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Are the evolutionary changes we seen in creatures occur with a purpose? or is it just due to random changes over millions of years?

It just came to me that evolution seems to be purposeful... meaning it seems to me that an organism changes/evolves almost(!) as if because it "wants" to change. In previous conversations we were talking about evolution happening as a series of mutations that results in benefit to the organism and that organism passing on that change to the succeeding generations. But lets take a look at these "mutations".. if these are just random changes then how did "random" changes push some sea creatures to generate anatomic structures to enable it to survive on land? Fins are said to have developed into feet/legs. Can random mutations actually develop that? to me these seem to be mutations with a direct purpose FOR the organism...that is to develop legs... if that is the result then can it actually develop from a random mutation? or lets take it in another way.. why did the wolf like creature that eventually developed into whales loose their hind legs? did random mutation just shut down those genes for leg development? Some say its because of disuse and eventually the whales lost them. But if its simple disuse, i would expect whales to STILL be born with legs that gradually atrophies as it grown older. But instead a whale is born without legs at all (at least with bone remnants)... to me this is like evolution is intentionally shutting down a system. If evolution is shutting down a locomotion system for the animal can that be a random occurrence? I find random mutation hard to achieve this kind of changes.
Can random mutation over millions of years actually drive the changes we see in animals including man. Or is there something more amazing happening with evolution... creatures developing something unique because it actually wants to evolve that way.... (i hope that made sense). Random? or somehow with some kind of "purpose"?

  • Jul 2 2013: There is a point of misunderstanding in this whole issue. It is a popular but wrong belief that the evolution process is random, but like I said, it is wrong and it is just a belief. Yes, mutations occur indeed "random" (please notice the quotation marks), however most mutations are not beneficial for the individual, just a very small amount of mutations are truly beneficial for the individual. In most cases the mutant individual is in disadvantage and dies before becoming adult, and that way is "deleted" from the "evolutionary record", giving the false impression such mutations did not occur, when they actually did. Evolution is driven by natural selection, a process which happens to be the exact opposite to random!!!, meaning evolution is not a random process at all.

    Another aspect of evolution that most people don't seem to understand is that evolutionary changes are cumulative, meaning they accumulate one on the top of the previous one. Most of the times changes are very small, almost unnoticeable for us, but when hundreds or thousands of them accumulate we can clearly tell the difference. Species are not statically waiting for a major change to occur all at the sudden in just one day, like magic. Magic is not science.

    Finally the core issue of your question: propose requires intention and intention is an act of consciousnesses, so whether you like it or not, the sole use of the word "propose" implies someone in charge, and the obvious question here is: who is that one in charge?... the most likely answers is: God, but then we are in big trouble here, because once you allow God to be part of the discussion it voids all its scientific relevance. So, the answer is: NO, there is no propose behind evolution, even if it SEEMS so. And the proof of it is that we humans can tap on it, interfere with it, and even manipulate it (partially) at will. If evolution had a propose of its own, we couldn't be able to develop new breads of pets, cattle and crops.
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    Jul 4 2013: I learned that genetic mutations occurred in reactions to environment or internal changes in Genes. Once a creature is pretty well adapted to it;s environment and not a lot of breakdowns or cross wires in the DNA. It pretty much is what it is and what what it will be. Turtles, sharks and alligators are about there.
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    Jul 4 2013: I don't know. It seems creatures mutate to a point where they are pretty much in tune with their environment.
    • Jul 4 2013: thats right. It.. the explanation lies in random mutation and natural selection... over millions of years it pushes a creature to seeming be at home in its environment. I just find it amazing.
  • Jul 3 2013: "Are the evolutionary changes we seen in creatures occur with a purpose? or is it just due to random changes over millions of years?"

    The answer is neither.

    Those changes are mostly the result of random variation (due to random mutations), natural selection (positive and negative selection), and semirandom drift. But not purely random changes. I see no reason to think that they are purposeful. For that to happen a mechanism for directing changes would have to have evolved in some organisms. So far, only humans seem to be on their way to directing their own evolution.
    • Jul 3 2013: Entropy.. thanks. But its still a bit confusing. Lets put the question into my frame of idea... its kinda simplistic so please help me understand. Very few of the sites on evolution seem to tackle my problem. Feel free to correct my questioning because i might be assuming a wrong idea in my question.

