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Author Topic:   Imported weed diversification supports macro-evolution
mark24
Member (Idle past 5313 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 4 of 59 (298105)
03-25-2006 4:32 PM
Reply to: Message 2 by Faith
03-25-2006 4:00 PM


Faith,
I agree it's not macroevolution, but speciation is not "just ordinary variation according to Mendelian principles of inheritance". The plants can no longer interbreed. Nowt to do with races or "varieties" of the same species.
Mark

There are 10 kinds of people in this world; those that understand binary, & those that don't

This message is a reply to:
 Message 2 by Faith, posted 03-25-2006 4:00 PM Faith has not replied

  
mark24
Member (Idle past 5313 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 6 of 59 (298108)
03-25-2006 4:43 PM
Reply to: Message 5 by kuresu
03-25-2006 4:32 PM


kuresu,
To paraphrase the definition of macroevolution given by Levinton in "Genetics, Paleontology & Macroevolution": Change that is indicative of placement in higher taxonomic ranks. In this case, your example does not meet the standard. I think you even have a problem shoe-horning it into your own preferred definition, it certainly isn't change on a grand scale.
The example you describe is good old common or garden microevolution that resulted in genetic isolation from the parent species. Speciation, to be sure, but speciation does not equal macroevolution.
Mark

There are 10 kinds of people in this world; those that understand binary, & those that don't

This message is a reply to:
 Message 5 by kuresu, posted 03-25-2006 4:32 PM kuresu has replied

Replies to this message:
 Message 7 by kuresu, posted 03-25-2006 4:57 PM mark24 has replied

  
mark24
Member (Idle past 5313 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 13 of 59 (298128)
03-25-2006 7:49 PM
Reply to: Message 7 by kuresu
03-25-2006 4:57 PM


kurusu,
Ah, but speciation is the first step towards macro-evolution, as predicted by ToE
But it still ain't macro.
Now then, coming from a college biology book that has as one of its central themes evolution, that's pretty convicing evidence.
Even this doesn't include speciation as being macroevolution.
I suppose I should have been unlazy enough to give the full definition rather than the one from memory:
(Levinton 1983) "The sum of those processes that explain the character-state transitions that diagnose evolutionary differences of major taxonomic rank".
But even the older & less accurate "evolution above the species level" definition doesn't allow Goatsbeard's speciation entry into the macroevolutionary fold.
The term "macroevolution" was always intended to mean something akin to large-scale evolutionary change, so a definition that reflects that is more efficacious & honest than one that includes "mere" reproductive isolation (ie speciation).
Don't get me wrong, kurusu, it's wonderful example of speciation, just not macroevolution.
Mark
This message has been edited by mark24, 03-25-2006 07:51 PM

There are 10 kinds of people in this world; those that understand binary, & those that don't

This message is a reply to:
 Message 7 by kuresu, posted 03-25-2006 4:57 PM kuresu has not replied

  
mark24
Member (Idle past 5313 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 14 of 59 (298129)
03-25-2006 7:59 PM
Reply to: Message 12 by Belfry
03-25-2006 7:12 PM


Re: Breeds, speciation, and macroevolution
Belfry,
Some people argue (and I'm inclined to agree) that Chihuahuas and great danes are anatomically incompatible enough that they would be reproductively isolated as "wild" populations, and could be thought of as different species.
I'm not inclined to agree. Chihuahua & Great Dane genes are capable of gene flow, it might take a generation or two to get a Great Dane to breed with a smaller variety, & a Chihuahua with a larger & so on, but eventually, a Great Dane gene can easily get into a Chihuahua population & vice versa.
If individuals in a population can't directly interbreed, but can still pass on genes to decendents of those individuals, then under the biological species concept they are still a "good" species.
Mark

There are 10 kinds of people in this world; those that understand binary, & those that don't

This message is a reply to:
 Message 12 by Belfry, posted 03-25-2006 7:12 PM Belfry has replied

Replies to this message:
 Message 17 by Belfry, posted 03-25-2006 8:29 PM mark24 has replied

  
mark24
Member (Idle past 5313 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 15 of 59 (298130)
03-25-2006 8:10 PM
Reply to: Message 11 by Faith
03-25-2006 5:32 PM


Faith,
Um. There's a lot more difference in the races than just melatonin
Yes there is, but that's not the point. There are more differences within supposed races, than between them. Think about it. What that means is that in order to maintain "races" we are forced cherry pick certain traits & attribute them to "races", whilst ignoring the rest of the data we have that actually contradicts the notion. No way to objectively define human groups.
Mark

This message is a reply to:
 Message 11 by Faith, posted 03-25-2006 5:32 PM Faith has replied

Replies to this message:
 Message 19 by Faith, posted 03-25-2006 8:54 PM mark24 has replied

  
mark24
Member (Idle past 5313 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 29 of 59 (298225)
03-26-2006 3:54 AM
Reply to: Message 19 by Faith
03-25-2006 8:54 PM


