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

Life cycle parameters, for example the rate of maturation, length of life, number of progeny and the related biodemographic parameters of the population (life history characters), for example population size and rate of growth, can apparently easily change as a consequence of various mutations.With a certain degree of simplification, it can be stated that almost every mutation is manifested to a certain degree in the life-cycle parameters of its carrier.Simultaneously, the life-cycle parameters can very substantially affect the fitness of an individual.The level of investment into reproductive organs in plants or into reproductive conduct in animals can very readily reduce or increase the number of progeny left by a particular individual by an order of magnitude and thus proportionally change the probability that the mutation that caused the particular change is passed on to the next generation.The importance of the individual types of mutations for the fitness of an individual can be indirectly estimated on the basis of the degree of inheritability of the relevant phenotype differences (Houle 1992).Genetically determined traits that very strongly affect the fitness cannot survive for long in the population in the polymorphic state, as one or the other form of the particular trait can be eliminated relatively easily in the population through natural selection.This is manifested at the population level in that most of the intra-population variability in the particular trait or in the particular category of traits is of nongenetic nature or, if it is of genetic nature, it has very low inheritability, i.e. degree (or probability) with which it is transferred from parents to progeny.Numerous observations in nature and the laboratory have shown that life cycle parameters and biodemographic parameters in general have, on an average, much lower inheritability than morphological parameters (Mousseau & Roff 1987)(Fig. XII.11).

The life-cycle parameters are very closely interconnected so that they not only mutually affect the fitness of their carrier but also greatly influence one another.Because contemporary species have had a long period of gradual adjustment and optimizing of these parameters, this influence almost always has the character of a “something for something” relationship (trade-off principle).If a particular individual or species invests a major part of the available resources in its reproductive organs and immediate reproduction, it must invest a correspondingly smaller amount of resources in its vegetative organs and thus future reproduction or its own survival.If an individual invests in the production of a large number of progeny, it must correspondingly reduce the amount of resources that it provides to each individual progeny and thus reduce the probability that its individual progeny survive to reproductive age.Through the size and character of investments into the formation of vegetative organs, the organism can, on the one hand, increase the effectiveness of use of the available resources, measurable, for example, in terms of the amount of resources required for production of a certain amount of its own biomass and, on the other hand, to the contrary, reduce its rate of reproduction, i.e. the number of progeny produced by an individual over a time unit.According to the adjustment of the individual life-cycle parameters, ecologists can differentiate amongst a number of more or less different ecological strategies in the individual species or groups of species (Ginzburg 1992; Parry 1981; Grime 1979; Flegr 1994; Brommer 2000).It is necessary to be aware that the life strategy characteristic for a certain species is not generally a consequence of its “free choice”, but is forced on it from outside in the vast majority of cases.If the size of the population of a certain species is limited by a predator or parasite, then turbidostatic selection following from this type of regulation mechanism enforces a shift in the life cycle in the direction toward faster reproduction, frequently at the expense of effectiveness of use of the available resources.If the predation tends to be nonselective in character, for example as a consequence of the action of a filtrator, preference will be given to rapid reproduction shifted to the earliest possible stages of the life cycle.If the growth of the population is limited by the total amount of readily available and simultaneously nonrenewable resources, as frequently happens with a large number of species with parasitic life styles, preference will be given to effective use of resources over rapid reproduction.However, if there is greater probability that individuals with different genotypes will compete for the same stock of a non-renewable resource, for example if there is a high probability that a single host will be independently infected by mutually unrelated strains of the parasite, to the contrary the maximum rate of growth could be preferred, even at the cost of damaging or even killing the host organism and thus a reduction in the effectiveness of exploitation of the particular resource.If the reproduction of an organism is limited by the rate of renewal of a certain scarce resource, selection can prefer a strategy consisting in the smallest consumption of this resource, even if it could have been used more effectively with greater consumption.For example, some plants occurring in extreme habitats with minimal resources employ this strategy.The life strategy and thus, primarily, the life-cycle parameters are affected by a number of other factors, such as, for example, the character and degree of risk of accidental death or death affected by the phenotype of the individual in various stages of development, the intensity of interspecies and intraspecies and kin competition to which the members of the population are exposed, or the degree of relatedness of the interacting individuals, which can depend, for example, on the motility of the members of the given species and the level and character of assortative reproduction.s