Biggest misconceptions of human evolution
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
Which part of Kalimantan (Indonesian part of Borneo) are you in? Really curious and interested to know more about your work!
The illustration of evolution really highlights alot of thought provoking points to us. Mainly, how even the most radical and liberal unorthodox thinkers of the past still ascribe what we how see as dogmatic. It's not to say that Darwin is wrong, it's just that we now know more than what he did thanks to his work as our foundation and continual research by his successors.
And also how the Bayesian theory is true in everything. We will never know for certain of anything. Nothing can be 100% true in a truly scientific manner. There is always new data that will disrupt the current thinking that bring us nearer to understanding how things work. We now know that human evolution (or evolution for the matter) isn't a linear process. But a web of many many factors contributing to what we are now.
A very good read that made me go "hmmmm". Upvoted and followed for more of your stuff!
hey @awesomianist glad you appreciated the post and I dig the thoughtful response. Agreed, although nothing can be certain, it's amazing how much we CAN learn! New methods every day. The genetics data we get from fossils nowadays is insane.
I was in West Kalimantan at Gunung Palung National Park. Ever been around this part of the world? I loved it. I was working at a long-term research site called Cabang Panti. Lots of great work done there with orangutans and rainforest ecology. Sadly I'm not sure when I'll get the chance to go back next. Thanks again!
I happen to live north of Central Kalimantan in the state of Sarawak. That is a part of Malaysia, another country but virtually on the same island that is Borneo! So yea, I am from THAT part of the world although I live a city life.
Appreciate the response. Good posts always makes me think deeply and it'll be sad to not write down my thoughts and mental reactions down as comments.
Lobe to hear from you more and hopefully you get to travel back there if not more bizarre places and uncover stuff that might changes the way society thinks of its ancestral history!
Really great post! What irritates me most about the classical depiction of human evolution is that the diagram has us evolving from what looks to be a modern day chimpanzee, when in reality the evolution from our LUCA with the chimpanzee resulted in two different evolutionary lineages, one which became us, and the other which eventually became the modern day chimpanzee. We didn't evolve from the chimp, both we and the chimp coevolved from the same organism at some point back far enough in the tree.
on the nose @justtryme90! recent findings might show that our ancestor could have looked more like a bonobo than a chimp, even!
tl;dr (though I'm no anatomist): neck/shoulder muscles in bonobos look different those from chimpanzees and have some things in common with humans, which hints that chimpanzees have evolved off in a different direction while bonobos look more like our last common ancestor
*edit = fixing link
I did not know about this research pointing to the bonobo. Thanks for the info!
Fascinating to see how subtle (and not so subtle) racism permeated these evolutionary illustrations. That's not something I would have thought about at first glance... I really like your annotated diagrams. Very effective. Thanks for sharing @benfink!
well waduya think of this??
Evolution of the "party animal"??
yuk yuk yuk...
Wonderful post - absolutely spot on. It's kind of a shame that we need posts like this. This should be absolutely common knowledge - common sense even. Let's say you have a cousin - the both of you share a great grandfather. It would be like saying your cousin gave birth to you...
There's no scope for disagreement, there's overwhelming evidence.
On an obscene tangent, I wonder how Hitler would react were he told the only "pure Humans" are Sub-Saharan Africans?
i'm glad you liked the post. I think people with particularly extreme views have a hard time hearing facts. People with extreme opinions who also have invested their identity into those views have a near impossible time. As we learn more about evolution, bigots like those who believe some groups of humans are superior to others keep trying to co-opt new findings into their racist worldview. No matter what we learn, they can spin it! It makes me wary to post on charged-topics like human evolution online, but I'll try to do my best and present things responsibly :)
edit: grammar
You don't need to apologize for basic facts backed by overwhelming evidence. Your responsibility should be purely to evidence and not avoiding offending bigots :)
What happened to god creating us all? Nice and simple ;) I wonder how messy that diagram will get once we have all the data, if that point can even be reached.
if only things we're that simple, I'd have an easy job! :)
Our story will keep getting messy, but it's worth noting that our diagrams and species lists dont' have to be. Paleoanthropology can divide into splitters & lumpers.
On one hand, splitters say that there are many distinct species in our lineage, that it looks more like a BUSH than a TREE. On the other, lumpers say that this means drawing arbitrary lines just to make more species. They'd rather group a bunch of these hominins together, like ergaster, erectus, heidelbergensis, and just call them all one thing.
The diagram I showed makes me look like a splitter, but you know, I think lumping some species together makes sense!
If folks are interested, maybe I'll do a post on this later: just how many species of humans have there been?
Sorry for late reply! Truly interesting info and insight, thank you for that.
Man that was so awesome. I would like the pictures to have been bigger so I could actually get a good look. The new species Homo Naledi where does it fit on the family tree?
Thanks @edwoodt1. I totally agree on the pictures. I'm not especially graphically savvy so formatting images into this first post was a challenge. I'll make sure bigger for future posts. In the mean time, let me know if there's any particular you want to see up close and below I've embedded a higher quality of the original tree.
Re: Naledi. That's a big open question. It's so new, there's no consensus yet. JUST this week they released the dates for it: between 236,000 and 335,000 years!
Excerpt form new paper, Berger et al. 2017
TL;DR Woah, there were many hominins running around even super recently. We didn't evolve from this one, but it's possible that Naledi a) invented tools we thought we had, b) interbred with us, c) coexisted with the lineage that became humans, bringing potential of ecological competition or co-evolution.
I'll consider doing a post on this, as it's all breaking news.
upvoted
@shayne