Register | Sign In


Understanding through Discussion


EvC Forum active members: 58 (9173 total)
4 online now:
Newest Member: Neptune7
Post Volume: Total: 917,575 Year: 4,832/9,624 Month: 180/427 Week: 93/85 Day: 0/10 Hour: 0/0


Thread  Details

Email This Thread
Newer Topic | Older Topic
  
Author Topic:   Imported weed diversification supports macro-evolution
Coragyps
Member (Idle past 812 days)
Posts: 5553
From: Snyder, Texas, USA
Joined: 11-12-2002


Message 16 of 59 (298131)
03-25-2006 8:26 PM
Reply to: Message 12 by Belfry
03-25-2006 7:12 PM


Re: Breeds, speciation, and macroevolution
article in Science (link gets you the abstract, full text by subscription only
Free registration sould be all you need if the article is over a year old (and newer than 1996.) They don't spam you, either.

This message is a reply to:
 Message 12 by Belfry, posted 03-25-2006 7:12 PM Belfry has not replied

  
Belfry
Member (Idle past 5163 days)
Posts: 177
From: Ocala, FL
Joined: 11-05-2005


Message 17 of 59 (298132)
03-25-2006 8:29 PM
Reply to: Message 14 by mark24
03-25-2006 7:59 PM


Re: Breeds, speciation, and macroevolution
mark24 writes:
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.
Those of us who work with plants find this species concept to be rather zoocentric! Animal examples such as "ring species" create problems for it, as well.
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.
I know, I know- Off topic, do not respond!!!

This message is a reply to:
 Message 14 by mark24, posted 03-25-2006 7:59 PM mark24 has replied

Replies to this message:
 Message 30 by mark24, posted 03-26-2006 4:01 AM Belfry has not replied

  
kuresu
Member (Idle past 2590 days)
Posts: 2544
From: boulder, colorado
Joined: 03-24-2006


Message 18 of 59 (298133)
03-25-2006 8:33 PM


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.
I must stress again that race is a social, not biological concept. If there was enough differences between the races in their genetics then they should be classified as sub-species. There is not enough difference to actually distinguish separate biological races in man.
i need to pay attention to posts. I posted this thinking there was but a single page. Wake up!
This message has been edited by kuresu, 03-25-2006 08:35 PM

All a man's knowledge comes from his experiences

Replies to this message:
 Message 20 by Faith, posted 03-25-2006 8:57 PM kuresu has not replied
 Message 31 by mark24, posted 03-26-2006 4:05 AM kuresu has not replied

  
Faith 
Suspended Member (Idle past 1521 days)
Posts: 35298
From: Nevada, USA
Joined: 10-06-2001


Message 19 of 59 (298135)
03-25-2006 8:54 PM
Reply to: Message 15 by mark24
03-25-2006 8:10 PM


I don't care what you call them, call them tribes or families or whatever you want, it's no different from what happens in any population isolation phenomenon. Sheesh all this pickiness over the term "race." Call it a "species" then. The same degree of genetic specificity would be called that by the evos for any animal.

This message is a reply to:
 Message 15 by mark24, posted 03-25-2006 8:10 PM mark24 has replied

Replies to this message:
 Message 21 by kuresu, posted 03-25-2006 9:38 PM Faith has replied
 Message 29 by mark24, posted 03-26-2006 3:54 AM Faith has replied

  
Faith 
Suspended Member (Idle past 1521 days)
Posts: 35298
From: Nevada, USA
Joined: 10-06-2001


Message 20 of 59 (298136)
03-25-2006 8:57 PM
Reply to: Message 18 by kuresu
03-25-2006 8:33 PM


You also need to pay attention to the "reply" button at the bottom right of the message you are answering instead of hitting the "general reply" button which makes it hard to know whom you are addressing.
This message has been edited by Faith, 03-25-2006 08:57 PM

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

  
kuresu
Member (Idle past 2590 days)
Posts: 2544
From: boulder, colorado
Joined: 03-24-2006


Message 21 of 59 (298145)
03-25-2006 9:38 PM
Reply to: Message 19 by Faith
03-25-2006 8:54 PM


that specific reply button. I'll learn to use it, eventually. I have a question. Have you taken a college biology course? I just want to know why you insist that race is biological when there is no real definition. Actually, let me clarify a bit before getting massacred. By biological I mean that there is enough genetic difference to have separate biological races for mankind.

