The asymmetry of life

Artikel i vetenskaplig tidskrift, 1978

Stereoselective physical phenomena and their possible importance for the prevalence of D-sugars and L-aminoacids in living matter are reviewed. A classification is presented according to which a selective force provides a microscopic or macroscopic selection depending on its generality when taken over a macrosystem (a lsquounitary biospherersquo such as the Earth). The microscopic lsquoselectionsrsquo are not genuine selections because the final sense of asymmetry is here determined by chance, in other words the initial choice is lsquorandomrsquo, while it is lsquodirectedrsquo in the macroscopic selection. Two macroscopic selections appear possible: 1. selection due to an intrinsic energy difference between enantiomorph configurations, 2. selection accomplished by elliptically polarised radiation.