The scientific study of human evolution has historically reassured us of a comforting order to things. It has painted humans as smarter, more intellectual and more caring than our predecessors.
From archeological reconstructions of Neanderthals as squat, hairy and beastly, to ‘cavemen’ movies, our ancient ancestors have received a bad press.
In the last five years discoveries have overturned this unbalanced view. In my recent book, Hidden Depths: The Origins of Human ConnectionI argue that this matters as much for how we see ourselves today and imagine our future as for understanding our past.
Six revelations stand out.
1. There are more human species than we ever imagined
Items like Homo Longi they have only been identified in 2018. There are now 21 known human species.
In recent years we have realized that our Homo sapiens ancestors may have encountered as many as eight of these different types of humans, from robust and stocky species, including the Neanderthals and their close relatives the Denisovans, to the short (less than five feet tall) and small-brained humans such as Homo naledi.
But Homo sapiens it was not the inevitable evolutionary destination. Nor do they fit any simple linear progression or progression scale. Homo Naledi’Its brain may have been smaller than that of a chimpanzee, but there is evidence that they were culturally complex and mourned their dead.
Neanderthals created symbolic art, but they were not the same as us. Neanderthals had many different biological adaptations, which may have included hibernation.
2. Hybrid humans are part of our history
Human hybrid species, once considered by experts as science fiction, may have played a key role in our evolution. Evidence for the importance of hybrids comes from genetics. The pathway is found not only in the DNA of our own species (which often includes important genes inherited from Neanderthals) but also in the skeletons of hybrids.
An example is ‘Denny’, a girl with a Neanderthal mother and a Denisovan father. Her bones were found in a cave in Siberia.
3. We got lucky
Our evolutionary past is messier than scientists thought. Have you ever been bothered with back pain? Or did you look enviously at your dog as he chased through a rugged landscape?
That should be enough to show you that we are far from being fully adapted. We have known for some time that evolution combines solutions in response to an ecosystem that may already have changed. However, many of the changes in our human evolutionary lineage may be the result of chance.
For example, where isolated populations have a trait, such as some aspect of their appearance, that makes little difference to their survival, and that appearance continues to change in offspring. Neanderthal facial features (such as their prominent eyebrows) or body (including large rib cages) may have simply resulted from genetic drift.
Epigenetics, where genes are only activated in specific environments, also complicates matters. Genes may predispose someone to depression or schizophrenia, for example. However, they may only develop the condition if they are triggered by things that happen to them.
4. Our fate is intertwined with nature
We may like to imagine ourselves masters of the environment. But it is
increasingly clear ecological changes shaped us.
The origin of our own species coincided with major changes in climate as we became more distinct from other species at these points in time. All other human species appear to have disappeared as a result of climate change.
Three main human species Homo erectus, Homo heidelbergensisand Homo neanderthalensis died with major climate changes such as the Adams event. This was a temporary collapse of the Earth’s magnetic field 42,000 years ago, which coincided with the extinction of the Neanderthals.
5. Kindness is an evolutionary advantage
Research has revealed new reasons to feel optimistic about future human societies. Scientists used to believe that the violent parts of human nature gave us a leg up the evolutionary ladder.
But evidence has emerged for nurturing human nature and its contribution to our success. Ancient skeletons show remarkable signs of surviving disease and injury, which would have been difficult if not impossible without help.
The footprint of human compassion stretches back a million and a half years. Scientists have traced medical knowledge at least as far back as the Neanderthals.
Altruism has many important survival benefits. It enabled older members of the community to impart important knowledge. And medical care kept skilled hunters alive.
6. We are a sensitive species
Evolution has made us more emotionally exposed than we like to imagine. Like domestic dogs, with whom we share many genetic adaptations, such as greater tolerance for strangers and sensitivity to social cues, human hypersociality comes at a price: emotional vulnerabilities.
We are more sensitive to how the people around us feel and more vulnerable to social influences, we are more prone to emotional disturbances, loneliness and depression than our predecessors. Our complex emotions may not always be pleasant in life, but they are part of key transformations that have created large, connected communities. Our emotions are essential to human partnerships.
This is a much less reassuring view of our place in the world than we had five years ago. But seeing ourselves as selfish, rational, and entitled to a privileged position in nature has not worked well. Just read the latest reports on the state of our planet.
If we accept that humans are not the pinnacle of progress, then we can’t just wait for things to work out. Our past suggests that our future will not get better unless we do something about it.
This article is republished from The Conversation under a Creative Commons license. Read the original article.
Image credit: Neanderthal-Museum, Mettmann / Wikimedia Commons