To thrive in the twenty-first century, can we learn to steer evolution?

Cliff Swallow in flight

Cliff swallow in flight. (Flickr: Don DeBold)

Many of the biggest challenges humanity faces in the next hundred years are biological: dwindling wild lands and disappearing biodiversity, antibiotic-resistant bacteria, and emerging new viruses, but also feeding nine billion people or more a healthy diet in a climate-changed world. As Theodosius Dobzhansky famously remarked—and as this very website’s name proclaims—nothing in biology makes sense except in the light of evolution. So are there evolutionary answers to all these biological challenges? According to a big new review article just released online ahead of print in the journal Science, the answer is emphatically yes.

The long list of authors, led by Scott P. Carroll and including Ford Denison, whose lab is just down the hall from my office at the University of Minnesota, explicitly connect evolutionary principles to global goals for sustainable development. These include the reduction of both “chronic lifestyle” diseases and infectious diseases, establishment of food and water security, clean energy, and maintenance of healthy ecosystems. Carroll and his coauthors divide the applications of evolution to these problems into cases where evolution is the problem, and those where evolution may offer the solution.

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Why the whale kept its hips

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A bowhead whale’s highly (but not entirely) reduced pelvis. Image via Wikimedia Commons.

Thanks to a remarkably good fossil record, it’s now well established whales and dolphins evolved from land mammals, their forelimbs adapting into flippers, and their hind-limbs almost entirely disappearing. If you’d asked me yesterday what’s going on with that almost—the last vestiges of the hip bones that whales retain, which have no legs to support or direct contact with the rest of their skeletons—I’d have told you they were evolutionary leftovers, and probably going to disappear in another million years or so. I think a lot of other evolutionary biologists (those who aren’t whale specialists, anyway) would’ve agreed with me. But it turns out we’d have been wrong.

As Carl Zimmer describes, a paper recently published in the journal Evolution points out that whales’ hips do have one remaining function, an important one—they anchor muscles that control the penis. And that function is under ongoing sexual selection.

The more promiscuous a [whale] species was, the bigger its pelvis bones tended to be. The scientists also found that as whales evolved to become more promiscuous, their pelvic bones changed shape. These changes weren’t part of some general change to their skeleton, however. The ribs near the hips didn’t show the same patterns of size and shape change.

I strongly recommend Zimmer’s whole article, and you can also read the original research article in Evolution.

Skeptical that PMS is an adaptive response designed to break up your relationship? Me too.

In a pleasantly surprising turn of events, this week a take-down of some dubious evolutionary psychology was published by the popular media!  The original article, a perspective piece published in Evolutionary Applications, claims that moodiness associated with PMS may have historically served an adaptive role by driving infertile couples apart. 

Premenstrual syndrome (PMS) affects up to 80% of women, often leading to significant personal, social and economic costs. When apparently maladaptive states are widespread, they sometimes confer a hidden advantage, or did so in our evolutionary past. We suggest that PMS had a selective advantage because it increased the chance that infertile pair bonds would dissolve, thus improving the reproductive outcomes of women in such partnerships. We confirm predictions arising from the hypothesis: PMS has high heritability; gene variants associated with PMS can be identified; animosity exhibited during PMS is preferentially directed at current partners; and behaviours exhibited during PMS may increase the chance of finding a new partner. Under this view, the prevalence of PMS might result from genes and behaviours that are adaptive in some societies, but are potentially less appropriate in modern cultures. Understanding this evolutionary mismatch might help depathologize PMS, and suggests solutions, including the choice to use cycle-stopping contraception.

Check out the response, published by The Daily Beast, here:

Here’s the scapegoat unhappy spouses have been waiting for: According to a paper out last week by Michael R. Gillings, premenstrual syndrome (PMS) can ruin a marriage. Gillings claims that PMSing women—in infertile couples in particular—may use feelings of “animosity” as well as risk-seeking and competitive behaviors to leave their husbands and find someone new. I’m sorry to say, but the evidence in favor of this hypothesis is thinner than Always Infinity menstrual pads.

Selecting for a butterfly of a different color

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Bicyclus anyana in its low-key natural look. Photo by Gilles San Martin, via Wikimedia Commons

Via NPR: a paper published online this week ahead of print at PNAS reports the results of an artificial selection experiment that changed butterflies’ wings from brown to blue.

We used artificial selection on a laboratory model butterfly, [Bicyclus] anynana, to evolve violet scales from UV brown scales and compared the mechanism of violet color production with that of two other Bicyclus species, Bicyclus sambulos and Bicyclus medontias, which have evolved violet/blue scales independently via natural selection.

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A guide to the science and pseudoscience of A Troublesome Inheritance, part III: Has natural selection produced significant differences between races?

