Metabolism or Replication First?

Discussion of everything related to the Theory of Evolution.

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AstusAleator
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Post by AstusAleator » Sun Nov 04, 2007 9:47 pm

That's a very interesting read. It's good to have a source to run back to when I forget some details (which I do all the time).

Also, as far as I've read, it supports my position that replication came before metabolism :).
What did the parasitic Candiru fish say when it finally found a host? - - "Urethra!!"

nornerator
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Post by nornerator » Tue Dec 04, 2007 4:01 pm

I would think that self-replication would come first, before "metabolism" if we are talking about metabolism in the sense of energy production and storage and not the more general sense of all the chemical reactions happening.

I imagine that self-replicating molecules had been around for some time. Replicating slowly. Although considering these are very basic chemicals we are talking about, I would assume that their selectivity for replication would have been quite low, and so the "daughter" molecules may have not always been exact replications of the first. Eventually one of these molecules was created in that way, and this molecule perhaps allowed some energy to be stored within it (perhaps a phosphoanhydride bond) so that the replication process was not completely dependent on external energy but had energy stored up from the environment in this form. Obviously the molecules that could reproduce easier, reproduced in the largest of numbers. More changes happened via poor selectivity in these molecules that eventually allowed for a more complex system of metabolism. Then over billions of years simple metabolism systems grew off of one another, until we reach today when many organisms like EColi, can produce any molecule they need from very simple starting materials, like CO2, H2O and Nitrogen.


If the ability to produce and store energy comes first, not replication, how can the information about the system of energy storage be "passed" on to molecules that do self replicate?

Perhaps the only other alternative I can see being possible is if both processes started out as separate systems.

Perhaps a system of molecules interacting with a hot ocean vent would pick up heat energy, convert it to chemical energy, and self replicating molecules arose due to the abundant chemical energy. Because there is no membrane to hold this system together, any sort of shock to the system would wash this system away.

Once the self-replicating molecules were dispersed away from the primitive metabolism system the ones that were best able at storing and harnessing energy were best able to replicate and therefore the most successful continued perpetuating their information.

Of course all of this is complete conjecture, unless we find out the the universe in infinitely entangled with itself, we will never be able to know exactly how it happened. We can only discuss possible ways that it could have happened, in which in reality, there are in infinite number of ways "life" could form. Life is simply a measure of complexity within a system.

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woolleyy
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Post by woolleyy » Tue Dec 04, 2007 4:35 pm

nornerator wrote:If the ability to produce and store energy comes first, not replication, how can the information about the system of energy storage be "passed" on to molecules that do self replicate?

I'd call this myth busted.

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