Isn't this just awesome? It's ideal and obvious that the most ancient life had to be the subterranean "extreme-ophiles" and anaerobic, heat-loving simple single-cell type, as nothing else would survive this:

“Chiron, a recently-discovered planetesimal, is on an unstable orbit near Saturn and measures 180 km across. The consequences of it hitting the Earth are too horrible to contemplate. And Chiron is by no means the largest known minor planet. Four billion years ago such objects would have been far more common than they are today. [...]

An impactor 500km in diameter would excavate a hole 1500 km across and at least 50 km deep. A huge volume of rock would be vaporized in a gigantic fireball that would spread rapidly around the planet, displacing the atmosphere and creating a global furnace. The surface temperature would soar to more than 3000 ºC, causing all the world's oceans to boil dry, and melting rock to a depth of almost a kilometre. As the crushingly dense atmosphere of rock vapour and superheated steam slowly cooled over a period of a few months, it would start to rain molten rock droplets. A full millennium would elapse before normal rain could begin, presaging a 2000-year downpour that would eventually replenish the oceans and return the planet to some sort of normality.”
"The Origin of Life" by Paul Davies, p140-141.

I read The Origin of Life while on holiday (I'm back now! Hi! Photos to follow!) and have got quite a few quotes from it. It is not groundbreaking stuff anymore, but it also gave me a good understanding of the hardy little critters that we call extreme, but they'd call cosy. It is us, desperately relying on the sun for heat and production, living on the cold, weather-prone surface of the planet that are the extreme ones, trekking out to the surface where we have to build our own metabolisms because everything is so cold!

Tags: abiogenesis, asteroid, bacteria, biogenesis, collision, death, evolution, extinction, extremophiles, life, meteorite, oceans, paul davies, rock
Current Location: Monchengladbach, Germany
Listening To: "Sex dwarf" by Soft Cell

For some reason, it has struck me as brilliant and wonderful, the history of how single-cell organisms evolved to detect chemicals in their environment (simply using lipid-membrane spanning molecules)... and that the same mechanisms are now the same methods that multicellular organisms use to co-ordinate activities between cells.

It really struck home to me that we are (in Dawkins' words) "colonies" of cells acting together...

I can imagine each cell "thinking" it is alone in the environment, simply not knowing that actually it is busily communicating with millions of other cells' products, rather than with the environment external to the body.

“The mechanism of chemical sensation that originally evolved to detect environmental substances now form the basis for chemical communication between cells and organs, using hormones and neurotransmitters.”
"Neuroscience" by Bear, Connors and Paradiso, p189</p>

Anyone else find this oddly inspiring and awesome? So simple... there wasn't two different paths of evolution for cellular senses, but one... which became used in two very different circumstances!

I guess that is why some diseases which are basically single-cell sometimes react en masse or change their behaviour en masse. (We have found that sometimes a critical mass of a certain excreted chemical causes a group change in single-cell disease behaviour).

I've added some of this to "The Evolution of Life from the Primordial Soup to the Cell" by Vexen Crabtree (1999) - the page really does need to be made scientific, rather than rambling!

Tags: bacteria, biology, cells, evolution, hormones, multicellular life, neuroscience, neurotransmitters, psychology, richard dawkins, single-cell life, staphylococcus
Current Location: Monchengladbach, Germany
Listening To: "Try to Forget '98" by De/Vision