Portal:History of science/Picture/27

Ernst Haeckel, the great populariser of Charles Darwin's theory of evolution, was the first to use a literal tree of life to express evolutionary relationships based on common descent. This version comes from his 1866 General Morphology; several different versions, some highly elaborate and artistic, are found in other Haeckel works. The icon of a tree of life has been used widely since that time; some modern versions include a tangled root system to represent the effects of horizontal gene transfer and symbiogenesis early in evolutionary history.