When I was first old enough to be aware of such things, I learned that the theory of “continental drift” had fallen out of favor with geologists. At that time, anthropologists were also trying their best to fit every hominid bone they’d dug up into a clear, linear sequence, with Neanderthals the last of the ancient brutes to give way to us graceful modern humans. We didn’t know, then, that dinosaurs hadn’t really completely disappeared (or that they sometimes sported “feathers”). We also didn’t really know the age of the universe. We had seen the earth from space, but had not yet traveled to the moon. AIDS was twenty years in the future, and there was still debate over whether cigarettes had any causal relation to lung cancer (one of the many cancers that still carried a stigma that is difficult to imagine today).
(I imagine that every generation has been astounded by the discoveries made during their time. 11 years after the Wright Brothers flew, my father was born in a house with no electricity, and didn’t learn to drive a car until long after World War II.)
But the march of new technologies brings with it new discoveries made possible by those technologies. So we now know how old our universe is, and have proven by measurement both Einstein’s theory of relativity and the reality of plate tectonics (the more refined version of “continental drift”). We have sequenced both the human and the Neanderthal genome, and now know that Neanderthals were a branch off the family tree that died out (but not before mixing their DNA with some of our modern human ancestors). And though we’ve been unable to recover any dinosaur DNA, we have seen through current DNA and biology dinosaur’s continuation in modern birds such as the humble chicken (which is now being “reverse engineered” back into its earlier, dinosaurian form — we’ll have to see how that works out!).
But besides the “big” discoveries, what strikes me as equally significant is the slow but steady softening of our hard-edged ideas of how the world works and how living things came into being. Take the linear approach to human evolution, where one animal form leads inexorably to the next. We now realize just how broken our fossil record is when it comes to human evolution, and that many of the specimens we have recovered were likely not in our direct ancestral line. We now think more broadly when it comes to the human family tree — seeing it more like a true tree with many branches splitting off from the trunk at many different points at many different times. Of course we living modern humans represent a single branch that can trace its beginnings back to the, well, beginning. But we now realize that not every fossilized hominid bone we find can be confidently called mom or dad. They are often more our aunty or uncle.
Which is why I found Carol Jahme’s recent article (“Lice, sex, gorillas and genetics”) in The Guardian so bracing. It turns out that our ability to study DNA has given us a tool with which we can estimate the time in the past when related species split off from their parent stock (when they branched off from their particular family tree). In the case cited in this article, scientists studying the differences in the DNA of gorilla and human head and pubic lice were led to an interesting conclusion: there was clearly a lot of hanky-panky back and forth between our diverging hominid ancestors as they evolved into different species.
This seems to me to be a bit of dramatic news, in that it calls up a sort of re-imagining of my primate-hominid ancestors somewhat akin to finding out that stolid old great-great-granddad was making a few extra kids on the side with the hired help. But having just recently absorbed the news that I might have a bit a Neanderthal blood in me, this is just one more step into a more healthy and realistic understanding of how evolution (and, well, sex) works.
I find it all a bit exciting, especially as I realize that science is leading us ever deeper into a much more realistic understanding of life, and taking us further and further away from the mythology that has passed as knowledge for (lets be frank) most of our history as modern humans. We are learning that certain cancer treatments, say, work at an incredible level in certain groups of patients, but do nothing for others. In the past, we would have stopped at that fact, and called it a modestly successful treatment. But medicine is taking the next step, and figuring out ways to determine what makes one group of humans genetically different from another, which could therefore allow doctors to test for the patients for whom the treatment is very likely to be effective, while sparing others a difficult and hopeless treatment. This is incredible progress. It is also technology-dependent and complex, even as it holds out promise for pulling medicine ever-more out of its own medieval roots.
All of these twists and turns — as we discover them — begin to paint a picture of the ebb and flow and endless mixing of life, as genes mutate, re-combine in new offspring and respond to new (and old) environmental pressures. Each and every one of us is a singular microbial ecosystem, related, yes, but also, in a way, our own unique world. To my mind, such awareness carries me away from the simplistic, teleological ideas of our past. The idea that such a system is the result of an intelligent creator who had us in mind from the start becomes so fanciful as to be beyond consideration.
Life is a wondrous mess — a cohesive chaos so improbable as to be considered impossible were it not for the fact of its existence. Living in a time where we are able to come to a genuine appreciation of our true state is, I think , rather remarkable. We will never have the experience of those who saw man make his first flight in a airplane, or ran in terror at the noise of the first steam locomotive. No, we have become used to the advance of machines. We have not, however, proven ourselves so adaptable to the advance of ideas about our own origins and evolution. In that regard, we are like the Londoners who resisted more efficient coal stoves that could have cut their waste and pollution by a factor of four: they feared the new, and instead wanted to keep the comfort of the smoky, inefficient open fireplace.
And so I have to regularly remind myself that there are many who regard most of the information I’ve referenced here as false and iniquitous. They cannot appreciate the latest discoveries about human evolution because they will not accept that humans evolved at all. As one woman snapped when I referred to (my street painting of) Tiktaalik as one of our “ancestors”: “Well, it’s not one of MY ancestors!”. I just hope she doesn’t hear about our hominid great-great-grandparents fooling around with their gorilla cousins! I don’t think she’d take that too well.