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Author | Topic: Does the history of life require "macroevolution"? | |||||||||||||||||||||||||||||||||||||||
Taq Member Posts: 10084 Joined: Member Rating: 5.1
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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: 10084 Joined: Member Rating: 5.1 |
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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Taq Member Posts: 10084 Joined: Member Rating: 5.1 |
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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Taq Member Posts: 10084 Joined: Member Rating: 5.1 |
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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Taq Member Posts: 10084 Joined: Member Rating: 5.1 |
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: 10084 Joined: Member Rating: 5.1 |
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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Taq Member Posts: 10084 Joined: Member Rating: 5.1 |
Faith writes: 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. How else can you get changes in phenotype other than changes in the DNA sequence?
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Taq Member Posts: 10084 Joined: Member Rating: 5.1
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Faith writes: All the increases in genetic diversity by mutation still get reduced when you are getting evolution, And then genetic diversity increases again when new mutations occur.
Evolution always cuts down the genetic diversity, no matter what. Mutations add genetic diversity.
Also the mutation is occurring to a gene, which governs a particular trait, so the best you can get is a new version of that trait. It may even be selected and become part of the new species, but it will never get you beyond the one trait of that one species. Then how is it that different species have different traits?
AND that many beneficial mutations in a sex cell, which is the only way they would get passed on, is not possible anyway. Based on what evidence? There are 40 million mutations that separate chimps and humans, yet they both function just fine.
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Taq Member Posts: 10084 Joined: Member Rating: 5.1 |
Faith writes: You don't need changes in the DNA sequence at all. You could get a new breed or species or subspecies without a single mutation. It's just a matter of changed gene frequencies. How do you get new phenotypes beyond those that are possible with combinations of already existing alleles?
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Taq Member Posts: 10084 Joined: Member Rating: 5.1 |
Faith writes: It doesn't matter how many mutations you have, TO GET EVOLUTION, MEANING A CHANGE IN A POPULATION, THEY HAVE TO BE DECREASED. Add a hundred if you like, you are going to have to get rid of most of them in order to have evolution. In my example we started with this DNA sequence: AAAAAAAAAAAAAAAAAAA After several steps, we ended up with this DNA sequence: AAATAAAATAAATAAAAAA Are you saying that a 15% (3 out of 19 bases) change in DNA sequence is not evolution?
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Taq Member Posts: 10084 Joined: Member Rating: 5.1 |
Faith writes: Mutations are not necessary for evolution. Doesn't change the fact that evolution does occur through mutations.
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Taq Member Posts: 10084 Joined: Member Rating: 5.1 |
Faith writes: But it doesn't occur through mutations at all. We can watch mutations occur and change phenotype. We can watch those mutations being selected for.
Mutations are absolutely and completely irrelevant, Then how do you explain the difference in phenotype between species? Is it due to a difference in DNA sequence or not?
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Taq Member Posts: 10084 Joined: Member Rating: 5.1
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Faith writes: The differences in DNA sequence are built into the genome of the Kind. They are capable of producing a great deal of variation within the Kind. In order to evolve a new kind you would need to change the DNA sequence, correct?
The processes that bring about the changes in phenotype entail loss of genetic diversity, Mutations increase genetic diversity. You are simply wrong.
so that you get new variations or subspecies (or breeds) by losing the alleles for other variations, and ultimately, down a particular line of evolution (or breeding) the new species or breed has only those alleles for that species or breed and has lost the alleles for other species or breeds. You are once again ignoring the mutations that increase genetic diversity. For example, the mutations that produce black coat color in pocket mice. That phenotype was caused by mutations. It changed a phenotype and increased genetic diversity.
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Taq Member Posts: 10084 Joined: Member Rating: 5.1
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Faith writes: To evolve a new KIND something drastic would have to happen to the genome, far different from mutations to genes for the usual traits. I would assume that you think chimps and humans are in different kinds. So what difference is there between the chimp and human genome that can't be produced by the types of mutations we see occurring every day?
As I keep saying increasing genetic diversity 1) is not evolution and 2) to get evolution requires reducing whatever genetic diversity is present, no matter what its origin. And I keep showing how that argument is refuted by the fact that mutations increase genetic diversity.
Evolution as I'm using it means establishing a new population with new traits that differentiate it from the parent population. THAT is what requires reducing genetic diversity. That's exactly what mutations do.
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Taq Member Posts: 10084 Joined: Member Rating: 5.1 |
Faith writes: I've argued this many times before on my own threads and others' threads. And we have repeatedly shown you that mutations increase genetic diversity.
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