In human evolution what came first: bipedalism or increased brain size?

Question

In human evolution what came first: bipedalism or increased brain size?

Answer 1

Clearly, it was bipedalism.  There are numerous bipeds, Australopithecines and related species that have ape sized brains and were still bipedal.  It should be noted that existing apes and fossil Hominidae apes with the appropriate fossils have had similar large and similarly sized brains (but smaller than ours)  Sahelanthropus and Ardipithicus were probably bipedal and existed  5 to 7 million years ago.  It is likely they had a chimp sized brain.  People created the Piltdown skull to demonstrate that brain power came first. They were wrong and Piltdown was a hoax.

Answer 2

Bipedalism allowed for the use of hands and thus opposable thumbs, which allowed for the use of technology. Technology gives increased brain capacity a greater evolutionary advantage.

Answer 3

My guess is bipedalism since this allowed for greater brain activity since the option to run up the nearest tree was removed from the equation. This, owing to Geophysical upwelling in East Africa about 4 million years ago forcing our ancestors out of the trees and onto two legs.

This physical posture also allowed for an elongated laryngeal organ resulting in more complex sounds eventually leading to proto-languages.

The additional adjustments of this major topographical evolution forced new and more complex brain activity and exercise is the best method of development.

So walking upright required new brain activity for survival so I'd pick walking on two legs.

Answer 4

Since increased brain-size correlates with eating meat, as well as hunting for meat, and most hunted meat is not found in the trees, it makes sense that bi-pedalism would have preceeded increased brain size, especially since our earliest ancestors ate vegetable matter almost exclusively!

Answer 5

Bipedalism, I'm pretty sure, since it allowed freedom of the hands, a development which lent itself to more specialized actions.

Answer 6

According to the fossil record, bipedalism came first. This was about 7 million years ago.this was an advantage that allowed or ancestors to scan vast differences and hold things, then came increased brain size. It has been increasing over the past 2 or 3 million years

Answer 7

Bipedalism seems more logical.  A larger brain would be useless without hands to implement ideas.

Answer 8

Bipedalism. The first biped we know about lived millions of years ago. Called Australopithecus afarensis. Increased brain size in humans or relatives of humans is relatively new.

Answer 9

Bipedalism, definetely.

Answer 10

Evolution doesn't work that way.  It all happens at the same time and very gradually over thousands of years.  You can see this in our time as we are slowly losing blue eyes and wisdom teeth.