Pterosaur Size, Weight, ST and Maximum Encumbrance when Flying

[Rupert]

Originally Posted by Icelander

I gather, then, that it would not be wildly implausible to propose humans living in a place with a pressure of 1.5-2 atmospheres, with atmospheric oxygen around 30% in the air?

But could such humans (or human like natives) ever form a civilization?

Would they have to find highlands and mountains, where it might be drier and the air pressure less?

Huh, and where they might be competing with pterosaurs with living space!

As I recall, in Space:1889 the human outposts are indeed in what passes for highlands. The sapient, though primitive, lizard men seem to live anywhere there's 'land'.

[Icelander]

Originally Posted by Rupert

As I recall, in Space:1889 the human outposts are indeed in what passes for highlands. The sapient, though primitive, lizard men seem to live anywhere there's 'land'.

I don't know if dcarson will play a 100% canonical Space: 1889 game or not, he might want to tinker with some assumptions to better suit his sense of verisimilitude, high adventure or something else.

In any case, I was wondering in a more general sense, as in what the plausible physical effects of such a setting would be. Nevermind why Venus or some other world is like that, just, if it was, what would be the effects, in terms of reality and GURPS rules.

Luke, of course, has provided some guidelines, but I'm still unsure what the effects would be on a fire-using, metal-crafting human culture. Or if these conditions might perhaps be exactly the justification a world needs to be stuck in an eternal Stone Age society of barbarian pterosaur-riding hunters with flint spears and stone axes?

[Varyon]

Originally Posted by Icelander

What will be the effects on other wildlife?

Higher oxygen can justify larger land arthropods. Combine with lower gravity and/or magic, and the results can be downright terrifying.
(That's a chasmfiend from The Stormlight Archives. I should note the human size comparison at the bottom is likely using Kaladin Stormblessed, who is taller than an average human - probably 6' tall or so).

[Flyndaran]

Arthropleura lived in the carboniferous period due in large part to the higher oxygen levels.
Imagine a millipede relative over 7 feet long and over 1 foot wide.

Now imagine if it had been the predatory centipede relative as initially thought.

[Icelander]

Originally Posted by Varyon

Higher oxygen can justify larger land arthropods. Combine with lower gravity and/or magic, and the results can be downright terrifying.
(That's a chasmfiend from The Stormlight Archives. I should note the human size comparison at the bottom is likely using Kaladin Stormblessed, who is taller than an average human - probably 6' tall or so).

Originally Posted by Flyndaran

Arthropleura lived in the carboniferous period due in large part to the higher oxygen levels.
Imagine a millipede relative over 7 feet long and over 1 foot wide.

Now imagine if it had been the predatory centipede relative as initially thought.

Right, thanks. That's nice.

What kind of flora or fauna that exist under Earth-like conditions does higher atmospheric concentration, higher atmospheric pressure and maybe slightly lower gravity discourage or exclude?

What won't pterosaurs who live under such conditions on a Venus (or Hollow Earth) be eating or competing with, that they might have coexisted with under conditions closer to the Earth that humans evolved on?

[Flyndaran]

I think a massive advantage birds have is their super efficient lungs. With a denser more oxygen rich environment, I don't think they'd be so awesome comparatively. They could certainly still exist, but probably nowhere near as ubiquitously as on Earth.

I think it's easier to imagine what just wouldn't benefit which is effectively being disadvantaged compared to what life would benefit.

[Icelander]

Originally Posted by Flyndaran

I think a massive advantage birds have is their super efficient lungs. With a denser more oxygen rich environment, I don't think they'd be so awesome comparatively. They could certainly still exist, but probably nowhere near as ubiquitously as on Earth.

I think it's easier to imagine what just wouldn't benefit which is effectively being disadvantaged compared to what life would benefit.

Yeah, but is there anything which is fairly common on Earth and prerosaurs might eat or compete with (or might eat pterosaurs) that would be Hollywood levels of Failing Biology Forever to put in such a fantastical Venus analogue world?

Because for my Hollow Earth world, which the PCs might someday visit in the course of a game where powerful magic can allow world-walking, I kind of want the climate to be very old-school SF Venus, with ferns, giant insects and dinosaurs, but I also want biology and physics to work normally except where a magical effect (which can be detected, analyzed and even countered using normal GURPS rules) is somehow changing the rules.

[Rupert]

Originally Posted by Flyndaran

I think a massive advantage birds have is their super efficient lungs. With a denser more oxygen rich environment, I don't think they'd be so awesome comparatively. They could certainly still exist, but probably nowhere near as ubiquitously as on Earth.

They aren't the only creatures with that sort of lung - crocodilians do and at least some pterosaurs did also, though not quite as extreme it seems. I think some lizards, also. It seems to me that we've made some fairly serious errors in non-mammalian physiology by assuming that if it's not obviously different, it's the same (and probably also a carry-over from the time when mammals were held to be 'more advanced' than birds, reptiles, etc.).

[Flyndaran]

I knew about crocodilians, but hadn't heard of the pterosaur evidence for avian type lungs. That is interesting.

[Rupert]

I forgot the references I found for that:

https://www.newscientist.com/article...rosaur-flight/

https://www.nationalgeographic.com/s...d-their-lungs/