Autocells, The Origin of Life and Gaia Theory
The famous Martian meteorite ALH 84001 contains a “fossil” that was ruled out as life because of its small size, however it could still be an autocell – a precursor to life. Credit: NASA
The World Fantasy Convention 2013 took place at the Brighton Metropole earlier this month. My father was one of the guests of honour. His thing is science fiction, and on one of his panels he mentioned a discovery of a new scientific phenomenon to a dumbfounded fantasy audience. You see that’s the difference between fantasy and science fiction – the former is escapism, the latter merely disorientation but often based on fact.
Dad spoke about a potentially revelatory breakthrough that starts to answer the questions of how and why life first started to form on earth. Let’s get to the science in a minute, but the reason that this is now a hot topic is due to the discovery of what has now been called an autocell on a fragment of a meteor from Mars with what looks like a fossilised life form on it’s surface (picture above).
It’s such a hot topic scientists have been fighting over it for years:
The fight continues over a meteorite that some say contains evidence of past life on Mars. Both sides claim to wield Occam’s razor, believing that biology – or anything but – provides the simplest explanation of the Mars rock´s many strange features.
The meteor actually fell in 1984. You can read more about it here: http://www.astrobio.net/exclusive/3653/
The science bit starts with a simple statement – that complex (molecular, cellular) life as we know it couldn’t have just started out of nothing. How were molecules created in the first place? From space.com:
A tricky challenge that must be overcome before life can form is that order must be generated. However, this is not as simple as it sounds because the laws of physics state that things will naturally descend into a state of disorder.
Heat can create order. Terrence Deacon, of the University of California Berkeley, outlined in a recent talk how this step could have taken place. [7 Theories on the Origin of Life]:
…if you don’t keep pumping heat into the system, it’ll shut itself down. In fact, self-organizing systems destroy the conditions that enable them as fast as possible.
Deacon also speaks on other important factors of order, such as ‘reciprocal catalysis’ which helps pass on energy from one molecule to another, and ‘spontaneous self assembly’ which some cells can do to build a protective environment for this catalysis. This is what an autocell is – one that can ‘reproduce’ but is not alive in the traditional sense because they still lacks processes that are essential for life.
Still with me?! Anyway the really exciting part of all this, and the reason that Gaia Theory is related, is because there is no way that Earth as it was back then (a soup) would be able to start this autogenic process. However with the the high levels of methane and ammonia on Jupiter for example, hydrogen cyanide polymers would be produced called polyamidines. From astrobio.net:
If these polyamidines hitched a ride to the Earth in earlier epochs when the Earth was being bombarded by outer solar system material, they would come into contact with water. However, these particular polymers will resist being broken down for some time. Instead, they replace their side chains with the carbohydrates characteristic of proteins.
Could the fossil on the Martian meteorite could be a tiny autocell? If so this also effects Gaia theory (something also close to my fathers heart and writing such as his Helliconia trilogy).
Gaia theory “proposes that organisms interact with their inorganic surroundings on Earth to form a self-regulating, complex system that contributes to maintaining the conditions for life on the planet” (Wikipedia). The autocell theory extends Gaia into our solar system. To my mind it also makes the likelihood of life in other solar systems far more probable and likely.
I love science. I love science fiction.
A microtubule in a cell is an example where something in life is created spontaneously with self assembly. Credit: Eva Nogales