The Forager - Australopithecus

I meant to get this out by yesterday (which, if you weren't in the know, was Charles Darwin's 209th birthday,) but I've been going through some pretty severe executive burnout lately. Even so, I was able to finish it soon enough to maintain its relevance somewhat, and this blog is no closer to disappearing!
Anyways...
Australopithecus was a genus of primate extant from around five to two million years ago on the plains of Eastern Africa. Each species was remarkably unique- some showed extreme dimorphism, with males weighing fifty to sixty pounds more than their lightweight females. Others had massive crushing molars, used to browse for tubers and roots in times of drought. Even so, they all had one thing in common that separated them from other apes.
Around the time the first fossils were found, seismic activity in the continent's eastern plate gradually formed the Great Rift Valley. Alongside forming an entirely new habitat, the new chasm restricted the flow of water and created a new rainshadow. The vast forests that ancient apes lived in couldn't cope with the pressures and retreated West. Many of these primates moved with it, but a small group stayed behind to brave the openness. Out here, it was a handicap to crawl around on all fours like their cousins did- it was much too exhausting to walk the miles between each next tree, and certainly more dangerous with the wealth of carnivores.
So how did these magnificent apes solve this problem?
They started walking upright.
As it became more and more necessary to see what was on the horizon, the Australopithecus and its relatives started developing longer and thinner feet. While bad for grasping, they provided perfect leverage to allow for longer strides across the savannah. Their femurs moved from directly under the belly downwards to help maintain their balance. Their spines started attaching to the skull from the bottom instead of the back to keep the eyes facing forward.
It may not seem like such an evolutionary leap forward, but this gait was so successful that this primate's descendants would spread all across Africa and beyond. Their hair would disappear and their brains would grow. Tools would become regularly used in their communities, which would grow to include millions of individuals. Because their trees disappeared, these apes would take over the world.

Rendered in Photoshop