This is the third in a series of guest posts in which Chris Smith will examine the evolutionary claims made in Nicholas Wade’s book A Troublesome Inheritance. You can read part I here, and part II here. Chris is an Associate Professor of Evolutionary Ecology at Willamette University. He uses population genetic approaches to understand coevolution of plants and insects, and he teaches the interdisciplinary course “Race, Racism, and Human Genetics” with Emily Drew.

A Troublesome Inheritance was published in 2014 by Penguin Books. Cover image via Google Books.

This spring former New York Times science writer, Nicholas Wade, released his latest book on human evolution, A Troublesome Inheritance: Genes, Race, and Human History. In it, Wade argues that genetic studies completed in the eleven years since the Human Genome Project was completed reveal real and important differences between human races. Unsurprisingly, the book’s release has been met with a sharply divided critical reception.Whereas the book has been widely embraced by those on the political right, and by the white identity movement, it has been panned by anthropologists, evolutionary biologists, and population geneticists. For the last two weeks at Nothing in Biology Makes Sense, I’ve been looking in depth at the literature that Wade uses to support his ideas. Last week I considered Wade’s argument that natural selection acting on the MAO-A gene – a neurotransmitter implicated in aggression and impulsivity – has led to behavioral differences between races. This week I will consider Wade’s larger claim that natural selection has produced numerous differences between races.

Throughout the book Wade continually repeats the mantra that natural selection on humans has been “recent, copious, and regional.” It would be hard to find an evolutionary biologist that would disagree with these rather vague pronouncements. Indeed, there are a multitude of studies showing that natural selection has acted on humans, and there is persuasive evidence that selection has caused evolutionary changes in human populations as we have adapted to diverse environments over the course of the last several thousand years (see, for example, Yi et al., 2010).

However, scratching the surface reveals that when he says that natural selection has been “recent, copious, and regional,” what Wade actually means is that natural selection has been “radical, complete, and racial.” By Wade’s account, natural selection has dramatically reshaped the human genome, producing major differences between races. This much more dramatic interpretation is entirely unsupported by the literature, however. In truth, Wade vastly overstates the portion of the human genome that shows evidence for natural selection, and where there has been recent natural selection acting on humans, its effect has primarily been to create genetic differences between members of the same race, and similarities between people of different races.

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A guide to the science and pseudoscience of A Troublesome Inheritance, part II: Has natural selection favored violent behavior in some human populations?

This is the second in a series of guest posts in which Chris Smith will examine the evolutionary claims made in Nicholas Wade’s book A Troublesome Inheritance. You can read part I here. Chris is an Associate Professor of Evolutionary Ecology at Willamette University. He uses population genetic approaches to understand coevolution of plants and insects, and he teaches the interdisciplinary course “Race, Racism, and Human Genetics” with Emily Drew.

A Troublesome Inheritance was published in 2014 by Penguin Books. Cover image via Google Books.

Last week at Nothing In Biology Makes Sense, I began critiquing Nick Wade’s latest book, A Troublesome Inheritance. The book has produced a firestorm of criticism, largely because it argues that evolution has produced significant cultural and behavior differences between races.

Wade makes many sweeping claims, among them: that natural selection has made the English inherently fiscally prudent and more likely to defer gratification by saving for tomorrow, that events early in the history of Judaism caused the Jews to evolve features predisposing them to careers in banking, and that genetic variation in certain neurochemicals has made Africans inherently more violent.

Wade hangs these seemingly bizarre conclusions on the mantle of modern population genetics, which he claims confirms the existence of ‘three primary races,’ that have evolved real and significant cultural differences between them. By heavily referencing the scientific literature, Wade manages, as Mike Eisen put it, to “give the ideas that he presents… the authority of science… What separates Wade’s theories – in his own mind – from those of a garden variety racist is that they are undergirded by genetics.”

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Pollination syndromes point to species interactions present and past

Ruby-throated Hummingbird at Cardinal Flower

Want hummingbirds? Paint the town red. Photo by U.S. Fish and Wildlife Service Northeast Region.

In my part of North America, spring is finally underway after a long slog of a winter. The trees lining the streets of my Minneapolis neighborhood are lacy-green with budding leaves, flowerbeds all over the University of Minnesota campus are yellow and red and pink with daffodils and tulips, and violets are popping up in the edges of lawns everywhere I look.

Of course, all of this colorful display isn’t for my benefit. Showy flowers are an adaptation to attract animal pollinators. Some flowers are quite precisely matched to a single species of pollinator, but most flowers have lots of visitors. These less specialized flowers are still adapted for their attractive function, though—and this is the origin of pollination syndromes.

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