Abstract
AN investigator anxious to obtain information as to the relationship of a particular species puts the question “What characters do the young stages exhibit?” and in order to answer that question he makes a study of the developmental phases exhibited by those stages. He may argue that if he finds certain characters in the young stages indicative of, and adapted to, habits of life which the adults do not possess, then there must have been a time in the ancestry of the species when such habits of life were of particular value, otherwise they would never have been developed. Or he may simply give, as the reason for his method of research, the concise statement “ontogeny repeats phylogeny,” or he may hold to the theory of acceleration of development—which is more than a theory, because it is an actual fact of palæontology—that the characters of adult ancestors tend to become the characters of youthful descendants, thus producing specific diversity, without the necessity for a theory of natural, or any other form of selection, merely by inequality in the rates of developmental acceleration in different stocks. Wherefore vice versâ the characters of youth must at one time have been adult characters; and their differences from those of the adult indicate the degree of different environment under which the adult ancestors lived.
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BUCKMAN, S. Human Babies: What They Teach . Nature 62, 226–228 (1900). https://doi.org/10.1038/062226a0
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DOI: https://doi.org/10.1038/062226a0