Graven images

I began research before I graduated from college, graduated in 1987, worked in research for two years, and began grad school in 1989. Evolutionary biologists know what this means: I was trained right in the thick of the cresting of popularity and conflicting interchanges between Richard Dawkins and Stephen Jay Gould.

It’s true that a lot of my starting grad class arrived firmly clutching an allegiance to one or the other, ready to fight about it. By the time we were finishing our degrees in the mid-90s, however, most of us had decided this was silly. There was no reason to collect the mini-positions held by either of them into a single basket, many of those positions were not incompatible across the two, no one of those positions was particularly sacred or irrefutable, there was a galaxy of important questions well outside either’s range, and neither person was being particularly proactive about addressing the issues with research. Neither owned any damn intellectual thing, or acted as its overseer. Any reasonable scientist could address any one of these things professionally, so aside from proper citation, who cares which one said what?

Unfortunately their over-hyped confrontation became hot intellectual property outside the discipline itself. And now I find that it’s bled all over pop culture and the social sciences, having gained absurd qualities and various books and t-shirts and who knows what else.

As I remember him

Disclosure: I haven’t met Dawkins, although my time in grad school at the U of Florida just missed overlapping with his temporary appointment there, and his presence was still keenly felt in a variety of ways. I knew Gould, although not long enough, and liked him as a person – and when it comes to academics of his status, believe me, that is a very binary thing. He was kind to me as a younger scientist, treating my thoughts with respect in public and providing reasonable counter-arguments. Many experiences through others confirmed to me that he cared about others’ success and put a lot of effort into being decent all the way down the hierarchy to the incoming undergrad. My present point isn’t about his main ideas, or anyone else’s – I’m talking about the objectification of him and others from people into fixed, monstrous images composed of bits of this and that which they happened to have said … and missing both the memory and experience of them as people, and the individual value or lack-of-value of the things that were said.

It would be dramatic to highlight an early exchange between these two specifically, but intellectually, the best example is the dialogue in 1987 between Gould and John Alcock, whom if you must know, I consider more significant in the study of animal behavior than Dawkins, which I hope will support my ultimate point all the more. It was conducted in that earlier version of the internet, the in-house Harvard journal Natural History. I’m considering the original exchange, not the version published in Chapter 8 of Gould’s 1991 Bully for Brontosaurus.

The problem is that it’s all way too much posturing and not enough biology about the organs. I’m going to say it once, clearly, and with any luck you’ll instantly see what’s up and get your thinking on, without who said what about God knows what.

In mammals, this is the same organ – pure and simple homology. That they have different names is a minor matter, that they do somewhat different things in male and female mammals is of some interest. You can see the size difference and an elaboration or modification of some c. cavernosum into c. spongiosum in the pic. You can see too that the penis accommodates the urethra, and the clitoris doesn’t, as the urethra ends in its own orifice (not shown here). The penis is an intromittent organ and the urethra transmits gametes as well as urine; the clitoris is not employed this way and the female mammal does not emit gametes outside the body at all.

This is a very ancient structure associated with amniote vertebrates, perhaps even with that group’s origin. To say “the penis is adapted for copulation” is … simplistic. The first thing to know is that mammals didn’t make or evolve it, they inherited it, with minor modification compared to birds (most of whom have lost the penis or rather its intromittent role) or squamates (who have lost it and use a different intromittent organ, the hemipenis). So don’t talk about “needing” it, as birds do just fine with their charmingly-termed cloacal kiss. We have it, done; what’s interesting about that is the devil details, i.e., what a given mammal is doing, and how each piece of it has evolved.

Having researched and written my dissertation on that very thing, here’s a paraphrase of what I said about the exchange at the time:

That a given organ has a homologue is not an indicator of whether and how much selection is involved in that structure’s current form. No matter what either version is doing.

That a given organ is physiologically present and connected to the various systems of an organism’s body, and “does a thing,” is not an indicator of whether and how much selection is involved either. No matter how it’s connected, or how many other organ systems are integrated with it.

All organs have homologues, between and within species. To say, “it can’t be a selected-thing, because its homologue has all these other functions,” is nonsense. All attached pieces of an organism’s body are part of its systemic apparatus. To say, “it’s supplied with blood and has nerves and doesn’t kill the organism where it stands, therefore it’s an adaptation,” is nonsense too.

You see what’s going on here? It’s not about “different levels” or “talking past one another” as later writers claimed (P. W. Sherman, 1989, American Zoologist 32; S. D. Mitchell, 1992, Animal Behaviour 37). These eminent poo-bahs had forgotten about the biology and were being plain careless. If they hadn’t been famous or if people hadn’t been so willing to associate themselves with their names or so interested in who “gotcha’d” the other, the exchange would have been called out by the editor of Natural History, who’d have told them to go pound sand, or failing that, laughed outta the joint at first reading by anyone.

