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Author Topic:   How do you define the word Evolution?
arachnophilia
Member (Idle past 205 days)
Posts: 9068
From: god's waiting room
Joined: 05-21-2004


Message 16 of 934 (260058)
11-15-2005 9:05 PM
Reply to: Message 11 by U can call me Cookie
11-15-2005 11:08 AM


Re: First Post , Woot!
Biologically, it is change in allele frequencies between successive generations, sometimes leading to phenotypic change.

welcome.

glad to see some people aren't totally confused. :P


אָרַח

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U can call me Cookie
Member (Idle past 2426 days)
Posts: 228
From: jo'burg, RSA
Joined: 11-15-2005


Message 17 of 934 (260119)
11-16-2005 1:34 AM
Reply to: Message 14 by bkelly
11-15-2005 8:59 PM


You're using the wrong definitions
An ALLELE is just an alternate form of a gene. there aren't necessarily only two forms; many genes have hundreds of alleles.

A LOCUS is basically a position on a chromosome. This applies to genes, short DNA sequences, or even base pairs; and almost never changes, unless a translocation occurs, which is rare.

To say " Alleles at a certain locus" is basically the same as saying "Alleles of a certain gene", for most intensive purposes.

If you remember, we each get a set of chromosomes from each of our parents, 23 + 23 = 46 chromosomes, wherein you have two chromosome 1's, two chromosomes 2's, etc. Each chromosome from your father will have a counterpart from your mother - these corresponding chromosomes are HOMOLOGOUS to each other.

With the above information, you can see that my definition does not bear the restrictions you said it did.

a point to make tho', is that evolution is NOT a "change of gene" from parent to offspring, every generation. If that were the case, no advantageous allele would ever gain a foothold since it would be replaced, almost immediately! This "change in gene" i.e. a mutation would occur, for instance, once off. The offspring that has this mutation (possibly advantageous) would then pass it on to their offspring.

maybe if you look at it from the population perspective, and not the individual perpective it would make more sense.

a change in allele frequencies, due to, say, positive selection, means the increase in frequency of an advantageous allele in a population, resulting in a decrease in frequency of other alleles of that gene.

hope this clears a few things up. altho' very hard to explain these things in 90 words.


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Lammy
Member (Idle past 128 days)
Posts: 3575
From: Chicago Suburbs
Joined: 03-29-2004


Message 18 of 934 (260128)
11-16-2005 2:58 AM
Reply to: Message 1 by bkelly
11-14-2005 4:10 PM


Evolution is a drastic physical change in many individuals of a population or species within one or two generations resulting in the birth of a new population or species and the extinction of the parent population or species by some unknown or unidentifiable mechanism.

This message has been edited by Lam, 11-16-2005 02:59 AM


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deerbreh
Member (Idle past 365 days)
Posts: 882
Joined: 06-22-2005


Message 19 of 934 (260207)
11-16-2005 10:40 AM
Reply to: Message 10 by bkelly
11-15-2005 10:48 AM


Why exclude human intervention? Change is change, regardless of the cause. No reason why humans can't be part of natural selection and evolution.

This message has been edited by deerbreh, 11-16-2005 10:43 AM


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Percy
Member
Posts: 15646
From: New Hampshire
Joined: 12-23-2000
Member Rating: 2.5


Message 20 of 934 (260235)
11-16-2005 1:13 PM
Reply to: Message 18 by Lammy
11-16-2005 2:58 AM


Lam writes:

Evolution is a drastic physical change in many individuals of a population or species within one or two generations resulting in the birth of a new population or species and the extinction of the parent population or species by some unknown or unidentifiable mechanism.

Uh, no.

--Percy


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Ben!
Member (Idle past 1094 days)
Posts: 1154
From: San Diego, CA
Joined: 10-14-2004


Message 21 of 934 (260243)
11-16-2005 1:32 PM
Reply to: Message 18 by Lammy
11-16-2005 2:58 AM


Be serious. Let people speak for themselves within the topic, I don't see the use of trying to characterize others' positions (besides discouraging others from responding).

Go listen to some Billy Joel or something.

Ben


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New Cat's Eye
Member
Posts: 11562
From: near St. Louis
Joined: 01-27-2005
Member Rating: 2.6


Message 22 of 934 (260246)
11-16-2005 1:44 PM
Reply to: Message 15 by bkelly
11-15-2005 9:04 PM


Obviously we don't. I was and am hoping that some that hold the concept of evolution to be false would post their definition.

understood, but it seems like it'd be like raising your hand in the classroom when you're unsure of the answer....people just don't do that.

When a descendant’s inheritable characteristics differ from those of its parent(s).

That’s just a mutation and not evolution

To me, any gene that changes from parent to offspring represents evolution to some degree regardless of what or where that gene is. And why must there be a change in frequency? I have seen that phrase several times and have yet to understand it.

It has to be a change in frequency because an individual cannot evolve. It is something that happens to a population. Say 50% of a population has one allele and the other 50% has another. After some time if the ratio of that allele changes to 51% and 49%, then the frequency of that allele has changed and the population is said to have evolved.

