What is the Mechanism of Natural Selection for Evolution?

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

  1. matthew809 Registered Senior Member

    Messages:
    480
    This evidence does support the theory of evolution.

    But this thread isn't about the clear relationship between different species in time. This thread is about whether natural selection can account for evolution.

    Although I do find the whale evidence interesting and will explore it right now...
     
  2. Google AdSense Guest Advertisement



    to hide all adverts.
  3. Grumpy Curmudgeon of Lucidity Valued Senior Member

    Messages:
    1,876
    matthew809

    Special creation explains nothing, it presupposes the creator, which just regresses the question from "how did life begin" to "how did the creator of life begin". That trumps nothing, it just avoids actually answering the first question, it becomes a "Black Box" containing god. And nothing for which no evidence exists can be "proven" or "disproven". Example, prove there is no unicorn. But it would be silly to think that a unicorn created the world as it appears today(with only micro-differences). It is no less silly when "unicorn" is replaced by "god". God is only a way for men to say "We don't understand this, therefore magic". That is not an acceptable paradigm for reality.

    Yet you seek to limit that process to minor changes. Major changes(even entirely new forms of life)come from the accumulation of smaller changes(which you admit happen). If you accept the finches changed due to evolution, what do you propose stops those small changes from accumulating to large changes in a genome? It's the same process. Are there stop signs? And that's before you consider "sports", small changes in genes causing large changes in the organism. When a gene changes even a little bit, the results can be large or small, it depends entirely on what the gene that changed did before and what it is doing now.

    Given your posts, I have no confidence that you know how science works. The evidence is overwhelming and multidisciplined, it is in no way limited. And facts are facts, they don't have built in bias. And there is no other conclusion a rational person could come to than that all life(excluding the first life)came from other life of different form. The frog has exactly the same skeletal structure as we have because we both had a common ancestor that had that skeletal structure. That skeletal structure was so good at what it did that it was retained by almost all forms of advanced landwellers. That means all creatures with our skeletal structure came from the first form that had it, no matter how different they are to each other they shared a common ancestor. Undeniable evidence, wouldn't you say? Or you could posit "and then a miracle occurred", but that is not a valid statement in math, science or even just daily life.

    No, the evidence excludes "kinds", it's a meaningless word that even you cannot define(I guess that keeps it flexible). Evolution is a nested hierarchy of common traits. You can trace those traits back through time to the first organisms that developed them. Descent with modification is obvious just by examining the evidence, making evolution a fact, not a theory. Darwin proposed Natural Selection as the cause of evolution, that was his theory explaining that fact. We know more now, but Natural Selection is still the bulk of what causes evolution, though it is much more complicated and nuanced than we thought at first.

    Then you are just wrong, through ignorance of reality or resistance to reality. Either way, simply wrong. If you knew even just a bit about the evidence you would not be able to think that way, continuing to do so takes conscious effort to ignore what the evidence actually is. Again, where did you get such misinformation? Texas? Louisiana? Mississippi? The damage the religious right are doing to our education is criminal. If I were you I would sue whoever "educated" you for fraud.

    No, their changes are known to be caused by mutation followed by selection, just like dogs, cattle, Orchids and disease resistant bacteria. We even know exactly where in the genomes these things have happened. There can be no RATIONAL doubt.

    Grumpy

    Please Register or Log in to view the hidden image!

     
  4. Google AdSense Guest Advertisement



    to hide all adverts.
  5. Walter L. Wagner Cosmic Truth Seeker Valued Senior Member

    Messages:
    2,537
  6. Google AdSense Guest Advertisement



    to hide all adverts.
  7. Aqueous Id flat Earth skeptic Valued Senior Member

    Messages:
    6,152
    I think the point is that special creation was the default position for a lot of philosophers, including Darwin, until he discovered speciation at Galapagos. At that point, special creation was trumped by incontrovertible evidence. What other logic could lead to any other conclusion?

    What's wrong with the judgment which says "Galapagos disproves special creation"? How is that kind of judgment inferior to the judgment that says "if it's not in the Bible then I don't want to hear it", or, in your case "since something like the Creation Myth could have happened, I remain reluctant over evolution"?

