It doesn't seem like there can be a strong natural selection anymore. There is no survival of the fittest, we don't live and die by predators and prey.
No, but we live and die by
our own interaction.
In the Paleolithic Era ("early stone age") there was no agriculture so people had to subsist on the meat they could hunt and the fruits and nuts they could gather--using only tools made of stone and wood. There was no food surplus--and even if there were, they had no pottery for storing it and they couldn't carry much with them, without wheels or draft animals. So in a bad year (low rainfall, competition from other predatory species, etc.) famine was a real threat. The only way to survive it was to fight with the tribe in the next valley and take over their hunting and gathering range. Humans were a
pack-social species like wolves, hyenas and elephants, sharing their food with a small extended-family tribe that practiced efficient group-hunting techniques, but regarding other tribes as hated and feared competitors for scarce resources.
This pack-social instinct was programmed into our synapses by our DNA, and continued to be passed down even after we invented farming and animal husbandry (the twin technologies that comprise agriculture and launched the Neolithic Era or "late stone age") and no longer had to kill rival groups to survive. Humans had to learn to make peace with other tribes, having quickly discovered that economies of scale and division of labor (which are only possible in larger communities) increased productivity and allowed some people to have "jobs" outside of the food production and distribution "industry."
But as our communities became so large that everyone no longer knew everyone else personally, the pack-social instinct came to be a blessing and a curse. On the one hand it allowed people to live in harmony and cooperation with their neighbors, but on the other hand it caused them to be suspicious and hostile to the folks on the other side of town. As towns grew into cities, cities grew into states, states grew into nations, and (in our lifetime) transnational entities such as the E.U. arise, it's not easy for us all to feel a sense of collegiality with anonymous strangers thousands of miles away who are nothing more than abstractions to us.
Yet, most of the time, we do it! Why? This is my own hypothesis and since I'm not a biologist or psychologist I haven't discussed it with any professionals... but I see clear evidence that
our pack-social instinct is evolving. We now live much more like
herd-social (or perhaps flock-social) animals such as cattle and geese. We don't necessarily love all of our fellow humans, but most of the time we treat them with a minimal level of respect: not knocking the next bison over in our haste to find a tasty blade of grass and even showing him where the best grass is; not stepping on another wildebeest who slipped and fell down and even helping him up; not shitting in another goose's nest and even scaring off the crows that want to eat her eggs.
We are indeed evolving, but in the ways that are important to our species
now, not 12,000 years ago when a stranger was automatically an enemy. It's not an evolution that's easy to see because we individual human beings don't look much different from our stone age ancestors. But boy oh boy our
communities look so much different that our stone age ancestors wouldn't understand them. Giving strangers food? Working in cooperation with thousands of other people on a project that might not be completed in our lifetime? Having friendships with people we'll never meet, by clicking little plastic blocks and looking earnestly at a bunch of weird symbols on a backlit slab of something that looks vaguely like quartz?
I'm not sure that the average denizen of the Paleolithic Era could ever become comfortable in the Post-Industrial Era, even assuming that he's intelligent enough to learn how to work all of our large and small devices. He had
different instincts. We have
evolved beyond that.
We keep the weak alive, and there's affirmative action where we actually give advantage to the vulnerable groups, the minorities and the needy ones. By virtue of keeping the dumb and weak alive, have we stopped evolving as a race?
We've learned that both uniformly high intelligence and uniformly great strength are not necessary to keeping civilization running. There are plenty of jobs for stupid people--jobs that would bore a smart person to death. And there are plenty of jobs for weak people--jobs that would cause a strong person's muscles to atrophy. There are even jobs for people who are both weak and stupid, it's called "government." (Pardon the joke from a man who spent most of his lifetime in civil service.) Everybody doesn't have to be a genius or a champion weightlifter.
My son has no wisdom teeth. His orthodontist says he sees more of this than his dentist father did. Is that evolution? Do we really need wisdom teeth?
Not only do we not need wisdom teeth (and haven't since we learned how to cook our food) but they're a downright handicap. Janus's experience is rare; it's more common for them to crowd the other teeth, pushing and twisting them out of alignment and reducing the efficiency of our chewing. They often are
impacted and have to be dug out and removed surgically. One of mine was growing sideways, creating a little breeding pocket for bacteria. It was difficult for even 15th-century dentists to solve these problems; a stone age healer with no precision metal instruments would have been flummoxed and some of his patients would have died.
Are we evolving physically, intellectually or which way.
You left out "emotionally." That's the way we've been evolving.
You can see this mirrored clearly in our dogs. They have not had to rely on natural selection because we've been culling the individuals who don't have the traits we want, so they have evolved faster. The traits we want, to a large extent, are the traits that make them lovable. Baby wolves bark, wag their tails, chase sticks and roughhouse good-naturedly, but they lose these behaviors in adulthood. We have bred dogs (which are actually just a subspecies of wolf: a Chihuahua and a Great Dane share more DNA with a wolf than with each other) for the phenomenon of
neoteny: the retention of baby traits into adulthood. (BTW, lactose-tolerance in adult humans is also an example of
neoteny; before the development of dairy farming only babies needed to be able to digest milk, and in places where milk-drinking never caught on lactose-intolerance is still almost universal.) Dogs have other emotional differences from wolves. Their alpha instinct is muted: they are much more gregarious, forming huge packs without fighting for leadership--which they happily relinquish to a member of
another species who singlehandedly brings home an entire dead cow every two weeks.
Dogs have evolved
emotionally to
adapt to human civilization.
So have we.
