Tuesday, June 26, 2012

How did life start? Where did it come from? Prometheus and science...

SHOOT: Personally I feel the idea of the origins of life have never been more topical than now. Firstly, we're seeing some of our world's most resilient and wealthy powers (the USA. Europe and Japan) appear scarily...mortal. Secondly, as the Space Shuttle has been retired, other scientists and geniuses including SA born Elon Musk (co-founder of PayPal) have proved that putting a rocket into space is just another game for geeks, and apparently rocket science isn't what it was.Thirdly , the movie Prometheus probes very bravely the idea that God may not exist, and that what is out there might be grim - things like worms, and monsters (some apparently inside of us, or in our image, and of our own making). Fourthly, at the same time exophiles have been discovered deep inside South Africa's gold mines - tiny worms living off bacteria. Finally there are a few probes and spaceships either on their way to prospect for life (Curiosity reaches Mars in August, about a month from now) including missions to the moons of Jupiter. In addition, the SKA is probably going to improve our ability to look into space; we'll see better, further and in more detail in the universe, and the processing power that goes with that could be some kind of game changer in terms of our ability to know whether there is life out there (or whether, even if there is, we'll ever have some kind of encounter).

For my part, I believe bacteria are the basic seeds of space. I'm pretty sure that bacteria ought to live in subterranean situations wherever conditions aren't too volatile. Bacteria might actually be very abundant. The point being, we shouldn't be looking for little green men, but into a petri dish, which might say: TAKE US TO YOUR LEADER.

For the rest of this blog post I defer to the experts in this field. If this New Scientist article stimulates you, be sure to read the whole thing by following the link at the end.

Life: is it inevitable or just a fluke?

It is generally assumed that once simple life has emerged, it gradually evolves into more complex forms, given the right conditions. But that's not what happened on Earth. After simple cells first appeared, there was an extraordinarily long delay - nearly half the lifetime of the planet - before complex ones evolved. What's more, simple cells gave rise to complex ones just once in four billion years of evolution: a shockingly rare anomaly, suggestive of a freak accident.

If simple cells had slowly evolved into more complex ones over billions of years, all kinds of intermediate cells would have existed and some still should. But there are none. Instead, there is a great gulf. On the one hand, there are the bacteria, tiny in both their cell volume and genome size: they are streamlined by selection, pared down to a minimum: fighter jets among cells. On the other, there are the vast and unwieldy eukaryotic cells, more like aircraft carriers than fighter jets. A typical single-celled eukaryote is about 15,000 times larger than a bacterium, with a genome to match.
The great divide

All the complex life on Earth - animals, plants, fungi and so on - are eukaryotes, and they all evolved from the same ancestor. So without the one-off event that produced the ancestor of eukaryotic cells, there would have been no plants and fish, no dinosaurs and apes. Simple cells just don't have the right cellular architecture to evolve into more complex forms.

Why not? Read the rest.

No comments: