Monday 16 March 2020

Bipedalism And Opposable Thumbs

"Territory."

Nicholas van Rijn to Joyce Davisson on t'Kela:

"'Now humans, the experts tell me, got started way back when, as ground apes that turned carnivore when the forests shrank in Africa for lots of megayears. This is when they started to walking erect the whole time, and grew hands fully developed to make weapons because they had not claws and teeth like lions.'" (pp. 55-56)

Years back, I read a different account and have quoted it on the blog:

quadrupeds evaded predators by climbing into trees where they were free to chatter and developed opposable thumbs for grasping branches;

descending from the trees, they walked upright across the plains in still chattering groups with forelimbs freed to manipulate their environment and to make weapons.

I still think that that account is both possible and plausible but have since been told that the evidence is that upright gait preceded opposable thumbs, as van Rijn says, not vice versa.

5 comments:

Sean M. Brooks said...

Kaor, Paul!

And I also immediately thought of Anderson's story "The Little Monster," where we get a glimpse of a possibly different explanation of the beginnings of human evolution and intelligence. Developing of the first crude weapons and defenses against attack by large predators, mastering of fire, etc.

Ad astra! Sean

S.M. Stirling said...

Mammals started out as small generalists — roughly equvialent to rodents today and including many arboreal species.

Sean M. Brooks said...

Kaor, Mr. Stirling!

And, of course, many mammalian species did become specialized, such as predators like the lions and tigers. True intelligence arose among primates, hominids, humans partly because of that lack of specialization?

Ad astra! Sean

S.M. Stirling said...

Sort of a specialized non-speciality. Our body plan remained generalized for a long time, until about 2 million years ago, when we became fully bipedal.

That produced an animal that does have a speciality — long-distance running. No other mammal is anything like as good as we are at that. The canids come closest, but men can run wolves to death, or even African ‘jag hond’.

But a lot of our equipment remained generalist. Our hands, for example, retain many primitive features, and changed to become sort of “more so”. While our -feet- are as specialized as a horse’s. Our digestive system has sort of half-way transitioned from a chimp-like to a carnivore-type setup — not as simplified and specialized as a cat’s, but much more so than a chimp’s.

Sean M. Brooks said...

Kaor, Mr. Stirling!

Hmmm, we humans are a kind of non specialize specialist species? Neatly put, and it makes sense. And it's good that we don't have to depend entirely on meat to survive, as tigers and lions need to do!

Ad astra! sean