Evidence for Evolution
- The theory of evolution by natural selection is now widely accepted by the scientific community due to its being supported by a great deal of evidence
- Scientific discoveries are made which confirm the findings of previous studies
- Many structures and processes, including at a molecular level, are conserved across organisms
- Evidence supports the evolutionary links between organisms in all domains
- Data from many disciplines feeds into the evidence to support evolution:
- Geological and geographical evidence looks at the distribution of organisms around the world and how proximity implies shared ancestry
- Physical evidence from the fossil record, compares structures or homology as evidence of ancestry
- Biochemical analysis provides molecular-level evidence on common ancestry using DNA or protein sequences
- Mathematical data, collated from the evidence can be used to quantitatively determine levels of ancestry between organisms
- A central pillar of the theory is that all organisms share a common ancestor, a life form from which all known life has evolved
- Two closely related species share a recent common ancestor
- Two distantly related species share a more ancient common ancestor
- All species are related in some way
Darwin's Tree of Life
- Darwin provided the early model of a "tree of life" as a way of picturing and thinking about evolution and ancestry
- This suggests that extant species evolved from ancestors, some of which are themselves extant, with many more others extinct
Charles Darwin's first tree of life sketch from his notebooks, dated 1837 (22 years before publication of his book On the Origin of Species)
Charles Darwin, Public domain, via Wikimedia Commons
Exam Tip
When answering a question about evolution, it is crucial that you present evidence in your answer. These kinds of evidence are set out in the following subtopic page and can be used to explain all evolutionary steps undergone by organisms.
