What is the Mechanism of Natural Selection for Evolution?

Discussion in 'Biology & Genetics' started by matthew809, Feb 22, 2014.

  1. matthew809 Registered Senior Member

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    How does a minor biological variance(yet theoretically advantageous one) come to dominate the gene pool... over and over and over again.... millions of times.... to create what we see today?
    Besides the relatively sparse dramatic environmental change, what fundamental mechanism can explain such consistent "natural selection" for the evolution of life?

    For example, lets imagine some weird frog-like creature on some hypothetical earth-like planet, billions of years ago. There's millions of these frugs on this planet, and hundreds of other equally weird, young species. One of these frugs has a spot of harder flesh on it's underbelly. It is unique, and will be the basis for a new body part of a new species, billions of years in the future.

    But let's not worry about the far future of these frugs just yet. For now, how does this minor biological variance (yet theoretically advantageous one) initially come to dominate the gene pool?

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  3. Aqueous Id flat Earth skeptic Valued Senior Member

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    Individuals with successful traits (coloration that camouflages) survive long enough to procreate.
     
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  5. Sorcerer Put a Spell on you Registered Senior Member

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    Read 'The Selfish Gene' by Dawkins.
     
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  7. matthew809 Registered Senior Member

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    That would be simply natural selection, which obviously happens.

    My point is that natural selection does not seem to account for the countless insignificant changes that must occur to life for it to evolve to it's current state. By "insignificant" changes I mean changes that don't have any effect on survival or procreation, but are required for evolutionary change.
     
  8. Grumpy Curmudgeon of Lucidity Valued Senior Member

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    matthew809

    Insignificant traits that have no effect on survival may or may not become common in the genome. Blue eyes provide no known advantages, but women might just prefer blue eyed mates, so it becomes quite common. The feathers in the tail of the Peacock are a disadvantage to survival, but the sexual selection pressure insures they remain. And you seem to be saying that traits are built up from unique structures. They are not. Instead Nature modifies existing structure into new configurations, those new configurations have purposes at every stage of change, they are not prepositioned waiting on some future trait. Evolution has no predetermined outcomes, it all happens through mutation followed by the test of survival to reproduce. Successful(and even neutral)traits become more common in the genome because they have more offspring, simple as that.

    Grumpy

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  9. James R Just this guy, you know? Staff Member

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    Variation comes about through the mixing of genes in sexual reproduction, and through mutation.
     
  10. wellwisher Banned Banned

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    Evolution and natural selection is not only connected to the DNA, but is also a function of environmental potentials. Say we have a herd of similar animals living in a warm climate. Some of the offspring develop extra thick fur due to a mutation. This change may not be selected, since this may cause the animal to be too warm in extended activity like hunting or the male mating Olympics. Although this may not work in the warm, this same genetic variation, if it occurred in a cooler climate, might now mean selection. Genes throw up a variation but it is up to the environment to give it a thumbs up or a thumbs down in terms of persistence due to practicality.

    The earth is not a static place, as we see with climate change. The earth will change locally and globally with time, such as the last ice age and the eventual warming again to the present age. These changing potentials have an impact on previous selections, as well as on new selections. The ice age fur may not be useful after the warming started to occur. We don't see many wooly elephants which was predictable.

    Darwin developed his theory on a controlled island environment where change is slower than many places on earth. It would have been hard to make his same inferences if he had stayed in England to develop this theory, which has environmental pressures from humans populations. Or if he had done his research in a place like the YellowStone national park, subject to large forest fires, where nature burns and recovers in a decade with new flora and fauna dominating in such a short time.

    Humans bring to light another factor, connected to choice, which implies the brain. For example, if a male bird is colorful to help attract females. The bottom line is the female's brain is making a choice for natural selection. If you altered her brain new selection could occur. She is using sensory input to trigger the brain, with her brain making a gut choice.

