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Author | Topic: Does the history of life require "macroevolution"? | |||||||||||||||||||||||||||||||||||||||||||||
bluegenes Member (Idle past 2499 days) Posts: 3119 From: U.K. Joined:
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It's common for creationists to dismiss any evolution that can be directly observed as "microevolution". It's also common for creationists to claim that bits of "microevolution" do not add up to "macroevolution".
One thing that has been observed in labs is mutation on coding genes that produces new proteins with new function. So, that must be "microevolution" to creationists. Another observed mutation is gene duplication. Also, therefore, microevolution. The interesting thing is that the second of those followed by the first would create an additional, unique protein coding gene. According to the dogma that bits of microevolution do not add up to macroevolution, then presumably this must still be microevolution. That means that genes can be added and evolution can produce complicated organisms with tens of thousands of coding genes without involving "macroevolution", whatever it might be. It seems that, when creationists claim that macroevolution doesn't happen, they are describing something which, on the molecular level, doesn't seem to have been required in this life system. Does everyone agree that all the life we see around us can be produced by microevolution, or is the addition of new genes macro, and the creationists' dogma (micro does not add up to macro) wrong? Edited by bluegenes, : typo
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Admin Director Posts: 13018 From: EvC Forum Joined: Member Rating: 1.9 |
Thread copied here from the Does the history of life require "macroevolution"? thread in the Proposed New Topics forum.
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RAZD Member (Idle past 1427 days) Posts: 20714 From: the other end of the sidewalk Joined:
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Does everyone agree that all the life we see around us can be produced by microevolution, ... It has been. And for simplicity sake it is evolution. Micro and macro are just focal lenses for looking at evolution. The micro lens looks at the changes in traits within a breeding population generation, and (in scientific usage anyway) the macro lens looks at the accumulation of changes over many generations ... but all the changes are due to "micro" evolution -- all evolution occurs within the living generations by microevolution. Creationists often have a misconception of "macroevolution" as some sudden appearance of new species that are not of the same "kind" -- a preposterous interpretation -- and that is why I prefer to not use those terms. Enjoy Edited by RAZD, : .by our ability to understand Rebel☮American☆Zen☯Deist ... to learn ... to think ... to live ... to laugh ... to share. Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)
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Faith  Suspended Member (Idle past 1466 days) Posts: 35298 From: Nevada, USA Joined: |
All the mutations you refer to occur at a particular gene for a particular trait so all they can do is vary that trait. If it's rabbit fur color assuming they can produce something new it will be just another fur color. If it's the immune system it will supposedly provide a new protection against a new disease. In other words all such changes occur within the genome, which is the same thing as saying "within the Kind."
And evolution, the production of a new phenotype, requires the loss of the genetic material for other phenotypes. That means no matter how many mutations you get the production of a new phenotype means losing all but those that contribute to the new phenotype. This is a process of overall loss, not gain. You need gain to keep evolving. The definition of the Kind it seems to me is the point where you run out of genetic diversity. Macroevolution implies the open-ended continuation of change until one species becomes a recognizable new species. This can't happen. You run out of genetic diversity after producing lots of different rabbits or whatever the genome defines. You can never get beyond the rabbit.
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Taq Member Posts: 10044 Joined: Member Rating: 5.3
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Faith writes: And evolution, the production of a new phenotype, requires the loss of the genetic material for other phenotypes. That means no matter how many mutations you get the production of a new phenotype means losing all but those that contribute to the new phenotype. This is a process of overall loss, not gain. You need gain to keep evolving. Why would you need "gain" in order to keep evolving, as you define it? It seems that the production of new phenotypes and the loss of old phenotypes is all you need to keep evolving.
The definition of the Kind it seems to me is the point where you run out of genetic diversity. Since every individual in every generation is born with new genetic diversity it would seem that your definition of Kind can never be used.
Macroevolution implies the open-ended continuation of change until one species becomes a recognizable new species. This can't happen. You run out of genetic diversity after producing lots of different rabbits or whatever the genome defines. You can never get beyond the rabbit. How can you run out of genetic diversity when new genetic diversity is being produced in every generation?
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Taq Member Posts: 10044 Joined: Member Rating: 5.3 |
bluegenes writes: It seems that, when creationists claim that macroevolution doesn't happen, they are describing something which, on the molecular level, doesn't seem to have been required in this life system. I completely agree. When asked for a single DNA sequence difference between the human and chimp genome that required macroevolution instead of microevolution, I have yet to see a creationist point to a single difference that required macroevolution.
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Faith  Suspended Member (Idle past 1466 days) Posts: 35298 From: Nevada, USA Joined: |
Why would you need "gain" in order to keep evolving, as you define it? It seems that the production of new phenotypes and the loss of old phenotypes is all you need to keep evolving. Everybody here except you argues that mutation is the necessary gain, acknowledging that gain, or increased genetic diversity, is needed for evolution. New phenotypes only come at the cost of genetic diversity, so eventually no further evolution is possible. No matter how many mutations are produced, evolution eats them up. I've argued this a million times already.