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 22 by Faith, posted 03-25-2006 10:05 PM kuresu has replied

  
Faith 
Suspended Member (Idle past 1521 days)
Posts: 35298
From: Nevada, USA
Joined: 10-06-2001


Message 22 of 59 (298151)
03-25-2006 10:05 PM
Reply to: Message 21 by kuresu
03-25-2006 9:38 PM


Just how much genetic difference qualifies? Discussions about population genetics here tend to be pretty sloppy about specifying degree of change -- if a population of chipmunks gets isolated from another population completely enough and long enough to display recognizably different characteristics from the first (or in fact both develop differences due to a change in the frequency of alleles in both populations), that usually gets called "speciation." {abe: In fact, this is what happens with "ring species" -- just a bunch of them separating and changing into a number of identifiably different populations in one general geographical area}.
Isn't that what happens when human populations separate and isolate themselves? Over a few generations of inbreeding they develop recognizable characteristics as a group in exactly the same way.
Actually it's kind of amusing how everybody shies away from this obvious normal fact of population genetics when it comes to human beings.
This message has been edited by Faith, 03-25-2006 10:07 PM
This message has been edited by Faith, 03-25-2006 10:18 PM

This message is a reply to:
 Message 21 by kuresu, posted 03-25-2006 9:38 PM kuresu has replied

Replies to this message:
 Message 23 by kuresu, posted 03-25-2006 10:17 PM Faith has replied

  
kuresu
Member (Idle past 2590 days)
Posts: 2544
From: boulder, colorado
Joined: 03-24-2006


Message 23 of 59 (298155)
03-25-2006 10:17 PM
Reply to: Message 22 by Faith
03-25-2006 10:05 PM


but speciation, as far as sexually reproducing species are concerned, involves the reproductive isolation. If those two populations of chipmunks differentiate enough so that when they crossbreed the offspring are infertile, then two species are where one used to be. All human races can crossbreed and produce fertile offsrping, with the occasional exception of a mutation or accident that causes the fetus to not develop properly or abort or die. Of course, H. neadertalensis may have been a subspecies of H. sapiens because there are fossils that show H. sapiens and H. neandertalensis characteristics. However, we can't know that we actually crossbred with them and had viable, fertile offspring. Keep in mind I'm not stating that H. neandertalensis contribuited to H. sapiens evolution because the mtDNA of the neandertals is not found in our mtDNA.

All a man's knowledge comes from his experiences

This message is a reply to:
 Message 22 by Faith, posted 03-25-2006 10:05 PM Faith has replied

Replies to this message:
 Message 24 by Faith, posted 03-25-2006 10:22 PM kuresu has replied

  
Faith 
Suspended Member (Idle past 1521 days)
Posts: 35298
From: Nevada, USA
Joined: 10-06-2001


Message 24 of 59 (298159)
03-25-2006 10:22 PM
Reply to: Message 23 by kuresu
03-25-2006 10:17 PM


In the discussion about chipmunks that happened here, nothing was said about inability to crossbreed, but I believe something was mentioned about a lack of INTEREST in breeding with the other population.
But again, here I simply dispute the classification of species in terms of inability to breed. I think that's artificial. Inability to crossbreed is the natural result of enough reduction in genetic potential from a lot of selection pressure or population splits to make for genetic mismatches that prevent successful interbreeding. The result is an overall loss of genetic diversity rather than anything that looks like it could lead to further speciation. And sometimes it can't. Sometimes it gets so far out genetically that further genetic adaptation is impossible. Hence extinctions. And they are pretty common. Speciation ultimately tends to lead to extinction in a fallen world. Not to evolution.
This message has been edited by Faith, 03-25-2006 10:23 PM
This message has been edited by Faith, 03-25-2006 10:24 PM

This message is a reply to:
 Message 23 by kuresu, posted 03-25-2006 10:17 PM kuresu has replied

Replies to this message:
 Message 25 by kuresu, posted 03-25-2006 10:48 PM Faith has replied
 Message 48 by DBlevins, posted 03-26-2006 8:40 PM Faith has replied

  
kuresu
Member (Idle past 2590 days)
Posts: 2544
From: boulder, colorado
Joined: 03-24-2006


Message 25 of 59 (298165)
03-25-2006 10:48 PM
Reply to: Message 24 by Faith
03-25-2006 10:22 PM


as far as I know, there is no fallen world in the scientific community. Extinctions do not happen becasue of reduced genetic variability. Since life has been on earth for about 3.5 billion years, I would guess that there should be no genetic diversity if your case exists. Species go extinct because they cannot adapt quickly enough to changing pressures.
The dinos went extinct because they could not adapt quickly enough to survive the drastically new climate. The tiny mammals, having endothermy and being capable of surviving in the new climate found a pretty empty world to explore.

