Re: The young age of Earth

Kevin O'Brien (
Fri, 19 Mar 1999 16:39:46 -0700

>>I suspect that if you did it would involve some kind of
>>vitalistic nonsense about how "life" is some mystical quality that sets a
>>living cell apart from a test tube containing chemicals, or some such
>Actually, no.

Actually my above comment was a direct response to David Tyler's comments,
not yours. I thought I had made that clear, but I guess I did not; sorry
for the confusion.

>I think I have a very applicable working defintion which can
>easily be applied and even must be applied to get from "simple chemicals"
>to a "living cell" as it is expressed on earth and has been for the last 4
>billion years. It requires a dynamic information system. The genetic code
>and it's necessary machinery.

This not unreasonable, but in fact there is, and has been, a great deal of
controversy over just this kind of question. As you mean it, any living
organism must have some form of information system, but most professional
biochemists -- including myself -- do not accept your definition of
information (as you explained it in another post). Instead, we recognize
that the physiochemical forces are in many ways quite sufficient an
information system to produce not only biomolecules, but primitive metabolic
systems as well. As such, we do not believe that any genetic code is _a
priori_ absolutely necessary for life, as long as there is some way in which
to produce biomolecules and polymeric catalysts. And in fact many
abiogenetic experiments support this realization.

>Now, for abiogenesis to be a fact, in my book, a "genetic code" (it doesn't
>have to be the one in use currently (with some minor variations) in every
>living thing on earth) must be observed to emerge without design from
>whatever biochemical soup is thought up for such an experiment. It must
>also have the ability to express itself.

See above. Your requirement is too stringent from a biochemical point of
view. Let me ask you a question: are red blood cells alive by your
definition? They contain no nucleus, hence no genetic code, yet they have a
fully functional metabolic system that allows them to process food into
energy and use that energy to build new structures.

Let me ask you another question: are viruses alive? They have a genetic
code, but no metabolic system.

Kevin L. O'Brien