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Taq Member Posts: 10044 Joined: Member Rating: 5.3 |
Faith writes: Everybody here except you argues that mutation is the necessary gain, acknowledging that gain, or increased genetic diversity, is needed for evolution. The problem is that you haven't shown that "genetic diversity", as you define it, is needed for evolution (or macroevolution).
New phenotypes only come at the cost of genetic diversity, so eventually no further evolution is possible. You keep forgetting that mutations produce new phenotypes on a continual basis. New phenotypes become old phenotypes as new mutations appear. Added in edit: Just to make this a bit clearer . . . Let's say you start with a single gene that has one allele, allele A, that is fixed throughout the population. A mutation occurs in gene A to produce allele B. It turns out that allele B is fitter than allele A, so over time allele A diminishes in number until it is completely replaced by allele B. A few generations later a mutation occurs in allele B to produce allele C. Turns out that allele C is fitter than allele B. Over time, allele C replaces allele B. A few generations later a mutation occurs in allele C to produce allele D. Turns out allele D is fitter than allele C. Over time, allele D replaces allele C. A few generations later a mutation . . . well, you should get the idea by now. Edited by Taq, : No reason given.
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Faith  Suspended Member (Idle past 1466 days) Posts: 35298 From: Nevada, USA Joined: |
Producing new phenotypes that become characteristic of a new population or species requires the loss of competing phenotypes. Doesn't matter if they are the product of mutations or built in alleles, the same processes have to occur to get a new population or race.
Or a breed: domestic breeding makes the point most clearly: to get the breed requires the loss of all the traits for other breeds: to get a Chihuahua all the alleles for a Great Dane are rejected from the gene pool. That is how evolution occurs in the wild too, often by random processes: some individuals from a population leave and start a new population, and depending on the degree of reproductive isolation produce a completely new "species." By losing the traits that belonged to the parent population while forming new phenotypes from a new set of gene frequencies. You can get lots of variation and lots of new species from mere splits in the population, but eventually enough evolution in one direction will lead to the condition of depleted genetic diversity from which further evolution is impossible. Evolution defeats evolution. You can never get anything but variations on a species, never a truly new species.i Edited by Faith, : No reason given.
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RAZD Member (Idle past 1427 days) Posts: 20714 From: the other end of the sidewalk Joined:
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Straw man Evolution defeats Straw man evolution. Fixed it for you. Mutations happen, the evidence is undeniable to people that look at evidence. Mutations can cause new phenotypes, the evidence is undeniable to people that look at evidence. When you only look at half the picture you only see half the picture. You can blind yourself, but you can't blind others, and that is why your silly arguments are never accepted as rational explanations of the real world. Enjoyby our ability to understand Rebel☮American☆Zen☯Deist ... to learn ... to think ... to live ... to laugh ... to share. Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)
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Taq Member Posts: 10044 Joined: Member Rating: 5.3 |
Faith writes: Producing new phenotypes that become characteristic of a new population or species requires the loss of competing phenotypes. When those new phenotypes become fixed in the population, then they become the old phenotype as new alleles appear.
You can get lots of variation and lots of new species from mere splits in the population, but eventually enough evolution in one direction will lead to the condition of depleted genetic diversity from which further evolution is impossible. New mutations replenish that genetic diversity.
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Faith  Suspended Member (Idle past 1466 days) Posts: 35298 From: Nevada, USA Joined: |
New mutations mean no evolution is going on. If you have evolution then you have the elimination of anything that doesn't contribute to the new phenotype, i.e., reduction in genetic diversity. You can have all the mutations you like, for evolution to occur you have to lose most of them. Of course you don't HAVE to have evolution. But I thought that's what we're talking about.
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Taq Member Posts: 10044 Joined: Member Rating: 5.3 |
Faith writes: If you have evolution then you have the elimination of anything that doesn't contribute to the new phenotype, i.e., reduction in genetic diversity. First, neutral drift will preserve mutations that have nothing to do with phenotype. Second, new mutations are occurring in each individual in each generation which increases genetic diversity.
You can have all the mutations you like, for evolution to occur you have to lose most of them. But you still keep some of them, and they accumulate over time.
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Taq Member Posts: 10044 Joined: Member Rating: 5.3 |
For discussion purposes I will use a simple DNA sequence to see what happens over time.
Here is our sequence: AAAAAAAAAAAAAAAAAAA A mutation occurs in this sequence that is beneficial: AAATAAAAAAAAAAAAAAA Over time, it replaces the previous allele. After the new allele replaces the old allele, yet another beneficial mutation occurs in that gene: AAATAAAAAAAATAAAAAA This new allele replaces the previous allele. Once the newest allele reaches fixation a beneficial mutation occurs in the newest allele: AAATAAAATAAATAAAAAA Each step along the way is microevolution. How many times does this have to occur before creationists will label it as macroevolution?
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Faith  Suspended Member (Idle past 1466 days) Posts: 35298 From: Nevada, USA Joined: |
Mutations are not microevolution. Microevolution is changes in the phenotype not the DNA. Mutations may or may not play a part in a new phenotype.
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