    Don't be surprised if folks identify you as a religious crank since you are using the same lexicon and talking points as the Creationists. Science is not an 'ism' (belief/ideal), so it's taken as a form of disparagement to call scientists idealists/believers. Here you're exposing some unexplained antagonism against science, which, if we want to cut to the chase, readily explains your stance on evolution. Evolution is just science. There is no alternative explanation that fits under the umbrella and there is no other branch of science so universal.

    Then that's the judgment call that comes into question here. There is only one plausible explanation.

    Here again you can expect rebuttal as to the judgement. The evidence comes first [observation of new species on a remote isolated atoll which did not exist "In the beginning" and can not therefore have been part of the purported Special Creation] and after weighing all the evidence [including the geology of atolls, dating them, and the geographic origins of the earliest breeding pairs] , there simply is no choice but to admit that the species evolved there. As emotionally difficult as that may be for people tied to their faith in themselves and their reluctance to accept that they were wrong, the science prevails. Once all the evidence is in hand, even a religious believer such as Darwin is forced to take his medicine. (i.e. God cannot lie through His own works.) It's a bitter pill for some to swallow, hence the present culture wars.

    Once you acknowledge the evidence for speciation, it's quite easy to see how accumulated speciation explains the genera, and the rest of taxa. Thus the religious question is out of touch with science. Of course the biological evidence also explains the the amassing DNA evidence, which in turn fully corroborates accumulated speciation. Now it makes sense why human DNA and the DNA of yeast have commonality. There's some of the proof that confronts you.

    How science works is that it teaches people how to distinguish fact from fantasy. Apparently that's the piece of human logic that science lays exclusive rights to by default, since Religion won't stake any claims there. But the evidence is free. Hell, people flock to Galapagos in droves out of the love of free evidence. As far as I'm concerned the whole world stops turning whenever I come across another documentary of Darwin's work. There are few subjects in science so freely available -- so easily grasped -- as a 45 minute tutorial from PBS or the Discovery Channel on this question which holds you in a bind.

    Except there can be no special creation or else Galapagos could not exist as Darwin found it. It's not even remotely plausible to suggest it. And of course a century after Darwin published, the now-famous Wilkins, Watson & Crick discovered DNA. Indeed the building blocks you speak of are there. This discovery corroborated Darwin's observation that there was an underlying systemic cause to types and frequency of variations within a generation of organisms, which we now understand is the result of genetic mutation (subjected to selective pressure). That leaves the idea of "building blocks being used to create" out in the cold. At some point, faulty propositions simply have to be discarded. Science is very good about rooting them out, to its credit, not otherwise.

    You mean species. All you need to worry about in deciding how to get out of your bind is that the theory of evolution is a theory on the origin of species, not of any other taxa. None of that even matters, since it relates to religion. It did have an entirely different application in a sidebar discussion over gradualism, but the Creationists highjacked the word and blew it up into the meaning you've ascribed to it. (Another thing that connects your statements to Creationism.)

    That sounds a little like the Catholic interpretation of evolution which at least answers the mail as far as Galapagos is concerned. It accepts that species evolved by genetic mutation, as operated on by natural selection. The "ability to change over time" for purely stable cases where no selective pressures are in play (rare but also crucial) is covered by the post-Darwin discovery of genetic drift. But you can't have genetic drift without the mutations which give populations the specific alleles available to them. To be clear, genetic drift is a post-mutation stochastic process carried out usu. over many generations. That process is related to the randomizing effect of opportunistic fertilizations and the crossover during meisos which was mentioned by one or more posters here.

    Actually, no, there is nothing obvious to me about your beliefs. They seem to be based on some fundamental error but it's not clear to me exactly what that error is.

    If all we do is rehash Galapagos we've served the purpose of the thread. But of course there are lots of other great subtopics already introduced by the pro-science posters here which are equally as relevant.

    That's a good step. Next you need only decide whether spontaneous mutations occur (they do) and whether mutations can also be induced (yes) and your practically out of the bind.

    Oops. That contradicts massive evidence. Even to get genetic drift (which seems to be your preference over mutation) the availability of alleles is governed by the prior mutations which introduced those variations into the pool.

