Twelve days of evolution. #3: Have we seen evolution in real time?

December 21, 2015 • 12:30 pm

This short video, about evolution in real time, is the best yet in the sequence of the “Twelve Days of Evolution” videos, produced by PBS and “It’s Okay to be Smart. ” I’ll be presenting, reviewing, and annotating these over the holidays:

The creationist canard dispelled here is the idea that if we can’t see evolution in real time, it doesn’t happen. (Never mind that the fossil record gives us tons of evidence for the process.) The example it gives is a nice one: the work of Marlene Zuk and her colleagues (she occasionally comments here) on the loss of sound-producing structures in crickets. You can read about it in detail at this site, but the upshot is that the invasion of a cricket-parasitizing fly in two Hawaiian Islands imposed strong selection on the resident crickets to lose their song, for the fly uses that song to detect its prey. Not only was evolution extremely fast in this case, but it involved only a single mutation on the X chromosome, one that ablated the stridulation combs of males. Soundless males survived, for the survival advantage more than outweighed their loss of ability to attract females through singing.

The example is not just evidence for evolution, but evolution via natural selection. Remember that there are other causes for evolution besides natural selection, most notably genetic drift.

But of course we’ve had examples of natural selection in real time for ages. John Endler’s book Natural Selection in the Wild gives several hundred, all from nature, and we’ve known about microbes evolving resistance to antibiotics for decades. Ditto for plants evolving resistance to herbicides, insects to insecticides, and plants to heavy metals brought to the surface by mining.

And most of you have heard of Peter and Rosemary Grant’s work on selection in the medium ground finch (Geospiza fortis), one of the best-documented examples of natural selection in vertebrates. A drought killed off small plants on the Galápagos island of Daphne Major, enabling only those individuals with larger beaks, who could crack the remaining big seeds, to survive. The population’s beak size increased by 10% in one generation, and the genetic and ecological basis of the trait change is well understood.

Section 5 of Douglas Theobald’s magnificent evidence-for-evolution website, 29+ Evidences for Macroevolution, gives other examples, though I can’t seem to access it now.


35 thoughts on “Twelve days of evolution. #3: Have we seen evolution in real time?

  1. Well, given the audience and the presching-to-the-converted aspect, maybe I’m not surprised at the lack of comments.
    I met a sane (-sounding ; IANA-psychiatrist) UKIPPER today. Verily, the Plains of Englandshire are a strange and unusual place.

  2. Second the kudos for Douglas Theobald’s 29+ website. Every once and a while I devote an evening to going back through it.

  3. “their loss of ability to attract females through singing.”

    I would guess that alternative abilities to attract females might arise in the silent population. Maybe the ridges that once created chirps will become modified to produce a sound of a lower tone that the flies can’t hear. Or, maybe they will fall back on that old male talent for generating odors. 😉

    1. I hadn’t come across this before, but the really interesting things is that strong selection acted on a secondary sexual trait. Since singing loudly is always risky and costly to some lesser degree, probably there was a sexually selected female preference for singing males to offset that risk. I wonder what happened that preference during the period when both singing and non-singing males were available for mate choice? The non-singers may have been wiped out so fast that nothing interesting had time to happen with sexual selection. But what happens going forward with sexual selection seems very interesting.

      I’ll have to go and read Marlene Zuk’s work, I’m sure she has thought about this.

  4. That one was very good. Feels more like culling than adapting, except for the fact that two different mutations occurred (Kawaii and Oahu). Of course they could have all been wiped out anyhow.

    1. I don’t thin this example will impress evolution-deniers. They have no problem with loss-of-function mutations. In fact this example is a bad one, because it reinforces their belief that loss-of-function mutations are all we ever see.

      1. I was thinking too that a loss-of-function mutation (and loss of structure mutation) is not as big a ‘sell’ as evolution in the other direction. There are cases of those as well.

      2. Indeed, antievolutionists deploy a variety of rejection responses (including several both YEC & ID taking aim at Theobald’s older macroevolution post, a topi of itself). You spotted the loss of function aspect, but more generally they will say “but they’re still crickets, aren’t they?”

        Underlying antievolutionism is a pervasive inability to connect the dots between microevolutionary processes and bigger scale macroevolutionary transitions. All antievolutionists are in a muddle on conceptualizing speciation, and fail to pay attention to anything like most of the available data. On this point, I’m directly measuring the antievolutionist citation of primary source science papers in my #TIP “Troubles in Paradise” project ( & html modules at, and currently record only about 2000 papers total having been cited (biology, paleontology, geology, cosmology, the gamut) from a field of 6800 antievolutionist works written ovber the last decades by over 1900 authors (though over half are generated by a much smaller core of 70 activists), which is roughly 10% of the 17,000 relevant technical paper baseline in #TIP currently.