    The brain brings up another feature of evolution called migration. If an animal migrates, with a given set of genetic qualities, it becomes possible to find an environment that suits its DNA, giving itself the possibility of natural selection. The brain will help drive its genetic selection process. For example, if the hairy critter in the first example, had the urge to migrate from the warmer weather (driven out by the herd), to where it was cooler, now it can become selected. When people write in these forums each has certain areas of expertise where we feel more comfortable; gives each person better odds for selection. If you are a troll you will be driven out to another environment. This is all brain not genetics.

    Migration not only helps the critter that migrates, but it will also impact the new environment. In the case of human migration, during the settling of the America's, the settlers brought germs and disease to the indigenous people, thereby changing the parameters of local selection process. Immunity to these particular diseases was not a main factor for local selection before the migration. Immunity, which was always there for some, which allowed many to be resistant, had no real value, until after the environment changes. Now the change bring it out as important.

    With humans, fads change the image in the mind of the ideal women, from thin to full figure and then back to thin or the new normal which is heavier. The distribution of ladies may be the same, but environmental pressures, and the brain, change breeding selection back and forth. As we control the potentials of the environment, like in Galapagos, some of these effects become factored out allowing a simpler theory that create intuitive yellow flags for many like myself.
     
  11. matthew809 Registered Senior Member

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    IMO:

    There are too many incremental steps that evolution must take in order to create the advanced level of life that we have today; the intricate complexity of biology demands a delicate creation. These tiny, inconsequential variations of form (with negligible variation of function) would not be significant enough to affect survival and reproduction, regardless of changes in the environment, and therefore natural selection can not be the main force for this evolutionary change.
     
  12. Grumpy Curmudgeon of Lucidity Valued Senior Member

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    matthew809

    And actual observation of evolution proves your opinion of no value, you are simply wrong. You have no concept of deep time(it's common, nobody does), nor is it evident that you have actually studied the facts. Evolution occurred, that's a fact not a theory. The theories may be more or less accurate and complete but it is a fact that every creature on Earth with a backbone came from a species of fish with a notochord, that your skeleton is nearly identical with a frogs and your DNA is virtually identical with a chimpanzee. All of these mean your ancestors were the same as their ancestors. Oh, your DNA is also about 40% identical to a Banana's, they are your distant cousins.

    Grumpy

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  13. Motor Daddy ☼☼☼☼☼☼☼☼☼☼☼ Valued Senior Member

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    So if I extrapolate some concepts from that concept in which you just mentioned, would you say that it would be logical to conclude that Bananas came from the earth? ...and take an additional leap and say the earth came from the sun?

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  14. matthew809 Registered Senior Member

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    Natural selection is definitely observable. Limited changes in form and function of species are also observable at times. Therefore mainstream science considers "evolution" to be observable, despite the fact that the bulk of evolutionary theory is extrapolated from the former and not observable in the least. So it's really just semantics whether or not you consider "evolution" to be observable. The sort of evolution which my argument addresses is completely different than the observable evolution which you are referring to.

    So, I think you missed my point.
     
  15. matthew809 Registered Senior Member

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    Also, let me make it clear that my argument in this thread isn't necessarily against the idea that life evolved. I am simply making a point that natural selection can not account for most of evolution.
     
  16. spidergoat Valued Senior Member

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    You are basically correct, the vast majority of evolutionary changes have no effect at all on our form, they are the result of random genetic drift, and are neutral and not affected by natural selection. Nevertheless, natural selection still plays a part. Natural selection is not the main force for evolution. However, so-called tiny random changes in DNA can have a major effect on the life that results.

    http://freethoughtblogs.com/pharyng...onary-theory-may-not-be-what-you-think-it-is/
     
