The evidence for evolution: in images
Darwin brought together many lines of evidence to support his theory. Since his time, other studies have added to the weight of evidence for evolution
1. The fossil record
The fossil record has provided evidence of a multitude of organisms that once existed but are now extinct, and it shows that life has existed on Earth for a very long time indeed. Similarities between fossils also suggest how one species might change and give rise to another.
Credit: Illustration © Glen McBeth
2. Adaptive radiation
Adaptive radiation shows how – when starting with a basic structure – many variants can evolve, each adapted to a particular environment. The beaks of Darwin’s finches on the Galapagos Islands, for example, have evolved into a multitude of forms related to the birds’ diets on different islands.
Credit: Illustration © Glen McBeth
3. Comparative anatomy
The limbs of mammals have diverged in multiple ways, to create wings in bats and flippers in dolphins as well as our own arms. From the outside, these may look very different, but a detailed analysis of bones has identified how they each evolved from the same set of ancestral skeletal structures.
Credit: Illustration © Glen McBeth
4. Phylogenetics
Genes accumulate changes over time. Comparisons of genes between species can show how closely related they are, and the number of differences provides clues to the time when they diverged along different evolutionary paths. Family trees can thus be drawn up showing how organisms are related to one another.
CC BY NC ND Illustration by Bret Syfert