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Thursday, April 20, 2017

The last molecular evolution exam: Question #2

The paper by Andrews et al. (2011) lists a number of common misconceptions held by their students. One of them is the idea that, “Evolution is a process that will never stop, even in the human species.” Why do they think this is a misconception? Do you agree?

Andrews, T.M., Kalinowski, S.T., and Leonard, M.J. (2011). “Are humans evolving?” A classroom discussion to change student misconceptions regarding natural selection. Evolution: Education and Outreach, 4:456-466. [doi: 10.1007/s12052-011-0343-4]
Question #1, Question #2, Question #3, Question #4, Question #5, Question #6


  1. To be fair, the misconception they list is what they call the "principle of inertia" in which the "student believes selection has always occurred and so will continue to occur". They provide the statement you quote as one example of this from their students' responses. In other words, the misconception is that selection will always occur simply because it has always occurred. We can argue about whether that is a reasonable inference or a misconception, but they didn't actually claim that “Evolution is a process that will never stop, even in the human species” is a misconception unto itself, it was given as an example of the "inertia" argument. They also list "Student believes natural selection no longer occurs in first world countries OR that selection only happens when organisms die" as another misconception.

  2. So, what, it won't occur anymore, maybe if all Hardy–Weinberg conditions were ever actually met in a wild population haha? I say that sort of jokingly.

    I get that it hasn't always occurred, as in, before life even existed it surely wasn't occurring. And mass extinction ending all life on Earth, it would surely stop.

    But cease all together while life still continues to any degree? I can't imagine how Evolution as a process ever would stop, short of extinction?

    If writing this exam I surely would have fell into the disagree this is a misconception camp!

  3. I think their original point is that "selection has always happened, so it will always continue" is not a good explanation. Rather, selection will continue to occur because the conditions necessary for selection (heritable variation, differential survival and reproduction) will still apply.

  4. The issue is that the authors did NOT claim that "Evolution is a process that will never stop, even in the human species" is either true or a misconception. It was an example of a response from a student said that they considered to be an expression of the "principle of inertia" misconception.

  5. Actually, all three of the examples of student responses that these authors include for their "principle of inertia" are totally reasonable answers. Here they are:

    "Evolution is a process that will never stop, even in the human species."

    "I believe humans are still evolving because there is no reason why this process would have gone on for so long without stopping and suddenly come to a halt."

    "If we accept the theory of evolution as an explanation for historical data, we must assume that we will continue to evolve."

    If randomly selected individuals from the public actually espoused these "misconceptions" I would think that we were doing a good job of education in evolutionary biology.

    I will admit that these statements do not go into specifics of mechanisms, or present a mechanical view of evolution. But they are entirely reasonable and students who believed these things would be well equipped to read and understand work on selection in humans as it in fact has occurred.

    1. As I think about this, I think that the authors' examples are just terrible ones. A good example of a misconception about inertia would be:

      "For the past two million years, human brain size has increased. This history shows that it will continue to increase in the future."

    2. "It is hoped that skull size will keep pace."

  6. Simple:

    To be fair, the misconception they list is what they call the "principle of inertia" in which the "student believes selection has always occurred and so will continue to occur".

    The bolded word is key. The reason why evolution might well continue to occur as far into the future as we can conceive isn't "because it always has."

  7. If by "evolution" you mean mindless genetic mistakes proofing new body parts (or parts of parts) into existence then evolution never even started. No physical biological feature got here via random mutation.

    1. that would be your job to prove me wrong...with science.

    2. Tommy, they don't want you meddling with their beliefs. This is about religion. It is not about science, scientific method, evidence or logic. Those are just words they like to use.

    3. Hi Tommy,

      No, by evolution nobody means mindless genetic mistakes "proofing" new body parts, or parts of parts (did you mean "poofing"?). Maybe you should rethink your points. As if stands, it shows that you haven't bothered to check what's said about the evolutionary history of [some examples] of body parts and parts of parts. If you started checking, you might find that the proposed processes, based on the evidence, show stages in the development of those parts (not "poofing"), and that those proposed processes work very well at explaining what happened.

      Some books in comparative anatomy are filled with examples, if you care to go and check.

      I suspect that you were being facetious with your phrasing though. That you're not about to run to the library to learn about how the evidence has been found, what kind of evidence, models proposed, models rejected, then new models suggested, etc.

  8. I don't agree that it is a misconception, I think it is true to say that evolution, defined as changes in the frequencies of alleles in populations, will always happen. As such, the human population is still evolving and always will be. Even if selection is totally absent.

    The frequency of alleles will always be in a state of changing with the coming generations. Even if not for adaptive reasons, then the frequencies will just be subject to random drift. I suppose you could bring in the drift-barrier hypothesis to point out that mutations can probably never be completely eliminated, so new alleles will arise and be subject to random real world events.

  9. I don't think this is a misconception in itself.

    Exception any species, including us, stops evolving when it goes extinct. And eventually the sun will die and all life on earth with it.

    In the meantime, though, allele frequencies change even if conditions don't, and conditions do change. Evolution happens. Improvement (whatever that might mean) doesn't always happen, but that's another thing.