Monday, June 16, 2008

The Origin of Life -- Abiogenesis

It's been 55 years since the Miller-Urey Experiment, and science has made enormous progress on solving the origin of life. This video summarizes one of the best leading models.


SuiginChou said...

Very good video. I didn't think I'd sit for more than 1 minute of it, but 9:59 later I'm proven wrong. :)

This model makes for great "food for thought," but it makes for a weak theory in the classical sense -- it's hard as fuck to test a lot of the claims made here for the very reason the Youtuber provided in the opening minutes -- if this model is true, it would take millions if not hundreds of millions of years to test it out. The challenge (for these professors) now is to try to find a way to test the model the way Einstein tested relativity. People said to prove relativity Einstein would need expensive equipment or perhaps even to venture out into space, and he proved them wrong. (Though we used both to solidly prove him right once we entered space and started building particle accelerators! :)) I hope, in a sense, that I am one of those critics right now who can hopefully be shut up by a brilliant experimentalist down the road.

One thing I liked about the video: it made me (yet again!) marvel at how the macroscopic and microscopic mirror each other. People have long talked about how "conscienceness" is a phenomenologic construct (some might prefer to call it "an illusion") born out of natural processes which were simply selected for evolutionarily for the fitness they conveyed upon their bearers; it seems now we might also talk of how "the genetic code" is another illusion of sorts, and how the first "life-forms" not only lacked a sense of genetics (no consciousness) but lacked genetics, strictly speaking, entirely! (and were merely replicating empty-cassette shoelaces for no reason at all and merely continued to do so because they could)

If this model is correct, it further drives home the message which I think many atheist biologists *cough* have had to grapple with: the message that life is, in many ways, intrinsically purposeless. Insofar as we *again, cough* may choose to believe in purpose, we have to accept that any purpose either (a) exists extrinsic to the system or (b) is an illusion.

But no more an illusion than choice. ;)

One thing I disliked about the video: it gave non-biologists the impression that the first life-forms used a monolayer of lipid for their cell membranes. This is, in point of fact, thermodynamically untrue and provable right here right now. Open any textbook on biochemistry or cell biology and it will tell you what I have heard in college countless times: "micelles are the spherules formed from a monolayer, but they can only exist when their acyl tails are close to one another in the core. As you add additional fatty acids to the layer, the perimeter outgrows the diameter, i.e. the acyl tails are less and less able to play Footsie in the center of the micelle, and eventually the spherule splits; it is in that moment of "splitting" that the double-layer is made possible and, thermodynamically favored, is made realized; fatty acids pour into what was once the micelle and strengthen the integrity of the perimeter by forming a double-layered membrane. From there, the globule can grow macroscopically large -- visible to the naked eye -- before the volume it encompasses proves to be too much for the non-covalently associated fatty acids." (my words)