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The Evolution Jog
What happens if the timeline of evolution takes place over a 5k run?
Richard Dawkins said in The Selfish Gene that "the theory of evolution is about as much open to doubt as the theory that the earth goes round the sun.” While this is true, the mechanics of evolution are much less intuitive than the mechanics of the earth orbiting the sun.
Even for those who fully accept the implications of the theory of evolution, it’s easy to look around at all the life on our planet and feel a general sense of disbelief that literally everything alive shares a common ancestor.
The unfortunate key to this disconnect is that human brains are quite bad at comprehending huge numbers, and the workings of evolution fits comfortably in the huge number category. We need analogies to help us understand concepts that are outside our normal experience. For example, I know our galaxy is unfathomably large, but it helped to learn that the size of the solar system compared to the entire Milky Way galaxy is similar to the size of my palm compared to the entire continental U.S.
For the timescales that evolution works on, it’s difficult to understand just how long 4.1 billion years is, which is the approximate amount of time that life has been evolving. This is obviously a LONG TIME, but how exactly did our planet become so incredibly diverse? How does an angler fish a mile deep in the ocean possibly have any family relationship with a sloth? How has there possibly been enough time to connect everything that has ever lived backwards to a single common ancestor? It’s hard to wrap your head around.
So in an effort to really feel the timescale of evolution, what if the entirety of evolution happened over a 5k (3.1 mile) jog?
The assumptions of the evolution jog
To make create this running analogy, I had to make a few assumptions about how fast you would be running and how many steps you would take over the total distance. Here are the choices I made for our a little jog:
That the starting point of life was 4.1 billion years ago. The actual moment might be plus or minus a few hundred million years, but you have to start somewhere.
I used the timeline of evolution from this well-sourced compilation.
This study from the Health & Fitness Journal tells us that a much larger variable for steps per mile is speed, rather than gender or height. We’ll assume you’ll be running at around 6 mph, which provides a reasonable average of around 1,700 steps per mile for any runner.
This means that a 5k run would take 31 minutes and 5,270 steps total.
4.1 billion years divided by 5,270 steps equals 777,989 years per step!
This means every two steps you take would be about 1.5 million years. It could be a mantra of sorts for every time you land on your right foot. "One and a half million, one and a half million, one and a half million..."
Starting the run
It’s 4.1 billion years ago and the first bits of the primordial soup start replicating themselves as if by magic. If this miraculous event was one-in-a-million luck or inevitable is something we won’t know until we get the chance to study other life out in the universe. But that’s a subject for a different day.
You start your timer and take your first step out onto the course. The first minute is very uneventful other than billions of awkward early bits of life replicating themselves endlessly in the early oceans.
A minute and a half in (200 million years)
As you cruise along, another miracle happens. Prokaryotes (single cells with no nucleus) arrive on the scene. Not much happens again for a while except bountiful bacteria bumbling around for hundreds of millions of years.
Four and a half minutes in (600 million years)
Three minutes and a full 500 steps after the first prokaryotes evolved, another type of prokaryote shows up called archaea. These are similar to bacteria but have different internal processes that allow them to thrive in extreme conditions like hydrothermal vents deep in the ocean or highly acidic environments. An early form of photosynthesis also evolves around this time.
Congratulations, this soup of asexually reproducing goo is all there is to think about for the rest of the first half of your run. Asexual reproduction trillions and trillions of times across almost two billion years.
17 minutes in (2.25 billion years)
Something interesting suddenly happens. Eukaryotes (single cell with nucleus) and bacterial viruses show up. The three domains of life (bacteria, archaea, eukaryota) are now intact and continue down their different branches of evolution. They all appear to be similar single-celled organisms, but they quickly become distant genetic relatives.
Keep it up, you are already over half way there and 2,900 steps into your run.
21 minutes in (2.8 billion years)
Four minutes and almost 700 steps after eukaryotes, fungi say hi. This little innovation that eukaryotes stumbled upon took over three times longer than the entirety of the span of dinosaurs roaming the Earth (but we'll get to them).
22 minutes in (2.9 billion years)
And finally, sexual reproduction appears in eukaryotes. You've already taken about 3,700 steps total, each one representing 778,000 years. Nothing but single-celled organisms still.
Now relax for the next three and half minutes because it's your last chance.
