Join me on a trip back in time through millions of generations
Peterborough Examiner – November 29, 2024 – by Drew Monkman
There’s something captivating about tracing our roots back through time and learning what we can about our ancestors. I’m very fortunate in that both my parents did extensive genealogical research on their respective sides of the family. My father, for example, was able to trace the Monkman lineage back seven generations to the 1700s in Yorkshire, England.
Today I’d like you to join me as I continue my father’s work, only this time going back an additional 16 million generations to about 400 million years ago! My goal is to remind readers of the wonder of evolution, the interconnectedness of all living organisms and the fact that there never was a “first person”. It’s like asking: When did you stop being a baby and become a toddler?
A thought experiment
To make this journey, I’ll be using a thought experiment – an experiment in your imagination – described by Richard Dawkins in his 2011 book, “The Magic of Reality”. It involves placing photographs or illustrations – 16 million to be exact – on a long and winding shelf. Imagine the images standing upright like books. Each millimetre of the shelf represents 75 years or three generations, making it just over five kilometres long. That’s the distance from the corner of Water and Charlotte Streets in Peterborough all the way up to the intersection of Water and University Heights Blvd.
The first image is one of me. Beside it, I place a picture of my father, Cy. I continue with pictures of my grandfather, Gordon (Illustration 1); my great-grandfather, Edwin; my great-great-grandfather, Robert; and my great-great-great-grandfather, William. Not having actual photos or drawings of more distant great grandfathers isn’t a problem. Remember, this is a thought experiment. However, thanks to paleontology – the study of fossils – we have a surprisingly accurate idea of what most of my (and your) distant ancestors looked like and when they lived.
Let’s start walking
We’re going to walk along the shelf and sample pictures as we go. We’ll be passing an unbroken line of tightly packed images. Keep in mind that every image will look almost identical to the images before and after it. This is because change through evolution is very gradual.
Starting at the intersection of Water and Charlotte and walking north, our first stop is just 13 cm along the shelf at image 400. It’s from 10,000 years ago when my 400th great-grandfather lived. We wouldn’t notice any real difference compared to a modern person – once he’d had a shave, of course.
Carrying on, let’s stop at 1.3 m (one big step) and pull out a card from 100,000 years ago. Here, we’d see a picture of my 4,000th great-grandfather and notice at least one significant difference. His skull would appear thicker, especially under the eyebrows.
Walking another 15 m or so will take us back 1.25 million years and to a picture of my 50,000th great-grandfather (Illustration 2). At this juncture, we’d be looking at someone dissimilar enough to count as a different species, the one we now call Homo erectus. This gentleman would not have been able to mate successfully (i.e., have viable off-spring) with a modern human, even if a time machine was involved. Based on fossil and genetic evidence, our species, Homo sapiens, has only been around for about 300,000 years. Maybe we should stop for a breather to let all of this sink in!
The journey continues
Resuming our pilgrimage, we’ll stop at six million years ago – just 80 m from the start or about half-way between Charlotte and Simcoe Streets. This is where we’ll find a picture of my 250,000th great-grandfather. He would probably have looked like a modern day chimpanzee – not some caveman in a leopard skin. However, he wouldn’t actually BE a chimpanzee. He’d be the common ancestor that all humans share with modern chimps. He’d also be the 250,000th great-grandfather of a chimp living today. One of his off-spring would have started the evolutionary branch that led to humans, while another would have begun the branch that resulted in modern chimpanzees.
Carrying on, we’ll pause at the corner of Brock Street and pick out the card showing my 1.2 millionth great-grandfather who lived 30 million years ago. Yes, that would be a tail we’re looking at. This is not surprising since even modern humans still have a tail bone – the coccyx. The primates ancestral to humans, chimpanzees, gorillas, lemurs and orangutans lost their tails about 25 million years ago.
When we reach the corner of Water and London Streets, we’ll pull out an image of my 2.5 millionth great-grandfather (Illustration 3). He lived 63 million years ago which is just after the dinosaurs went extinct. He would have resembled a lemur and have been the common ancestor of all modern primates (i.e., lemurs, monkeys, and apes, including humans).
Up to the zoo
It’s time to tighten our shoe laces because our next stop isn’t until we arrive at the Sabre jet at the south entrance to the Riverview Park and Zoo. This is where we make the acquaintance of my 12 millionth great-grandfather from 300 million years ago. He would have been the ancestor of all modern mammals, including our cats and dogs. Pride aside, this “Monkman” would have resembled a shrew (Illustration 4).
At card number 168 million at the north end of the zoo parking lot, we come face to face with my 13 millionth great-grandfather. This inconceivably distant relative lived about 380 million years ago and had the hallmarks of both a fish and a lizard (Illustration 5). So much for family dignity. He would have been the ancestor of all modern vertebrates (i.e., mammals, reptiles and birds).
Another 300 metres takes us to the end of the shelf at the corner of Water and University Heights Blvd. Here, we finally get to meet my 16 millionth great-grandfather. It’s time to brace ourselves once again, because we’d be looking at a picture of the earliest known “bony fish” who lived in the Devonian seas 400 million years ago (Illustration 6). Terrestrial vertebrates did not yet exist.
Back to the Big Bang
We could extend the shelf even further back in time, but a lack of fossils makes it hard to know what these more ancient great-grandfathers (and great-grandmothers) would have looked like. We do know, however, that at the 47 kilometre mark – 3.5 billion years ago and just north of Burleigh Falls – we’d see a picture of the first life-form to exist on the planet. Let’s call him Great Grampa Microbe.
At 4.5 billion years ago and just north of Apsley, we’d see images of our planet forming. Continuing even further north, we’d watch the first stars dying in stellar explosions known as supernovae. It’s in these stars that helium and hydrogen atoms were transformed into carbon, oxygen, phosphorous and iron – the stuff of life. This “star dust” is what we’re made of. Maybe it’s fair to call supernovae great-grandfathers as well.
At 13 billion years ago and north of Bancroft, we’d feast our eyes on images of hydrogen and helium atoms forming and gathering together to make the first stars. Finally, at 13.7 billion years ago as we enter Algonquin Park, the very last image would be one of the Universe flaring forth, expanding and cooling in what we call the Big Bang.
Obviously, this is a hugely simplified version of the full story of the Universe and evolution. Even so, isn’t it more wonderful than human-made myths? Of course it is. And we know for certain it’s absolutely true. In a world full of disinformation and conspiracy theories, what’s actually real matters more than ever.
I would like to thank Rob Moos for the illustrations used in this article.