    That's impossible in the real world. And of course it's moot since mutation is the clearest evidence which debunks special creation, and it does so in real time (contrary to the "you can't prove it's happening now" claim). Even the Catholics found it intolerable to think that God is so obsessive-compulsive that he simply can't stand to leave his little monsters alone.

    Given that DNA is so well understood these days, relative to the evidence that confronted Darwin, what other building blocks would you introduce, and why? And why would you think that DNA does not spontaneously mutate from generation to generation?
     
    Last edited: Mar 2, 2014
  8. wellwisher Banned Banned

    Messages:
    5,160
    Here is another angle that I don't full understand and rarely hear discussed.

    Say we begin with male and female gamete cells at fertilization. After this combination, the fertilized cell continues to divide and differentiate, with each of the hundreds of billions of cells divisions involving duplicating of the DNA. Why doesn't the entire body, have random mutations, everywhere due to trillion of DNA duplications that need to form to make an entire critter? Should the odds be the same a say bacteria forming trillions of units?

    Since body systems need to interact and integrate, like an internal ecosystem, does this imply there is also internal natural selection. As an example, say early in development one early daughter liver cell had a mutation and continued to divide to form half the liver? The two sides of the liver will have their own type of competition for whatever livers do. Natural selection should favor that which can reproduce better? How the DNA in the next generation of gamete cells carry on the binary liver or does it pick the best side? Or could such a change not even show up in the next generation, even if it brought advantage for one critter?
     
  9. matthew809 Registered Senior Member

    Messages:
    480
    Maybe an analogy could better explain my argument. Imagine a function within a computer program, which "randomly" fills a variable with a number between 1 and 100. This variable presents 2 limitations:
    1) The storage location for this variable is fixed.(these supposed "mutations" touted by evolutionists usually only happen within these variable genes)
    2) The range of possibilities is limited to 100.(there is a limit to the number of possible "mutations")

    In the case of this computer function, the random part of the code is specifically isolated, not general, and was intended to add a controlled variability to the program. The entire code of the program itself is not subjected to random changes(under normal conditions).

    This is how I view DNA code. Certain genes are like variables, which are "programmed" to change within a certain range. These variable genes are what is responsible for changes in species(ie. blue eyes or brown; tall or short; long beaks or short...). I don't consider these controlled changes to be mutations, for the same reason I don't consider a fully functioning computer program to be corrupted just because there is a random element programmed in. A mutation would be a change not specifically allowed by the code... an unintended change in DNA code(down syndrome; a third ear; etc.).

    IMO, bacterial resistance is an example of intended change, not mutation.

    I understand that this is not how evolutionists view mutations, but then again evolutionists, like everyone else, do not know the language of DNA so nobody can say for sure. I am just making an educated guess.
     
  10. matthew809 Registered Senior Member

    Messages:
    480
    Because if mutations were spontaneous and common, stability of the species would erode quickly over time(despite the relatively weak effect of natural selection), rather than get more ordered and complex.

    edit: Mutations are common(at least in the present time), but what I mean is that mutations are not responsible for natural "creation". My point is that mutations are overall and overwhelmingly a destructive force. According to the thinking of evolutionists though, natural selection overcomes this destructive aspect, making it a wholly creative force.

    The argument I originally made in starting this thread is that natural selection is not as powerful a force as it's made out to be.
     
  11. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

    Messages:
    23,198
    Yes, that is true, but just another way to say the existing gene pool is not optimum for the current environment so erodes over time. (Thanks for observation supporting evolution. I have a pet bird - I'm very glad it is not still a dinosaur.)

    But "quickly" is quite rare and some times the species goes extinct before it can become suitable for the changing environment. Here is probably the fastest formation of a new species by evolution that has ever happen in the long history of the world:

    Quoting from Denial of Evolution II post 84 and 83 (posted 25March 2009):
    1. “A tiny population (40 or perhaps only 20, initially) living on the edge of extinction for 8000 years (due to limited food, not predators) have very rapid evolution compared to a large population living relatively easy, except for being eaten. (The predators eat the beneficial genetic innovations often before they can become a dominate part of the large gene pool) Thus the preá did in 8000 years what normally might have taken 8 million years. Became a new species.

    Also interesting to note that once genetic idenity has been achieved and ill effects of incest eliminated, then when a hail storm or huricane killed most of the preá, they could quickly rebuild the population back up to the food limit so long as one male and a few females made it thru the storm. In this sense, what is normally a problem (lack of genetic diversity) is actually a survival aid!”

