Common descent
Concept · Biology, stage 1: Learn the vocabulary
Common descent is the claim that any two living organisms share an ancestor if you go back far enough, and that all known life descends from a single ancestral population. The evidence is convergent rather than resting on one line: the fossil record, the nested pattern of shared anatomy, the near-universality of the genetic code, and the agreement between trees built from unrelated genes. Darwin argued it from anatomy and biogeography a century before sequence data existed.
Why it matters
It is what makes biology a single subject rather than a catalogue: a result found in yeast or in a fruit fly can bear on humans because the machinery was inherited from a shared ancestor.
Part of
Common descent in the glossary
Sources
- Common descent Wikipedia
- The Origin and Evolution of Cells NCBI BookshelfThe molecular side of the case, from the shared genetic code down.
- On the Origin of Species Wikipedia
