Thought experiment, if a bunch of people went to live underground, would they evolve differently? Assuming they would live, die and reproduce the same as they did on the surface?
Like, does evolution only stem from survival of the fittest, or does our offsprings genetics change at all from the environment (outside of radiation and such of course)?
Random mutations happen, if those with a mutation gain benefits to surviving better than their counterparts then they are evolving to suit the environment. And yes epigenetics play a role also
Yes, assuming they are completely isolated from the surface population. It’s called genetic drift.
There’s a pretty interesting group of people who were pretty isolated in Kentucky who turned blue, which would be an example of this. https://en.wikipedia.org/wiki/Blue_Fugates
Neat, very interesting
I’m not sure I understand the question.
does evolution only stem from survival of the fittest, or does our offsprings genetics change at all from the environment
Those are the same thing. The environment determines who can reproduce (most successfully) by selecting the fittest (meaning the one who is best able to adapt to the environment), thus changing the genes of the group in the next generation.
So yes, of course humans would evolve differently if they started living underground. For example they’d probably evolve larger eyes because larger eyes can see better in low light and make survival (and reproduction) more likely.
Or maybe I’m misunderstanding.
I’ll try to explain my thought process. Due to modern medicine and other aspects driving down mortality, human evolution isn’t really based on survivability (I assume it’s more based on attractiveness currently?). If we assume that people who have less sensitive eyes would have the same survival rate, would people still evolve to have more sensitive eyes?
Death is not the only driver. Reproduction is by far more important. Death only affects evolution because it prevents reproduction. With modern medicine then sexual selection becomes a bigger driver.
And even then evolution will always happen as mutations will always happen. Even if it is mostly just random drift in features.
We see many aspects of this over and over. Birds on island tend to lose their ability to fly. Larger animals on islands tend to shrink over time. Even isolated humans in extreme places (like high up on a mountain or that do a lot of deep sea diving) show adaptations to their environment. Once isolated even small pressures on your ability to reproduce will affect the population over time. It just might take a lot longer.
Oh you mean because we have developed technology to balance out evolutionary pressures and the people going underground would take that technology with them. Good question.
I’m no expert (just an interested layperson). But I’d assume the evolutionary pressure would be lower so evolution towards larger eyes might be slower. There’d still be a certain advantage in being able to see better in low light. Technology can fail after all.
The thing is that we’ve had technology to circumvent our bodies’ weaknesses only for an extremely short amount of time, from an evolutionary point of view, so there’s no precedence. There are scientists speculating that we’re now driving our own evolution.
Attractiveness btw is just fitness made visible. We generally find things attractive that promise offspring that will be able to adapt to the environment. That’s the very very short version, in reality it’s of course a lot more complicated. And again, we now have technology to fake fitness so who the fuck knows what’s going to happen.
This will depend a lot on your conditions. To see a specific set of traits, you first need to isolate them completely. Over a couple of generations (ten maybe, maybe more or less depending on how many your bunch is) you will probably see they sort of look like they belong to the same family. Similar skin, similar hair shade, probably a certain range of eye color, etc. This is just the product of genes mixing and sort of homogenizing a bit over time.
Like someone mentioned, you could get a mutation, and if the mutation turns out to be either advantageous or simply dominant gene wise then you will eventually see it in most people.
Then finally you have adaptation by natural selection, and this will depend a lot on the type of pressure you subject this bunch of people to. Do they have access to electricity? Are they living completely in the dark? Any diseases affecting them or other creatures underground? Do they have access to space or is this limited? Food? You will likely see your surviving population becomes immune or resistant to underground pathogens, simply because those who can’t will die before reproducing. Similarly if you are short on nutrients or physical space, you will see them shrink over time. If your conditions are more extreme and they’re completely in the dark, you will probably have a population develop some sort of echolocation sense (and this shouldn’t take too long, blind people can develop this to a degree already), and their metabolism will adapt to a much lower vitamin D (unless they can acquire it from some abundant food source). Over an even longer period of time they will either lose their eyesight or if they have access to light (fire? A few narrow openings to the surface?) they will adapt to see much better in the dark. Those are the more obvious adaptations I can think of but there could be a lot more depending on so many factors.