    2. There are approximately 40 little animals, called Preá in Portuguese, living on tiny island called Moleques do Sul, which is about 8 km separated for a much larger Island called Florianopolis that have been studied by Pontifica Universidade Católic under leadership of Sandro Bonatto.

    The following is from post 83, which I took mainly from her papers and newspaper articles when the existence of the Preá became public knowledge in Brazil, where I live:
    About 8000 years ago, these two islands were one as the sea level was much lower. The tiny island is about the size of a football field and mainly rocks. But has some grass on ~10% of it.

    These Preá are so inbreed that DNA tests (type used in Brazil to determine disputed paternity, at least) cannot determine any differences. They are about half the size of the main island animals they evolved from during 8000 years of separation. Smaller size was favored by selection because of the very limited food supply. They are the only mammals on the tiny island and have no predators. - I.e. population is limited only by the lack of food for more than 40 but probably has been slightly increasing as they evolved to be ever smaller each 1000 years. (Probably no more than 20 of them lived after the connection to the main island was cut off 8000 years ago by the melting ice.)

    They are now a new species (Cavia Intermedia) but closely related to Cavia Magna of the main island. They are about the size and shape of a small rat, but with a face that looks much like a monkey, or even human, and fur covered (except the feet) with no tail. Head and back fur is brown and belly fur is whitish grey.

    Until they were discovered it was not thought by experts that a population of only 40 animals max could survive for thousands of years. They have, no doubt, lived all that time on the edge of extinction and practiced incestual mating with no ill effects, at least for the last 6000 or 7000 years. They are all now genetic identical. The ill effected off springs of inbreeding were selected out long ago as all live hungry on the edge of extinction at least in the mild winters. (Perhaps, like bears, they store fat during the summers - just my guess, not mentioned in the paper.)”

    Their tiny island is part of a state park, now with special protection - only qualified researchers can legally visit, but some fishing boats do at times. The great fear is that one will leave a cat on the island. - Then this recently evolved new species will go extinct.

    3. Comment added in March 2014:
    What you need for such rapid evolution is EXTREME and CONTINUOUS environmental pressure. I. e. at least ¾ of each new litter, dying of starvation and not by being eaten by predators* and very tiny gene pool, so in only half dozen or so generations any genetic benefit is very dominate in the gene pool. The Preá are half the size of the ancestors they evolved from.
    -----
    *What prey animals, like their ancestors, normally have is an eye on each side of head so they can have more nearly 360 degree notice of predator’s approach, but that comes at the cost of good stereoscopic vision. One change that got selected for on island with no predators was more forward looking eyes – better stereoscopic vision and in this they do differ significantly from the ancestor animals they evolved from but their eyes are not as forward looking as in typical predator animal like lion or eagle.

    In addition to that and being smaller than your siblings so needing less food to survive on a mainly rocky island having relative stronger hind legs to jump over rocks to look for some grass to eat would be an advantage. The Preá don't run like most four legged animals, including the ancestors they evolved from, but sort of hop forward and just use their shorter fore legs to stabilize the landing for the next hop.
     
    Last edited by a moderator: Mar 2, 2014
  12. Aqueous Id flat Earth skeptic Valued Senior Member

    Messages:
    6,152
    You seem to think mutations are not witnessed and their rates counted, and that species are stable. In the first place mutations are witnessed in vitro. The study of their rates and locations (which gene) is a huge field of research for molecular biologists. Grumpy mentioned the evolutionary evidence, such as in the study of Y chromosome morphology among distant relatives. Second, the idea that any species is stable is relative and subjective. Overall, species are not stable. The estimated rate of exinction for all species that ever existed is roughly 99%. At issue is the stability of the niche. That's a completely different set of processes, also entangled with ecosystem collapse, cataclysm and changing pressures due to co-evolution.

