similarities and patterns that indicate a shared genetic heritage. Additionally, the fossil record provides evidence of transitional forms and the gradual changes in species over time, supporting the idea of a branching tree of life.
While the precise details of the origin of life itself are still an active area of scientific research, the concept of common descent is well-supported by the evidence and forms the foundation of modern biological understanding.