What is Natural Selection?

Hurray! There is another video in the “Stated Clearly” collaboration with Bird and Moon Comics explaining evolution!


You might also like their earlier video, What is Evolution?


Bug_girl has a PhD in Entomology, and is a pointy-headed former academic living in Ohio. She is obsessed with insects, but otherwise perfectly normal. Really! If you want a daily stream of cool info about bugs, follow her Facebook page or find her on Twitter.

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    1. Well, by it’s very nature, an introduction to natural selection will have to cut some corners. It’s an introduction to an incredibly complex topic that we still aren’t done understanding. Also, I would like to hear from PZ himself if that 2010 post applies to this particular bit of work.

      This video focuses on observable changes as documented facts in our biological history. Personally, I am in favor of getting people *close* to reality, but I don’t have a problem cutting a few corners in order to capture someone’s interest online. We have just a few seconds of attention to work with. Cuteness sells. And isn’t as threatening as Evilution.

      I would rather have someone discussing evolution than discussing creationism, UFOs, or boobs. PZ and I don’t agree on that, either because I am a damn accommodationist :)

      1. Hmm. Can’t say what exactly you might have done to be declared an accomodationist, but.. I would say that the two most common things I have seen that would cause me to call someone such a thing, using “other” examples, is:

        1. Insisting that we should bring someone to the table when talking about food safety, that, for example, might be pro-FDA, but thinks the invisible hand of the market will “fix” the existence of poverty wages, if we just deregulated the markets. In other words, that, somehow who supports a single idea, which we value, isn’t still a serious danger to everything else, due to the fact that, while they may agree on, say, evolution, they are not, at the same time, half way to deciding to deny it, if it should suddenly, in some manner, conflict with other delusions. I.e., suddenly becoming Anti-FDA, if the FDA came out with a study suggesting that poor pay levels was causing poor food safety in grocery stores, and restaurants, so pay should also be “regulated”. And, this is my big problem. The enemy of my enemy may be an ally, in the temporary sense, but still and *enemy*.

        2. The suggestion that, when the primary source of opposition to an idea comes from a particular group, there shouldn’t be at least some additional level of care taken, when someone from that group shows up and starts claiming they actually changed their minds (instead of, for example, going out of their way to get a science degree, so they can appose science, or, dog forbid, join a science conference, on evolution, as a means to water down evolution, or even undermine it behind the conferences back). And, that one happens as well.

        Its not just important if someone supports, on the surface, some general shared principle. Libertarians, as another example, support a lot of the same principles as I do. I would not, however, trust them to so much as offer to hold my watch, never mind my wallet, or for one minute presume that their definition of how to get from principle to actual reality is not, more often than not, scary, underhanded, inhumane, unjust, or just outright delusional, self serving, and/or naive. Not one of those attribute of which help anyone to actually achieve a real change, instead of engendering more chaos. Many of those would would “ally” with us on one subject, would undermine us in a long list of other ways. And, in many cases, perhaps without even being aware of it, by supporting causes, and people, who they **also** argue have a few dozen good ideas, and thus willingly support, but for which the net result is – supporting things that undermine/contradict, and/or appose, the very things that we are both fighting for.

        I suppose there is a sort of twisted symmetry to that.. but, for some reason I think, and I tend to suspect PZ would agree, that we would be, overall, better off to not have such a symmetry of mutually destructive support going on, especially where our “allies” don’t even have a clue that they are directly, or indirectly, supporting our opposition, or worse, not caring (and, for the precise same reason those called accomidationist so often argue we need such allies, “They might not support everything I believe, but they support one thing I find important.”)

        1. Oh, PZ and I get along just fine! I am a self declared accommodationist. We just have agreed to disagree about how to deal with people who are religious and also accept the reality of evolution. There is room for lots of different approaches.
          Mine tends to be:
          “Hi! I’m an evolutionary biologist. I made some cookies. Want one?”

