Wow… I generally tend to stick to narrative posts discussing natural history, but in light of a short commentary that I just read from The Society for the Study of Evolution’s journal, I feel obligated to throw a couple of reckless comments onto the web…
The article in point, ADAPTIONISM—30 YEARS AFTER GOULD AND LEWONTIN, was written by Rasmus Nielsen of the University of Copenhagen and to the best of my interpretative ability seems to be making a plea to so called ‘adaptationists’ to reconsider their errant ways..?
Apparently, the author is under the impression that the world’s evolutionary biologists can be dichotomously classified as either ‘adaptationists’ or ‘pluarlists.’ And further, that those classified in the former category should seek reincarnation as enlightened members of the latter.
The commentary’s argument begins (predictably) with Stephen J. Gould and Richard C. Lewontin’s ‘The Spandrels of San Marco,’ an article originally published by the Royal Society in 1979. The broad point of the original Gould piece was to encourage scientists to look beyond natural selection as the sole process of change and to instead consider organisms as complex entities influenced by a myriad of evolutionary forces. In short, to think of the organism’s evolutionary history as being an emergent property derived from its whole, not one measured through the summing of its individual traits. This cautionary imperative is certainly as valid today as it was back in ’79 and it should be heeded; however, it isn’t by any means novel, nor does it say anything in regards to the reality of research – it is simply a warning to be cautious of personal and professional bias.
The Nielsen article moves from The Spandrels to contemporary times in order to assess what valuable lessons have been gleaned from that momentous (?) work of 30-years past. Unfortunately for the field, in conducting this assessment it becomes blatantly apparent that the Gouldian forewarning has fallen on deaf ears…
“…although Gould and Lewontin’s paper did not spell the end to adaptationist storytelling, it radically increased the awareness among evolutionary biologists about the pitfalls of adaptationism.”
Whew... What a relief; but what does that mean exactly?
“Evolutionary biologists are today, arguably, much more reluctant to invent adaptive stories without direct evidence for natural selection acting on the traits in question. We still regularly encounter very naive adaptive stories, particularly about human behavior, but rarely in journals such as Evolution or other related journals with high standards…”
‘Rare’ in this case is good – I think? I’m so glad we have The Society for the Study of Evolution’s journal to guide our path!
What should we do to remain of wholesome purity; what should we do to keep the path?
“…we must rely on inferences regarding past events by observing scant fossil evidence and the current pattern of genetic and phenotypic variation. We may be able to detect selection, but we may never be able to directly determine which traits selection acted on.”
So, we can see selection, but our ignorance blinds us to the characteristics driving that selection…
“Although the presence of selection acting on genes underlying a phenotypic trait of interest does help support adaptive stories, it does not establish that selection acted directly on the specific trait of interest.”
“[m]ost genes have pleiotropic effects and establishing the direct cause of selection in an organism such as humans might in most cases be difficult or impossible.”
That’s a reasonable statement, but couldn’t the before-mentioned inferences guide the ‘adaptationist’s’ filthy lust for storytelling? What prophylactics are available in the event that an adaptationist fails to maintain self-control?
“…speculation… must be done acknowledging that no simple experiment or functional data can falsify or “validate” historical adaptive hypotheses.”
Geee, thanks for the heads-up, I’m going to spread the good-word!
“And in communicating with our peers, and with the popular press in particular, we may individually, and as a scientific field, benefit from understanding the societal impact of the statements we make.”
Or, on the other hand, maybe not…
In closing, I have difficulty believing that radical adaptationists are running rampant in evolutionary biology. I can’t think of a single practicing biologist, in academia or otherwise, that doesn’t consider the impact of drifting allelic frequencies and other possible influences outside the scope of natural selection. As far as the relative importance, or weight, granted to such alternative processes in determining an organism’s evolutionary path, that isn’t a question of individual preference. Rather it’s something that is assessed quantitatively through experimentation and study.
I can’t help but wonder if the entire “adaptationist Vs pluralist” debate is an artificial construct intentionally designed for generating publicity. Judging by this post and similar arguments had at Sandwalk it seems to work…
Nielsen, R. (2009). ADAPTIONISM-30 YEARS AFTER GOULD AND LEWONTIN Evolution, 63 (10), 2487-2490 DOI: 10.1111/j.1558-5646.2009.00799.x
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