How did humans evolve? What happened in the last 6 million years that made us so unique?
Hi steemit! I recently introduced myself as a student and researcher in biological anthropology. In my first post, I also explained what primates can teach us about human evolution.
My day job: studying primate food items. Here I am working at a field site in Borneo, Indonesia.
I thought today I'd present some reasons why I think human evolution is fascinating. In particular, I want to address some common misconceptions.
This is the image many of us are used to. A cave-man-looking ape slowly standing up. Just like those dudes at the start of 2001 Space Odyssey.
But researchers have spent the last few centuries poking holes in this narrative.
Much speculation has focused on what our last common ancestor looked like. This first figure in the image above represents this ancestor, which is the point at which our ancestors split with the Pan lineage of chimpanzees and bonobos. One thing is certain, this ancestor was not a chimpanzee! Chimpanzees have also spent the last ~6 million years evolving. Understanding what this ancestor looked like has important implications for how we evolved in the following millions of years. Maybe it was more like a bonobo than a chimp?
Perhaps most critically, the first humans were Africans. We all come from Africa, so it's a pretty weird choice to draw human evolution as leading up to a white person. Historically, anthropology has gotten mixed up in some pretty racist ideologies. Nowadays, anthropologists are working hard to correct this legacy, but the old errors stubbornly stick around.
Here's an illustration by the artist Eduardo Saiz Alonso that I like better.
We now know from studying fossils that the earliest apes who left the forest and began exploring the savanna were pretty comfortable walking on two feet. Fossils like Lucy (an Australopithicus) were not slouching, shuffling apes! We were fully bipedal even before we got big brains.
Scientists don't agree on everything, but drawing a picture of human evolution that emphasizes the complexity of human evolution is a good start. Importantly, this image portrays groups historically excluded from human evolutionary narratives: women, children, and people of color.
Here's a classic example of an evolutionary tree from an intro to biological anthropology text book
As humans dispersed out of Africa, they encountered what we call Archaic hominins like neanderthals. Modern genomics reveal that humans actually mated with these other hominins, and even cary their genes with us today. On average, non-Africans have about 2% of their genes from a neanderthal ancestor. We've even found evidence that humans mated with another hominin, the Denisovans (not pictured).
Obligatory evolution is real plug
Every time we learn something new it just gets messier, which is cool and frustrating at the same time. The newest hominin, just described in 2015, is called Homo naledi.
This has highlighted some parts of human evolution that make it a dynamic and ongoing field of study. Researchers by no means agree on everything, so the evolutionary tree above is imperfect, but hopefully provides a general idea for an introduction. I'll make sure to include citations and supporting sources in future posts, but this one was so general.
Please let me know what you think! Layout? Facts? Clarifications? I'll happily engage in any scientific debate if you disagree! I will never claim to be right all the time.
Follow me for more science posts on human evolution, primates, and soon field research (t-minus 1 month until I'm in the forest with chimps!)
Bonus chimp photo: Atwood and her son, Chingachgook