      This is my question: Lets presume there are no moving animals on land and only fish exist and in water (naturally).. then over mllions of years... fish somehow used fins for locomotion on land and developed the capacity to survive longer on land but still had to return to water.. then over millions of years again, those fins developed into a rudimentary leg (or equivalent) and developed the ability to breath air without returning to water.
      Ok this is the question:
      1. Would you agree the change from a water creature to something can live on land is evolution (by any mechanisms) in action?
      2. You mentioned that these changes are due to random variation(random mutation)... if these changes are random... how is it that "random" mutations are enabling the development of a limb for land movement or lungs that can resist drying? --i am lost as to what mechanisms could have happened in between that seems to make evolution seems soo directed.

      I understand examples on different colored beetles survival , antibiotic resistance etc,what i am curious about the development of organs for a different function which seems to be absent in most of my readings:

      3. for example: Cetaceans were said to originate from hoofed mammals..Dolphins developing sonar is a mystery to me. I don't suppose those hoofed mammals have sonar capabilities? Lets assume they don't. But what kind of random mutation could have pushed dolphins to develop sonar detecting capabilities?
      If those hoofed animals have sonar capabilities then that capacity evolving into the present dolphins, i would understand that scenario. But the development of a new sense "organ"? If by random mutation its kinda hard to swallow
      • Jul 3 2013: "i am lost as to what mechanisms could have happened in between that seems to make evolution seems soo directed"

        But you keep forgetting selection. You seem too fixated on the random nature of mutations and forget that no matter how random mutations are, survival is not random. That survival filters out crappy mutations and leaves inconsequential, semi-inconsequential, and advantageous mutations.

        In your example of fish going into land, some fish have, for example, that "inflatable" floating thing (I don't remember the name, but many fish have that thing). Now, all it takes is variability (semi-random--"semi" because they still have to do what they originally do) for those floating things to vary in how permeable they are to atmospheric oxygen. Now, if a population of these fish lives close to coastal areas, those whose floating things take enough oxygen might survive better if stuck into some shallow waters left after a tide goes low. Several such events might increase the number of fish with floating things that work somewhat like a lung. Such increase in proportions will increase the probability that semi-lung-ed fish will mate with other semi-lung-ed fish, increasing the mixing of mutations that make those floating thingies work like lungs. Such recombination and further mutations increase lung-like variability ...

        See? You are missing a very important process: survival is not random. Background mutations might be, but survival is not.

        I am pretty sure that textbooks are not silent in this matter Jeff.
        • Jul 4 2013: Entrophy, i think its called an air bladder... i just googled it.. swim bladder.. you are correct. i am fixated on random mutation and not on natural selection as a driving force for change which is why i asked you to correct my question since it may not reflect a correct idea.
          So, if i were to take your example to my point of view, here is the thing: i find it amazing that random mutations can bring about improvement in the swim bladder over the course of time. and with natural selection, its almost as if only those with the best bladders will survive. The natural selection is easier for me to understand... but random mutations bring out the best in swim bladders..? find it strange and amazing. However i am aware that even single nucleotide changes may be enough to bring about a large effect in an organism.
          Therefore I think my the answer to my problem now is rooted in evolutionary genetics since i think my question is focused on how these random mutations spread to the population in question.
      • Jul 4 2013: "i think my question is focused on how these random mutations spread to the population in question."

        It's not really spreading, it's more like each generation those with the best mutations breed with each other while those without those advantages don't succeed as much at reproducing. This gives the appearance of "spreading," but it's more differential in survival and reproductive success.