    The idea that things can't get more ordered and complex is borrowed from Intelligent Design. It's controverted by a mountain of evidence. You might as well argue that atoms cannot exist since they are "ordered and complex". Yet they do. And, as we well know, they climb the ladder of complexity simply by adding and subtracting energy from natural sources (gravitational accretion, critical mass, fusion and supernovae). Indeed atoms evolve from primitive forms in ascending complexity and order, and they go on to form more ordered molecules. The crystal lattices in common metals is a prime example of low-complexity, high order. Yet all of these are the natural result of intrinsic properties of the atoms and the relevant laws. Hell, snowflakes show high complexity and order in their crystals. Do you really want to believe that they get this property from a cosmic consciousness?

    The laws governing evolution are just as rooted in real biological processes as the evolution of atoms is governed by physics. It just takes a little knowledge to get over the suspicion that such things seem implausible. For most of science, seeing is believing. We can't simply toss out mountains of evidence. Similarly, you can't avoid the realities of evolution by circumventing the actual facts. So far you seem disinterested in what is actually going on in the world around you.


    That doesn't come close to modeling a mutation, and if it did it would account for only one triplet error (change the 100 to 64). Nor does it account for the molecular interactions that affect the probability density function. A good random number generator would come close to a uniform distribution which has no bearing on the probability of successful recombination. The most likely of densities is the Gaussian distribution. But then you need to know the mean and variance of each possible mutation. It's exceedingly complex, not something that could be fairly treated by an oversimplification.

    The problem I see which is coloring your beliefs is that you have no interest in the actual evidence which confronts you. You seem more interested in talking about something else, as if it really doesn't matter whether evolutionary science is is working with a full set of puzzle pieces or not.

    Ok ... I'm not sure what you're getting at, though. Analogies are the worst way to tackle this. You'd be better of saying something about actual observation.

    Until you go searching for what DNA is and how it works your view will remain in the dark with this jaded view.

    If I were you I would go looking at what mutation actually involves:

    http://evolution.berkeley.edu/evolibrary/article/0_0_0/mutations_03

    Those are specific adaptations of one or more traits which may involve more than one gene. The trait for blue eyes is not an adaptation but the residual effect of another adapation (skin pigment) which is an adaptation for the lack of vitamin D due to a reduced sunlight exposure due to living in higher latitudes and covering up in cold climates. As you see, there is no room for oversimplification when it comes to systemic causes for variations.

    There is nothing controlled about a purely stochastic process. The only control in effect here are the pressures of the niche. That occurs at the macro-macro scale and can not be directly correlated to molecular level interactions.

    You arrived at that through the wrong model. Rewrite your program to a piece of self replicating code, and see how difficult it will be for you to ever get the generated sequence to load and run due to corruption.


    Chemicals do not possess intent. DNA is a chemical. DNA cannot therefore intend anything. It does however obey strict laws. These laws do not guarantee a particular outcome (whether or not a codon transcribes successfully). In fact DNA is metastable. The chemical bonds are relatively easily broken. Hence specific genes can be unzipped by chemical cues (gene expression). That kind of fragility guarantees that there will be some nominal rate of error. So as you see it's a consequence of the nature of a self-replicating molecule -- of a colossal length never before possible in nature -- that it would have a given rate of mutation.

    There can be no intent in a chemical. It simply follows the laws of chemistry. In any case, mutation in bacteria is well documented, so your beliefs are confronted by massive evidence to the contrary. The mutations are spontaneous and/or induced, and the resulting variation in the population is due to selection.

    You haven't yet told us why you are so cynical of science.

    All scientists who do actual research in DNA are already schooled in evolution. I'm not sure what your purpose is in characterizing experts in their respective field with virtually no working knowledge of the technical matters you dispute. As an expert in cosmology might refer the blinking light on the dash to a mechanic, isn't it only natural that the repair technician would turn to the cosmologist for information about orbital mechanics?

    Confronting that statement is this paper from 50 years ago discussing actual comparative rates of mutation. It's just the first one that popped up. I suspect we could go find a million pages more.

    http://www.genetics.org/content/47/8/1097.full.pdf

    I guess the level of education is proportional to the accuracy of any guess.
     
    Last edited: Mar 2, 2014
  13. Grumpy Curmudgeon of Lucidity Valued Senior Member

    Messages:
    1,876
    matthew809

    1. All genes are "variable", all genes are subject to mutation, only currently active gene sequences are subject to self correction during mitosis, so those genes are more resistant(but not immune)to mutation. If the gene that mutates is important to the functioning of an organism, that organism dies(likely is gestation in the higher animals, we call it spontaneous abortion or miscarriage). If the mutation makes it easier to survive in the current environment it becomes part of the genome.

