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Author Topic:   Evolution - recent examples?
crashfrog
Member (Idle past 1467 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 7 of 39 (118475)
06-24-2004 11:39 PM
Reply to: Message 1 by tubi417
06-24-2004 8:52 PM


You might be interested in these links from Talkorigins. The first details a number of observed instances of speciation:
Observed Instances of Speciation
This second link details the evidence for "macro" evolution, which I think you're referring to:
29+ Evidences for Macroevolution: The Scientific Case for Common Descent
That's the best I can think of. These pages should have references to the literature, if you want to dig a little further. If you're interested in more scholarly material I suggest you search http://www.pubmed.org for abstracts.

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crashfrog
Member (Idle past 1467 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 16 of 39 (118929)
06-26-2004 1:45 AM
Reply to: Message 15 by tubi417
06-26-2004 12:31 AM


well how would a new species some how be the result of that?
New species ("speciation") result when natural selection operates in a situation of reproductive isolation, where a sub-group is split off from the main population. In this situation, because of the lack of gene flow between groups, the sub-group "drifts" genetically from the original population until cross-breeding ceases to be possible. At that point we have a new species.

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crashfrog
Member (Idle past 1467 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 18 of 39 (118953)
06-26-2004 3:50 AM
Reply to: Message 17 by Wounded King
06-26-2004 3:38 AM


If its due to drift is it therefore natural selection?
As far as I know, genetic drift is not selective. As far as I know, genetic drift is a change in allele frequencies as a result of the randomizing effect of sexual reproduction. The effect on the gene pool is generally less than selection, but in the absence of a selection pressure, sometimes genetic drift alone is enough to cause speciation between two isolated populations.
Oh, wait. I see what you're asking. Yeah, I wasn't referring to genetic drift per se, but rather, the accumulation of genetic differences between gene pools, whatever the cause.
This message has been edited by crashfrog, 06-26-2004 02:51 AM

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crashfrog
Member (Idle past 1467 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 24 of 39 (120324)
06-30-2004 9:50 AM
Reply to: Message 23 by RRoman
06-30-2004 9:31 AM


Great post, RR. That's one of my favorite examples.

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crashfrog
Member (Idle past 1467 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 37 of 39 (170315)
12-20-2004 11:49 PM
Reply to: Message 34 by Cicada
12-20-2004 8:45 PM


One of the greatest things about the "theory of evolution" is that its arguments have evolved considerably thanks to the pressure of the creationists.
The scientific arguments haven't changed; not really.
What has improved as a result of creationist opposition have been the arguments we use in these casual debates. Which really makes sense, since creationist arguments are generally so impotent that they never draw the attention of the scientific community.

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