          I go for the happy friendly Really-I’m-Harmless approach. :)

  1. “It’s almost as if these island creatures have been perfectly sculpted to survive within their unique environments.”

    I don’t like the use of “perfectly”. There’s a general tone of nature worship here that chafes a little. But it’s not a bad.

  2. I am constantly trying to get the point across that Evolution is *complicated*. As an undergrad, I had to take 5 pre-requisite courses just to qualify for a semester on Evolution, and even that was still a pretty introductory discussion.

    1. I believe you are forgetting about the billions of insect minions that will be backing me up, PZ. I sent an advance team over to demolish some of your sweaters.

    1. Sometimes I wish there was a ‘like’ option for these comments, because I would thumbs up Melanie’s response!

      I do like the simplified explanations to help give laypeople a general understanding of a very complex topic. Most people just want a general overview without the need to get a science degree. It’s the explainer’s duty to ensure that there is no way the explanation does not end up becoming misleading.

  3. Evolution is complex, but the basic mechanism is not difficult to understand if we can show people that it is happening and that it works. I agree with Bug, you have to start where people are. They need to understand the fundamental concepts (e.g., what is a random mutation, and how does it lead to variation in a population? And what does the environment have to do with which variants are successful? etc.) before they can get into the more complicated stuff.

    And as a self-proclaimed bug_girl minion (though the kind without wings and antennae), I am with her on the “honey over vinegar” approach. I mean, who doesn’t like cookies, amirite?

    1. You say “the basic mechanism is not difficult to understand,” but there is not just one basic mechanism. Perhaps you did not mean to imply that there is only one mechanism, but language is important. When you say something like “evolution is complex, but the mechanism is not,” that seems contradictory to me. Evolution is complex for many reasons, including that there are multiple mechanisms behind it. The concept of natural selection is not necessarily difficult to understand (which I think is what you’re getting at?), but it’s not the only thing one needs to grasp in order to understand how evolution occurs.

  4. Real evolution is complex, but one thing is obvious it doesn’t follow the Darwinian model. The video was incorrect on several points.

    Natural Selection was conceived by creationist Blyth, Darwin plagiarized the idea as documented by University Pennsylvania Provost Loren Eisley.

    Nature frequently kills off the fittest as well as the weakest since the fossil record shows extinction is rampant and not the result of competition for survival (see Bad Genes of Bad Luck by Paleontologist David Raup). Hence, the notion “survival of the fittest” is not exactly right since the presumption is there is survival to begin with. The rapid extinction of insect species today is a powerful testament of this.

    Furthermore, for weakly selectable traits, the fittest may not be selected, and for nearly neutral defects, the bad may not get weeded out. In fact, if there is sufficiently high rate of random variation that is bad, the bad will NEVER get weeded out. For example if we have 100 organisms, and each has 3 unique bad mutations, the next generation is guaranteed to have on average to 3 bad mutations which the ancestors did not have. Hence, selection in principle won’t select the fittest (as in the ancestral parents) since the fittest died of old age! Some have named the problem for humans as Nachman’s Paradox. Kondrashov wrote a paper on why we should be dead 100 times over…obviously something other than Darwinian selection is why we’re still alive.

    Natural selection actually has to be absent for evolutionary innovation to happen in many cases because intermediate forms would be selected against not for, Gould put it well, “what good is half a wing”. Lynch’s recent book on Genome architecture says as much.

    What is often swept under the rug is how natural selection has selected against biological innovation (such as blindness in cave fish or gammarus minus).

    Selection could work to build large scale complex biological systems if the each component of a complex system is individually advantageous, but this is the exception, not the rule, and hence, in the wild selection selects against complexity, not for it.

    If one wishes to argue Natural Selection creates biological diversity, this is problematic, because Natural Selection, according to Fisher’s fundamental theorem of natural selection, succeeds by removing biological diversity. Hence the notion that Natural Selection creates biological diversity by removing biological diversity is a contradiction.