ABE:

If the population size is 100 individuals, in the case above, only one individual had a change in its allele. That individual did not evolve, it had a mutation and that mutation was the reason that the one allele became more frequent and the population evolved.

This message has been edited by Catholic Scientist, 11-16-2005 12:49 PM


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New Cat's Eye
Member
Posts: 11562
From: near St. Louis
Joined: 01-27-2005
Member Rating: 2.6


Message 23 of 934 (260247)
11-16-2005 1:45 PM
Reply to: Message 15 by bkelly
11-15-2005 9:04 PM


double post

This message has been edited by Catholic Scientist, 11-16-2005 12:45 PM


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EZscience
Member (Idle past 2626 days)
Posts: 961
From: A wheatfield in Kansas
Joined: 04-14-2005


Message 24 of 934 (260259)
11-16-2005 2:13 PM
Reply to: Message 1 by bkelly
11-14-2005 4:10 PM


Evolution is simply a character change in a population over time.

*Biological* evolution requires that this change have an underlying, heritable (genetic) basis.

However, behaviors can also change through 'cultural evolution' without any genetic foundation.

What many fail to recognize is that evolution is exclusively a population-level phenomenon - individuals cannot 'evolve'.

Evolutionary change can only be confirmed by measuring changes in quantifiable character sets among populations over time, or among populations that have been geographically separated for some period.


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bkelly
Inactive Member


Message 25 of 934 (260351)
11-16-2005 7:57 PM
Reply to: Message 18 by Lammy
11-16-2005 2:58 AM


small is good
Lam writes:

Evolution is a drastic physical change ...

I can say that is indeed incorrect. The smallest detectable change in inheritable characteristics from parent to child is evolution.

What is your position on ToE? Do you think that species can evolve into new species?


Truth fears no question.

bkelly


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bkelly
Inactive Member


Message 26 of 934 (260360)
11-16-2005 8:06 PM
Reply to: Message 22 by New Cat's Eye
11-16-2005 1:44 PM


Catholic Scientist writes:

That’s just a mutation and not evolution

I do not agree with that. Assume we have a population of blue eyed people that have had blue eyes for many thousands of generations. For no apparent reason a person with green eyes is born from mother and father with blue eyes. You would call that a mutation. I say there has been some amount of evolution.

Lets say the blue eyes spread to that persons 3 children, then to the 9 granchildren, then the 27 of the next generation then the 100 of the next, etc, etc. As what point does this change from a mutation to evolution? Why do you select that point?


Truth fears no question.

bkelly


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bkelly
Inactive Member


Message 27 of 934 (260363)
11-16-2005 8:12 PM
Reply to: Message 19 by deerbreh
11-16-2005 10:40 AM


in agreement
Hello deerbreh,
We are in agreement. Someone I worked with did not like the ToE. When I laid out some examples he said that they did not count because humans caused it rather than nature.

Needless to say, we did not agree. I am tempted to say that the roots of our disagreemet was found in our differing definition of the word evolution. On further reflection, I suspect that was the method he used to justify an opinion he did not want to surrender.


Truth fears no question.

bkelly


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New Cat's Eye
Member
Posts: 11562
From: near St. Louis
Joined: 01-27-2005
Member Rating: 2.6


Message 28 of 934 (260416)
11-16-2005 10:46 PM
Reply to: Message 26 by bkelly
11-16-2005 8:06 PM


For no apparent reason a person with green eyes is born from mother and father with blue eyes. You would call that a mutation. I say there has been some amount of evolution.

Well, the apparent reason would be that the green eyes are a mutation, an allele of the blue eyes. Evolution is mutation but on the size scale of an entire popualtion, on the individual scale it is mutation.

Lets say the blue eyes spread to that persons 3 children, then to the 9 granchildren, then the 27 of the next generation then the 100 of the next, etc, etc. As what point does this change from a mutation to evolution?

Each step would be considered evolution because the frequency of the green eye allele has changed with each generation. In the real world the numbers aren't so well defined so everything is based on statistics, i.e. allele frequencies.

Why do you select that point?

Because that is what I was taught in a 100 level college biology course on evolution.


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U can call me Cookie
Member (Idle past 2426 days)
Posts: 228
From: jo'burg, RSA
Joined: 11-15-2005


Message 29 of 934 (260450)
11-17-2005 1:32 AM
Reply to: Message 28 by New Cat's Eye
11-16-2005 10:46 PM


Is a mutation evolution?
One could say that a mutation could be regarded as the "first step" in evolution.

The occurrence of a new allele in a population (thro' mutation in one individual) would, technically, change the allele frequencies of that gene in the population; albeit to the tiniest extent.

The point to make, however, is that mutation is not the be-all and end-all of evolution.


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Percy
Member
Posts: 15646
From: New Hampshire
Joined: 12-23-2000
Member Rating: 2.5


Message 30 of 934 (260549)
11-17-2005 9:07 AM
Reply to: Message 25 by bkelly
11-16-2005 7:57 PM


Re: small is good
Lam is an evolutionist. He was posting his parody of a Creationist misunderstanding of evolution.

--Percy


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