Is is possible (via mankinds intervention/experimentation) to de-evolve something? For example, could we hypothetically speaking, de-evolve mankind into say cromagnum man using un-natural selection? Or is it too late, once somethings evolved, it can’t go back?
Is it theoretically possible? And I also would like to know if it’s actually probable?
I admit that I don’t know a whole lot about evolution beyond some of the fundamentals, but I do feel that it is rather important and I am trying to learn.
You could try to create an environment that favours the physical characteristcs of a cromagnan and let natural selection take effect for a few hundred thousand years. What you’ll get won’t be exactly cromag, but it might be close.
There isn’t way to “undo” evolutionary change and revert to an earlier state. The only way to lose acquired characteristics is to create an environment that no longer supports them. Maybe if you selectively killed the most talkative humans and encouraged the grunters to breed, and kept up that pattern for each generation, you’d eventually have nonspeaking humans, though not an actualy cromagnan. It would take a long time, though.
I don’t think that de-evolution is possible by definition.
In some cases a sort of de-evolution might be possible. If the required genes are still available in a population - but just not in the right mixture - it might be possible to create artificial environmental conditions that favour offspring in which those with the ‘desired’ mix of genes. Of course, this would be artificial selection, but by such means it might be possible to, say, achieve a wolf-like breed of dog.
However, even here evolution would in a sense be moving forward - the breeding population would be evolving in it’s environment. In this case, the environment is very unnatural and the selection pressure is simply being pleasing to the humans that are in control.
and if you did say selectively breed giraffes for shortness to try and get a population similar to a giraffe’s ancestor, the result would probably be very genetically different from the ancestor (some kind of average -sized antelope-like thingy *). Instead you’d likely have an animal with the giraffe’s height genes plus another extra set of genes which turn off the height genes. As well as all the other genes that giraffes have picked up since they diverged from the antelope-thingy line.
I don’t know anything about the true ancestry of giraffes, and whether they’re really related to antelopes. this is a hypothetical example.
It seems to me that true de-evolution would require the precise reversal of the genetic mutations that led to the evolution in the first place. This would require knowing the beginning state of the genome. It could probably be done for fruit flies, or the like, but since we don’t have the genome for any human ancestors, we cannot recreate it with genetic engineering.
A species might evolve gills, and then lose them again (as has in fact happened).
All all stages of the process, it is still evolution. The whole point is that mututations are random. In a random system, it is entirely possible that one mutation might be precisely the reverse of a mutation which has already occured - a gene sequence might be reversed, and then reversed again, or it might be doubled, and then halved. Each mutation is unrelated to the previous mutation, so it is not meaningful to speak of a process of “de-evolution”. The same process is at work all the time, and it is called evolution.
Interesting question. By definition: No. Simply stated, evolution is change. It doesn’t specify direction, complexity, or any of that qualitative stuff.
To use your example: If selectors began favoring Cro-Magnon traits, it would simply be further evolution. It is a common error to assume that only higher intelligence or greater complexity are examples of evolution in action. In reality, it is just selection based on the current environment, whatever the outcome.
PJ O’Rourke once did a very funny piece on why dolphins are wimps because they came up on to the land, found the going too tough and returned to the water.
Dolphins and most marine mammals started returning to the sea from around 100 million years ago (though obviously as entirely different organisms from when their ancestors emerged from the sea).
If you made the assumption that going back to the sea was a backward step, then you might (at a stretch) say that dolphins had de-evolved
I’ll just throw this bizarre bit of trivia out here for thought. Buckminster Fuller claimed that man wasn’t descended from apes, but that apes were descended from man. His argument was that if you bred atheletes together for thousands of years, you’d end up with an ape.
The thing is that humans ARE apes. We just are not, IIRC, included in the great apes like gorillas are.
But yeah, the idea must have been a joke. A prominent feature of many athletes is their running ability. I doubt that if we bred the Jackie Joyner Kersees and Michael Johnsons of the world that such adept practitioners of bipedalism would become knuckle walkers the likes of Kanzi, Nim, and Koko.
Ok, so “de-evolve” isn’t an accurate term, so to speak.
If I’m understanding you all correctly, the only way to go to a previous state would be to know the genome exactly and then put into motion a very selective breeding process.
So it is technically possible (as is monkeys typing shakespeare), but not probable.
Or, if you know what you are looking for, and the descendant stock hasn’t modified too much, you can breed a line that is superficially identical to the original beast. This was done with tarpans, but as the last “pure-bred” had only died out in 1876, and the first recreated individual was born in 1933, there was no time for the original genotype to be completely lost, although it was spread out among a number of bloodlines in domestic stock.
Whether they had really recreated tarpans, or just developed a breed that looks like tarpans did, is, of course, a different question.
I don’t think such a program would be capable of recreating a, say, Merychippus or even a Dinohippus as that genetic information has been bred out of the descendant species over the past ten million years or so. But, if we try to breed lines with weaker teeth and smaller stature, we could come up with a breed which looks arbitrarily like one of the ancestors.
I have my doubts about the Quagga project’s method. Even selective breeding results mainly in random shuffling of genes. You may end up with something that looks like a Quagga, but it will be unlikely that it is any closer genetically than a random zebra.
The real solution is to map the genome of everyone in the world. Then work out the pattern of gene shufflings that has occured. Once you identify the gene pattern of the ancestor, you can genetically engineer that pattern.
But it’s probably mathematically impossible to work back to, say, Homo erectus.
