I got into a conversation last night about the changes that have happened to the human species, but neither of us knew enough to talk sensibly about it.
The question we ended up asking ourselves is what would happen if someone traveled in time back to the beginning of Homo sapiens sapiens, stole a very average female infant, brought her back to our time, and raised her in Ohio? (Ignoring any time paradox or stuff like that.)
Would the child grow up to be completely undifferentiated from her peers?
Mainly, we wondered how tall she would be, given modern food sources. She would probably be lactose intolerant, right? Would there, or could there, be other foods she would be unable to eat? Are there nasty bugs that we’re resistant to that she wouldn’t be? Would she tend to put on weight as easily, or more easily, than her peers?
Are there obvious things I’m forgetting (I assume so)?
The earliest population of Homo sapiens sapiens was pretty certainly in Africa. That population would probably have had darkish skin, though otherwise it would probably not have been identifiable with any modern populations. Some of the earliest branches still extant of the early sapiens radiation are evidently the Khoi-san peoples of Southern Africa (aka “Bushmen”) and the pygmies. One of the earliest groups outside of Africa seems to be the population from which the Australian Aborigines are descended. Which of these groups - which are diverse in appearance and height - retains the most physical resemblance to the earliest sapiens population is impossible to say.
As pure guesswork, IMO the earliest sapiens population most likely would not have been as tall as the modern US population on average, and an individual that received a modern diet from infancy would probably not reach that height either. They almost certainly would not have been able to digest lactose. They might have a strong tendency to store fat if given a diet with excess calories, depending in part on the actual habitat of the earliest population (which is unknown). They probably would be very susceptible to various contagious diseases, especially those that may have developed over the past 100,000 years.
I think you hit on the types of physical differences you would see. Diseases (like smallpox) that Europeans gained resistance to would likely be a problem, although I don’t know that a person would get exposed to smallpox in Ohio these days.
The key area of contention is what you mean by Homo sapiens sapiens. That term isn’t used much these days, but if you mean it only to designate the difference between us and, say, Neandethals then it might matter exactly when in time you plucked that infant from pre-history. Although we generally say our species developed about 200k years ago, there are some biologists who think an important mutation (or set of mutations) occured somewhere around 65k years ago that set us apart from early versions of Homo sapiens. For instance, it is possible that language* as we know it today wasn’t part of our mental abilty until that later timeframe (although there isn’t a consensus yet in the scientific community about this).
If you mean to use the term Homo sapiens sapiens to differentiate the more recent populations from what ares sometimes called Archaic Homo sapiens, then it is unlikely you’d be able to detect any difference in mental ability at all.
*For example, the discovery the FOXP2 gene as it relates to language acquisition is evidence that the evolution of language is a very recent phenomenon in our speices. This cite gives some good background and (correctly) cautions about making too many overly simplistic assumptions about what the data surrounding this gene tells us. But other data in the fossil record itself hints at a “something” happening less than 100k years ago that affected our ability to use symbolic thought-- it’s only in the more recent sites left by our ancestors that we see clear evidence of art and personal adornment, as well as significant advances in tool technology.
Are these 2 traits really genetic and not acquired after birth? My uneducated guess would have been that an infant, raised on today’s diet and in today’s environment, would be both able to digest lactose, and would have the same immunities as the kid next door. Is susceptibility to disease really genetic?
Infants of course are able to digest lactose. The ability to digest lactose as an adult is genetic, and is found mainly in European-descended populations and a few others.
Resistance to many diseases is in part genetic (although resistance is in part acquired through exposure in childhood). New World populations (and in other remote areas) were decimated upon contact with Europeans due to the lack of resistance to Old World diseases.
“Normally,” after weaning, the body shuts down production of lactase, the enzyme that lets you digest lactose. People who are able to digest lactase as adults have a mutation that prevents the shutdown of lactase production.
I remember when I first read about that I thought: I’m a certified mutant!
As a further clarification, lactose intolerance in adults is the norm for mammals in general, so there isn’t anything unique about that trait in humans.
She could have any of the normal variations. Extra digits, webbed toes, cleft palate, bunions, be missing a heart valve, have an overactive thyroid, giantism, dwarfism, and any of the thousands of types of tooth and jaw deformities. How you derive any valid information from one individual is a puzzle that many scientists refuse to face. They will find a single 4-foot skeleton and decide that was the average size of the tribe.
By the time of early H. Sapiens, was chimplike bone density and accordant strength already gone completely, or would this individual likely be a wrestling champion and weightlifter in the modern-day world?
Infants are extremely susceptible to contagious diseases, especially for the first few months of their life. But the mother’s milk (especially the first, the colostrum) contains elements to help the infants’ body fight off these contagious diseases. That is, those diseases the mother has been exposed to.
But in the OP scenario, the infant got her colostrum from the mother of 100,000 years ago, and so increased immunity to the diseases of 100,000 years ago. But she’s missing the immunity to modern diseases that a modern mother’s colostrum milk would give her.
So the infant would be at increased risk from modern contagious diseases. On the other hand, she would have modern sanitation, medical care, infant feeding, etc. in her favor. So it would probably balance out, or be a net advantage for the infant.
Chimp-like stength was surely gone, but you might have found the individual to have a slightly more robust skeleton than today’s average, depending on how far back you went. You might find some more prominent brow ridges, as well, depending on how far back you went. This link has a reconstruction of what a 160k year old skull found in Ethiopa would’ve looked like in its day. He might seem a bit odd if you looked him over very carefully, but you probably wouldn’t think twice if you passed him on the subway.
Yes, that did cross my mind as I was typing that last post.
For a little background on why I posted that: When I was in Jr. High (late 60s) and I started to develop an interest in human evolution, it was common to read that a Neanderthal would go unnoticed if you put him in a suit and tie and took him on the subway. That was back when many anthropologists classified Neanderthals as Homo sapiens neanderthalensis (just a subspecies of our species) and those anthropologists seemed to go out of their way to minimize the differences between them and us. Times have changed and we now have Homo neanderthalensis in a species all to itself, and anthropologists often emphasize the differences between them and us. Anyway, I was using an old allusion with a new twist-- one that should stand the test of time better than the older version.
It’s possible that your human from the past would have a weakness for alcohol; she wouldn’t be able to “take it or leave it alone”. The vulnerability of native peoples to alcoholism in the Americas, Africa and elsewhere was widely noted by Europeans. Many hypothesize that people of Eurasian descent have been selected for tolerance to alcohol over the thousands of years since agriculture was devised.