        For antievolutionists who slough off loss of functions, there are example like the fish antifreeze proteins (clearly a gain of function, based on single mutations also), Chen et al.(1997) “Evolution of antifreeze glycoprotein gene from a trypsinogen gene in Antarctic notothenioid fish.” PNAS 94: 3811-3816. I’m currently assembling for #TIP an array of biological papers that turn on such single mutations in driving novel features, and the extent to which their apologetics ignores them.

        I also like to toss out the new paleogenomics field, where ancestral biomolecules are retroengineered and their precursor properties experimentally assayed, eg review Harms & Thornton (2013) “Evolutionary biochemistry: revealing the historical and physical causes of protein properties.” Nature Reviews Genetics 14: 559-571. Its only a matter of time before higher level cis-regulatory cascades are explored in the same way as proteins, but given the track record of antievolutionism, the apologetics will not think about that info either, and I’ll be taking note of their not doing so in #TIP.

        1. That’s a great comment. Too bad the makers of the video aren’t as familiar as you are with the actual details of creationist denial. Your fish antifreeze example would have been far more powerful than the example they gave.

          All creationists know and acknowledge that loss-of-function mutations exist. Part of their mythology is the Fall, which sort of covers and countenances these kinds of mutations.

          1. Thank you. Its precisely to get our ducks better in a row, and update our ammo pile to better target the soft underbelly of antievolutionism (their core methodology) that is the goal of my #TIP work.

            You might like to take a gander at TIP 1.3 as the model of the work to come: I cover (and I believe flatten) ALL currently known instances of antievolutionists on the Puncuated Equilibrium issue (they don’t discuss the subject even when they bring it up themselves), including Stephen Meyer’s “Darwin Doubt” chapter (in which he made several bonehead wrong assertions, not previously spotted so far by critics I think). Richard Lenski liked TIP 1.3 a lot, and supported the project as a result (Nick Matzke did likewise just yesterday, so making some slow progress on that crowdfunding front).

            It is noteworthy that only two antievolutionists (Fazale Rana & Casey Luskin, neither YEC btw) even tried to invoke primary source science lit on P-E, and both got all their data wrong. QED slam dunk 100% wrong, not good for them having a fallback position here.

            If only I can keep at the #TIP project, the plan is to do that level of analysis for all antievolutinist claims and assay all the sources they invoke in service of it. (Everybody needs a hobby lol).

    2. Culling is a powerful description of the process of natural selection, especially when high lethality due to a predator or parasite is the mechanism.

      The mutation for the ablated stridulation comb was already present in the population and possibly being moderately selected against. The crickets can’t be said to have evolved this defense against the flies, erecting it after the predation began. Rather, the vulnerable variant was rapidly culled from the population.


  5. “The creationist canard dispelled here is the idea that if we can’t see evolution in real time, it doesn’t happen.”

    I know how they feel. When I was very young my mom taught me how to tell time. First she pointed out how the second hand moves around the clock face, and I had no problem accepting that because I could see it move. Then she claimed that the minute and hour hands were also moving, but I refused to believe that because I could plainly see that they were standing still.

      1. Patience cricket, patience.

        The 9 foot long hour hand of Big Ben moves 339 inches in an hour or 0.1 inches in a second.

        Easily perceptible I expect, though you would need to be up close to see it. They give tours.

        It might be fun to put an analogue watch under a microscope and note the motion.

    1. Yep. Or, “that’s MICRO evolution” , they’ll say. “Show me a cricket that turned into a cat and then you’ll have my attention.”

  6. And what about fast human evolution, as when a hitherto unencountered disease (eg. smallpox) devastates a population, but maybe 10% survive, and their progeny are more resistant to the disease. That’s human evolution in just 1 generation isn’t it?

  7. I wasn’t aware of Zuk’s cricket evolution work, so thanks for heads up on that, Herry, and will be adding the primary sources in the berkeley website to my #TIP data set.

  8. Hypothesis:
    Tinnitus (ringing in the ears) is a evolutionary symptom from the need for a prey to be ever vigilant of predators and now persists as a nuisance ( in some people) due to our changed environment.

      1. Tinnitus is a repetitive sound. All physical and emotional signals like pain, hunger, anxiety etc have a repetitive nature, thus attempting to gain conscious attention (and keep it) and thus serving a survival need. Repetitive stimuli, like flickering lights, smoke alarms create an urgency of response but once the absence of danger is realised, only serve to create an annoyance. The fact that sufficient neural machinery has evolved to create this attention seeking mechanism (and a response mechanism) may denote its importance as a “warning alarm” in survival.
        In a predator coexisting environment, such a method of surveillance is essential. These methods essentially only depend on the basic available perceptory armamentarium i.e. the senses, for an immediate response as opposed to the ‘learned’ response.

