All-natural, all-artificial selection

Admittedly, a very important colleague

No, it’s not a discourse on the naturalistic fallacy. I figure if you’re reading this, you’ve already skirted that pit. I’m going back to the initial categorizing of selection, from the mid-late 1800s. To Darwin, no less, which of course means from the prophet … oh wait, no it doesn’t. As I am wallowing in scientific idealism, and no longer bound by the standards of academic discourse, I maintain that Charles Darwin is “only” a colleague. Let’s see if what he said about the kinds of selection works.

Selection in and of itself, originally called “natural selection,” results from inheritable variations coming face-to-face with consistent reproductive outcomes. This is right out of The Origin of Species itself, and the modern re-wordings like Bill Lewontin’s put it into clearer focus without changing its meaning.

The relationship of the adjectival natural to the definition is highly historical: the argument in the book goes, since we see X happening right here in our farms and homes, X could well be happening all around us as long as the same variables are present. It’s a completely solid argument in which natural is strictly and only a wider application of the here-and-now real. The nominally artificial version is not presented as a contrast, but rather as “lab” evidence for what’s going on “all around,” without human influence. But very quickly, the discourse fell into three pitfalls and never really climbed out, generating a false contrast of kind rather than of local situation.

  • Pitfall #1: elevating the role of human influence into “intention”
    • introducing the dubious quality of human intention as if it were boxed away from the physical universe of everything else, instead of being itself one feature thereof; and
    • the tacit but very present implication that there is a real, or natural intention which would have played out “properly” without humans gumming it up
  • Pitfall #2: assuming that “natural” selection operates for “the good of the species
    • prompting echoes of the “unnatural” and its synonym, “ipso facto wrong” (as opposed to the accusations of unethical or even selfish, which can easily be leveled at the practice, as I see it)
    • revealing the interesting blind spot that confounds individual experience (health, putative happiness in being “fit”) vs. abundance and/or persistence of that population over time
  • Pitfall #3: inferring human mastery of nature, the notion that we can do “whatever we want” with a species
    • whereas it’s much more like shooting an arrow and claiming that whatever you hit is what you nailed – “right in the bullseye!”

To summarize, the purported categorical difference is better understood as a situational difference, specifically that of domestication, which is one of many possible situations, and not a difference of kind at all. Which finally permits us (you, me, the scientific community, “people”) to check out this situation sensibly and to find that it’s very, very interesting.

Domestication is some tricky waters! Human control, or to be fair, any other species’ control, over the nuts-and-bolts variables of selection – which is to say, reproduction – is definitely a thing. But let’s tease it apart with the pitfalls in mind, and with the help of Francis’ excellent book.

His solid “think it over” starting point is that initial animal domestication proceeded via a single variable, the increased tolerance for human presence and its accompanying sensitivity to human moods. All the rest are subsets within the result of that, and many things we associate with domestic animals (many of which I consider to be infantilization, but not all) are connected to that via genetic linkage, or classically, pleiotropy, or in Evo Devo language, developmental interpenetrance.

Therefore one doesn’t say, “gee, let’s breed wolves so they point when we hunt, or have a white stripe right here,” but rather interesting actions and features are observed among already-domestic creatures, already embedded in the context of socially-relevant to humans, and then those are bred for. When they “breed true,” which is to say, demonstrate noticeable inheritability, then that’s another domestic trait, and when they don’t, it’s not. You can’t make a domestic species’ new trait de novo, nor can you rely on anything you observe in it to be amplified via selection.

That point highlights those I discussed in Same thing(s) and We are, in fact, Devo: that genetic diversity does not track 1:1 to developmental or eventual phenotypic diversity. Rather, a tiny shift in genetics may correspond to a large physical consequence, or vice versa; and also, even the same genes may yield very different results given a specific, different developmental context.

Another is this: the very selection that yields outright pathologies as characteristic of a population, which one might decry as unethical and selfish (even without the fallacy of calling it unnatural), is carried out such that the population itself is vastly more abundant and widespread over much more ecology than it ever would have been otherwise. In other words, the process necessarily splits – and demolishes – the common assumption that selection “saves” a population from becoming extinct in the face of environmental adversity by making individuals “better and stronger.”

Hush up, heretic!

I’ll go one further than that, even, to suggest that consequential ecomorphological selection of any kind, especially those we think of as resulting in an obviously “different” creature, occurs in the complete absence of extinction threat – i.e., it happens with/in species who are persisting in a given area, rather n those in danger of not doing so. Those marine lizards were successfully cruising back and forth among the rocks and shore before they had the features we say “make” them marine-savvy.

Another point concerns more difficulties of even defining or identifying species-relevant selection. In practice, identifying wild species relies much more on the pragmatic (or desperate) device of the morphological species concept than most textbooks admit. And the first observation of domesticated selection is that it yields way more diversity within a single species than one observes even among most different closely-related species … so, uh, “how much” difference makes a species, again? (see Where do little species come from? for more about that)

And at last, with no surprise to anyone, it raises the question of whether we, ourselves, are a domesticated species. Which is quickly and easily answered, yes, obviously. But it raises some neat questions.

For example, we’re a fairly diverse species, with many regional variations, but they aren’t big variations, or about much, biologically speaking – certainly not to the degree of any of our domesticated animals or plants. Therefore is our species unity not to do with domestication, but rather simply with our enthusiastic tendencies to roam and also to roam back, hence resulting in uneven but nevertheless continuous genetic continuity?

For another example, when does ultrasociality “tip” into domestication? The former is defined by social identities, alliances, and tensions providing the primary selection pressure, as opposed to, for example, this-or-that predator or climate. Are there any other ultrasocial species who qualify as (for lack of a better word) auto-domesticated? Is it even to do with sociality at all – do any of the many mutual or commensal species-pairings out there qualify as domestication of one by the other, now that we’ve disposed of the “intention” bugaboo? Is domestication a subset of mutualism? If so, then the entire context of technology and culture is not required for domesticating another species; it would merely be another “thing lots of creatures do” which we happen to do in a more gaudy way.

Or taking it the other direction, in thinking of domestication specifically (if not uniquely) as a human cultural thing … when does it kick in, in terms of the species diversity of Homo? Is there some odd as we to you, so you to us phenomenon at work here, in that when we domesticated other animals and plants, they domesticated us?

This is especially fun philosophically because it means removing “under human control” from the definition of artificial selection, which is all to the good, and finding a better definition altogether for which nonhuman species domesticated by humans is a subcategory.

[Clever readers will probably now be clamoring about the other ostensibly dichotomous category, that of “natural” vs. “sexual,” which I’m saving for the next column.]

Scheduling issues: I’m shifting to Fridays-only columns for a while, planning to fill in Mondays with teaching seminars. I figure getting that all organized is the work of the summer.

Next: Dimorphic diversions


Leave a Reply

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

You are commenting using your 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