Wednesday 4 December 2019

Evolving Limbs

We are descended from quadrupeds that stood upright.

In "Wings of Victory," an Ythrian seen in flight is described as having legs whereas, in "The Problem of Pain," it is explained that:

"'What were formerly the legs have evolved into arms bearing three taloned fingers, flanked by two thumbs, on each hand. Aground, the huge wings fold downward and, with the help of claws at the angles, give locomotion. That is slow and awkward - but aloft, ah!'"
-Poul Anderson, "The Problem of Pain" IN Anderson, The Earth Book Of Stormgate (New York, 1979), pp. 23-48 AT p. 31.

In flight, an Ythrian's metabolic rate as well as the sky and the winds around him make him more alive than a human being can ever be but they are at a loss if confined or immersed in water. An Ythrian cannot wear a spacesuit and an Ythrian spaceship needs a large chamber for its crew to spread their six-meter wingspan, pump oxygen into their bloodstream and fly. They belong to the winds, not to the void.

10 comments:

Sean M. Brooks said...

Kaor, Paul!

And these difficulties you listed explains as well why Ythrians were slower to adapt to space travel than other races. Plus, it was much more difficult for Ythrians to REPRODUCE away from their native planet. At least not till Ythrian colonists had adapted to planets they settled on, which needed time.

Ad astra! Sean

S.M. Stirling said...

We're not actually descended (not immediately) from quadrupeds. We're descended from animals that spent most of their time climbing in trees. That's how we evolved hands. Hands in turn made bipedalism an evolutionary option.

Chimps have become more quadrupedal,. but they're not very -good- quadrupeds.

paulshackley2017@gmail.com said...

I thought that that was how we evolved but I have been told that the evidence indicates that bipedalism preceded opposable thumbs.

S.M. Stirling said...

Paul: -fully- opposable, in the sense we have them. That coevolved with bipedalism. By the time australopithecines like -africanus- were around, 3.5 million years ago, the hand functioned pretty much exactly the way it does for us -- in fact, their hands were much more 'modern' than their hips and legs, which still showed signs of arborealism.

The fully modern body plan evolved by the time of Homo Erectus, about 2 million years ago -- apart from having rather thicker bones, h. erectus was identical in size and body plan to us everywhere below the neck. That means they were specialized as cursorial predators -- "running hunters", since that's what the human body plan is best at, combined with weapon use for the actual killing with spears and clubbing.

Australopithecines already used stone tools and consumed meat; hominins proper did a lot more of both.

Sean M. Brooks said...

Kaor, Mr. Stirling!

And of course there were the Neanderthals and those Hobbit like hominids on Flores!

Ad astra! Sean

S.M. Stirling said...

Sean: the Flores hobbits seem to have been a reversion to generalized foraging; and the Neanderthals were a hyperspecialized big-game hunting tyoe -- the isotope ratio analysis of their bones indicates they ate nothing else but large grazing animals.

S.M. Stirling said...

The unique modern-human adaptation is to be a predator that uses resources -consciously-, adapting to precisely to the ecology of a region to maximize its resources.

Eg., by storing seasonal surpluses and/or adjusting to seasonal migrations among prey species.

This enabled them to support much larger populations than, say, Neanderthals, from the same environment.

Sean M. Brooks said...

Kaor, Mr. Stirling!

I certainly don't disagree with you about how "modern" humans were more sophisticated than the Neanderthals. But these two types of humans were "compatible" enough that a small percentage of Neanderthal genes passed into those of "modern" humans. Mostly into Causcasians and northern Asians, I believe. I like the idea of having some Neanderthal ancestry!

Ad astra! Sean

Nicholas D. Rosen said...

Kaor, Sean!

According to 23andMe, I do have some Neanderthal genes, although fewer than a majority of their customers. A friend to whom I mentioned this said that I don’t look very Neanderthal. (I’m slender with a high forehead, and don’t have much of a tendency to brow ridges.)

Best Regards,
Nicholas

Sean M. Brooks said...

Kaor, Nicholas!

That is cool, that you definitely have some Neanderthal ancestry! And I would not expect most such persons to LOOK like Neanderthals (maybe about 3 or 4 percent of the ancestry of Caucasians and northern Asians).

I tend to think the "typical" looks of a Neanderthal has been exaggerated by some to make them look more brutish, anyway. We see Neanderthals in Poul Anderson's story "The Long Remembering."

Ad astra! Sean