Human Origins

Last year, I was at the California Academy of Sciences with Val where we saw an exhibit about human evolution entitled Human Odyssey. It emphasised how similar everyone is, despite the diversity of our racial ethnicities. It also showed that the evolutionary path was far from straight. There were many turns along the way, and even a near-extinction event for Homo sapiens. 

This year, I visited the Smithsonian National Museum of Natural History while Val was in his econometrics class. I found that the David Koch Hall of Human Origins is a great complementary exhibit to Human Odyssey. The text in the Hall of Human Origins say that though humans are primates (great apes) and are related to the chimpanzees, the progenitors of humans are not directly related to the great apes that now co-exist with humans.

Research findings indicate that chimps and humans are more like distant cousins. The common ancestor has not been found... yet.

My knowledge of hominids is very limited. In primary and secondary school, I've learned about Australopithecus spp. whose fossils have been found mostly in Africa. The locations of their remains suggest that human evolution originated in Africa. What I didn't know was that hominids have also been classified into a different genus called Sahelanthropus. This genus is theorised to be the point of divergence of chimps and humans. Could this be the common ancestor?

After some point, Australopithecus spp. died out and was replaced by Homo spp. There were many species of Homo; the exhibit showed that H. neanderthalensis (neanderthals) existed at the same time as H. sapiens (modern human). But did they exist in the same location? It is possible because a team of scientists have found Neanderthal DNA in modern human genomes (1) and another team determined that fossils they have discovered in Italy were of an interspecies family, with a hybrid child (2). H. heidelbergensis, a human species found in Germany, appears to be the first human to hunt large animals, build shelter, and control fire (3).

That neanderthals and humans existed at the same time reminds me of a Bones episode from 2013. In it, Temperance Brennan and her team at the fictional Jeffersonian Institute discovered an interspecies family consisting of neanderthal and modern human parents and a hybrid child among the effects of a murdered archeologist. 

But I digress...

The earlier human species died out, just like Australopithecus and Sahelanthropus. Homo sapiens outlasted all other human species. If H. neanderthalensis was there at the same time as H. sapiens, what happened to the neanderthals? Did H. sapiens wipe them out through competition? Or did genetic and anatomical challenges caused the neanderthals to fade away? With their genes integrated to the modern human genome, did they really fade away or is the neanderthal legacy still living through their genes in modern humans? Scientists are still debating on these questions so in the meantime, the bottomline is that H. sapiens is the last extant species of Homo.

This topic is not easy to take, particularly for people who strongly believe in the literal interpretation of the Creation story in the Bible. I saw one woman storm out of the Hall of Human Origins highly frustrated, perhaps finding the captions, the scientific findings, and the interpretations highly unpalatable. I expected Roman Catholics to be at odds with the scientific explanations. However, Pope Francis said that the evolution story is compatible with Church teachings (4). It is possible that the woman is of another religious denomination; but that's assuming that she's upset with the exhibit, of course. 

References:

1. https://www.nature.com/news/modern-human-genomes-reveal-our-inner-neanderthal-1.14615

2. https://www.seeker.com/first-love-child-of-human-neanderthal-found-1767365937.html

3. http://humanorigins.si.edu/evidence/human-fossils/species/homo-heidelbergensis

4. https://religionnews.com/2014/10/27/pope-francis-evolution-inconsistent-notion-creation/