Monday, November 2, 2009

Summary of meeting on 10/24 (part 5!!)

I'm really sorry to have dragged this summary out like this. There's just so much to talk about!

Back to our discussion of the origin of life: one of the main predictions (or, more like expectations) of our naturalistic scenario is that the first life was initially simple, and only later evolved to become complex. This was expectation was seemingly borne out in the early days of microbiology: the simplest known life forms at that time, bacteria, when viewed under the microscope seemed to simply be "bags" of jelly, with very little structure or organization. If these life forms are really that simple, there is a possibility that the earth's first life was also that simple, or perhaps even simpler. This would fit well into a naturalistic paradigm.

On the other hand, as we have grown to understand microbiology more, we now realize that the internal and surface structure and organization of prokaryotes such as bacteria are incredibly complex; it's just that this organization couldn't be seen under a simple light microscope. By itself, this doesn't rule out the possibility that the first life was simple. However, further research into the minimum complexity of life has shown that even the simplest life form possible, which could not exist/thrive without constant TLC from intelligent agents (ie, laboratory scientists), requires at minimum roughly 200 genes. That's 200 different sets of instructions to build 200 different complex molecules. If that is indeed life's minimum complexity, then the first life form must have had at least 200 genes. That indeed is an uncomfortable fit into a naturalistic scenario.

Further geobiochemical evidence has supported the notion that earth's first life was complex. As far back as 3.5 billion years ago, an evolutionary instant after the end of the late heavy bombardment (see my previous post), we have evidence of entire ecosystems of microbes in symbiotic relationships.

In addition to that, very early on -- and I must confess, I am not sure about the published date for this -- we have photosynthetic life on earth. Why is that important? The biochemical machinery required to have photosynthesis is quite complex; not something you would expect from the earliest, most simple life forms posited by naturalistic models.

I just realized something. This blog post is supposed to be a summary of the meeting we had two Saturdays ago, but I just rambled on about something we didn't actually talk about. I guess it's bonus material.

And please, if you guys have any comments or questions, criticisms, I welcome them.