The now discredited theory of recapitulation, also known as the biogenetic law, states that the stages in an organism’s embryonic development and differentiation (ontogeny) correspond to the stages of evolutionary development characteristic to its species (phylogeny). Ernst Haeckel, who proposed the theory in 1866, produced a number of controversial embryo drawings to support this premise. How did he interpret the presence of gill slits in human embryos? Discuss
Source: The Free Dictionary