Fitness reproductive

Natural selection improves the "fitness" - reproductive capacity -of the individual organism. (An exception is discussed in the next paragraph.) It can very well have disastrous results for the population as a whole. Consider schooling in fish, that is, their tendency to swim in compact formations. Suppose that initially the fish swim in a more scattered way but that a mutation occurs that leads its bearer to seek the center of the group. This is a useful mutation, since that fish will receive greater protection from predators. As more and more fish behave in this way, the formation will become more and more compact, since every fish will try to be at the center. As a result, the predators task will be made easier. More fish will get caught, as a result of a mutation that reduced the risk for each individual fish compared with the prospects of others that lacked the mutation. What counts in natural selection is rela-... 

Figure 11.11 shows examples of the three basic genetic operations of reproduction, crossover and mutation, as applied to a population of 8-bit chromosomes. Reproduction makes a set of identical copies of a given chromosome, where the number of copies depends on the chromosome s fitness (see below). The crossover operator exchanges subparts of two chromosomes, where the position of the crossover is randomly selected, and is thus a crude facsimile of biological sexual recombination between two single-chromosome organisms. The mutation operator randomly flips one or more bits in the chromosome, where the bit positions are randomly chosen. 

This basic difference equation - known as the Schema Theorem [holl92] - expresses the fact that the sample representation of schemas whose average fitness remains above average relative to the whole population increases exponentially over time. As it stands, however, this equation addresses only the reproduction operator, and ignores effects of both crossover and mutation. 

M. L. Bernard et al, CRAcadSci, Ser C, 272 (26), 2112-15 (1972) CA.75, 101675 (1971) A generalization of the previously described (Bernard et al, 1971) ablation theory (for AP) combustion to include AP-based solid propints provides satisfactory fits to the exptl data of M. Summerfield et al (1960), with reproduction of the two distinct pressure regimes observed in the combustion of AP-based powders between 0 and 100 bars. The solid binding agent is assumed to be easily pyrolyzable, with each mol producing several combustible gaseous mols, as in the case of pyrolytically degrading polymers... 

Tatara CP, Mulvey M, Newman MC. 2002. Genetic and demographic responses of mercury-exposed mosquitofish Gambusia holbmoki) populations temporal stability and reproductive components of fitness. Environ Toxicol Chem 21 2191-2197. 

Wysocki C.J. (1989). Vomeronasal chemoreception its role in reproductive fitness and physiology. Prog Neurol Neurobiol 50, 545-566. 

A functional explanation for a particular trait does not stipulate by which mechanism within the organism a particular effect is produced. The function can be realized in physically different ways and the only relevant feature is that it must enhance fitness, i.e. serve survival and reproduction (Macdonald, 1992). Various causal factors can then be invoked to explain how the function is performed, although these factors cannot explain why the traits are present unless an appeal is made to selection pressure. 

Simulating the INS spectra using the Stevens parameters extracted by Riley and coworkers provides a nice reproduction of the INS spectra. However, as previously discussed, it was necessary to adjust these parameters in order to reproduce the static magnetic data (see above, Figure 5.8). Fitting the linear region of the relaxation time for the Er(trensal) SMM yields an energy barrier of 20(1) cm-1... 

Marine mammals have adapted to an aquatic or semi-aquatic lifestyle with such features as reduced or eliminated limb structures, a blubber layer for thermoregulatory, nutritional, buoyancy and locomotory roles, and reproductive strategies conducive to fitness in a given biogeographic zone (habitat). The environmental challenges faced by newborn marine mammals at birth may explain there largely precocious nature and the apparent maturity of the immune system of newborn marine mammals [1],... 

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