We humans tend to think we’re pretty much perfect. We’ve taken over the world, produce more food than any other time in history, have the ability to kill every plant and animal out there (often to the point of extinction), and can harness the power of both simple atoms and the Sun itself. It’s all thanks to our prodigious development of technology — most notably, in the survival sense, is the Agricultural Revolution — which has allowed us to far surpass the capabilities of our doughy bodies alone. That fact has led some to posit that humans are no longer evolving in the Darwinian sense.The idea that we’ve somehow insulated ourselves from the most elemental process of nature has gained popularity in the computer age. However, as new research suggests, that’s not the case. Instead, humans, like most living things, are continually changing to adapt to our environment and smooth out our many rough edges.The study, published today in PNAS, studied church records of around 6,000 Finnish folk born between 1760-1849, when farming started going (relatively speaking) high-tech. The authors focused on Finland because of the country’s long obsession with genealogy, which made for great records, and because during that period few people were moving in and out of the country. Thus, those records provide a detailed set of data encompassing Finland’s agricultural revolution.That’s the period during which humans’ most basic evolutionary quandary — finding food to survive — was being most quickly resolved. The fact that the populace was becoming more removed from food struggles than ever before suggests a fundamental shift in pressures affecting our natural selection. Why would we need to evolve to be faster, stronger, and more efficient if we no longer need to chase down our food? That question, along with the common misconception that all of human evolution happened sometime way long ago in the caveman/Neanderthal days, is the basis for people assuming we’re simply not evolving any more.Neither are true. According to the report, we may have incredible access to food and healthcare these days, but we’re still evolving, and it’s all due to sex.“We have shown advances have not challenged the fact that our species is still evolving, just like all the other species ‘in the wild,’” said study leader Dr. Virpi Lummaa, of the University of Sheffield. “It is a common misunderstanding that evolution took place a long time ago, and that to understand ourselves we must look back to the hunter-gatherer days of humans.”The Darwinian view of natural selection is based on individuals’ differing abilities to survive in a given environment. Over time, individuals that are more successful are more likely to be able to produce more of themselves, pushing the species as a whole in that direction. The authors looked at that specifically by compiling data on individuals’ survival to reproductive age, mate access, mating success, and fertility per mate, which are all indicators of evolutionary fitness. Because humans are still sexual creatures, we’re still mixing our genes, some combinations of which are better suited to our current environmental pressures, which include our resistance to disease and our penchant for learning.“We have shown significant selection has been taking place in very recent populations, and likely still occurs, so humans continue to be affected by both natural and sexual selection,” Dr. Lummaa said. “Although the specific pressures, the factors making some individuals able to survive better, or have better success at finding partners and produce more kids, have changed across time and differ in different populations.”As is common throughout the animal kingdom, the sexual selection found by the authors showed a difference in evolutionary action on men and women.“Characteristics increasing the mating success of men are likely to evolve faster than those increasing the mating success of women,” said principal investigator Dr. Alexandre Courtiol, of the Wissenschftskolleg zu Berlin. “This is because mating with more partners was shown to increase reproductive success more in men than in women. Surprisingly, however, selection affected wealthy and poor people in the society to the same extent.”Driving another nail in the coffin of the “we’ve beat nature” thought was the study’s surprise finding that evolutionary pressures acted equally both the rich and poor — in this case, landowners and the landless. If our ability to insulate ourselves from nature was indeed slowing our evolution, it might be expected that the rich — who have better access to everything — would experience less natural selection. (For example, a guy with bad genes might have no problem finding mates and whatnot if he’s rich.) But the authors didn’t find that to be the case.So what’s it all mean? From an ecological standpoint, the study supports the view that sex drives evolution by mixing organisms’ genes up in a wild soup. But, perhaps more importantly, it also shows that there are an untold number pressures shaping us, outside of just food and shelter which we tend to focus on. In other words, despite our capacious egos, we haven’t removed ourselves from nature yet.Follow Derek Mead on Twitter: @drderekmead.
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