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Re: DefinitionsPosted by GPP on November 12, 2003 In Reply to: Re: Definitions posted by R. Berg on November 11, 2003 : : : Is "ontogeny recapitulates phylogeny" the precise phrase? If so, what exactly does it mean? Who conined the phrase? And is it still taught as a correct principle in biology? : : : : : : : Ahem : : : : : : Meaning something like 'birds of a feather flock together' is it? : : : : : No, not that. It means that an individual goes through a succession of stages in its development that resembles the stages of development that its species went through when evolving. For example, human fetuses at one (early) stage of development have gills. : : : : : I don't know who coined the phrase or whether the principle is still thought to be correct. : : : : R.Berg's explanation is correct. The concept, however, is wrong, although it still appears in many textbooks even today. The German biologist Ernst Haeckel coined the phrase (as well as the word 'phylogeny') near the end of the 19th C. For more information, see http://www.ucmp.berkeley.edu/history/haeckel.html as a starting place. You'll find more by googling on the phrase, or on Haeckel's name; but be aware that 75% of what you'll find online is total BS; look for sites sponsored by univerities. : : : When googling use 'site:edu' as one of the required search phrases to get mostly universities and fewer BS hits. : : : : : From Merriam-Webster online: : : Main Entry: cre.a.tion.ism : : Main Entry: evo.lu.tion : : I am a Bible-thumping fundamentalist who believes that Genesis describes how God created the World and, through evolution, its creatures. Have I created a new theory? I need a name for it. : It isn't just creationists who reject Haeckel's theory, it's mainstream biologists. However, human embryos do have gills and tails, and occasionally these structures aren't completely reabsorbed before birth. Some people have extra nipples, too, a reminder that many mammal species have litters to nurse. In that way, ontogeny recapitulates phylogeny, just not in all other ways. Again, R.Berg's explanation is correct, as understood by mainstream biologists. This is not at all an appropriate forum for arguments about religion vs science, or creationism vs evolution. I would simply point out that there's a grievous LOGICAL error in supposing that because one particular postulate--that of "ontogeny recapitulates phylogeny"--may be demonstrated to be an oversimplification of what actually occurs, and is to that extent incorrect, that this therefore can be construed as bolstering any particular opposing argument (such as that of creationism). Many details of exactly how evolution works are disputed within the scientific community, but this is not an either/or situation; NO such disagreement over details in one theory can give support for any opposing theory--each must stand on its own. I might add that a great deal more is known and understood about the 'theory' of evolution than is known and understood about the 'theory' of gravitation. Again, this board is not an appropriate forum for arguments about religion and science. I do think, though, that's it's an entirely appropriate forum for trying to get a handle on some working definitions of terminology. There's a vast difference between the way words may be defined in a dictionary, or used colloquially, as opposed to their use as TERMS OF ART. Here's a beginning list of terms that might be useful to explore in this manner, simply because the words have very different meanings in different contexts, and these differences are rarely understood. The first rule for any coherent argument to take place is for all participants to understand and agree on WORKING DEFINITIONS of the words being used; otherwise there is no communication taking place. |