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Author Topic:   Definition of Evolution
Ihategod
Member (Idle past 4138 days)
Posts: 235
Joined: 08-15-2007


Message 121 of 212 (419314)
09-02-2007 2:06 AM
Reply to: Message 101 by Xaruan
08-31-2007 1:23 PM


Re: Denial, Definitions and Reality
Isn't this the thread about "Definition of Evolution" not the thread about "Proving the Theory of Evolution"? Seriously, threads have topic titles for a reason.

Thank you, your input is wonderful.

From xuraun:

"Change in a population's genetic traits across generations"

Is this acceptable? Please no more extra twists to supplicate your religious beliefs/.


This message is a reply to:
 Message 101 by Xaruan, posted 08-31-2007 1:23 PM Xaruan has not yet responded

Replies to this message:
 Message 122 by Modulous, posted 09-02-2007 5:58 AM Ihategod has responded
 Message 123 by nator, posted 09-02-2007 7:25 AM Ihategod has not yet responded

  
Modulous
Member (Idle past 212 days)
Posts: 7789
From: Manchester, UK
Joined: 05-01-2005


Message 122 of 212 (419329)
09-02-2007 5:58 AM
Reply to: Message 121 by Ihategod
09-02-2007 2:06 AM


So what is this evolution thing, anyway?
"Change in a population's genetic traits across generations"

Is this acceptable?

Yes - it is acceptable. There are other acceptable definitions such as 'Evolution is the change in hereditary traits within populations of species over time'. Futuyuma wonderfully put it like this 'Biological evolution ... is change in the properties of populations of organisms that transcend the lifetime of a single individual...The changes in populations that are considered evolutionary are those that are inheritable via the genetic material from one generation to the next.'

Curtis and Barnes' "Biology" gives us "evolution can be precisely defined as any change in the frequency of alleles within a gene pool from one generation to the next.""

Larry Moran has collated these quotes in this rather famous article - and he has recently expanded on this article at his blog. In which he tackles some of the issues that have arisen in this thread:

quote:

Many people are confused about the difference between a definition and an explanation. That's why we often see incorrect "definitions" that describe how natural selection works. This is wrong. In order to be useful, a definition has to enable us to distinguish examples of evolution from non-evolution but the definition should be neutral with respect to how evolution occurs. It should not distinguish, for example, between Lamarckian evolution and Darwinian evolution even though we know that one of these explanations is incorrect.

He also warns us of confusing the scientific term of biological evolution with the modern vernacular definition. The latter is of little interest to us here! He concludes with

quote:
The amazing thing about the minimal definition of biological evolution is that it doesn't carry any baggage concerning the history of life or its future. As soon as we try to define evolution in terms of the historical record, we run into all kinds of problems because we confuse evolution as a process with evolution as a history of life.

To be honest - I think that should conclude things nicely, no?


This message is a reply to:
 Message 121 by Ihategod, posted 09-02-2007 2:06 AM Ihategod has responded

Replies to this message:
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nator
Member (Idle past 278 days)
Posts: 12961
From: Ann Arbor
Joined: 12-09-2001


Message 123 of 212 (419337)
09-02-2007 7:25 AM
Reply to: Message 121 by Ihategod
09-02-2007 2:06 AM


Re: Denial, Definitions and Reality
quote:
Is this acceptable? Please no more extra twists to supplicate your religious beliefs/.

Is it your position that Biologists, Evolutionary Geneticists, and Paleontologists accept the theory of Evolution on nothing more than religious faith?


