We actually have less genetic variation than most animals. There was a lot of bottlenecking in the paleolithic. And what little we do have is still mostly confined to Africa, because the rest or the world shared common ancestry as we left our original continent.

Like, 1 in 200 people is colourblind, or something? I don't think that's a reasonable argument that we're not trichromats.

Yeah, I've noticed the lack of insects, and also different plants growing than I remember from when I was a kid, not all too long ago. Every once in a while I'll be talking to someone about the weather and how freakish it is, and they'll suddenly get quiet if I use the word "climate" instead of just weather, because they were (and maybe still are?) denialists.

The thing about mammals is that at least some - ourselves included - can migrate. If we have to, we'll set up banana plantations on Antarctica, and there's no known scenario where it gets that bad. Others are not so lucky, though.

Yeah, we played paintball even, but stopped because one guy ran straight off like a 6 foot mini cliff. A couple of us were chasing him and he just disappeared. Was freaky as shit like that scene from LotRs.

Lol, yup, that sounds right. I did that once, although it was only like 3 or 4 feet, and I didn't like it one bit. Is was a sinkhole or something too, because it was cliff all around, and I had to find a spot to climb out. I didn't visit that area again.

I forget where I heard about the sailing thing now. That would be a 1 on the Bortle dark sky scale, though.

Optimised just means designed for something at the expense of other parameters. We lost our tepetum lucidum at some point in evolution, probably for the 3x-ish resolution gain, while becoming much more shit in lowlight in the process. That's a tradeoff, but a good one for a tree-based diurnal frugivore.

Cats (for example) still have theirs, which means light as two chances to hit their retina, but means there's an upper limit on how clear an image can be, exactly because there's light bouncing around. It sounds like 20/100 is typical for them, from a quick search. Cats are traditionally thought to be dichromats, as well.

I could nitpick some of the details there, but instead maybe I'll just ask what point you're trying to make? A healthy human can still pick out something small way better than a goat.

Hmm. Are we talking a high canopy, and fairly level ground? I feel like I'd definitely break an ankle if I tried sprinting otherwise.

I never had too much trouble, but sometimes things hiding in tall grass would surprise me, and in heavily treed patches I'd occasionally hit a low branch I didn't notice.

I also have to account for the fact that there was some light pollution, and I could always see skyglow from towns in the distance. I doubt land ever gets close, prehistoric or not, but in the darkest conditions that happen at sea apparently you can't see your own hands.

We're diurnal, and have eyes optimised to see maximum colour and detail instead of well in dim light (at least by mammal standards). It makes sense we'd gravitate to fairly dark conditions to sleep, because while nature at night is not perfectly unlit, it's still pretty dark. Darker than a developed-world urban area will ever get, for example.

That being said, many people are completely capable of sleeping in a bright area, myself included.

As for the bonus question, yes, the hormones at least work backwards in nocturnal animals. Melatonin wakes something like a shrew up.

but even in the absolute middle of nowhere with no artificial lights, you’re going to be able to see fairly well.

I'm not sure I'd say fairly well. Maybe always well enough to not walk directly into a tree in otherwise open terrain. A full moon will be comfortable to walk around in, but new moons happen just as often, and sometimes the moon is below the horizon.

Source: Have walked around in the country at night.

It sounds like Gantz will rescue it, though. Or at least would be willing to and has enough seats for a majority; I'm not sure if they'd still have to call an election.

I'm not sure how much exactly, but a lot. In my own defence, I'm not on anything else.

This isn’t the only potentially human civilization-ending event I first heard about this past month, and that doesn’t include climate change that we’ve known about for literally decades, which many of the major players involved including the USA and China still don’t seem to care much about even now.

To be fair, every damn headline is framed as civilisation-ending for clicks. Nuclear war is the only one I can think of that's both fairly plausible and could actually end it. Others are at various significant but lower levels of suck, or are just geologically rare.

In particular, climate change is going to suck hard, and I'll miss coral reefs, but some form of civilisation will endure. I know, someone's going to argue with me, and I look forward to making you move around the goalposts on what "end of civilisation" means.

Otherwise, yeah, you're just right. Humanity runs on apathy.

I'm guessing it's unknown. There's microplastic in testes, and it's not good for fertility. Getting that far probably required a lot of research. Understanding the mechanism and projecting it forwards will require way, way more.