    2. There is no limit to the number or kind of mutation. Nor are they limited in where they occur.

    Oh, by the way..."touted by evolutionists"...marks you as coming from a creationist background...your(Freudian)slip is showing. Not that we had any doubt given your nom de plume.

    All you are describing here is the range of variability within a genome(or in an operating system). That's inheritance, not evolution. That has nothing to do with mutations or evolution, it's just the range of characteristics the genome has gotten already from the process of mutation tested by survival. You're missing the forest, claiming that the nearest tree is the only thing in the forest and those are the only characteristics a tree could have. If, on the other hand, you looked at the first computer, the first transistor, the first hand held electronic calculator, a Timex or Trash 80, a Commodore 64 and 128...and THEN compared it to your program running on Windows 8 or Linex you would be looking at the evolution of that computer and it's programming. Then you would see the forest has Oaks and Pines, vines and mosses. Their interconnectedness is a direct result of common descent from the same source in an unbroken line of DNA replication. Each organism has a direct line, but each species has a unique history of mutation and testing, so each went in it's own direction from some reproductive branching. The line from about 400 million years ago to today was identical between us and apes until 8 million years ago(it was the same history), we've gone different directions since then. Our differences have all developed in those 8 million years, we've even found skeletons of upright walking humans from 4.5 million years ago, though their brains were no bigger than a modern chimpanzee. The first controlled use of fire was dated to over one million years ago. There were several species of humans living at the same time, the Neanderthals were the last ones to die out about 25,000 years ago. Modern Humans have only existed as a separate species for around 175,000 years, all the differences between all the different peoples alive today evolved in those 175,000 years since mankind started in Africa. Oh, and man didn't discover fire, that was either Erectus or Robustus or one of the other species we may not have even known about.

    Where did you get the idea that any species is stable? In Nature it is change or die way too much of the time for stable genomes to survive. There is no survivable stability in the long run, and often in the short term as well. DNA evolution is a dynamic process, constant change occurs at all times(we call it genetic drift then), it is usually centered around a set of traits under calm times, the environment(niche)will decide what those are and if the environment changes the genome does, too. Or it dies. If the environment changes quickly you get rapid genetic change plus rapid die off of those who can't adapt rapidly enough. We call the constant changes punctuated equilibrium then because selection is fierce and brutal, changes rapid and severe for a short time, but then the organisms adapt to the new environment(those that survive, anyway)and change is slow, the eating good. Environment determines which traits an organism needs of the ones that evolution makes available through mutation, survival to produce offspring is the selector of those traits. That is evolution.

    What's making it so hard for you to understand that life does not consist of the destructive and deadly mutations. Life nearly exclusively consists of the constructive mutations(however rare you think they are)plus some that are neutral or outdated. That's because the constructive mutations had children(by definition). 3.5 billion years of collecting constructive traits constructed us. Every human sexual reproductive event passes over 200 NEW mutations to the offspring from each partner. That child's survival to pass those particular mutations(plus 200 more)to it's own offspring is the test of those mutations. If any of those mutations are destructive the fetus will not come to term and those new mutations are not passed on. Birth defects, sterility, diseases and other childhood horrors can result. Most mutations have no effect or are neutral, thankfully. It only takes a really advantageous mutation to occur once and it will become more common in the gene pool simply by having more children(the measure of success, after all). Destructive mutations have no children and are removed from the genepool when they show up. This is an oversimplification, but they tend to do so.

    That argument is based on disinformation and ignorance. We call it Creationism as a shorthand. It isn't valid and it just makes you more ignorant of reality.

    Grumpy

    Please Register or Log in to view the hidden image!