This message is a reply to:
 Message 121 by Ihategod, posted 09-02-2007 2:06 AM Ihategod has not yet responded

    
Xaruan
Junior Member (Idle past 4160 days)
Posts: 8
Joined: 08-31-2007


Message 124 of 212 (419348)
09-02-2007 10:35 AM
Reply to: Message 122 by Modulous
09-02-2007 5:58 AM


Re: So what is this evolution thing, anyway?
You summed it up nicely.
I'm going to repost the same quotes, because no one should overlook them.

quote:
Many people are confused about the difference between a definition and an explanation. That's why we often see incorrect "definitions" that describe how natural selection works. This is wrong. In order to be useful, a definition has to enable us to distinguish examples of evolution from non-evolution but the definition should be neutral with respect to how evolution occurs. It should not distinguish, for example, between Lamarckian evolution and Darwinian evolution even though we know that one of these explanations is incorrect.

The amazing thing about the minimal definition of biological evolution is that it doesn't carry any baggage concerning the history of life or its future. As soon as we try to define evolution in terms of the historical record, we run into all kinds of problems because we confuse evolution as a process with evolution as a history of life.


Edited by Xaruan, : No reason given.


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Dr Adequate
Member
Posts: 16093
Joined: 07-20-2006
Member Rating: 9.0


Message 125 of 212 (419353)
09-02-2007 11:14 AM
Reply to: Message 119 by Ihategod
09-02-2007 1:55 AM


Re: Denial, Definitions and Reality
Aren't you a moderator?

No.

Why are you OT?

I'm responding to your post.

And why are you presenting your opinion as fact?

I present the facts as facts because they are facts. When I write "There are also people who "contest" the Holocaust, the Big Bang, the round earth, heliocentrism, and the fact that the law says that you have to pay income tax" --- those are what we call "facts". As in true things that, y'know, correspond with reality.

I rest my case. www.evcforum.net/cgi-bin/dm.cgi?action=msg&f=14&t=1973&m=1 -->www.evcforum.net/cgi-bin/dm.cgi?action=msg&f=14&t=1973&m=1">http://www.evcforum.net/cgi-bin/dm.cgi?action=msg&f=14&t=1973&m=1

By which I take it that you mean that your fantasy that I am a moderator corroborates your fantasies about the moderators.

Edited by Dr Adequate, : No reason given.

Edited by Dr Adequate, : No reason given.

Edited by Dr Adequate, : No reason given.


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RAZD
Member
Posts: 19818
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 10.0


Message 126 of 212 (419452)
09-02-2007 11:15 PM
Reply to: Message 122 by Modulous
09-02-2007 5:58 AM


Re: So what is this evolution thing, anyway?
Thanks. I've borrowed some of this for Message 117

The blog is good reading too.

"Change in a population's genetic traits across generations"

Is this acceptable?

Yes - it is acceptable. There are other acceptable definitions such as 'Evolution is the change in hereditary traits within populations of species over time'.

Works for me.

Enjoy.


Join the effort to unravel AIDS/HIV, unfold Proteomes, fight Cancer,
compare Fiocruz Genome and fight Muscular Dystrophy with Team EvC! (click)


we are limited in our ability to understand
by our ability to understand
RebelAAmericanOZen[Deist
... to learn ... to think ... to live ... to laugh ...
to share.

This message is a reply to:
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Replies to this message:
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Doddy
Member (Idle past 4018 days)
Posts: 563
From: Brisbane, Australia
Joined: 01-04-2007


Message 127 of 212 (419468)
09-03-2007 12:12 AM
Reply to: Message 115 by Rrhain
09-01-2007 5:18 AM


I think I've spent enough time reading creationist works to answer these:

Rrhain writes:

But what is a "kind" and how does the genome know that it isn't allowed to evolve beyond that limit?


Firstly, the genome doesn't know what a kind is. Just as evolutionists will point out that creatures do not know to evolve. Rather, it is just something that occurs due to physical laws.

Now, because the laws of the universe (as read by creationists) prohibit information increasing without intelligence (more information) instructing it to do so, evolution is limited to the information it began with after creation. So, whatever the original created organisms were, evolution can only modify (i.e. make worse) those organisms. A 'kind' simply refers to all those organisms that are commonly descended from this perfect created kind.