        Some logical considerations may provide a clue as to why the repetitive value:
        1. The visual sensation is actually the most reliable for survival and only a 360 degree vision in all axes, at all times, would be helpful but this is a physical unreality under available anatomical constraints and any other misinterference with vision would itself threaten survival. Some organisms may have followed this path with possible fatal consequences.
        2. The olfactory sensation is the most unreliable for survival and hence the most likely to be ignored by the organism. The smell sense is more primitive in evolution with individual (not species) specific preferential links (and related only to specific odorants) to the limbic /autonomic systems. Thus it is unlikely to create an atmosphere of urgency. Also, in the competition for attention, hearing trumps olfaction. In falling to sleep (losing consciousness) hearing is the last sensation to disappear. Also, because of the paucity of spatial localisation, olfaction cannot be concerned with precise environmental details. Chemical sensitivity is the oldest response of animals to the environment and with the development of the neopallium, it appears that auditory and visual sensations gained prominence. It is a common experience of pet owners that unfamiliar smells provoke curiosity and unfamiliar sounds provoke caution.
        3. The touch and taste sensations are “too close for comfort “ under predator supervision. Again, this path may have been followed by some organisms with fatal results.

        The “siren” sound creates an atmosphere of present-centeredness triggering limbic and autonomic events. Habituation will not occur as this noise is centrally induced.

  9. Pretty cool. But they left the de trop Dropbox promo off today’s edition. I was getting used to having that to carp about.

  10. Here is an off-topic question, for which I request tolerance. I wish to read Darwin’s Origin, but would like to have a version with adequate notes to point out where modern interpretations differ. Any suggestions?

    There is an “Annotated Origin”, which sounds good. But the intro is supposedly written by a creationist, Ray Comfort, at least according to one Amazon reviewer. So…

    1. Interesting issue. I’m not sure there is (as yet) a work of quite that type (one that wouldn’t be twice the length of the book it was annotating). Jerry mentioned Costa’s 2009 annotated version (which I have not seen myself) Quamman’s 2008 illustrated Origins (which I do have) has useful pictorial info and added letters, but not strictly technical followup annotations of the sort you would enjoy.

      Overall the big area where Darwin bumped into a conceptual wall concerned the fact that nobody actually knew how inheritance and development worked at the genetic level, and it can be said most everybody remained a lot in the dark all the way down to the mid 1990s when homeobox genes were discovered to show a hidden inherited unity to the seeming diversity of form showing up at the phyletic level.

      Darwin’s geologist side would also marvel at our understanding of plate tectonics (long kicking into gear in mid 1970s), rendering unnecessary the strained landbridge hunts that plagued biogeographical dispersal thinking for most of a century (and even inadvertently spawned a few imaginary supercivilizatons in wackaloon lore, Lemura and Mu).

      Though there have been a lot of fiddly bits filled in since Origins on what lived when, his picture of life Cambrian on had less blips but the overall sequence today would be fairly familiar to him. That bacterial life stretched back so much farther into the Precambrian would have doubtless fired his imagination, but not necessarily surprised him.

      If anyone knows of a targeted annotated Origins to suit your needs, though, reades here should be the gang to spot it for you.

  11. Here’s a recent PNAS article featuring quick evolution in sticklebacks:

    Evolution of stickleback in 50 years on earthquake-uplifted islands


    On several Alaskan islands, phenotypically variable threespine stickleback fish now live in ponds that were formed during uplift caused by the 1964 Great Alaska Earthquake. We analyzed phenotypic and genome-wide genetic divergence of resident freshwater and oceanic threespine stickleback populations from three islands. These data support the hypothesis that the freshwater populations evolved repeatedly from their oceanic ancestors in the past half-century, and have differentiated to nearly the same extent as populations that were founded thousands of years ago. This work raises the possibility that much of the evolution that occurs when oceanic stickleback invade fresh water takes place in fewer than 50 generations after colonization, rather than gradually over thousands of years.

  12. It would seem that (cricket) males, once they have done their duty, are expendable.

    With the singing population gone, it is too late to establish a baseline, so we will never know the relative fecundity of the two populations. Island biology is interesting.

    I confess that I do not know how long male crickets live after mating, or anything of cricket biology.

      1. Thanks, Ralph. Which of Jerry’s links are you referring to? Thanks for your link.

        No pun intended, but were silent males present in the population and/or were there “silent” genes present in the singing population before the invasion. Have the females evolved toward a preference for the strong, silent types (or are the silent ones just shy nerds that now find themselves in paradise?

        1. Same link, I reposted it because it’s a little hard to spot in the middle of Jerry’s text.

          The summaries are a quick read, just follow it through. They have pre-sweep population specimens, and it appears the females did not have strong preference beforehand, perhaps because of a bottleneck; and that this may have facilitated the sweep. Nevertheless, silent mutant males appear to be hanging around piggybacking off a small number remaining singers, and bogarting the females who come by.

          1. I’m not sure “bogarting” is the right term, but I have heard tales of elk harems being penetrated by bachelor males while another bachelor takes on the herd bull. Anyone else heard of this? I have no first-hand knowledge of this.

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