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Author Topic:   MACROevolution vs MICROevolution - what is it?
Allopatrik
Member (Idle past 4416 days)
Posts: 59
Joined: 02-07-2007


Message 19 of 908 (393270)
04-04-2007 6:04 AM


quote:
The words “microevolution” and “macroevolution” are relative terms, and have only descriptive meaning; they imply no differences in the underlying causal agencies.

--Theodosius Dobzhansky, (1951) Genetics and the Origin of Species, Third Edition, Revised, p. 17



Natural Selection is not Evolution-- R.A. Fisher
Replies to this message:
 Message 21 by Brad McFall, posted 04-04-2007 4:38 PM Allopatrik has responded

  
Allopatrik
Member (Idle past 4416 days)
Posts: 59
Joined: 02-07-2007


Message 22 of 908 (393475)
04-05-2007 11:02 AM
Reply to: Message 21 by Brad McFall
04-04-2007 4:38 PM


Mesoevolution
quote:
He also suggested the term "meso evolution" but where is the description of *this* in=between evolution in the literature?

I know of several papers by Spiess, Wallace and Dobzhansky himself where it’s mentioned or described. But that doesn't change the basic fact that these terms (including 'megaevolution', for that matter, which Dobzhansky also coined) do not imply different processes at work.

A


Natural Selection is not Evolution-- R.A. Fisher
This message is a reply to:
 Message 21 by Brad McFall, posted 04-04-2007 4:38 PM Brad McFall has responded

Replies to this message:
 Message 31 by Brad McFall, posted 04-05-2007 5:27 PM Allopatrik has not yet responded

  
Allopatrik
Member (Idle past 4416 days)
Posts: 59
Joined: 02-07-2007


Message 24 of 908 (393490)
04-05-2007 12:26 PM
Reply to: Message 23 by Fosdick
04-05-2007 11:55 AM


Re: Defining the terms of evolution
How are the two definitions you cite conceptually different?

A


Natural Selection is not Evolution-- R.A. Fisher
This message is a reply to:
 Message 23 by Fosdick, posted 04-05-2007 11:55 AM Fosdick has responded

Replies to this message:
 Message 25 by Fosdick, posted 04-05-2007 12:49 PM Allopatrik has responded

  
Allopatrik
Member (Idle past 4416 days)
Posts: 59
Joined: 02-07-2007


Message 26 of 908 (393496)
04-05-2007 12:55 PM
Reply to: Message 25 by Fosdick
04-05-2007 12:49 PM


Re: Defining the terms of evolution
quote:
Wilson says the species level is where macroevolution occurs.

Wilson says nothing of the kind. He simply calls micro small and macro large.

A


Natural Selection is not Evolution-- R.A. Fisher
This message is a reply to:
 Message 25 by Fosdick, posted 04-05-2007 12:49 PM Fosdick has responded

Replies to this message:
 Message 27 by Fosdick, posted 04-05-2007 1:05 PM Allopatrik has responded

  
Allopatrik
Member (Idle past 4416 days)
Posts: 59
Joined: 02-07-2007


Message 28 of 908 (393502)
04-05-2007 1:33 PM
Reply to: Message 27 by Fosdick
04-05-2007 1:05 PM


Re: Defining the terms of evolution
quote:
took this part of Wilson's definition—"A large amount of change would be referred to as macroevolution or simply as evolution"—to imply speciation. I beieve that's fair.

So, you think that Wilson considers macroevolution to occur at the level of the species and above, while Mayr considers it to be at the genus and above. Does it matter where the line is drawn, conceptually? How does the process that results in speciation differ from the kind of divergence that results in different genera?


Natural Selection is not Evolution-- R.A. Fisher
This message is a reply to:
 Message 27 by Fosdick, posted 04-05-2007 1:05 PM Fosdick has responded

Replies to this message:
 Message 29 by Fosdick, posted 04-05-2007 2:45 PM Allopatrik has responded

  
Allopatrik
Member (Idle past 4416 days)
Posts: 59
Joined: 02-07-2007


Message 30 of 908 (393526)
04-05-2007 3:20 PM
Reply to: Message 29 by Fosdick
04-05-2007 2:45 PM


Re: Defining the terms of evolution
quote:
Is there only one process? I can think of five know processes that can provoke an evolutionary event, or a divergence

It is divergence--of one population from another-- that underlies the existence of all taxonomic groups, from species to kingdoms. So it doesn't matter how many ways that divergence can occur. Divergence is the process common to both micro and macroevolution. Therefore, the terms are, as Dobzhansky said, merely descriptive in nature.

A

Edited by Allopatrik, : No reason given.


Natural Selection is not Evolution-- R.A. Fisher
This message is a reply to:
 Message 29 by Fosdick, posted 04-05-2007 2:45 PM Fosdick has not yet responded

  
Allopatrik
Member (Idle past 4416 days)
Posts: 59
Joined: 02-07-2007


Message 34 of 908 (393743)
04-06-2007 5:04 PM
Reply to: Message 33 by Fosdick
04-06-2007 11:25 AM


Re: Defining the terms of evolution
quote:
From where I stand on this, I think "microevolution" can happen without speciation, but "macroevolution" (or just "evolution") entails speciation. What do you think?

That sounds as reasonable a place to draw what is ultimately an arbitrary line. I think it's where most biologists are comfortable drawing the line, if forced to do so.

A

Edited by Allopatrik, : No reason given.


Natural Selection is not Evolution-- R.A. Fisher
This message is a reply to:
 Message 33 by Fosdick, posted 04-06-2007 11:25 AM Fosdick has not yet responded

  
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