I was thinking recently about how humans could only have evolved to be relatively hairless if they developed clothes at the same time. That got me thinking about other examples of evolution that required some form of technology. We can’t eat much raw meat so fire presumably went hand-in-hand with that adaptation (incidentally, how is it an advantage to be so sensitive to pathogens and parasites? Better absorption of nutrients?)
Are there any other examples of human evolution that relies on a technology which would now be practically impossible to survive without?
We can eat just about anything. I do not believe we are any much more senstitve to pathogens and parasites than any other omnivore in the state of nature, we just complain about it more.
An upright ape on the African veldt needs protection from the sun on the top of its head, and anti-chafing hair in various other places. The cooling system works better with as much bare skin as possible after that.
Why does no one ever speculate why warthogs are relatively hairless, which compete for the same general niche that Australopithecines and early Homos occupied.
I hate facile “Just-So” stories in evolutionary biology.
I think it’s more likely that humans developed clothes as they moved into colder climes, to compensate for being hairless. Many tribes in hot countries don’t ware clothes. We can and do eat raw meat, but mostly prefer it cooked.
Hairlessness was probably a boon to (nude) early humans. Africa tends to be rather hot, you see, and the ability to shed body heat is an important factor in an animal’s physical endurance in a hot environment. Combined with bipedal locomotion, our hairlessness and sweatiness gives us excellent physical endurance compared to many other species. We probably wouldn’t be as good at curosrial hunting, for instance, if we were all shaggy.
Cooking food isn’t only about making it safer to eat. It also makes it easier to digest than raw food, allowing us to get more net calories out of a meal. Breaking down food takes energy; better to get some of that energy by burning some wood than from your own body.
This is clearly not true. To some extent we’re just not so used to eating things that are raw or slightly rotten, but no amount of getting used to it would make a lot of the half-rotten or raw meat that most other omnivores can eat safe for us to eat.
I considered the possibility that humans are mostly hairless because it was necessary for cooling and that later they developed clothing as they moved to colder places, but that’s not very flexible. Besides, even if hair is not a good example, the question asking for other examples still stands.
“Safe to eat” from a 21st century Western urban civilized viewpoint is not equivalent to the “eat this or starve to death” situation humans faced for 95% of our time on this earth.
And omnivore does not equal scavenger, most of what omnivores eat is fresh-caught or collected, not carrion.
I realize “omnivore does not equal scavenger”, but many omnivores are, to some extent, scavengers and many animals that do catch their own meat will eat it days later too, not just when it’s fresh. The warthogs you mentioned are, in fact, omnivores that eat carrion. Although I don’t know for sure, it seems unlikely that an animal that needs to eat at least once a day would be at all successful if there were anything more than a very small chance of health problems from eating its normal diet. Lastly the smell of rotting food is repulsive to humans, but interesting to many animals. Perhaps this is a product of our modern lifestyles, but I’d guess it’s more ingrained than that.
You’re not even arguing with the assertion that human digestion has evolved significantly differently as a result of cooking. Even if everything else in my OP was complete rubbish, the final sentence and actual point of the thread is legitimate.
Seems to me that it’s as flexible as can be. Migrate to a hot climate? Wear less clothing. Migrate to a cold climate? Wear more clothing.
Sewn clothing, which is necessary to survive in genuinely cold climates, appeared around the great leap forward. This was a sort of tipping point when humans suddenly (in evolutionary terms) developed all sorts of new skills and practices (fishing, archery, art, burial, etc.). Even if the humans residing in Africa didn’t have a pressing need for clothing, those who migrated into colder regions were clever enough to invent clothing when the need arose.
Compare this to the migration of the earlier Homo erectus. They made it as far as China, but their inability to fashion proper clothing was probably why they never made it into Siberia or most of Europe.
You have a limited understanding of evolution. We have expanded our range and the carrying capacity of our territories through technology. We have a much more diverse gene pool right now because civilization grants support to people who would not survive in a nomadic hunter-gatherer culture. As our environment now includes civilization, we have eliminated much of the pressure of natural selection but have been domesticating ourselves in its stead.
We have become dogs, not wolves, but that is a social, not an evolutionary change.
Yeah, sorry I wasn’t very clear. I meant that it’s not very flexible to lose hair before having clothing. It would limit humans to places where it’s warm enough during both the day and night. Maybe that’s enough though, I don’t know.
I’m aware of that. But the purpose of General Questions is so people with limited understandings can attempt to learn something through asking. It wouldn’t be a very interesting forum if people only responded as you have, by ignoring the actual point of the thread with an “if you don’t know then I’m not going to tell you” attitude. I’m well-aware that I am, to some extent, over-simplifying the issue. But to act as if it’s impossible to discuss in layman’s terms is arrogant and kind of stupid. Almost anything can be broken down to an explanation which is perhaps not the whole story, but not wrong either.
Yes, but I’m talking about evolutionary, not social change.
Let me try to make the question clearer:
What attributes have humans evolved that force us to use technology in order to survive as a species in numbers high enough that we are not in any real danger of extinction?
Here are few facts that you will find interesting. You have probably encountered them, but have never connected together. Strangely, it answers your question.
Gathered with a quick google search:
Oldest tool use: ~2.6 million years ago
Oldest fire use: ~790,000 years ago
When did Homo erectus appear: ~1.9 million years ago
When did Homo sapiens appear: ~200,000 years ago
The suggestion, all taken together, is that technology predates us. We were not forced to use technology to survive, technology shaped who we are.
Its up to you to decide if H. erectus was “human”, but even if so, tool use predated them too. There is an interesting artists rendering of what they looked like on wikipedia, and you can compare their skulls to ours in many photos.
The current evolution narrative is this: (IANAEB)
human evolution began with the descent from the trees to the nearby plains - occasionally at first, then more and more as the dominant environment.
With the move to the plains came bipedal movement - mostly walking on two feet.
Proto-humans supplemented their gathering with scavenging from kills left from other predators, protein being a good source of nutrients.
Somewhere along the way humans figured out thatit was just as handy to kill their own food as to wait for the bigger animals to leave their kills
Somewhere there too, they figured out tools to chase off hyenas or other pesky critters - pointy sticks, clubs, fire.
The standard human hunting method tended to be chasing down four-legged animals. Humans on two feet were incredibly better endurance runners than most four-legged animals, and could chase them to exhaustion… then use their tools to kill them.
Somewhere in there they discovered fire was easy for softening up raw meat so it was (like the carcasses they used to pick over) softened up.
The key is the long-distance running. generally clothing was unnecessary on the plains of Africa, but the human sweat system is remarkably well designed for shedding all the heat generated by distance running, even in the hot sun. The reason why we have so litle hair, except where it protects from heat stroke or chafing, is so the sweat glands can work during nude marathons.
Clothing is an afterthought that, I assume, originally started as blankets that helped against cold nights on the savanah and later allowed us to move into colder climates.
So the OP has cause and effect backwards. We had no hair and developed clothes as a solution for colder situations.
Similarly, we probably lost our tolerance for extremely unhealthy (rotten) food because we had fire to help purify food. Even rotten meat, if cooked, is not full of dangerous live bacteria. Spices dull the bad taste.
I know clothing is not the cause of hairlessness, but assumed it evolved somewhat in tandem with the development of clothing, fire, more advanced shelters etc.
But then I also assumed bipedalism evolved in tandem with the development of tools, long distance hunting etc. rather than before those things.