Science as an activity, i.e., thinking scientifically, is or it isn’t. For any given topic or endeavor, you’re doing it or you’re not. But science as a culture, which is to say, profession, employment, income, status, funding, peers, reputation, “consensus” (for fuck’s sake), success, and much related matters, isn’t itself a scientific act or endeavor. It’s a baboon fest of baboon status, exacerbated by our technological reach in time and space.

Given my age group, or cohort for the population ecologists among us, it’s inevitable that I’ll be posting more about this-or-that thing which calls for mentioning Gould, Dawkins, and any number of other scare-names, Darwin included. But they’re not graven images, and I do not regard various key phrases of their contributions as scripture from either a unified church or a collection of cults. Talking about ideas which they’re associated with professionally doesn’t factor into how those ideas operate scientifically. In later posts, if you feel your cult membership fires burning, hop on back to this one and read about the dick-and-clit. That’s what matters.

Links: Peaceful Parenting (I quite like this one)

Next: Where do little species come from?

Advertisements

11 thoughts on “Graven images

  1. So, homology and system-connections tell us nothing about selection. Could I alter that to homology and system-connections IN THEMSELVES tell us nothing about selection? That is, could they be part of an explanation of selective processes, just not held up as sole, conclusive proof of the presence/absence of selection?

    Like

    • H’m, let’s see.

      1. For something to be part of a body at all, it’s integrated with its organ systems, period. That in and of itself cannot tell us what evolutionary process or processes are implicated in the particular form we’re looking at.

      2. Homology is the rule, not the exception. Closely-related species are not only homologous in all their parts, the parts themselves are so similar that the difference makes hardly any difference. The least-related living things on this planet are still homologous in their basic biochemistry and cell composition.

      So how do those two points help us? Let’s focus the first one a bit. Subculturally, for most of biology’s history, everything is “for” something, with the poor logic Alcock used, that “it’s all connected,” implying that evolution gets rid of “unneeded” things. Gould didn’t mind bucking the faith and even made the point of de-capitalizing “darwinian” just to be snarky. Clearly Alcock had been nettled, to go so far as to insist that organ function necessitated adaptation.

      Now let’s focus the second one a bit: to similar developmental substances and events that result in different structures. Is there a case to be made that selection for structure A was strong enough, or better, integrated with other development mechanisms enough, that structure B is present in the other creature for literally no other reason? That’s actually a pretty strong hypothetical case, whether for two sexes in a single species, between two fairly closely-related species, or any other comparable situation.

      In practice, unfortunately, experimental procedures to assess whether “natural selection did it” (or not) were and are pretty terrible, and discussions about it always founder on the subcultural variables of who’s being faithful to Darwin and whatnot (even though most of this whole “place for everything” faith comes from Wallace). I happen to think that without some acceptance that drift and mechanisms like gene migration are big players too, we aren’t going to get anywhere.

      Like

    • This may help too: that when two structures are homologous across identifiably different creatures (“different” within a species, like sexual dimorphism, or between species), any evolutionary change in either is likely to arise from similar principles, which in biology, means physical causes. It’s the easy concept that they’re made of the same stuff and in the same ways (genes/development). One example is the common phenomenon of parallelism.

      In the 1980s, this was particularly poorly treated, intellectually; the Devo Evo revolution (meaning outside its direct practitioners) was occurring primarily within my age group. Even though Gould had helped jump-start it, he didn’t actually study development and his influence is better understood as inspiration rather than contribution.

      In other words, the culture at the time had no vocabulary to address that selection in critter A could result in presence/difference in critter B, either because A and B were developing right there in the same species (in perhaps the clearest-cut case of homology), or because species B was a demonstrably direct offshoot of species A. In the latter case, too, phylogenetic methods were undergoing a seismic shift, rendering that context even harder to hold down as given.

      Gould did propose the term “co-aptation” as a replacement for adaptation, in part etymologically, because co-opting what’s already there is actually a very good, and better, understanding of how selection works than “going toward” something, which is what “ad-” means. Although the term didn’t catch on, the concept absolutely did, and I’d venture to say that most scholars of selection today use “adapt” in this sense instead of the “toward the proper niche” sense.

      Like

      • I think I’m following – “likely to arise from similar principles”, how exciting! Both when the likely and unlikely happen. But … exactly how do we evaluate and talk about it all, again in both/all cases? It turns out to have been a real problem, partially resolved but with plenty o’ room for more improvement.

