Actually I believe percentage of genetic difference is about three percent between humans and chimps. Probably higher between humans and the other great apes. But, oh that three percent.
There is strong evidence that hominids have always had upright or nearly upright posture. All the better to hang on to that gazelle haunch you just liberated from the leopard while hanging on to the branch you’re using to fight off the hyenas my dear. Seriously though, it has to do with the hole at the base of the skull where the spinal cord attaches to the brain. Ours is positioned a little differently than it is with the great apes. And that position proves that human it belonged to walked upright.
Said club and haunch held by a hand with a fully opposable thumb. Hands capable of randomly knocking two rocks together to create an early chopper or of creating astonishing beautiful stone tools, spear heads and arrow heads. And the ability to make and use tools crosses all all hominid groups from Erectus to Neanderthal to Homo (supposedly) Sapiens. That's us. Probably the only humans in the history of the planet who believe that a single, lone human can prosper and survive.
Apes vocalize. A lot. Experimenters have taught chimps and at least one gorilla American sign language. Others have learned to manipulate computer based symbols that function as a language. One gorilla even showed evidence of a sense of self. When she was asked who broke something in the lab she blamed it on the human assistant. "I didn't do it" apparently knows no species lines. There’s also evidence of being able to take words they already knew and combining them to describe something totally new to them. As in labeling watermelon “candy drink fruit.”
But no ape, that I know of, can use spoken language the way humans do. They have the brains. They don’t have the physical capacity. Their tongues don’t work the same way ours do. I still think the first complete sentence in any language may have run along the lines of “Grab kids, bad cats back.” Short, but effective.
But, I believe it’s our imagination that sets us apart from the rest of Creation. Chimps prep twigs to use to snag termites. In the lab they can and do pile boxes to get to food that would normally be out of reach. Groups of males fight or hunt. They even use sticks and stones. But, I’ve never heard of a chimp taking a rock (chipped or not) tying it to a stick and using the combined tool.
And that’s what I find endlessly fascinating. How did we come up with all the tools and textiles that we use? I mean, think of all the pieces that have to come together for a bow and arrow. The small, knapped arrow head, the stick to fasten it to, the fletching to make it fly straight, the flexible bigger stick and the length of gut, vine or string used to power the bow. That’s a lot of imagination coming together. And THEN finding uses for that bow besides using it to fire arrows. The bow/drill that can be used to make a fire or to fashion other tools. You have to go from the straight motion of firing the arrow to a totally different, circular motion.
And what about fire. Other critters are afraid of it. We not only got past our fear and tamed it, we figured out how to break free from having to tend a fire started by a lightning storm to fire on demand. Who figured out that if you rubbed two sticks together fast enough you could get a spark? And what bright boy (or girl) recognized that flint and iron ore struck together made a spark and that you could use that spark to start a fire?
Once we had sheep and goats who figured out you could make thread from the fleece? I mean I can see a bored kid on jackal lookout duty taking some fleece that got caught in a thorny bush and twisting it into a string, even making a string of loops like the base for a crocheted piece. But, who in the heck took a stick or a piece of metal, put a hook on the end and started going back and forth to make cloth. I mean that’s kind of a leap isn't it? Or taking multiple sticks, keeping the loops on one and working the thread with the other? Who the heck invented knitting? And who recognized that you could cut the fleece (coat) off a sheep and it would grow back? Talk about your renewable resource.
What about clothes? I mean it’s one thing to clean up a hide and wrap parts of it around yourself. It’s another set of actions entirely to cut pieces out of those hides (after you've invented tanning of course) and put them back together with lengths of string or gut. After you've invented a knife to cut the little slits for the “thread” and needles to carry it and basically create a second skin to keep your own hide warm and protected.
The list is endless and totally fascinating. Realizing that the wild grain you've been gathering is growing in last years rubbish tip is one thing, taming goats or cows is one thing. But, who made the jump from grain to bread and milk to cheese?
That’s one of the things that bugs me about the fundies. We've got one hell of a tool kit that humans have assembled over the millennia and they don’t seem to appreciate it. Time and imagination. Especially imagination. Now that I think about it if our ancestors had spent so much time and energy trying to prove that they were right and the other guys were wrong we’d probably still be stealing gazelle haunches from the leopards.
And it wouldn't surprise me if there wasn't an ancestor or two that believed that sticks and rocks were meant to be used separately and it was sacrilege to tie the two together. Oh God/dess do blasphemy charges go back THAT far???????????