    Most evolution is neutral, and in principle would have to be independent of selection. To illustrate, the human genome is 3 billion base pairs or so. If human populations were at times as small as a few hundred thousand, there is no way selection could be evolving things at the individual nucleotide level for most of the nucleotides, and if even .40% of the genome is found to be functional, that means the functioning evolved outside of the influence of selection. Kimura successfully demonstrated most evolution is free of selection at the molecular level. Some will argue Kimura dealt with molecular evolution not adaptation, well, that is flawed since molecular evolution dictates the ability to adapt, Nei of the National Academy has finally come out and said as much.

    Finally Pagel makes a good case that the origin of species is not by natural selection but by accident, hence, again, Darwin was wrong.

    Natural selection happens, but it doesn’t do what most think it does.

    Other than that, that was an entertaining video. Thanks for the link.

    1. Ladies and Gentlemen:
      Failure to understand online communication to non-specialists. Exhibit A.

      My biggest criticism of this video? It runs too long. To work well on the internet, you need a video no longer than 4 minutes.
      And if this video were even shorter, it would have MORE stuff wrong with it.

      1. Bug, can you tell me, are the views expressed by stcordova now mainstream or is that a niche view? I mean, I know a lot has happened to the theory since Darwin, but as an undergraduate 40 years ago the line was pushed very strongly that every variation was significant. I always thought privately that no, some of this stuff could be just random and of no consequence, so this now makes a lot of sense. My own work touches on this area sometimes, but I am pretty much isolated from the broad theoretical academic overview.

        1. That is an excellent question, Jack. Much variation *is* probably just random noise in the genetic background. It’s only when conditions are right that they become important.

          An example would be insecticide resistance. Insects have a wide variation (via mutation) of different enzymes in their bodies. Because of that variation, when a pesticide is sprayed, some of them are able to survive. And bugs with a particular enzyme variation that detoxifies the pesticide are now selected for and more “fit” (have more babies).

          But most of the time, in the absence of pesticides, the variations are just random changes in amino acids leading to slightly different enzymes. And the enzyme variation doesn’t do anything much at all, or has a very tiny effect on the insect that is counterbalanced by a different random enzyme variation.

          Did that make sense?

          1. Absolutely. but do you think the game (i.e. understanding of evolution) has changed that much over the last 40 years or was it perhaps just that I was being fed simplified undergraduate material? Because really, this kind of nuance is perfectly easy to understand and makes a lot more sense. Not that I disagree with your point about the video, but I mean for undergraduates.

          2. Oh, yes, huge changes in the last 40 years. Think about all that the genomics revolution and new molecular tools has brought us! PCR is still a relatively new innovation–it’s not 30 yrs old yet. Now we can look at organisms on a very broad or narrow spectrum!

            I think our understanding of evolution has changed massively, and will continue to change as we learn more.

  5. Thinking about the protein I deal with quite a lot, alpha-1 antitrypsin, – there are over 100 variants described but only a handful of clinical importance and only the latter are usually studied in any detail (the Z variant among others causes emphysema and liver cirrhosis). I suppose the proteins are very different in bugs.
    It’s interesting to meditate on all those enigmatic silent variants sitting there, quietly waiting for the continents to collide or the asteroid to fall – or the maximum summertime temperature to rise above 50 degrees Centigrade!

  6. There is no consensus about the mechanisms of evolution.

    There is a public feud between Jerry Coyne and a fellow scientist at the same university by the name of James Shapiro. Shapiro thinks natural selection has a very small role in evolution. One of the most respected evolutionary biologists believe evolution at the molecular level isn’t influenced very much by natural selection. See:

    And there was another school of evolutionary thought that was supposedly destroyed by neo-Darwinism:

    But I just saw a paper that said neo-Darwinism has been destroyed:

    Mark Pagel thinks Darwin was wrong:

    Bottom line: there is not much of a consensus, it depends on which evolutionary biologist you talk to

  7. stcordova, thanks very much for those links (I was thinking of asking), I really appreciate your taking the effort.

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