        See ya.
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    Jul 2 2013: Is the existence of many different breeds of dogs, some of which came into existence since such records have been kept, an example of what you are calling "evolutionary changes"? Also, is the fact that homo sapiens are becoming taller from one generation to the next proof of what you call "evolutionary changes"? Also, are the extinction events recorded in history examples of "evolutionary changes"? Not every change in a life form is attributable to, or explained by, the theory of Darwinian Evolution. Please define your terms Jeff. Thanks for asking an important, but volatile, question.
    • Jul 2 2013: Thank you edward. But i do know those dogs were bred specifically for their traits, humans being taller is due to nutrition. I wonder what you mean by volatile... I would like to hear why you think its volatile.
      I'm not trying to push an issue covertly towards my belief. My question is just looking at why evolution seems to "evolve" according to the needs of the animal (human intervention excluded). This may just be an illusion as George pointed out and i accept his opinion as highly possible.
      I cannot accurately define evolution.. I'm not an evolutionary biologist. but if you were to see it from my point of view.. im simply wondering if all the current state in some of the creatures that we see are somehow products of random chance or if a creature can somehow alter their genetic data actively in response to a unique state/environment. By saying "actively" I have this sort of idea that genetic components can be altered by the cells in response to the environment. I am aware of gene activation/overexpression BUT what i mean really is DNA code changes in response to envronmental shifts. I know there is not such evidence and is highly improbable and any mutations will be corrected immediately. But Im just exploring the idea.
      I will avoid the term "purposeful" changes. I don't want the literal meaning of the word be used in my question. Let me know your thoughts and I hope you'll be nice about it :)
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        Jul 2 2013: Oh great! Now you want me to be nice? I know from experience that confrontations, sorry, I meant dialogs, between those who accept Darwinian Evolution as proven, rock-solid scientific truth and those who reject it are unstable conversations which evaporate quickly into unscientific (religious) rants and raves. Good luck avoiding that outcome. It may be suggested that it is me who is volatile and not the topic, to which I respond by citing the plethora of examples here on TED in which I was not a participant. Anyway, back on topic, many people understand dog breeds and taller people to be proof of Darwinian evolution and that is why I suggest you define your terms meticulously. My convictions do not matter. Good fortune in your quest for Truth, Jeff..
        • Jul 2 2013: Edward,

          I know that you do not care about what I say to you and told me you would not answer. I still hope that you can tell me if what follows is an unscientific (religious) rant and rave (but feel free not to, after all, I'm but some guy in the web):

          I do not accept "Darwinian Evolution" as "rock-solid scientific truth." The thing goes as follows:

          (a) Darwin demonstrated that evolution happens. In other words, he showed lots of evidence that current species come from previously existing populations of different species. That leads to the fact of evolution. In other words, the fact that species come from previous species, that species diversify and diverge until they form distinct species compared to the ancestral form, and other diverging populations arising from the same ancestral species. That's not "Darwinian Evolution," but the observation that something, evolution, is going on. Today we have much more evidence than what Darwin accumulated. facts are unquestionable.

          (b) Darwin then considered what could be behind such divergence and arising of new species from the originals, and came to the conclusion that a main factor could be natural selection from the observable variability within a species' population. That's Darwinian Evolution: the idea that natural selection is the main factor behind evolutionary divergence. That's one theory, and it is not considered "rock solid scientific truth," but a proposal of what mechanism(s) might explain the facts I described in (a).

          (c) After Darwin, of course, the question as to where does the variability come from was answered by genetics. Random background mutations. Putting together natural selection and genetics gave us "Neo-Darwinian" evolution. Therefore, pretending that scientists accept "Darwinian Evolution as rock-solid scientific truth" starts here to be doubtful.

        • Jul 2 2013: ...

          (d) Further on, with molecular biology developed, others realize that, at least at the molecular level, most changes seem inconsequential, which lead to neutral and semi-neutral theory, which actually explain variability a good deal. You and me are very different, yet, we both survive all right. This could be considered semi-neutral variability. Anyway, that's a reflexion of what happens in molecules, which can vary much more with no consequence to individuals other than giving variability which can later on be the subject of natural selection should a challenge occur.

          (e) Later on, scientists realized that many changes in populations occur also randomly. In other words, not by natural selection. Therefore, they concluded, speciation events can occur in the absence of particular selection for some traits, which leads to completely non-Darwinian evolution. Therefore, saying that those who accept evolution accept Darwinian Evolution is quite a stretch.

          (f) I accept the facts demonstrated by scientific evidence. There has been evolution. I am not sure which factors have been the most important ones in shaping the history of life in the planet: natural selection, genetic drift, speciation by natural selection, speciation by random drift. There's a distinction between evolution and Darwinian evolution, and we have gone beyond Darwin for a long time already.

