A trivial point about selection that some people just don’t get

Another day, another talking head video. Sorry, this one is mostly just me talking at a camera — I’m too bogged down in work to make it fancy (classes start next week, which rhymes with “eeeeeeek”).

You really can just ignore it and go straight to Joe Felsenstein’s book, Theoretical Evolutionary Genetics. It’s mathier and more detailed.


  1. unclefrogy says

    I am amazed that anyone has such a hard time understanding the basics process of evolution. The specific details and the paths through time that have been taken by different species and traits are another thing. great one,
    defiantly a three base hit!

    uncle frogy

  2. Joseph Felsenstein says

    Very good, PZ. In case it helps, here is a simulation program (in Java) that people can download to play with the population genetics of natural selection, mutation, migration, and genetic drift.

    It looks like, for your filming on location, you got a very pleasant day on the Oregon coast — I couldn’t even hear the noise of the wind or the waves behind you. In fact the waves don’t even seem to be moving. A miracle, I guess.

  3. says

    Actually, that is the Washington coast, near La Push. Just the fact that it wasn’t raining would be miracle enough, you’d think.

  4. Ed Seedhouse says

    The video kept jumping around on my monitor, which was slightly distracting, but the words were interesting.

  5. chris61 says

    minor point PZ
    the probability of rolling 5 dice and having them all come up the same number is 1/6^4 not 1/6^5.

  6. The Very Reverend Battleaxe of Knowledge says

    Damn! I said to myself: “Self, that looks like La Push!” Used to go nearly every fall when the rates changed.

  7. Mobius says

    @8 chris61

    Quite. While the odds of rolling 5 of a particular number are 1 in 6 to the 5th, there are 6 ways of doing it, one for each number. Thus the odds of a Yahtzee in one roll is 1 in 6 to the 4th.

  8. jaxkayaker says

    I don’t remember her name, but there was an MD blogging on Salon years ago that I tried to explain this point to. She was confused that nonrandom implied intelligent design or theistic involvement of some sort. She had cited you (PZ) as an authority on some of her blog posts, so I found an appropriate quote by you and presented it to her. She was nonplussed. Her other readers seemed to think her MD granted her some special authority on evolutionary theory.

  9. Gordon Davisson says

    jaxkayaker @11: I’ve noticed that creationists/IDists tend to conflate the many related-but-different meanings of “chance” and “random”. Among others, there’s:

    – “Random” = nondeterministic (or stochastic)
    – “Random” = uniformly distributed (i.e. all possibilities are equally likely)
    – “Random” = unintentional/unplanned/not intelligently guided

    …and since evolution is random in the last sense, they leap to the conclusion that it’s pure chance in all of the other senses! Or in her case, the contrapositive: selection is nonrandom (=deterministic), so it must be nonrandom (=intentional)!

    BTW, when someone talks about mutations being random, it’s even more confusing, because what they should mean is that they’re random with respect to function. That’s stats jargon that means they’re uncorrelated with function. Mutations are presumably also nondeterministic (unless physics turns out to be deterministic at its deepest level) and unintentional (as far as we know), but they’re clearly not uniformly distributed.

  10. jaxkayaker says

    Gordon – you’re right, and I tried to explain that to her, but was just given the treatment that I was a creationist. I had to resort to pointing out that, as I said above, her MD didn’t give her any special authority in the area of evolutionary theory, and that I had just completed an MS thesis on eco-evolutionary population genetics and was working on my Ph.D. in biology and that if we were going to play the appeal to authority by degrees, I would (or should) win.

  11. slatham says

    Poker may be a better analog than poker because it also brings in the notion of competition. You don’t need perfect hands to win; you just need a high enough fraction of better hands and the right environment to have a profitable evening.

  12. chris61 says

    @14 slatham

    I think the problem with poker as an analogy for natural selection is that winning at poker involves strategy which requires intelligence. My impression is that creationist/IDers love analogies that involve intelligence because it reinforces their notion that the world is too complex to have not involved a designer.

  13. slatham says

    I know it’s a problem (see below). But alternative strategies can be developed at “random” (through mutation), and these can compete in games of chance (I wish I had a handy example), and this refutes the necessity of an intelligent designer.
    The problem with any analogy is that it takes something familiar and well-understood conceptually to stand in for evolution. The things that are familiar and best understood are designed by us, right?

  14. slatham says

    “Mutation” in my above comment should have been in quotes. I was hoping for that word to quite broadly represent a somewhat heritable change.

  15. chris61 says

    @17 slatham
    My favorite analogy for natural selection is one of the big lotteries (Powerball or MegaMillions). The odds of any one ticket winning a small prize are small but significant; the odds of winning the top prize are vanishingly small but enough people buy tickets and the odds of someone winning the big prize are significant.