Chemical evolution natural selection

In the course of chemical evolution, nature must have developed selective methods of amino acid synthesis and specific recognition. In this respect, what kind of chemical methods do we have presently to prepare amino acids in optically pure form and to selectively distinguish among enantiomers We will therefore examine in this section two approaches to asymmetric synthesis of amino acids using the concept of asymmetric induction and specific metal ion complexation. 

Wicken, J.S. (1987). Evolution, Thermodynamics and Information. Oxford University Press, New York Williams, RJ.P. and Frausto da Silva, J.J.R. (1996). The Natural Selection of the Chemical Elements - The Environment and Life s Chemistry. Clarendon Press, Oxford... 

These specific examples of evolution are relatively straightforward and interpretable. However, the evolution of special chemicals and their biological interactions is more complex and may take place over millions of years rather than only a few decades. Such developments are rarely understood in detail, but despite the greater complexity evolution here also proceeds by way of repeated genetic variation and natural selection. Some striking examples appear in the chapters that follow. 

Whittaker (4), Waller and Nowacki (5.), and Rabotnov (6) discussed the evolution of stable plant communities and species susceptible to allelopathic chemicals that were released by other plants. Such plants would have been eliminated by natural selection, and allelopathically neutral or allelopathically... 

Retained chemistry, changed substrate specificity (binding) Nature selects protein from a pool of enzymes whose mechanism provide a partial reaction or stabilization strategy for intermediates or transition states. Evolution decreases the proficiency of the reaction catalyzed by the progenitor. The underlying hypothesis states that chemical mechanism dominance starts with a low level of promiscuous activity and that once evolved it is beneficial for nature to utilize it over and over again. 

It follows from our foregoing discussion that such a system must be a culmination of a protracted period of prior evolution. This comprises chemical evolution (the complexification of chemical systems) and evolution by natural selection of chemical replicators of various kinds. It is likely that mineral surfaces have played an important role in precellular evolution (e.g. [9-12]). Surfaces have favourable thermodynamic, kinetic and selective effects on chemical and replicator evolution. Reviews of molecular selection dynamics on surfaces can be found elsewhere [ 13]. We mention this link because effects that surfaces can confer can be conferred even more efficiently by compartments obviously, a reproducing protocell is the strongest form of population structure, conducive to group selection [14,15] of the replicators included within. 

Historically, natural products have formed the oldest basis for new medicines, and natural selection during evolution and competition between the species has produced powerful, biologically active natural products. These can serve as chemical leads, to be refined by the chemist by creating analogues that will provide a more specifically acting drug, or perhaps avoid a delivery problem or an unwanted adverse side effect. 

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