Rrhain writes:

Is a "fox" part of the "dog" kind?


I don't know, and I don't think any creationist knows either. But just because we don't know, it doesn't mean the term 'kind' is meaningless or that 'evolution did it'.


Help to inform the public - contribute to the EvoWiki today!

What do you mean "You can't prove a negative"? Have you searched the whole universe for proofs of a negative statement? No? How do you know that they don't exist then?!


This message is a reply to:
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Replies to this message:
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Ihategod
Member (Idle past 4138 days)
Posts: 235
Joined: 08-15-2007


Message 128 of 212 (419506)
09-03-2007 10:59 AM
Reply to: Message 122 by Modulous
09-02-2007 5:58 AM


Re: So what is this evolution thing, anyway?
Sounds good. Case closed.
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Fosdick 
Suspended Member (Idle past 3608 days)
Posts: 1793
From: Upper Slobovia
Joined: 12-11-2006


Message 129 of 212 (419516)
09-03-2007 11:48 AM
Reply to: Message 126 by RAZD
09-02-2007 11:15 PM


Re: So what is this evolution thing, anyway?
RAZD wrote:

"Change in a population's genetic traits across generations"

Is this acceptable?

Yes - it is acceptable. There are other acceptable definitions such as 'Evolution is the change in hereditary traits within populations of species over time'.

Works for me.


Yes, it works for me, too. But the evo-devo people say evolution can happen even without the inheritance of genetic traits. Lamarck would have agreed. But I don't.

My own short definition of "this evolution thing" is simply: A population's success in fixing beneficial alleles. This definition goes a critical step beyond saying only that evolution is a "Change in a population's genetic traits across generations."

First Law : Second Law :: change in genetic traits : fixation of beneficial alleles

—HM


This message is a reply to:
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Replies to this message:
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 Message 139 by RAZD, posted 09-03-2007 9:26 PM Fosdick has responded

    
NosyNed
Member
Posts: 8842
From: Canada
Joined: 04-04-2003
Member Rating: 7.4


Message 130 of 212 (419525)
09-03-2007 12:06 PM
Reply to: Message 129 by Fosdick
09-03-2007 11:48 AM


Disagreeing with "beneficial"
I'm forced to disagree with your inclusion of beneficial HM.

Evolution happens through things like drift without any "benefit" being involved. Evolution may also happen that eventually leads to the extinction of a species. In fact, very often but only some of the time because of the evolution, more often because of too rapid environmental change.


This message is a reply to:
 Message 129 by Fosdick, posted 09-03-2007 11:48 AM Fosdick has responded

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RAZD
Member
Posts: 19818
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 10.0


Message 131 of 212 (419530)
09-03-2007 12:21 PM
Reply to: Message 130 by NosyNed
09-03-2007 12:06 PM


Re: Disagreeing with "beneficial"
But you could say that fixing of new alleles in a population is an important step. Most (surviving) mutations in populations are in recessive genes and this makes their spread within a population easier.

However, once fixed in a population they are still subject to variation in number within the population, so they are still subject to evolution as the change in alleles from generation to generation.

Enjoy.


Join the effort to unravel AIDS/HIV, unfold Proteomes, fight Cancer,
compare Fiocruz Genome and fight Muscular Dystrophy with Team EvC! (click)


we are limited in our ability to understand
by our ability to understand
RebelAAmericanOZen[Deist
... to learn ... to think ... to live ... to laugh ...
to share.

This message is a reply to:
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Wounded King
Member (Idle past 2203 days)
Posts: 4149
From: Edinburgh, Scotland
Joined: 04-09-2003


Message 132 of 212 (419537)
09-03-2007 12:36 PM
Reply to: Message 129 by Fosdick
09-03-2007 11:48 AM


Re: So what is this evolution thing, anyway?
But the evo-devo people say evolution can happen even without the inheritance of genetic traits.

