The universe didn’t really know how things worked back then, and tiny quantum fluctuations meant that some parts of this vast uniformity were slightly less uniform than others. Bits of the universe were more dense than others, and in one tiny, infinitesimal quantum fluctuation grew something called the Virgo supercluster.
Somewhere in here was a random clump and cluster of density, a bit like a birds nest in an overgrown bush on the edge of a wood that you drive by at 70kph. Within that cluster, the result of the minutest, random quantum fluctuations imaginable, is the Milky Way. That’s where you and I hang out, but without those minute fluctuations we simply wouldn’t exist.
Gravity, matter and anti-matter danced for around 9 billion years, forming our early solar system. 100 million years into the life of what we now call the Sun, the solar system wasn’t the homely place you and I are familiar with today. Chunks of rock whizzed all over the place on irregular orbits, and one day (scientists think it was about 4.5 billion years ago, a Tuesday) a lump of rock the size of Mars collided with the Earth, causing quite the stir. Some of the rock embedded itself here on Earth, while other fragments from the collision were blasted out into space.
Some of this material would eventually form the moon, an occurrence that’s generally regarded as a “good thing” as without the moon there would be no gravitational influence to steady the tilt of Earth’s axis, resulting in massive variations in solar heating and catastrophic changes in climate that would make conditions for life on our planet about as likely as Paris Hilton becoming a Nobel laureate.
But that wasn’t the end of the Earth getting walloped by rocks, with the “late heavy bombardment” around 3.9 billion years ago seeing a re-alignment of orbits in our solar system that resulted in a whole heap of trouble for us. Comets, asteroids and other space debris effectively kicked the shit out of the planet, some of them bringing ice from the outer reaches of the solar system which, due to our fortunate position close enough to the sun for water not to freeze but not so close that it boils, gave us water.
Then came life. Nothing as awesome as you and I at first, but single-celled bacteria filled the seas and pretty much had the run of the planet for a billion years or so. Nothing more than dumb chemicals that happened to give out a little oxygen into our sweet, breathe-it-all-in atmosphere, these little critters were perfectly okay as single-celled organisms go. But then an accident happened that changed things considerably.
A bacterium and an archaeon walk into a bar…
One day, one of these cells (a bacterium) was just hanging around wondering how to spend the day (coffee shops hadn’t been invented yet), when it was engulfed by another cell called an archaeon. These guys were a little surprised by the turn of events, but fortunately they got on like a house on fire and formed a clingy kind of relationship that could be termed symbiotic. That single event kicked off a chain of evolution that led to things like cell mitochondria (the batteries that create energy in your cells today) and sex (for which I for one am grateful).
Without these two little guys bumping into each other that day, no complex life would exist on Earth at all.
Not that it was a a straight line from there to here, not by any means. The planet was pretty damn tumultuous around 1.5 billion years ago, with molten eruptions and granite grinding against metal as areas of the crust cooled and shifted, creating a wonderful, wide array of elements for evolution to start playing with.
Then there was the accident that wiped out the dinosaurs some 65 million years ago, when (and this is our best guess, there’s no footage unfortunately) a 10 kilometre wide asteroid hit the Yucatan peninsula in what we now call Mexico. Not only did this create the conditions in which the dinosaurs and other reptiles perished, but created conditions where certain small, sex-loving mammals could adapt and survive, free from their mammal-munching predators. Thanks Mr Asteroid. We owe you our very existence.
Give us a freakin’ break…
You’d think at that point that we’d be given a break and left to our own devices, but from around 20 million years ago to 6 million years ago the Earth spewed enough magma to create two massive mountain ranges in Africa. Running from north to south and standing 2 kilometres high, these new mountain ranges blocked moisture-laden weather patterns, created deep water lakes that disappeared after a couple of hundred years and forced the local primates to adapt.
Being forced to migrate from area to area and to move food from one place to another, those environmental shifts created an evolutionary moment that (you could say) was the precursor to America’s Next Top Model. We learned to stand upright and walk on two feet.
As if that wasn’t enough cosmic coincidence for you, a gene mutation around 2.4 million years ago saw our jaws become weaker than our chimpanzee cousins. Perhaps because we no longer used a bite as a form of attack and spurred on by the ongoing need to either “think your way out, or eat your way out”, as Mark Maslin of University College London puts it, a smaller, weaker jaw meant that we no longer needed the thicker, supporting bone at the back of the skull. The removal of that constraint meant that evolution was able to give us a bigger skull and bigger brain.
But even that wouldn’t have been possible without our old pal Captain Protein. Proteins are made of long chains of amino acids that have evolved over millions of years to organise themselves within thousandths of a second into working, biological nanomachines. These proteins can fold themselves into a mind-boggling number of formations, and all it took was a single mutation in gene MYH16 to have these proteins form a little differently. And hey presto, smaller jaws.
Me got smarts…
With the constraints lifted, our brains grew and we became pretty darn smart. Changes in the brain caused a snowball effect, where mutations caused further changes that not only made sense in themselves, but opened the door for further mutations that enhanced the brain even further. Not only that, but we adapted ways to fuel our larger brains (they need around 20% of our energy at rest compared with 8% for other primates) by mutating ways to pump more blood and glucose into our noggins.
As we spread into the Middle East and Asia, we found all kinds of bountiful new environments and continued to flourish as a species. It was around this time (70,000 years ago) that a couple of mutations meant that protein FOXP2 was folded a little differently, changing just two of the amino acids needed to build it. Until then, we’d used sound to signal aggression, to call others to gather together and other basic calls to action. But this chance mutation allowed more complex vocalisations with more complex rules; the birth of language.
Now, some may argue that this isn’t such a good thing (watch Fox News, for example), but it’s hard to argue with the 16 mutations that lead to the evolution of our opposable thumbs, or the mutations that placed our eyes centrally and allowed us to focus at short distances, allowing us to create and build.
And this is where we arrive, more or less, at the present day.
By all rights, you shouldn’t be here…
From tiny quantum fluctuations, to cosmic collisions on an unfathomable scale, to the nuanced interplay of gravity and mass, to the grinding and spewing of elements and to the accidents of evolution, if even one piece of this chain had gone even slightly differently, humanity wouldn’t exist. You wouldn’t exist.
This whole chain of evolutionary accident and celestial coincidence, played out over billions of years, has given birth to you.
Go enjoy it.