  17. Grumpy Curmudgeon of Lucidity Valued Senior Member

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    matthew809

    There is only evolution, there are no different sorts(as you mean the term). And evolutionary theory is separate from the observed facts of evolution. The evolutionary theories are only models of the facts of evolution. And changes in the genome are the result of natural selection applied to sexual mixing and mutations of genes. Your great, great, great...grandfather was a slime mold. While our evidence is not complete and probably never will be, the facts are still conclusive, there can be no doubt about the findings that all life on Earth came from the same ancestors, the survivors of the pre-Cambrian struggle of single celled life. It's written in our DNA in more detail than any book. And while we have not deciphered all of it, we see the major plotlines and the interconnections of all of the players. The DNA that generates certain proteins in a carrot is the same one found in every cell of your body. At it's basic level, life is the DNA molecule and the differences between lifeforms only differences in the machinery of that DNA's reproduction of itself. Mammals share over 75% of their genome with all other mammals, from rats to giraffes, they are largely the same. All of their differences are found in the remaining 25%. The differences between you and a chimp are only a few percent. Between you and a cat, only 10% or so. You share the least with the monotremes and the most with the apes. You sir, are an ape. You evolved from apes and somewhere around 8 million years ago all apes were one species. That's what DNA tells us.

    Grumpy

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  18. Russ_Watters Not a Trump supporter... Valued Senior Member

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    "Irreducible complexity" is textbook anti-evolution crackpottery. Just look it up and read up on it: http://en.wikipedia.org/wiki/Irreducible_complexity

    The short answer though is that most of what crackpots term irreducibly complex really isn't. There are steps in between that are beneficial. I read Darwin's Black Box and it is pretty dumb, disproving itself by first claiming that the eye is irreducibly complex, then acknowledging that the author is aware that it isn't.
    Macro vs micro evolution is also textbook anti-evolution crackpottery. You should just read up on it too: http://www.talkorigins.org/faqs/macroevolution.html

    Note that macro evolution is studied through observation in exactly the same way that macro evolution of our universe is studied - by assembling snapshots in time. In astronomy, it is photos of different stages of evolution of planets, stars and galaxies. In biological evolution, it is currently observed species, fossils and DNA.
     
  19. Trippy ALEA IACTA EST Staff Member

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    Death.
     
  20. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    Or more precisely, early death. I.e. before fertility ends.
     
  21. James R Just this guy, you know? Staff Member

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    I'm not sure what you mean by "most of evolution". Which parts do you think it doesn't account for?

    You're right that there are things that influence evolution. For example, sexual selection is another form of selection.

    Obviously, natural selection doesn't account for why you aren't the same as your mother or father. Your genes are a mixture of theirs, and you are unique. That's just plain old sexual reproduction, with nothing to do with natural selection. Yet, you have "evolved" from your parents.
     
  22. wellwisher Banned Banned

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    One problem I always had with tiny random incremental changes is, if we assume this is true, for the sake of argument, how do we get the persistence of long term common things, under the constraint of random incremental changes? For example, If we have 40% similar genes to a banana, how could these 40% remain persistent if the DNA is under the pressure of constant random incremental change? The 40% are not subject to the same rate of random change or they would be as different as the remaining 60%. This suggested the 40% dice are loaded, so they persist constantly. Only the 60% are regular dice subject to the laws of odds.

    Random incremental change would imply nothing in common with the past, since nothing could be conserved. But many such things are conserved and therefore exempt from purely random, like loaded dice that fall one way. This is observed in cells, with certain parts of the DNA much more subject to change than other aspects of the DNA. How does the cell load the genetic dice so there is persistence and/or a sense of direction?

    Say all the children in a family have genes from the same mother and father, why so much potential output variation in the children? What this observation appears to show is the same genes can add up to many different integrated entities without needing random changes at the genetic level. As an analogy, we have nine children which we will organize into a baseball team. Depending on which child plays which position, can create totally different teams. We are not substituting new children to get these various results but only using the same in different ways, with some children persistent in position.
     
  23. Russ_Watters Not a Trump supporter... Valued Senior Member

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    You are wrongly assuming those 40% of DNA identical to a bananna's are no longer subject to evolutionary pressure.
     

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