Smoke particles coalesced into dust. Dust gathered to form gravel. Gravel clumped and formed stone. Stones joined together to form rocks. Rocks became planets.

Carbon dioxide gushed out of the core, blanketed Earth and kept it from freezing over. Fated asteroids crashed onto the surface with their water and formed oceans. Deep within, around the white heat of hydrothermal vents, carbon was forged together with hydrogen to form life. Life was kindled in the dark.

The beginnings were probably tentative. There might have been many false starts before one little cell replicated itself. Around 3.5 billion years ago, these little cells evolved into the Last Universal Common Ancestor, the ancestor of bacteria and archaea.

Bacteria and archaea, the prokaryotes, stayed relatively simple, single-celled creatures. Without nervous systems, they relied on their DNA for their behaviours. Since simple rules can lead to very complicated behaviours, they don’t need many genes to be able to hunt, hide and coordinate. For instance, before launching an attack, bacteria make sure they have the numbers, in a process called “quorum sensing”. They also hunt in ways that resemble wolves hunting caribou. When attacked, archaea clump together around viruses, trapping them, sacrificing themselves while protecting their communities. All of these behaviours come about through instructions encoded in their genes and without thought. When new behaviour is needed, they await random mutation, perform “horizontal gene transfer”, or absorb DNA from their environments. And, this is how life existed for about 2 billion years.

Then, an archaea engulfed a bacteria. This time, instead of digesting it, the archaea entered into a symbiotic relationship with it. Generations later, this bacteria evolved into mitochondria, the powerhouse of the composite cell. For its part, the host cell developed specialized compartments, the most prominent of which was the nucleus. Almost all of the DNA in the cell migrated to the nucleus. With the mitochondria taking care of power generation in the eukaryotes, they had the energy to improve their internal frames and evolve cell walls that could communicate. Most significantly, they had learned to bond together with other cells to form tissues. Soon after, different cells developed different abilities. Some became light sensitive, some others became sensitive to sound. Over time, these became full-blown organs. Nervous systems that were co-evolving were now tasked with making sense of all this information that was coming through. They started to become more sophisticated, eventually resulting in central nervous systems. With this came the ability to respond deliberately to changes in the environment. After that, at least in humans, came the ability to abstract. Tools, art, language and computation were the fruits of that.

In the 1970s, James Lovelock along with Lynn Margulis, introduced the Gaia Theory, a provocative idea which proposed that Earth and its organisms live synergistically. Ascribing no consciousness to nature, it proposed that living organisms maintained livable conditions on Earth. much in the way that predators and prey stay in balance in a given ecosystem. If methane is present in excess anywhere, archaea and bacteria work together to process them into more innocuous compounds. Another example is how corals and other shell-forming organisms leech out the salt that is constantly dumped into them by rivers. Plankton emit dimethyl sulfide, which form clouds which reflect away the sunlight that is warming the Earth. (Of course, all this works on planetary timescales. Climate change cannot be expected to be reversed in time for humanity to be saved.) In other words, organisms coordinate across species to keep Earth livable.

All this is to say that life is driven to hold onto life. Creatures themselves may die but the knowledge of how to live seems to be passed on from generation to generation. That is prized above all else. From the first creatures that came into being around hydrothermal vents, the one that got selected for was the one that could multiply. This ability to pass on the torch is what is selected for amongst the staggering numbers of descendants since. To what end? I’m not sure anyone can tell you that. And, what does it matter? A spark has caught within an infinite expanse of darkness. Desperately, unwittingly, miraculously, we are alive. Living well might be the only right thing to do.