I'd like you to clear up quite what you mean by this. Do you mean that they recognise that epigenetic factors such as methylation exist? The fact that there can be heritable traits outside of simply the primary sequence of DNA hardly means that 'evo-devo' people in any way discount the importance of genetics. Are you saying that epigenetic factors like DNA methylation are not heritable, there is considerable research showing they can be?

I have to agree with the other opinions questioning your focus on the beneficial nature of alleles being important for evolution, for the success of any particular species perhaps but not for the process of evolution.

TTFN,

WK


This message is a reply to:
 Message 129 by Fosdick, posted 09-03-2007 11:48 AM Fosdick has responded

Replies to this message:
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Fosdick 
Suspended Member (Idle past 3608 days)
Posts: 1793
From: Upper Slobovia
Joined: 12-11-2006


Message 133 of 212 (419549)
09-03-2007 1:25 PM
Reply to: Message 132 by Wounded King
09-03-2007 12:36 PM


Re: So what is this evolution thing, anyway?
WK:

But the evo-devo people say evolution can happen even without the inheritance of genetic traits.

I'd like you to clear up quite what you mean by this.

I have read Mary Jane West-Eberhard's entire "Developmental Plasticity and Evolution" (2003). She is a leading evo-devo-ist, and she argues for the role of "homoplasy" as an alternative to homology (genetic inheritance) for explaining evolution. She argues for a "homeostatic, canalizing, contraining force" coming from the environment that accounts for evolution. Well, who would deny that changes in environmental conditions will provoke adaptive responses by populations, but adaptation does not occur until the benefical alleles are fixed. That is where evolution happens, IMO.

The same criticism can be leveled at another evo-devo-ist, Simon Conway Morris, who, in his "Life's Solution/Inevitable Humans in a Lonely Universe," says:

quote:
So the beetle, no longer the butt of Haldane's jibe, is an example of the richness of a Creation...None of it presupposes, let alone proves, the existence of God, but all is congruent. For some it will remain as the pointless activity of the Blind Watchmaker...
Is there any doubt who he has in mind for this barb?

Then you ask:

Do you mean that they recognise that epigenetic factors such as methylation exist?

I don't see evo-devo-ists talking about methylation or introns or other factors relavant to evolution. But what if they did? Even those are members of a genetic complex that must be heritable or otherwise lost in a population

—HM


This message is a reply to:
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Replies to this message:
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Fosdick 
Suspended Member (Idle past 3608 days)
Posts: 1793
From: Upper Slobovia
Joined: 12-11-2006


Message 134 of 212 (419552)
09-03-2007 1:33 PM
Reply to: Message 130 by NosyNed
09-03-2007 12:06 PM


Re: Disagreeing with "beneficial"
Nosy wrote:

Evolution happens through things like drift without any "benefit" being involved.

I agree that selection is not the only way that alleles get fixed. Drift will fixed them, too. And whatever is beneficial will likely play its role when selective pressures arise.

—HM


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Dr Adequate
Member
Posts: 16093
Joined: 07-20-2006
Member Rating: 9.0


Message 135 of 212 (419594)
09-03-2007 6:29 PM
Reply to: Message 133 by Fosdick
09-03-2007 1:25 PM


Re: So what is this evolution thing, anyway?
I have read Mary Jane West-Eberhard's entire "Developmental Plasticity and Evolution" (2003). She is a leading evo-devo-ist, and she argues for the role of "homoplasy" as an alternative to homology (genetic inheritance) for explaining evolution.

Yes. We know about convergent evolution.

But that is not the same as saying that "evolution can happen even without the inheritance of genetic traits".

The same criticism can be leveled at another evo-devo-ist, Simon Conway Morris ...

He's a paleontologist.

Is there any doubt who he has in mind for this barb?

No, but there might be considerable confusion as to what this has to do about "evolution without the inheritance of genetic traits".


This message is a reply to:
 Message 133 by Fosdick, posted 09-03-2007 1:25 PM Fosdick has responded

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