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Author | Topic: "Best" evidence for evolution. | |||||||||||||||||||||||||||||||||||||||
frako Member (Idle past 332 days) Posts: 2932 From: slovenija Joined: |
I was talking about the emigration of a smallish number of individuals from a parent population to form a new daughter population in reproductive isolation. And a shorter way to say that would be??? Christianity, One woman's lie about an affair that got seriously out of hand What are the Christians gonna do to me ..... Forgive me, good luck with that.
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frako Member (Idle past 332 days) Posts: 2932 From: slovenija Joined:
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I was talking about the emigration of a smallish number of individuals from a parent population to form a new daughter population in reproductive isolation. And a shorter way to say that would be??? Christianity, One woman's lie about an affair that got seriously out of hand What are the Christians gonna do to me ..... Forgive me, good luck with that.
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Tangle Member Posts: 9509 From: UK Joined: Member Rating: 4.8
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Faith writes: I wasn't talking about a bottleneck, I was talking about the emigration of a smallish number of individuals from a parent population to form a new daughter population in reproductive isolation. That's a bottleneck.
Just this smaller number of individuals will produce a new set of traits for a new composite phenotype over a few generations of breeding in isolation, and depending on the number of individuals this will involve some level of reduced genetic diversity. Yes, that's what bottlenecks do. If two bison separate from a herd of 100,000, the two have less genetic diversity than the 99,998. (But overall there is no reduction in diversity.) If 50,000 separate there is probably no loss of genetic diversity. But so long as they never meet again the two populations will diverge.
Mutations don't enter into it. They may contribute a change from time to time but there's no reason to think they contribute more than that. And that exactly what they do do - introduce a change from time to time. That all evolution is.Je suis Charlie. Je suis Ahmed. Je suis Juif. Je suis Parisien. I am Mancunian. I am Brum. I am London.I am Finland. Soy Barcelona "Life, don't talk to me about life" - Marvin the Paranoid Android "Science adjusts it's views based on what's observed.Faith is the denial of observation so that Belief can be preserved." - Tim Minchin, in his beat poem, Storm.
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Faith  Suspended Member (Idle past 1471 days) Posts: 35298 From: Nevada, USA Joined: |
Make it a hundred that separate from a population of a thousand. I'm not talkinjg about a bottleneck, I'm talking about some normal number that would emigrate, some portion of a population that would possess less genetic diversity and that means just about any smallish portion. It would possess its own set of gene frequencies which is how you get the new traits in the new composite phenotype of the new species in the ring. If half the population emigrates then there will probably not be a lot of change but there will probably be some, and in this case in both populations.
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RAZD Member (Idle past 1432 days) Posts: 20714 From: the other end of the sidewalk Joined: |
\Why do they look alike Faith? Why does species A look like species B? Isn't that like a dog evolving into a cat Neither you nor I think that. Nor do I think they must be the same species as you first absurdly suggested. Just saying that if a population evolves to look like and behave like another population, that for all intents and purposes it has become a different kind, based on how "kind" is defined.
You call it convergent evolution, the idea being that they evolved separately. Which is pretty much what I''d say too. So there really isn't much of an issue here. But just calling it "convergent evolution" doesn't explain why "species A looks like species B" anyway, it just says it happens. I don't have an explanation either except that the same function can show up in different species, which doesn't explain it either, just says it happens, same as you say it happens. It's a wonderful mystery really. Convergent evolution is explained by similar ecological pressures. This is why there are several differently evolved gliding tree frogs -- it's easier to get from tree to tree and to evade predators.
In fact there are a lot of wonderful mysteries to ponder in either theory. The strikingly specific kinds of animals that I'm imputing to the same genome is a great mystery. I don't think they were separately created which would easily solve the problem, I do think they "evolved" from the original, say, bird, or cat or dog genome, but they are such specifically designed creatures with such specifically different adaptations it's truly wonderful. I have to try to understand how the penguin came out of the bird genome, or the ostrich. The penguin with its peculiarly specific bodily structure and behaviors, the ostrich with its peculiarly specific bodily structure and behaviors, each perfectly adapted to its environment. Evolution explains it quite well, adaptation to specific ecological habitats, over time becoming more and more adapted to those habitats. Whether we are talking about evolution within a clade (biological/evolutionary) or within a "kind" (creationist) the result is the same -- adaptation to specific habitats brings out specific adaptations.
In my scenaio they evolved, just as they did in your scenario, but their specificity is too wonderful for that explanation. No I don't think they were separately created, I do think they evolved from the original Bird Kind, but it's hard to see how the random methods of evolution could have brought that about. And of course I mean microevolution, and of course so do you. Their "specificity is too wonderful for that explanation" is easily explained by adaptation over many generations from the parent Clade/"Kind" population. This of course gets us into the question of how much time is involved: I have billions of years, you just a few thousand years, so they had to evolve at a much faster rate for your view than mine.
