Haeckel's observations on the link between ontogeny and philogeny? have been named the "recapitulation law," summed up in the phrase, ontogeny recapitulates phylogeny. As Haeckel's effort to prove the law was itself provably misguided and inaccurate, he became a favorite target of creationists seeking to discredit the theory of evolution.
See [1] for a biography.
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