          Now, of course, I could not have shown you all the evidence and scientific understanding and work behind all those things I mentioned. Getting the better scientific background and understanding is always up to the individual, yet I try and explain. I wouldn't pretend you to just believe what I say, but as a minimum, I would expect a reader to try and be better informed after reading comments. This paragraph might be a rant on my part (ranting because readers won't pay any attention to explanations), but no rave, and it would be far from being religious.

          See ya.
        • Jul 2 2013: Oh, sorry, a couple more little points:

          1. It is false that dog breeds are used as proof of "Darwinian" evolution. They are used to show the kinds of changes that can be obtained from selecting individuals with desired characteristics to demonstrate that if we can change the shape and other characteristics of dogs that much within relatively short time frames, then we can expect evolutionary processes to be able to do a heck of a lot in the millions of years it has have to shape the "endless forms most beautiful" that we observe in nature.

          2. I have never seen anybody use taller people as evidence for any kind of evolution (Darwinian or otherwise). I doubt that it is used at all though.

          (Was that a religious rant and rave?)
        • Jul 3 2013: Edward, thank you for your thoughts.
  • Jul 2 2013: Thanks george. Religion has no part in my question. Im more curious as to the exact evolutionary mechanisms that happens. I do understand natural selection and it is accepted in my system. Im just looking at it in a slightly "deeper" point of view. More like trying to think of a possible explanation without resorting to books. Im trying to speculate and learn at the same time.

    I was just wondering how small a beneficial mutation can actually occur such that it gains access to the population pool? (did that make sense?)... going back to the fish that evolutionarily sprouted legs... I would accept that millions of year of small beneficial genetic changes did the trick of transformation (over millions of years that would be huge change). But how small a genetic change would that be? Would such a small genetic change in leg development actually enhance the survival of a small lucky individual? I would probably think that a small mutation of benefit would NOT exhibit itself phenotypically much. And if it doesn't express phenotypically enough how would that translate to increased chances of survival? in which case that small benefit would probably be pushed out by the "unlucky" species without such a change by sheer numbers...

    Unless if another scenario would happen... that mutation is driven by somewhat big genetic events in an individual (only ONE individual) that is immediately expressed and definitely gives a bigger advantage and one that is spread by dominant genes. Say a small 1cm fish that suddenly developed a mutation that gives its jaws an added 2mm increase. If that gene were to spread to its offspring it has to be expressed immediately in its progeny to give its children a good start in spreading this trait.
    but if this is the scenario... here's my question.. what in the natural world would give a 1cm fish the mutation benefit of an added 2mm increase in jaw girth? random changes?.. that is one very very lucky fish!
    • Jul 3 2013: I think you are getting it backwards, the process works the opposite way. There are two wrong assumptions you are making: 1) all mutations are either beneficial or detrimental to the individual, and: 2) all mutations manifest themselves immediately so the individual is forced to succeed or fail right away.

      There are mutations that are neither beneficial nor detrimental for the individual, those mutation tend to spread among the population, just accumulating in the genetic aquis of the species, waiting for an external event to trigger them. On the other hand, a mutation not necessarily manifests itself immediately it might remain hidden for generations and only express itself when a change in the environment triggers it, making it look as if the whole population automatically evolved spontaneously to to respond to that change, however the fact is that natural selection simply wiped out those who didn't have the mutation. Look at the ants, is a well known fact that if you expose them repeatedly and steadily to the same poison they will develop resistance to that poison, but the trick they do is that even when they all come from the same mother, they have their own genetic aquis which makes all individuals slightly different, so when you poison them what you really do is to manipulate natural selection to kill all those for whom the poison is more toxic and let alive those for whom the poison is less toxic, that way only those who have better resistance to the poison survive, if you repeat the process again and again, one day all of them become resistant, but the price they pay is that their genetic aquis is diminished and because of that they (as a population) become less resistant to other poisons. Consider also this: if all mutations would manifest immediately, all individuals with detrimental mutations would die before reproduction, but that is not always true and the proof of that are genetic diseases.