Evolution.

Society for Experimental Biology

Date:: 1953

Catalogue details

Licence: Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)

Credit: Evolution. Source: Wellcome Collection.

480/484 (page 448)

44^ POSTSCRIPT conferring resistance to penicillin, one can see that resistance may originate from an occasional individual carrying a transformer for resistance or mutating to produce a resistant transformer. Under appropriate circum¬ stances such a factor could spread through a whole population, without mating being involved, and so lead to a mass adaptation. Such an effect would pursue an autocatalytic time course, with an apparent initial lag, as many adaptations do in fact. To sum up, evolution, looked at from the gene-mechanism level, is the process of adaptation to a changing environment of groups of highly compatible self-reproducing bodies. It is possible, if not probable, that most of such groups, although highly compatible, nevertheless have a dynamic rather than a static stability, so that they may exhibit change (i.e. may evolve) even in a constant environment. Furthermore, we must consider the possibility that each group may occasionally gain genes ' permanently ' from other unlike environmental groups and also occasionally lose genes 'permanently'. On this level, from an experimental point of view, the mechanisms of evolution are still almost unexplored. REFERENCES Auerbach, С. (1951). Cold Spr. Harb. Symp. Quant. Biol. 16, 199. Baldwin, E. (1953). Symp. Soc. Exp. Biol. 7, 22. Danielli, J. F. (1951). Nature, Lond., 168, 464. Danielli, J. F. (1952«). Nature, Lond., 170, 863. Danielli, J. F. (19520). Nature, Land., 170, 1042. Danielli, J. F. (1952Í:). Symp. Soc. Exp. Biol. 6, i. Demerec, M. (1953). Symp. Soc. Exp. Biol. 7, 43. Goldacre, R. J. (1952). Int. Rev. Cytol. i, 135. Goldacre, R. J. & Lorch, I. J. (1950). Nature, Lond., 166, 497. Hinshelwood, C. N. (1952). Symp. Soc. Exp. Biol. 7, 31. Hotchkiss, R. D. (1952). Chemistry and physiology of the nucleus. Exp. Cell Res. Suppl. 2, 383. Medawar, p. (1953). Symp. Soc. Exp. Biol. 7, 320. WiLHELMi, R. W. (1942). Biol. Bull. Woods Hole, 82, 179. WiLLMER, E. N. (1953). Symp. Soc. Exp. Biol. 7, 377.