Isn't this obvious? Why on earth would it stop?
I don't actually believe that 'humans stopped evolving' was ever a widespread belief among scientists. This article has gotta be lying to me.
I have definitely run into the belief that humans aren’t evolving anymore (though not among scientists). I think people with an incomplete understanding of evolution look around, see most human beings survive to adulthood, and assume that there must be no more evolutionary pressures on us (perhaps with the phrase “survival of the fittest” tinging around inside their head). I honestly don’t blame anyone who hasn’t been exposed to the concept of e.g. sexual selection for making the assumption.
There's been no biological change in humans in 40,000 or 50,000 years. Everything we call culture and civilization we’ve built with the same body and brain. -- Stephen Jay Gould, "The Spice of Life", 2000
Gould was an evolutionary biologist and Harvard professor, and one of the most prominent popularizers of evolution since Darwin, but somehow believed that it doesn't apply to modern humans.
That's such an extreme claim. It defies common sense. You'd have to proclaim that there was some event that _stopped_ evolution in humans, universally. How is that even possible? Especially 50k years ago. I'd be a little more forgiving if the claim was that evolution stopped in, say, 1999.
Emphasis should be placed on "everything we call culture and civilization". There is a thought experiment that might help. Imagine we had a time machine, and no scruples, and we could go back and pluck babies from the past to experimentally raise them in modern American families. I'm pretty sure Gould would have argued that babies from 40k years ago would grow up to be behaviourally indistinguishable from modern humans.
Well, evaluating the nature of this thought experiment reveals what you actually believe about human evolution and development. I find it extremely hard to believe that someone from 40k years ago would be indistinguishable from humans today. Believing this requires you to imagine that there are no genetic selection pressures for things like intelligence, behavior, physical ability ... 40k years ago had Earth as an almost entirely different planet. Europe was frozen for most of the year, for example. There were no trees. Very, very hard to believe that people born back then could grow up to sit in front of a laptop today.
All we know basically is that their skeletons are undistinguishable from ours, with a brain the same size as ours (slightly later on average iirc) and what they left, tools and paintings, look just like what we can do as well (behavioural modernity, thought to arise some time between -100 000 and -40 000).
You can find it hard to believe, but I think most people in that field agree that humans from the last 40 000 years would grow up as modern humans without problems.
Sounds like they just meant evolution takes longer than that?
To some degree it's true. We have all sorts of variable parameters that are probably different from back then (eg. Average height) but we still have the same body shape, etc
One should not read or pay much attention to anything Gould wrote or said. (http://cogweb.ucla.edu/Debate/CEP_Gould.html) The amount of damage Gould has done offsets any positives. It's not just even being wrong, indeed you can charitably read that quote as being almost correct (the phrase is "anatomically modern human"); the worst thing he's done is probably to mischaracterize the rest of the field as scientists believing things they don't (or haven't for many decades before he ever tried to address them).
Despite being so famous, I feel like his ideas haven't aged well. His ideas were contentious yet embraced by popular science writers, and there's never been a reckoning.
Perhaps it was not a widespread belief among scientists, I don't know, but if you were to posit in front of polite company that humans are today and always have been under evolutionary pressures that select for certain traits you would have gotten some odd looks. The implications are possibly a little uncomfortable, especially if what this article suggests is true and the pace of evolution is accelerating.
Nothing stops mutating. What you see with those species is that they found a zone of stability in the fitness landscape, a local optimum. They still have mutants, you just don't see them outcompeting and shifting the makeup of the overall population as the dominant form is already the most fit.
Now consider our own species and the pressures that got us to this present body plan. They just aren't there. The shark still is facing pressures that favor the hundreds of millions of years old shark morphology. Are we facing pressures that our hominid ancestors faced? Doubtful. Look at how our bodies often react when they meet the pressures of our modern society: we often become anxious, depressed, and obese. Most of our ill behaviors such as this have some survival advantage to it that just isn't getting pressured in modern society. Your constant anxiety keeping you up at night is actually saving your family clan from a lurking predator in the bush. Your lack of portion control abilities means you can eat all the fish you just caught and pack on more fat to your frame to smooth over leaner times. Today these selective advantages are seen as illnesses people see doctors to get pills for. Our bodies are so misplaced for the society we've built for ourselves. Our mind's can't even fully fit this society into a working model ourselves without missing a lot of important information. We've out ran our capabilities a long time ago in some senses with the cultural/technological evolution that overshot our own biology. We are tumbling into some new body plan I'm not sure what exactly, but things aren't in any way stable now.
1) maybe those species aren’t as unchanged as we think, because our evidence of the past is limited to things like skeletons, and maybe the skeletal structure of the shark didn’t change much, but other aspects did.
But more likely…
2) maybe unchanging requires a stable environment with stable selection pressures - but humans have had a rollercoaster of change in selection pressures, possibly more than any other species.
Crocodiles live in the river and mate with crocodiles in the same river.
Humans live in diverse ecosystems from artic to desert to city, each with differing environmental challenges, and mate with whoever they fancy when they swipe right.
Yeah, seems like either a clickbait title, or maybe they believe their readership is so misinformed as to believe that human evolution could and has stopped. I'd not be surprised if, especially in the US, a large percentage of the public does actually believe this.
>Yeah, seems like either a clickbait title, or maybe they believe their readership is so misinformed as to believe that human evolution could and has stopped. I'd not be surprised if, especially in the US, a large percentage of the public does actually believe this.
When the belief is that of "creationism"[0], it's not so far to go to reject evidence of, well, anything that runs counter to the narrative espoused by a variety of those belief systems. Including the fact of evolution.
I'd point out that those who subscribe to such belief systems are a large fraction of the human population, the largest contingent of which are not resident in the United States, nor are they Americans.
And perhaps those who create such titles are cynically exploiting the gullible. Then again, I'd posit that Hanlon's Razor[1] be assessed in this case. Such an assessment might well uncover cynicism/evil, but probably not -- as those involved may well subscribe to the belief systems referenced above and/or are ignorant/dumb.
All that said, such an idea isn't new. Here's an analog[0] from more than 400 years ago (circa 1600AD):
What a piece of work is a man, How noble in reason, how infinite in faculty,
In form and moving how express and admirable, In action how like an Angel, In
apprehension how like a god, The beauty of the world, The paragon of animals
Sure the US only comprises 5% of the global population, so insignificant in terms of global thought trends. I only mentioned the US since this is an American magazine and the title is probably chosen to appeal to an assumed mostly American readership.
I was referring to scientific illiteracy/denial rather than creationists (who don't believe we're the product of evolution in the first place).
I don't think Hanlon's Razor applies here. The author of a Harvard Magazine article is unlikely to be stupid, especially given the article in question, nor can choosing a clickbait title be considered as "malice". One can wonder what was the exact thought process in coming up with the title - perhaps more charitably they just thought that many people might think that human evolution is slowing, if not actually stopped, or maybe there really wasn't much thought put into it at all !