| Subject: More on Darwin |
Author:
Damoclese
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Date Posted: 02/27/02 4:48pm
In reply to:
Wade A. Tisthammer
's message, "Some quotes from Darwin." on 02/27/02 1:49pm
As far as I can tell, the idea of rapid evolution to explain the gaps in the fossil record did not exist in the Origin of Species. Quoting Darwin:
Why then is not every geological formation and every stratum full of such intermediate links? Geology assuredly does not reveal any such finely graduated organic chain; and this, perhaps, is the most obvious and serious objection which can be urged against my theory. The explanation lies, as I believe, in the extreme imperfection of the geological record.
-Origin of Species (Chapter 10)
Contrary to what you almost seemed to suggest Damoclese, the idea of rapid evolution to explain the gaps in the fossil record did not exist in the Origin of Species. Apparently, the “imperfection” was the only credible explanation. Quoting Darwin again:
Damoclese: It seems that you have managed to take a few quotes out of context to build ivory towers in marshes. I believe in a post to Ben you said you had never read the origin of the species. You probably should have before you ventured into this post. Allow me to disabuse you a few notions:
"When we see a species first appearing in the middle of any formation, it would be rash in the extreme to infer that it had not elsewhere previously existed. So again, when we find a species disappearing before the last layers have been deposited, it would be equally rash to suppose that it then became extinct. We forget how small the area of Europe is compared with the rest of the world ... when we see a species first appearing in any formation, the probability is that it only then first immigrated into that area." (p. 423)
"... varieties are generally at first local; and that such local varieties do not spread widely and supplant their parent-form until they have been modified and perfected in some considerable degree. According to this view, the chance of discovering in a formation in any one country all the early stages of transition between any two forms is small, for the successive changes are supposed to have been local or confined to some one spot." (pp. 427-428)
"... it might require a long succession of ages to adapt an organism to some new and peculiar line of life, for instance, to fly through the air; and consequently that the transitional forms would often long remain confined to some one region; but that, when this adaptation had once been effected, and a few species had thus acquired a great advantage over other organisms, a comparatively short time would be necessary to produce many divergent forms, which would spread rapidly and widely throughout the world." (p. 433)
I believe these quotes are sufficient to show that Darwin was aware of the notion of punctuated equilibrium. They are a subset of this page, and I’d recommend that you read it before we continue this conversation further. http://ucsu.colorado.edu/~theobal/PE.html
They have refuted the notion that Darwin knew nothing about it far better than I can, or have time to.
He who rejects this view of the imperfection of the geological record, will rightly reject the whole theory.
-Origin of Species (Chapter 11)
No mention here of “except for rapid evolution” or anything of the sort. Evolution can happen more rapidly in some cases than others, but Darwin patently did not think it could be rapid enough to explain the gaps. I think the imperfection argument was very valid at the time, but after the massive quantities of fossils that have now been unearthed this is no longer legitimate, and it would seem that Darwin did not believe evolution happening rapidly would be sufficient to explain the gaps that we have now, because of the above quote and this one from David Raup in “Conflicts between Darwin and Paleontology,” Field Museum of Natural History Bulletin Jan. 1979, Vol. 50 No. 1 p. 25:
Well, we are now about 120 years after Darwin and the knowledge of the fossil record has been greatly expanded. We now have a quarter of a million fossil species but the situation hasn't changed much. The record of evolution is still surprisingly jerky and, ironically, we have even fewer examples of evolutionary transitions than we had in Darwin's time. By this I mean that some of the classic cases of darwinian change in the fossil record, such as the evolution of the horse in North America, have had to be discarded or modified as a result of more detailed information—what appeared to be a nice simple progression when relatively few data were available now appear to be much more complex and much less gradualistic. So Darwin's problem has not been alleviated in the last 120 years and we still have a record which does show change but one that can hardly be looked upon as the most reasonable consequence of natural selection.
So the gaps are very real, and rapid evolution probably is the best way to go for macroevolution, but Darwin apparently did not anticipate it.
Damoclese: Read that page, refute those arguments, then perhaps I’ll consider it.
Damoclese
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