Frozen Evolution. Or, that’s not the way it is, Mr. Darwin. A Farewell to Selfish Gene.

The species recognition concept is a variation of the definition of a biological species (Paterson 1985). With a certain degree of simplification, this concept could also be termed the concept of an ethological species. Its proponents consider that the existence of specific mechanisms is actually the cause of the existence of species in sexually reproducing species; these mechanisms enable the members of a certain species to recognize suitable partners, i.e. members of the same species of the opposite sex. Amongst gonochorists, males and females can recognize members of the opposite sex on the basis of other traits and thus using other mechanisms. Altogether, the mechanisms of recognition of members of the same species but of the opposite sex form a specific mate recognition system (SMRS). As soon as a random modification of SMRS occurs in part of the population, its members will begin to preferentially reproduce together and only rarely with members of the population with the original SMRS variant. If this reproduction barrier is sufficiently impermeable and if there is sufficient time, the two subpopulations that originally differed only in their SMRS will also differ genetically and phenotypically and separate into two independent species. Consequently, it seems useful to consider that a species consists in a population of individuals sharing a specific mate recognition system. Of course, in its pure form, the concept of an ethological species can be valid only for animals. However, for plants pollinated by insects, traits employed by pollinators to recognize suitable flowers could play an analogous role.