Same wonderful mystery with dogs. As I concluded from the Linnaean taxonomy, the Dog Kind includes wolves and foxes and coyotes and dingos and perhaps some other odd variations. If I believe they all came from an original Dog Kind then I believe they evolved, just as you believe they evolved. Agreed, and again the issue of time is raised -- how fast they evolved generation by generation. Just as we saw with the mammal ear evolution. Out of interest where do you put hyenas and thylacines? They appear similar to dogs imho, more convergent evolution? Did the thylacines evolve to be like dogs for all intents and purposes?
I could raise the question from my point of view whether such specific variations had already arisen before the Flood and were taken into the Ark as separate species, or evolved AFTER the Flood from the two chosen. I probably won't be able to answer that for sure but my feeling is that they must have been treated as separate species so each would have been brought in twos onto the Ark. Which is irrelevant if there was not flood.
These very specific variations of birds or dogs or any other Kind or Class or Family seem very hard to explain on the basis of evolution which always suggests something piecemeal. ... Like microevolution generation after generation after generation ... where I have plenty of time and you don't.
... But these creatures have an organized wholeness whose parts would have to have evolved all together it seems. I ran into this same issue when thinking aobut how apes could have evolved into humanity. ... False assumptions lead to false conclusions.
... So many parts of the creature work together it's hard to figure out how they could have evolved one at a time through mutations. ... Because they evolved to work together as they evolved.
... In the case of the Kind it's hard to imagine how even though they share a genome all the different functions they need that are built into the genome still have to be inherited as a unit rather than piecemeal by population splits. The penguins all have total body feather coverage, they all nurture their eggs between their feet, they are all supremely adapted to swimming in freezing water, how did all that adaptation come together by mere evolution, whether the ToE version or the Kind version? it's hard to explain either way. Oh I know it can be explained but I mean such adaptations defy the usual explanations and need a more satisfying explanation than the usual ones. Again the issue comes down to time, which makes small steps over many generations over billions of years an adequate explanation, but limiting it to a few thousand years much more difficult. You need hyper-evolution and many lumps to get there, while evolution doesn't. That makes evolution the better explanation. Enjoy Edited by RAZD, : finishedby our ability to understand RebelAmericanZenDeist ... 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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Tangle Member Posts: 9509 From: UK Joined: Member Rating: 4.8 |
Faith writes: Make it a hundred that separate from a population of a thousand. I'm not talkinjg about a bottleneck That would be a bottleneck.
I'm talking about some normal number that would emigrate, There is no such thing as a 'normal number'. There is a minimum number though, that's the number at which the likelihood of survival is higher than the likelihood of extinction. That's actually quite a high number.
If half the population emigrates then there will probably not be a lot of change but there will probably be some, and in this case in both populations. The two populations will stay the same for as long as there's no environmental pressure for them to change. If the environments are the same, there will be little change. If they are different there will be greater change. (See Darwin's finches) If they are very different it's probable that one or both populations will go extinct. You may be interested in this
quote: Je suis Charlie. Je suis Ahmed. Je suis Juif. Je suis Parisien. I am Mancunian. I am Brum. I am London.I am Finland. Soy Barcelona "Life, don't talk to me about life" - Marvin the Paranoid Android "Science adjusts it's views based on what's observed.Faith is the denial of observation so that Belief can be preserved." - Tim Minchin, in his beat poem, Storm.
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Faith  Suspended Member (Idle past 1471 days) Posts: 35298 From: Nevada, USA Joined: |
Following a population bottleneck, the remaining population faces a higher level of genetic drift, which describes random fluctuations in the presence of alleles in a population. In small populations, infrequently occurring alleles face a greater chance of being lost, which can further decrease the gene pool. Due to the loss of genetic variation, the new population can become genetically distinct from the original population, which has led to the hypothesis that population bottlenecks can lead to the evolution of new species. Absolutely, juist what I'm talking about although I haven't regarded such a large portion of a population to be a bottleneck. But as usual that's just a semantic glitch people like to throw ibnto the discussion from time to time. No problem, the wpoint is that the smaller population WILL lose the infrequently occurring alleles and under those circumstance some dramatically new traits can develop and create a new composite phenotype quite different from the parent population and all the others in the ring species. This is due to the loss of genetic diversity, in this case the loss of the low frequency alleles. Just what I've been saying has to happen. And they call the resulting new population with its own new traits a "species." I'd call it a "subspecies" or variation myself, and since this is a ring species another population will develop out of this one two by the emigtation of some number to a new location where it will also develop its own peculiar composite phenotype due to reduced genetic diversity.
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RAZD Member (Idle past 1432 days) Posts: 20714 From: the other end of the sidewalk Joined: |
... I don't see any need to get into the strictly scientific designations. If such designations are clearly needed in some discussion or other, that's another story. Otherwise the insistence on the strictly scientific terminology is just a way of obstructing communication. No, it's a way to reduce confusion and promote communication.
Well I've many times shown that there is such a barrier and it's only a dogmatic blind adherence to the "science" that refuses to recognize it cuz it blows the ToE to smithereens. But I don't have to prove this at EvC, I can work it out for others elsewhere. You THINK you have, but your "proof" relies on a hidden assumption -- that mutations are inadequate to increase genetic variation, when this is obviously not the case. A "proof" based on false assumptions is not valid. Enjoyby our ability to understand RebelAmericanZenDeist ... 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 1471 days) Posts: 35298 From: Nevada, USA Joined: |
It's not an assumption, I've worked it out. First you can't maintain a species in the wild or a breed in artificial selection if you have any kind of increase in genetic diversity, wether through gene flow or mutation. Since both breeds and species in the wild maintain an identifiable characteristics we know that neither of these sources of increase occur, or that they are extremely rare.