        Like

  2. As usual, this is one of those posts that I understand the beginning, lose in the middle, and understand the ending.

    (For example, while I suspect my mom must have read the letters in Natural History at the time, I’m pretty sure she didn’t hold on to them all this time, and I haven’t read Bully for Brontosaurus, so I have no clue what the argument was about.)

    FWIW my mom was a Gould-digger and I have a family friend who basically tries to resolve any argument with an anecdote about Richard Feynman. Who was a cool guy and a nifty scientist, but is not the final word, on, say, cooking pasta.

    To do a Hyena-Swine / Doctor Xaos crossover: I sometimes feel that the people who fall into a popular scientist’s cult of personality (term used with affection) are a bit like guys like me who go gaga over Kirby, Lee, and Ditko. The way to show your admiration to these people is to be FEARLESS like them, to be IMAGINATIVE like them, to find entirely new ways to do things, instead of just slavishly imitating what they said and did. I’m neither fearless nor especially imaginative, but that’s certainly a more sincere form a flattery.

    Like

    • A bit more context for the middle: the issue is adaptation vs. constraint, as I wrote about in A world of debate in a strand of hair. At the time these were intellectually quite crude concepts, in which adapted meant “for something,” or even “faithful to Darwin’s memory,” and constraint meant, vaguely, “history,” or “by chance” (a phrase I consider especially debased) or “does nothing.”

      Gould had cited male nipples as a good example of a structure being present and in this case visible because it had undergone selection someplace else, which was and is an interesting concept, and had been incautious enough to mention the clitoris as similar. To be fair, they were supposed to be heuristic examples, not felony-conviction-worthy clinchers. Alcock was quick to pick up on the dubiousness of either specificclaim, especially the latter, and bulk it into a more general argument that adaptation established critters’ features ever and always, amen.

      Like

      • I’m way out of my depth, but for what it’s worth – my initial read was that the post was, along with the important critique of tribalism, predominately a criticism of Gould’s over-insisting that the clitoris isn’t a product of recent adaptation. In this comment, I see an emphasis on Alcock’s misguided faith in adaptation as explanation ever and always.

        Both can of course happily coexist; such coexistence emotionally supports (maybe logically too) my inclination to say “jeez, from what I can tell this stuff is likely to be darn complicated – maybe some adaptation way back, maybe some now, plus chance and other factors (your drift and gene migration?) … it’s all always in there. The interesting questions are always about the details.”

        I guess I assumed that EVERYONE scientifical considered the beaks of those finches a rare simplification that is simplified even MORE in common explanation; that no one would expect/insist that many evolutionary explanations look too precisely like Galapagos birds, neither as people casually understand them nor even as a rigorous examination of that specific evolutionary situation reveals. But I’m not TOO surprised if my guess is wrong.

        Aside: Does evo bio say those finch-beaks are homologous? I’d assume so, but maybe I’m missing something.

        Like

        • I’m answering in two parts, one of them in reply to your above post. Here, I’ll address the finches, responding to your last question first.

          1. Yes, the finch beaks are 100% homologous. There’s no dispute or difficulty with that – remember, homology isn’t some mysterious thing you have to winkle out. Once you identify which level you’re looking at (genes, developmental processes, anatomy-phys-behavior), homologous yes/no is pretty easy.

          2. The thing everyone leaves out in talking about the finch beaks is that the underlying genetic variation is clearly preserved across most or all of the island populations. When you get the big thick bills on the seed-cracking islands, the genetic possibility of the long thin bills is evidently still present. It’s not like every single shift in beak form is preceded by its own historically independent mutation.

          Therefore the whole island complex is a gorgeous example of the … I hate to say it, but the most evolutionarily trivial kind of selection, merely a matter of proportions per place for what’s genetically already there across all the groups and apparently not going anywhere. It doesn’t address how the genetic or developmental variation occurs in the first place and it doesn’t address change which closes doors on what may occur later.

          Like

        • About the Galapagos – similarly to s1Ayb0k, I often find myself following/agreeing, but realize there MUST be some bit I’m missing, then ultimately it all makes sense (though I’ll feel like what I missed is probably more important than I thought). This here is an example – at first, I didn’t see you saying anything about Darwin’s finches I didn’t basically already think. But … NO big-beaks that could no longer become other-beaks (and etc.)? NOTHING about how the slight-variation was present to become locally-exaggerated? Hmm. Maybe even simpler than I thought (to the point of, as you say, trivial).

          Like

  3. Pingback: What are little species made of? | Man nor Beast

  4. Pingback: Dimorphic diversions | Man nor Beast

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s