Well actually I lied! Life didn't start with a tree...trees come much much later in our story. But before we begin our odyssey I have something to tell you. A little secret. I feel a little embarrassed telling you this. But the devil take it! You see, the reason I studied Biochemistry at university was because I wanted to discover...nothing other than...the origin of life! I know, I know, how childish! Unfortunately somewhere amidst the boring lectures on the Krebs cycle, glycolysis and gene transcription the question got lost and I became embroiled in the serious business of passing exams. It is sad how academic study, instead of becoming an exciting quest for new knowledge; an adventure into the unknown, can turn into a wearisome struggle to pass exams. But I am back with a vengeance! Oh yes! After a break of almost ten years. The good thing is that ten years is a long time in science. Entire world views can crumble and brand spanking new shiny edifices rise up in their place. The scientific landscape I see before me today is different to the one that existed when I was an undergraduate. Things have moved on - and in science that is always good.
Before we begin our journey to the Origin of Life we must first understand what it is we are trying to find the origin of. Or, put more bluntly: What exactly is life? Is it something that moves? something that grows? that eats? that reproduces? that breathes? that shits? Trees don't move yet they are living. Viruses don't breathe and they too are living. Flowers don't shit and they are definitely living. Is there a definition of life that encompasses all? Yes there is:
Life is something that can maintain a state of order via the expenditure of energy.
We are blobs of order in a chaotic universe. What is the difference between a bird and a mountain? (apart from the obvious). A bird is vastly vastly more complex than a mountain. It has intricate parts that work together to make it do 'birdy' things like fly, bob its head, eat, and make copies of itself in the form of baby birds. It looks as if it was designed. Nobody looks at a lump of rock and says: 'Hey, look at that! It must have been designed by someone' - but the same can't be said for birds, worms, insects and humans. Look at the different parts of a human - the muscles, the guts, the bones, the nervous system. Surely a human being couldn't have come about just like that? A human being has purpose written all over it. There is the famous story by William Paley about stumbling upon a watch in the heath. If you spotted a watch upon the heath it would be obvious it was designed by someone for a purpose - wouldn't it?
The complexity of the living world is crying out for an explanation. From bats to penguins - from flowers to bees - from spider webs to birds nests. Where did this complexity come from? Surely it was designed? By someone? For a purpose? Just like a car, a laptop, a TV. But living things are vastly more complex than any man made object. If you think that this bewildering complexity does not deserve an explanation than you've got issues. If you've never marvelled at the natural world and thought: 'Hey, wait a minute! Where did it come from?' - if you've never done that than you need to sort out your priorities and start getting down to some serious thinking. In short: you need to get a life!
But enough philistine bashing for now. I'll get plenty of chances to bash you later. There is another point I want to make: it is important to note beforehand, lest I furnish you with unrealistic notions, that we can never really know with certainty how life began. It was an event that occurred such a long time ago. 3.85 billion years is an unfathomably long time. Imagine the age of the earth can be represented on a 24 hour clock. The earth was formed 4.5 billion years ago at 12 midnight. Life emerged at 4am in the morning and remained single-cell bacteria like until 8pm the following evening. After 8pm in our 24 hour clock it became multi-celluler and grew bodies arms, legs, guts and heads. And humans? Humans appeared in the last second at 11:59 (59secs) (!). The fact that we can say anything about an event that occurred so long ago is astonishing in the least. But we can do more than that. We can make educated inferences, based on what we know about life today and in the past, about the kind of process that the origin of life was and had to be. We know it had to be a chemical process; because there was no biology at the time. Thanks to recent advances in gene technology, thermodynamics and the discovery of hitherto unknown branches of life - we can now say, with a high degree of confidence, how life is likely to have begun.
It's been a long time coming. Man has lived in a state of 'duh-duh I dunno' for far too long. It is about time the veil of ignorance was lifted and our minds opened to the weird and wonderful. So lets venture into the well of the long deep past. It is the year 3.85 billion BC. It has been 700 million years since the earth was formed out of a red hot ball of interstellar material. The oceans have cooled and land risen. The atmosphere is noxious with methane, ammonia and carbon dioxide. Something momentous is about to happen...the story begins deep in the chasms of the earths oceans, in the mid-ocean ridges, many miles down, where thanks to the forces of volcanism and plate tectonics, continents collide and slide beneath one another, creating earthquakes and raising mountains... weird and wonderful and wholly extraordinary conditions are being created. It is safe to say that life probably began on earth in an alien environment...
