In classical Darwinian evolution, organisms have two functions. These are the replicator function, i.e. carriers of genetic information that enable transfer of information to further generations in more or less unaltered form, and also the interactor function, which enables the relevant genetic information to be manifested externally and to become a subject of natural selection (Dawkins 1976). Separation of the function of replicator and interactor, leading in sexually reproducing organisms to a substantial reduction in the heritability of fitness, probably has a fundamental impact on the character of the biological evolution of these organisms (see IV.9.2). While the properties of asexually reproducing organisms can evolve through natural selection for the whole term of existence of the species, the effectiveness of natural selection is very small under normal circumstances in sexually reproducing organisms because of the limited heritability of traits and the very limited heredity of fitness. Of course, this effectiveness increases very substantially in situations where the natural genetic polymorphism in the population is substantially limited and where a new mutation appears in each generation in the context of the same alleles and has the same effect on the fitness of its carriers. Under normal circumstances, this occurs primarily after a drastic reduction in the size of the population, which accompanies most types of speciation and the period immediately after speciation. While the properties of asexually reproducing species can change constantly through the effect of natural selection, in sexually reproducing species the periods of changes in properties are coincident with the moments of speciation, so that anagenesis is frequently temporally coincident with cladogenesis. Classical Darwinian gradualistic evolution can occur in nonsexually reproducing organisms while, in sexually reproducing organisms, evolution must have the character of punctuated evolution in the typical case (see XXVI.5.3).

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The classical Darwinian theory of evolution can explain the evolution of adaptive traits only in asexual organisms. The frozen plasticity theory is much more general: It can also explain the origin and evolution of adaptive traits in both asexual and sexual organisms Read more