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Author Topic:   Darwin- would he have changed his theory?
Quetzal
Member (Idle past 5147 days)
Posts: 3228
Joined: 01-09-2002


Message 65 of 195 (151602)
10-21-2004 10:28 AM
Reply to: Message 30 by SirPimpsalot
10-21-2004 8:49 AM


From punctuated equilibrium to heredity to the Big Bang theory, this is simply untrue.......because scientists HAVE had to change it plenty to keep it viable.

This is a pretty inaccurate (or at least misleading) characterization, IMO. The discussion of PE, for example, revolves around the mode and tempo of evolution, not the basic facts of evolution: descent with modification, non-constancy of species, lack of discontinuities, gradualism, and natural selection.

On heredity, Darwin recognized the fact that he didn't know how it was done - he had an erroneous idea that variation was unlimited but had no good idea how such variation arose in the first place. It was left to Hugo de Vries, one of the "rediscoverers" of Mendel's works around the turn of the century to show the particulate nature of heredity. In fact, de Vries corrected Mendel, who thought that heritable variation was discrete and limited because, either by design or accident, Mendel picked species and traits that WERE discrete - de Vries reproduced Mendel's experiments using different species and found radical new traits arising de novo; he called these traits "mutations". Ultimately Fisher, Wright and Haldane showed how a synthesis of Darwinian selection and Mendelian genetics explained the diversity of life. Up to now, this has been the last great conflict in the theory - Darwin's basic views have been borne out, not thrown out or replaced as you suggest.

All of the current arguments within biology revolve around details. Which is more important: ns or drift? How fast is "gradual"? Does the fossil record show more stasis than continuous transition? How important are regulatory genes in modifying phenotypes? etc etc. Not one single practicing biologist or ecologist to my knowledge denies the underlying fact of evolution - exactly as originally described by Darwin.


This message is a reply to:
 Message 30 by SirPimpsalot, posted 10-21-2004 8:49 AM SirPimpsalot has replied

Replies to this message:
 Message 92 by SirPimpsalot, posted 10-22-2004 8:23 AM Quetzal has replied

  
Quetzal
Member (Idle past 5147 days)
Posts: 3228
Joined: 01-09-2002


Message 104 of 195 (151924)
10-22-2004 9:06 AM
Reply to: Message 92 by SirPimpsalot
10-22-2004 8:23 AM


Topic Drift Warning
It speaks to gradualism........especially in the case of the Cambrian Explosion, which, as far as I know, PE doesn't even explain.

Right. PE doesn't "explain" the Cambrian so-called explosion. After all, they're two completely unrelated subject areas. OTOH, gradual is as gradual does - PE is an explanation of why some lineages show stasis followed by relatively rapid radiation. In addition, it explains the observed "abrupt" appearance of some new species in the fossil record. However, the mechanics of PE are basically gradualism in a small population - gradual change over a few thousand years in an isolated group rather than continuous change over millions of years in a continental or widely-spread population. This was already recognized (at least the stasis part) by Darwin in his writings.

Further discussion of PE needs to be taken to another thread. There are (or were) a couple of PE threads open that we can take this to.


This message is a reply to:
 Message 92 by SirPimpsalot, posted 10-22-2004 8:23 AM SirPimpsalot has taken no action

  
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