Second, if such increases do occur, usually from resumed gene flow rather than mutation, since mutation doesn't contribute much change in a short period of time, then if a population split occurs or any other kind of selection we will again have reduced genetic diversity which always occurs when new traits form a new composite phenotype. Selection IS the driving force of evolution and it always decreases genetic diversity.
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PaulK Member Posts: 17827 Joined: Member Rating: 2.3 |
quote: As we will see, you haven’t.
quote: That is obviously false. Maybe there is some sort of maximum to diversity but it is far from clear that any species has come close to reaching it. And if they have not then more diversity can be added.
quote: Species are not breeds. Breeds are derived from species and the breeds in aggregate will show greater phenotypic variation. Even if the breeds have less genetic diversity than the wild species they were derived from. Clearly it is NOT a simple matter of genetic diversity.
quote: Why assume only a short period of time? Not that population splits tend to greatly reduce diversity even if we consider the sub-populations against the combined population.
quote: Selection is the guiding force. Mutation drives it by providing the necessary diversity.
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Faith  Suspended Member (Idle past 1471 days) Posts: 35298 From: Nevada, USA Joined: |
All populations that have an identifiable homogenous composite phenotype (to use dwise's term which I think is a good one) have a reduced genetic diversity compared to the parent population they came from. It's got nothing to do with any "mqaximum" of diversity, it's a relative thing: daughter populations formed from a small portion of the parent population, that form in reproductive isolation, and are not subject to gene flow, have reduced genetic diversity from the parent population. instead of just pronouncing me wrong you have to prove me wrong and you always fail to do so.
Breeds are just like this kind of populaton in the wild that forms from a limited number of individuals in reproductive isolation. Genetically it's the same situation and reduced genetic diversity is always the necessary concomitant to the development of the new population or subpopulation or species or subspecies or varliety or whatever you want to call it. Mutation really has no role in this as I discussed above, and most of it is just wishful thinking anyway, as beneficial mutations don't occur frequently or fast enough to have the effects you imagine. Besides which, as I show above, they would only destroy any newly formed subpopulation's composite phenotype, or any breed, if they did occur, because they are just one form of gene flow which destroys what selection is trying to do. Edited by Faith, : No reason given.
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PaulK Member Posts: 17827 Joined: Member Rating: 2.3 |
quote: I disagree. It will take time, but if the daughter population is successful I expect it to catch up with the diversity of the parent population. There is no reason why it cannot.
quote: What you originally said definitely DID relate to a maximum, since you claimed:
you can't maintain a species in the wild or a breed in artificial selection if you have any kind of increase in genetic diversity That is NOT relative.
quote: Of course I have succeeded in proving you wrong on occasion. However, I need not do so, I only need to show that you lack a good case for your position. Indeed, even here you are arguing a different point rather than defend your original statement - and even so you have not made a case.
quote: No, they are not. Produce examples if you disagree. Genuine examples, not recognised species.
quote: But it is only temporarily necessary. There is nothing stopping diversity from increasing again.
quote: You are the one engaging in wishful thinking, not least because neutral mutations are quite sufficient to restore diversity. You have no numbers to back up your claims.
quote: You have never shown any such thing. You just keep saying it, without even an attempt to support it. Why do you say these things when you must know they aren’t true? In reality selection is not trying to do anything and the idea that new variations must directly target the loci under selection is obviously foolish. Yet if those loci are not targeted the obviously there can be no interference with selection. You obviously have not thought it through.
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frako Member (Idle past 332 days) Posts: 2932 From: slovenija Joined:
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So you are claiming that at a certen point a species would no longer be able to change because of a loss in genetic diversity if they are separated from the pack?
Um soo... how do asexual organism change/evolve then?From the moment they are borne they are separated from their populations genome, they cant exchange chromosomes or genes as they do not have sex. And given that their life cycles are shorter even in a 6000 year old universe they should have run out of genetic diversity and be unable to change/evolve, and yet they do. Could it be that mutations play a larger role than you think? Christianity, One woman's lie about an affair that got seriously out of hand What are the Christians gonna do to me ..... Forgive me, good luck with that.
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Faith  Suspended Member (Idle past 1471 days) Posts: 35298 From: Nevada, USA Joined: |
"Being separated from the pack" has nothing to do with anything I've said.
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frako Member (Idle past 332 days) Posts: 2932 From: slovenija Joined:
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You claimed that the changes we see are do to a loss of genetic diversity, when species undergoes a bottleneck. Well asexual beings go trough a bottleneck at birth. Each is an island un to its own, and yet they keep evolving/changing. How?
Christianity, One woman's lie about an affair that got seriously out of hand What are the Christians gonna do to me ..... Forgive me, good luck with that.
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