The theory goes that as the grasslands spread our ancestors were forced out of the forests and into the savannahs and evolution took hold, favoring a more upright posture because we could see further and so on. Being upright wasn’t really an advantage in the forests because the lousy trees blocked line of sight. The two developed at more or less the same time. Makes sense.
Well, according some new research by one Dr Feakins of USC, the grasslands were there in one form or another long before our ancestors ever started walking upright.
EDIT
Shortened title to prevent annoyance
[ Edited: 20 February 2013 09:16 AM by Dead Monky ]
Chris Stringer writes about that theory in his new book but doesn’t use it as the singular cause of bipedalism. Personally, I see a number of causes relating to standing upright, as in being able to run to the prey carcass making us more efficient food gatherers. And running from predators.
There is also a theory (supported my some evidence—they all are to a certain degree) that we, apes, went from walking on all four to becoming bipedal, to switching back to walking on all four, after which some apes (us) went back to bipedalism. Crazy stuff!
The theory goes that as the grasslands spread our ancestors were forced out of the forests and into the savannahs and evolution took hold, favoring a more upright posture because we could see further and so on. Being upright wasn’t really an advantage in the forests because the lousy trees blocked line of sight. The two developed at more or less the same time. Makes sense.
The problem with her theory is that she failed to take into account that a bipedal species had already been found in the forestlands. It was Ardipithicus Ramidus. The remains date to 4.4 million years BCE although some paleoanthroplogists speculate that the area was mixed grassland and forest. And just when something makes sense. Science, go figure!
Funny thing, you’re not really that wrong (depending on who you ask). There are growing questions about whether or not the dromaeosauridae (raptors) used their arms for holding on while they used their bitching claws for disemboweling their prey as was once thought. There’s a theory that at least the smaller varieties used them to climb trees and whatnot. But my personal favorite is the theory out now that they may have eaten like many modern birds of prey: chase down their prey, jump on it and pin it down with the sickle claws while they eat it alive. The arms (which would have been covered in feathers) would have been used in conjunction with the tail to maintain their balance. In a lot of ways, it’s even more horrible than jumping on and disemboweling their food.