     
  14. billvon Valued Senior Member

    Messages:
    12,793
    That's close. To make it more accurate:

    The computer program has no fixed amount of storage. It can be tiny (a small genome as in the parasitic nematodes) it can be enormous (as in genome of the marbled lungfish.) Some locations mean something, most do not. ALL locations (including both the program and data store) can change randomly to any new value that can be represented by the computer's storage size. (Often 8 bits in small computers; 4 base pairs in DNA.)
    Blue eyes vs brown eyes is not a mutation. It is an inherited genetic trait. The mutation that gave us all those colors happened a long, long time ago; we have conserved those genes because there is a (very small) advantage to being able to tell people apart and eye color helps that.
    Good! Because blue vs brown eyes is not a mutation. Now, a child born without eyes most likely IS a mutation. But unless he's born into a permanently dark world it is a disadvantage, and in a natural environment would be less likely to reproduce. Thus those mutations are generally not conserved. (We, of course, mess with that process by having Braille books, audible crossing signals etc etc.)
    Exactly. That's a mutation; eye color is not.
    There is no way that a bacteria could have been "pre-programmed" with resistance to an antibiotic that has never existed before. Billions of bacteria die before chance mutation gives just one a slight resistance to that antibiotic. Then that bacterium (and thus its DNA) is conserved.
     
  15. matthew809 Registered Senior Member

    Messages:
    480
    I appreciate all the responses but I feel like we are getting off topic and not really convincing each other of our ideas.

    Would anyone care to tackle the hypothetical question posed in my first post in this thread?
     
  16. exchemist Valued Senior Member

    Messages:
    6,613
    It's been answered, surely, hasn't it? If you think it hasn't, perhaps you could explain why you are unsatisfied with responses so far, to give us an insight into what it is that still bothers you.
     
  17. matthew809 Registered Senior Member

    Messages:
    480
    No, I mean I would like a specific answer to the specific question I posed.

    For the record though, I read a lot of good stuff in this thread which gave me a deeper understanding of evolution, even though I still disagree.
     
  18. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

    Messages:
    23,198
    Well it may not but on the average if it is a net benefit, then its representation in the gene pool will increase with time.

    It is sort of like playing craps with slightly loaded dice. Not a grantee you will walk away the winner every time - just if you could play 10 million times, it is certain you will win. (so long as the rules of the game remain constant - I. e. the slight advantage remains an advantage.)
     
  19. matthew809 Registered Senior Member

    Messages:
    480
    But can you specifically imagine a scenario where this spot of harder flesh would benefit the frug to survive longer than it's counterparts?

    These are the types of negligible mutations which would have to occur all the time, one on top of the other (with natural selection somehow selecting for it), in order for a new body part to eventually evolve.
     
  20. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

    Messages:
    23,198
    You were the one, not me who said it was an advantage, but I'll guess that frug slides over some sharp rocks to try to get the good looking female frug before the normal soft belly frug going around the rock does.

    He does not need to "survive longer" just to mate more often. In fact it is not rare that a "mating advantage" actually decreases life expectancy. Peacocks can barely fly but if your a peacock with the "tiny tail" birth defect and the best flier in the flock, its going to be a longer, no sex life.

    In a few hundred generations if you are a "Genetic Throw Back" GTB, frug and don't have a hard belly spot, you will find no female frug wants (or even will) mate with an ugly "deformed frug." This is the sad experience of about (as I recall) 1 in 20,000 GTB men who have thick dense hair all over their bodies and sometimes other "junk DNA" that should no longer get expressed, does as in photo below.

    Please Register or Log in to view the hidden image!

    Stephan Bibrowski, or "Lionel the Lion-faced Man," had congenital terminal hypertrichosis.
     
    Last edited by a moderator: Mar 3, 2014
  21. matthew809 Registered Senior Member

    Messages:
    480
    I admit that does seem like a partly plausible scenario. But, isn't it more than likely that the frug would be totally unaware of this possible benefit and behave according to it's more primitive instincts? These primitive frugs haven't evolved much intelligence yet.
     
  22. matthew809 Registered Senior Member

    Messages:
    480
    Also, wouldn't the rest of the frugs still have plenty of chances to get laid too? Some of the frugs will always arrive at a mate earlier than others, for equally miniscule reasons.... but does it really matter in the end since all of the average frugs are well suited for the job?
     
  23. matthew809 Registered Senior Member

    Messages:
    480
    The dice have to be loaded with enough imbalance to actually make a difference though. It is possible that the imbalance could be so miniscule that it wouldn't have any effect on the roll of the dice no matter how many times you throw them.
     

Share This Page