25 minutes in (3.35 billion years)
Protozoa and the beginning of animal evolution begins. Protozoa can move themselves and absorb (eat) other hapless organisms. By this time, everything about how life works is pretty much set. All the processes our modern cells use to reproduce, utilize energy, and generally keep us alive have been finely tuned over hundreds of millions of years, perfectly ready for the challenge of more complex life.
26.5 minutes in (3.52 billion years)
Just over a minute after protozoa, the Cambrian explosion explodes. It lives up to its reputation. Complex life finally starts rapidly evolving into many directions at once and the major groups of animals begin filling out the available niches across the planet. On a classic exponential growth curve, this is when things start going straight up. It took over 85% of your run, but the tree of life is finally starting to chaotically burst in thousands of new directions.
This Cambrian explosion only lasts 30 seconds but forever changes all life. Just ten seconds later vertebrates show up and within another minute Earth would be largely recognizable to us, with vegetation, insects, and even sharks. The planet goes from soupy life to sharks in less than two minutes.
If life were playing an RPG video game, it would be the type that would slowly build up its character to level 100 before setting out and dominating everything.
29 minutes in (3.80 billion years)
Now as we hit our 4,900th step, we are almost 29 minutes into our 31 minute run and humans, let alone primates, are nowhere to be seen. There aren't even conifer trees or flowering plants yet! Octopuses have arrived though, and they quickly take the crown of smartest creatures around (I don’t have proof, but c’mon).
About 30 seconds later, beetles explode onto the scene and have been handily taking over the earth ever since.
Then only 20 steps later, DISASTER! Massive volcanic eruptions cover the atmosphere in fine particles and dramatically warm the climate. You trip and fall onto the Permian-Triassic extinction, where 90%-95% of all marine species die off.
This allows for the earliest dinosaurs to evolve and thrive within 20 seconds.
During the reign of the dinosaurs, pine trees, flowering plants, and bees also evolve. Towards the end of this timeframe, the wild world of ants begins.
30.5 minutes in (4.034 billion years)
Just two steps after T-Rex and Triceratops evolve and feel pretty good about their place in the world, all the large dinosaurs meet an untimely end with the asteroid impact in the Yucatán Peninsula in Mexico. This entire span of dinosaurs can be covered in a total of 200 steps, or about 80 seconds of running.
This is when you can see the finish line and get a second wind. You are energized by the fact that even though you just said goodbye to the T-Rex, you are now closer to the finish than T-Rex was to the Stegosaurus.
Just eight steps later after the asteroid impact, mammals continue to thrive and early primates show up. Just a few more steps and birds have become diversified in a way that largely matches modern times.
Exciting things continue to happen at each step. Species are coming and going at every inch along the way. As you come in for the final seconds, let’s switch to the amount of steps you have left.
42 steps left (25 million years to go)
26 steps left (20 million years to go)
Hello giraffes and hyenas. Still nothing even close to modern humans.
Eight steps left (6.5 million years to go)
It’s around this time that one nondescript ape mother had two kids. One would develop down a path to the modern chimpanzee. The other would develop directly into us. This means that if all modern chimpanzee mothers and all modern human mothers held the hands of their own mothers backwards through time, an unbroken chain would form along each line and would meet together about 6 million years ago.
Six steps left (4.8 million years to go)
Five steps left (4 million years to go)
Hello Australopithecus and the Blue Whale.
Three steps left (2 million years go to)
The homo genus like homo habilis arrive and we are well on our way to modern humans.
The very last step as you hit the 5k mark and cross the finish line (778 thousand years to now)
Modern homo sapiens appear in Africa, move to other continents, transition from hunter-gatherers to farmers, and generally start wearing on the patience of the rest of the planet.
This questionable move to agriculture was only about 12,000 years ago, or only a 60th of one step. This is less than the distance of your pinky toe across the finish line. In fact, your toenail would easily contain all of recorded history.
The post-run cool down
As you wind down and stretch, you might think about things like how remarkable it is that the Cambrian explosion was only 580 million years ago, which was a clear demarcation line between simple and complex life. This didn’t happen until basically the final stretch of our run with five minutes left.
The first couple billion years of life (the green above), and therefore the majority of the run, was basically the tree of life growing an incredibly robust trunk so that when the time was right, millions of branches could rapidly grow chaotically and competitively in every direction imaginable.
The story of evolution is one of both unimaginable timescales and bursts of unbelievable rapid change.