THE END OF EVOLUTION?

Let me try another approach.Imagine a strip of wood with positions for three blocks to attach themselves. We are interested in spelling the word CAT using blocks containing all the letters of the alphabet. There are selective glues at the three sites that stick to the desired letters but to none else. We shake everything together and look, and one of the letters attached in the right location. We shake again and again and very quickly the word is spelled. By a random process information has been created! Entropy has been seemingly violated.Now imagine many such strips with the glue in place all shaken simultaneously. After just one round one has the word spelled right off the bat, so we discard the rest.."But selection only removes information, it can't create it!" You shout.The process of mutation involves more than randomness. It also involves chemistry. Chemical reactions are not random but are limited. They are also very specific as a simple look into biochemistry will show.The four letters of the alphabet for DNA, A,C,G, and T only have to spell 3 letter words to select among the less than 2 dozen proteins of life.

Hi DA,
The source for this strawman is the videos on the first post of this site. If you have the patience to get through it all, it will cost you a 50min investment.Bot Verification

Why? Life is already begun with left handed molecules. So only mutations that work with the existing machinery will be favored. Bad mutations will not compete and die off. Neutrals are, well neutral.But for the Abiogenesis part of the picture some of the amino acids that fall to earth from space are more left than right. Thus, the fact that we are made of L amino acids may be because of amino acids from space.Why do amino acids in space favor L? No one really knows, but it is known that radiation can also exist in left and right handed forms. So, there is a theory called the Bonner hypothesis, that proposes that left handed radiation in space (from a rotating neutron star for example) could lead to left handed amino acids in space, which would explain the left handed amino acids in meteorites.And when a majority of lefthanded amino acids exist in solution and the solution evaporates the lefthanded will segregate out first, so there is a mechanism to get all left-handed material. I did not keep that reference but note the following.

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Donna Blackmond at Imperial College London and colleagues dissolved a mixture of solid L and D versions of the amino acid serine in water. They found that a small difference in the initial proportion of one version gets amplified in the resulting solution. So a 100:1 mixture of L- and D-serine produces a solution made up almost entirely of L-serine, but so does a 100:99 mixture (Nature, vol 441, p 621).

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The parity-violating energy difference between enantiomers is not the only way in which the weak force could select biomolecular chirality. Radioactive beta decay is mediated by the weak force, and this causes a polarization of the electrons emitted in beta decay, which could produce selective destruction of one enantiomer. We are currently starting to develop the theory of this enantioselective beta-radiolysis.

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NASA scientists analyzing the dust of meteorites say they have discovered new clues to a long-standing mystery about how life works on its most basic, molecular level.

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Over the last four years, the team carefully analyzed samples of meteorites with an abundance of carbon, called carbonaceous chondrites. The researchers looked for the amino acid isovaline and discovered that three types of carbonaceous meteorites had more of the left-handed version than the right-handed variety — as much as a record 18 percent more in the often-studied Murchison meteorite.

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refPersonally I don't know why it matters if both are present. As soon as a system begins to self-replicate, however simple, that is what would take over and become dominant. Why couldn't it have been right as easily as left then?