07-10-2008, 03:31 AM
<!--QuoteBegin-Pandyan+Jul 10 2008, 02:36 AM-->QUOTE(Pandyan @ Jul 10 2008, 02:36 AM)<!--QuoteEBegin-->I think you're talking about the theory of recapitulation, which states that ontogeny mirrors phylogeny (embryonic development also showing evolutionary stages). I'm pretty sure the theory has been discredited now.
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The ontogeny (morphogenesis or shape/form) part, in the strict sense, is indeed proven to be not correlated well with phylogeny. I did mention that matching of shapes was controversial.
But that is not the end of the story. I guess Gould's book is the best one for this discussion.
http://en.wikipedia.org/wiki/Ontogeny_and_phylogeny
http://www.hup.harvard.edu/catalog/GOUONX.html
<!--QuoteBegin-->QUOTE<!--QuoteEBegin-->Turning to modern concepts, Gould demonstrates that, even though the whole subject of parallels between ontogeny and phylogeny fell into disrepute, it is still one of the great themes of evolutionary biology. Heterochrony--changes in developmental timing, producing parallels between ontogeny and phylogeny--is shown to be crucial to an understanding of gene regulation, the key to any rapprochement between molecular and evolutionary biology. Gould argues that the primary evolutionary value of heterochrony may lie in immediate ecological advantages for slow or rapid maturation, rather than in long-term changes of form, as all previous theories proclaimed.<!--QuoteEnd--><!--QuoteEEnd-->
So there are connections between ontogeny and phylogeny, but not as simplistic as thought of in the recapitulation theory.
Also check the Modern Observations section in wikipedia
http://en.wikipedia.org/wiki/Recapitulation_theory
<!--QuoteEnd--><!--QuoteEEnd-->
The ontogeny (morphogenesis or shape/form) part, in the strict sense, is indeed proven to be not correlated well with phylogeny. I did mention that matching of shapes was controversial.
But that is not the end of the story. I guess Gould's book is the best one for this discussion.
http://en.wikipedia.org/wiki/Ontogeny_and_phylogeny
http://www.hup.harvard.edu/catalog/GOUONX.html
<!--QuoteBegin-->QUOTE<!--QuoteEBegin-->Turning to modern concepts, Gould demonstrates that, even though the whole subject of parallels between ontogeny and phylogeny fell into disrepute, it is still one of the great themes of evolutionary biology. Heterochrony--changes in developmental timing, producing parallels between ontogeny and phylogeny--is shown to be crucial to an understanding of gene regulation, the key to any rapprochement between molecular and evolutionary biology. Gould argues that the primary evolutionary value of heterochrony may lie in immediate ecological advantages for slow or rapid maturation, rather than in long-term changes of form, as all previous theories proclaimed.<!--QuoteEnd--><!--QuoteEEnd-->
So there are connections between ontogeny and phylogeny, but not as simplistic as thought of in the recapitulation theory.
Also check the Modern Observations section in wikipedia
http://en.wikipedia.org/wiki/Recapitulation_theory