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Clive's Avatar Jump to comment 92 by Clive

Professor McIntosh fails to see the big picture. The question of life has been superseded a long time ago with the question of how did complexity arise.

McIntosh's reply is the standard theological argument that something even bigger and more complicated than life started the whole thing off, which is short-sighted in the extreme.

In view of the ability of evolution to cause an increase in complexity, the question is largely answered. Formation of the universe is well understood and its origin no doubt shares similarities with black holes. Where then is the magic wand waving?

The entropy argument cannot be used against evolution because we are subject to the flow of energy from the sun which gives a local reversal of the general trend for everything to wind down according to the second law of thermodynamics.

This energy causes chemical bonds to be created including the making of polymers.

Now, looking at the problem from the other end: Evolution gives an increase in genetic information because better phenotypes (usually with larger genomes) tend to do better in the world.

The genomes get bigger mainly due to random mutation and are selected for by natural selection which gives a "ratcheting" effect towards greater complexity over vast time periods.

Evolution is a positive feedback loop which starts with the most modest of beginnings. Take for example the full - volume scream of a microphone placed too closely to a speaker. The origin of the squeal is minute random noise within the transistors of the amplifier that forms part of the feedback loop.

Evolution too, would have its origins in a small and simple way such as a randomly assembled polymer (with some survival ability) that could split to produce a copy of itself, perhaps with the mechanical aid of the earths' tides or thermal vents etc. This tiniest thread of heredity could grow by the simple laws of evolution to produce more complex structures and eventually life, even though we may not know its initial history.

Thu, 24 Apr 2008 14:14:00 UTC | #159769