Imagine sitting on a comfortable sofa, closing your eyes, and going back in time a billion years. If you opened your eyes, you might be gasping for air, lucky to live for five minutes, and then die a painful death, either suffocating or drowning in a toxic ocean.
That’s because a billion years ago, Earth was a highly toxic place. The entire planet is practically uninhabitable due to the abundance of microorganisms and an atmosphere of harmful and toxic gases irradiated by ultraviolet light. Instead of pristine waters and unspoiled beaches, the ocean is a pitch-black pool of mud with a barren, dry, hostile coastline.
Before the Neoproterozoic period, roughly 1 billion to 500 million years ago, life on Earth was mostly entirely under the oceans. There was no plant or animal world as we know it today. Back then, the bottom of Earth’s deepest ocean was teeming with a diverse array of exotic eukaryotic protozoa.
As the planet cooled and the now more mature sun began to warm the planet, more complex organisms evolved, including choanoflagellates. This organism would be the forerunner of all modern multicellular life, including humans. Five of these groups became the ancestors of protozoa, slime molds, animals, plants and algae, and of course 21st century fungi.
A billion years ago, Earth’s landmass also looked very different. Instead of the well-known seven continents we have today, there was only one giant supercontinent called Rodinia. Note, however, that it is by no means the first supercontinent on Earth. Rodinia is just one of them, squeezed and torn apart by the colossal forces of plate tectonic movements. It further reshaped the Earth’s surface, forming a second supercontinent called Pangea, which lasted about 300 million years.
Despite its size, Rodinia is barren and barren, despite the mineral richness of the land. The sun emits harmful ultraviolet rays, and the oxygen content is only 2% (compared to our current 21%), still not enough to form an effective ozone layer. And two big ice ages (an extreme form of climate change).
A billion years ago, our planet underwent a slow, steady and silent revolution. Evolution is on the horizon, with simple microbial organisms slowly evolving into more diverse and complex life forms. Land masses were pushed together and pulled apart, slowly forming the terrain we are familiar with today. The weather is unpredictable, climate change is devastating, and the atmosphere has changed dramatically.
But it will also be the last time in the history of our planet that it will look very different from what we know today.