Faith,
The same degree of genetic specificity would be called that by the evos for any animal.
But that's just it, Faith, there is no genetic specificity that you get with other breeds & varieties. There is more genetic difference within races than between them. There is no biological rationale for race.
Mark

There are 10 kinds of people in this world; those that understand binary, & those that don't

This message is a reply to:
 Message 19 by Faith, posted 03-25-2006 8:54 PM Faith has replied

Replies to this message:
 Message 33 by Faith, posted 03-26-2006 11:31 AM mark24 has replied

  
mark24
Member (Idle past 5313 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 30 of 59 (298226)
03-26-2006 4:01 AM
Reply to: Message 17 by Belfry
03-25-2006 8:29 PM


Re: Breeds, speciation, and macroevolution
Belfry,
Those of us who work with plants find this species concept to be rather zoocentric!
And those that work with asexually reproducing organisms find it sexo-centric !
Animal examples such as "ring species" create problems for it, as well.
I'm sure you are aware that all species concepts have their share of problems. At the end of the day biologists come running back to daddy, or something centred around the BSC.
I was thinking after I posted that a better way to present it might be this: If alien biologists were to find an island populated by great danes and chihuahuas (with no dogs of intermediate size), they would be justified in regarding them as separate species.
Would they? That may be their first impression, but even using other species concepts they would after a little study realise that anatomically, genetically & phylogenetically they should be the same species, as compared to & distinct from foxes, for example.
Mark

There are 10 kinds of people in this world; those that understand binary, & those that don't

This message is a reply to:
 Message 17 by Belfry, posted 03-25-2006 8:29 PM Belfry has not replied

  
mark24
Member (Idle past 5313 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 31 of 59 (298227)
03-26-2006 4:05 AM
Reply to: Message 18 by kuresu
03-25-2006 8:33 PM


kurusu,
right, so speciation isn't macroevolution immediately, but following the definition I gave of macro evolution, which the other defintion given by Levinton appears to agree with, then this speciation will eventually result in macro-evolution.
Speciation is a part of a process that may result in macroevolution at some point, when compared to the "start" point.
Mark

There are 10 kinds of people in this world; those that understand binary, & those that don't

This message is a reply to:
 Message 18 by kuresu, posted 03-25-2006 8:33 PM kuresu has not replied

  
mark24
Member (Idle past 5313 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 39 of 59 (298342)
03-26-2006 2:23 PM
Reply to: Message 33 by Faith
03-26-2006 11:31 AM


Faith,
Is or is it not the very same process of population genetics that has produced the human "races,"
No, races as you understand them were not produced. It is in fact genetics that has taught us this.
There are populations of black africans that are more dissimilar to each other than whites are to them, genetically speaking. Australian aborigines are more similar to white caucasians than black africans. This means that we do when we declare races is that we are taking a small part of a large character set & attributing race in this way. Unfortunately we are also ignoring the larger picture which leads us to false conclusions.
I'm talking about something OBSERVABLE. One can usually tell a Norwegian from an Italian, an Arab from a Mongolian. Sheesh. And there are even recognizable differences in general appearance between members of isolated tribes who are nevertheless related.
None of the groups you cited are races. And as for assigning races to groups because of OBSERVABLE characters, how about big noses? They are observable. Eye colour? It goes on. Why not. Dark skin is not indicative of common descent in human populations, so why lump them together because of it?
Mark
This message has been edited by mark24, 03-26-2006 02:26 PM

There are 10 kinds of people in this world; those that understand binary, & those that don't

This message is a reply to:
 Message 33 by Faith, posted 03-26-2006 11:31 AM Faith has not replied

  
mark24
Member (Idle past 5313 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 43 of 59 (298403)
03-26-2006 6:33 PM
Reply to: Message 33 by Faith
03-26-2006 11:31 AM


Faith,
In addition to Schraf's post, what race are these children?
Mark

There are 10 kinds of people in this world; those that understand binary, & those that don't

This message is a reply to:
 Message 33 by Faith, posted 03-26-2006 11:31 AM Faith has replied

Replies to this message:
 Message 44 by Faith, posted 03-26-2006 8:07 PM mark24 has replied

  
mark24
Member (Idle past 5313 days)
Posts: 3857
From: UK
Joined: 12-01-2001


Message 50 of 59 (298513)
03-27-2006 3:03 AM
Reply to: Message 44 by Faith
03-26-2006 8:07 PM


Faith,
Where did I say I personally could recognize all the different races and tribes of humanity any more than I could recognize the five different races
You said it was OBSERVABLE. It is therefore implicit that you can place people into races by observation.
On the one hand you think you can recognise a Norwegian from an Italian, an Arab from a Mongolian, but refuse to place indiginous tribal folk into one of the five major races!
THIS is why races are bunk, Faith, because despite "talking about something OBSERVABLE", you are still unable to put tribespeople into racial slots.
Mark

There are 10 kinds of people in this world; those that understand binary, & those that don't

This message is a reply to:
 Message 44 by Faith, posted 03-26-2006 8:07 PM Faith has not replied

  
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