Ontogeny and Phylogeny

Ontogeny and Phylogeny is a 1977 book on evolution by Stephen Jay Gould, in which he explores the relationship between embryonic development (ontogeny) and biological evolution (phylogeny). Unlike his many popular books of essays, it was a technical book, and over the following decades it was influential in stimulating research into heterochrony (changes in the timing of embryonic development), which had been neglected since Ernst Haeckel's theory that ontogeny recapitulates phylogeny had been largely discredited. This helped to create the field of evolutionary developmental biology.

Context Ontogeny and Phylogeny is Stephen Jay Gould's first technical book. He wrote that Ernst Mayr had suggested in passing that he write a book on development. Gould stated he "only began it as a practice run to learn the style of lengthy exposition before embarking on my magnum opus about macroevolution." This later work was published in 2002 as The Structure of Evolutionary Theory.

Book

Publication The book was published in 1977 by the Belknap Press of the Harvard University Press.

Summary The first half of the book explores Ernst Haeckel's biogenetic law (recapitulation)—the discredited idea that embryonic developmental stages replay the evolutionary transitions of adult forms of an organism's past descendants—and how this idea influenced thinking in biology, theology, and psychology. Gould begins with the ancient Greek philosopher Anaximander, showing that the ideas formed a tradition leading to the French naturalist Charles Bonnet. Gould describes the recapitulationists in the 19th century, from the German Lorenz Oken and Johann Friedrich Meckel to the French Étienne Serres. The book examines the criticism of the theory by the Baltic German Karl Ernst von Baer and the Swiss-American Louis Agassiz, and relates 19th century phylogeny to Charles Darwin's 1859 theory of evolution, Haeckel's approach, and neo-Lamarckism. A chapter examines the pervasive influence of recapitulationism on such subjects as criminal anthropology, racism, attitudes to child development and primary schooling, and to Freudian psychoanalysis. The second half of the book details how modern concepts such as heterochrony (changes in developmental timing) and neoteny (the retardation of developmental expression or growth rates) influence macroevolution (major evolutionary transitions). Gould examines the ecological and evolutionary significance of heterochrony, with an analysis of its effect on insect metamorphosis and neoteny in amphibians. He ends by considering theories of neoteny in human evolution, including Louis Bolk's so-called fetalization theory.

Reception

Contemporary

The herpetologist David B. Wake, in Paleobiology, wrote that the topic was "at once so obviously important and so intrinsically difficult" that few people would tackle it. The parallelism that Haeckel noted between ontogeny and phylogeny was, Wake observed, a strong argument for evolution, but hardly anyone dared to discuss it. He called the book very good, and predicted that it would set the stage for "endless research", but found it also in a way unsatisfying, using "undigested theory from ecology to explain what is, as yet, unexplainable. Summing up, Wake calls the book "erudite, important, provocative, and controversial", but noted that it could have been much shorter. The embryologist Søren Løvtrup, in Systematic Zoology, noted that the book had two objectives, unexceptionably to gain practice, and "more dubious[ly]", to show that "in spite of the collapse of Haeckel's biogenetic law, the subject of parallels between ontogenesis and phylogenesis is still of importance to biology". In Løvtrup's view, this was because Haeckel's law had been refuted except where evolution had by chance happened to add to the end of development. Gould had little new to report, as people knew half a century earlier that development could be modified at other stages; the book was "a great disappointment." Haeckel could "of course be of historical interest" but Gould had chosen not to research Haeckel's influence. Work on "wrong theories" represented, Løvtrup wrote, "a terrible waste of effort and time, and block[ed] further progress."

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