This message is a reply to:
 Message 24 by Faith, posted 03-25-2006 10:22 PM Faith has replied

Replies to this message:
 Message 26 by Faith, posted 03-25-2006 11:50 PM kuresu has not replied

  
Faith 
Suspended Member (Idle past 1521 days)
Posts: 35298
From: Nevada, USA
Joined: 10-06-2001


Message 26 of 59 (298195)
03-25-2006 11:50 PM
Reply to: Message 25 by kuresu
03-25-2006 10:48 PM


as far as I know, there is no fallen world in the scientific community.
Yes. Sad. They'd understand SO much if they just took the evidence all around them seriously, the death and disease they think are normal, that are really evidence of the fallen state of the world.
Extinctions do not happen becasue of reduced genetic variability.
Sometimes they do. There is special concern about extinction in the case of those species that have such depleted genetic capacity, because of their inability to adapt.
Since life has been on earth for about 3.5 billion years, I would guess that there should be no genetic diversity if your case exists.
That is true, there wouldn't be. Evidence that the earth is only 6000 years old.
Species go extinct because they cannot adapt quickly enough to changing pressures.
Yes, and this is either because the circumstances would be lethal no matter what, or because they haven't the genetic diversity to adapt.
The dinos went extinct because they could not adapt quickly enough to survive the drastically new climate.
So goes the story. But the dinos are often found all jumbled up in fossil beds in a way that suggests they were washed there by a massive amount of water.
The tiny mammals, having endothermy and being capable of surviving in the new climate found a pretty empty world to explore.
So goes the interpretation. A likely story.
This message has been edited by Faith, 03-25-2006 11:52 PM
This message has been edited by Faith, 03-25-2006 11:54 PM

This message is a reply to:
 Message 25 by kuresu, posted 03-25-2006 10:48 PM kuresu has not replied

Replies to this message:
 Message 27 by crashfrog, posted 03-26-2006 12:03 AM Faith has replied

  
crashfrog
Member (Idle past 1544 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 27 of 59 (298198)
03-26-2006 12:03 AM
Reply to: Message 26 by Faith
03-25-2006 11:50 PM


They'd understand SO much if they just took the evidence all around them seriously, the death and disease they think are normal, that are really evidence of the fallen state of the world.
You seem to forget, though, that at one time that was taken as the framework with which we viewed the world, with the result that we didn't understand anything.
I mean, you're sitting here saying "gosh, things would be so great if only scientists took genesis literally, we'd understand so much" butm being completely ignorant of history, you're ignoring the fact that for one thousand years we operated from those assumptions, with the end result that human technological progess was halted for centuries.
A likely story.
It is, indeed, the most likely explanation.

This message is a reply to:
 Message 26 by Faith, posted 03-25-2006 11:50 PM Faith has replied

Replies to this message:
 Message 28 by Faith, posted 03-26-2006 1:35 AM crashfrog has not replied

  
Faith 
Suspended Member (Idle past 1521 days)
Posts: 35298
From: Nevada, USA
Joined: 10-06-2001


Message 28 of 59 (298219)
03-26-2006 1:35 AM
Reply to: Message 27 by crashfrog
03-26-2006 12:03 AM


I think the view of fallen nature that we understand now is not what they were working with in the early days of science. From what I've seen they had some very strange ideas about how Biblical truth played out in the world, and we are a lot clearer about it now for some reason.

This message is a reply to:
 Message 27 by crashfrog, posted 03-26-2006 12:03 AM crashfrog has not replied

  
mark24
Member (Idle past 5272 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 5272 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

  
Newer Topic | Older Topic
Jump to:


Copyright 2001-2023 by EvC Forum, All Rights Reserved

™ Version 4.2
Innovative software from Qwixotic © 2024