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Author | Topic: How do you define the word Evolution? | |||||||||||||||||||||||||||
arachnophilia Member (Idle past 1365 days) Posts: 9069 From: god's waiting room Joined: |
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.
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U can call me Cookie Member (Idle past 4974 days) Posts: 228 From: jo'burg, RSA Joined: |
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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coffee_addict Member (Idle past 498 days) Posts: 3645 From: Indianapolis, IN Joined: |
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 2914 days) Posts: 882 Joined: |
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: 22480 From: New Hampshire Joined: Member Rating: 4.8 |
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 1419 days) Posts: 1161 From: Hayward, CA Joined: |
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 Inactive Member |
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 Inactive Member |
double post
This message has been edited by Catholic Scientist, 11-16-2005 12:45 PM
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EZscience Member (Idle past 5175 days) Posts: 961 From: A wheatfield in Kansas Joined: |
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 |
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 |
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 |
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 Inactive Member |
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 4974 days) Posts: 228 From: jo'burg, RSA Joined: |
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: 22480 From: New Hampshire Joined: Member Rating: 4.8 |
Lam is an evolutionist. He was posting his parody of a Creationist misunderstanding of evolution.
--Percy
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