Natural selection
Natural selection follows inevitably from inherited variation in the ability to reproduce to pass their progeny from generation after generation. The systematic accumulation of chance variations is the only process that can lead to biological adaptations, thereby produced organisms that can live in extreme environments and on diverse energy sources (Nealson, 1999). When applied to natural evolution, question arises whether actual rates of adaptation are close to any limitation or whether actual genetic systems have evolved so as to improve the response to selection. Following Darwin and Wallace's proposal of adaptation by natural selection had emphasized that enough time had not been there since the formation of the earth …show more content…
Fitness may be decomposed into its genetical and environmental components that are captures the non-additive genotypic effects (such as dominance, epistasis, synergy and frequency dependence) as well as other more obviously environmental effects. The change in average fitness responsible to the action of natural selection is equal to the additive genetic variance of the trait (Fisher, 1930, 1941). The significance of this result was that as variances are non-negative, natural selection can only have an improving effect on fitness. Fisher (1930) represented the fundamental theorem as an explanation for the idea that individuals will adopt themselves to maximize their fitness (Grafen, 2002). Usually, the fundamental theorem is not concerned with total evolutionary changes that develop due to fitness rather explain only the action of natural selection (Price, 1972b). Non-selective change in fitness leads to mutation and changing associations between genes and fitness collectively called as deterioration of the environment by Fisher (1930) that owing to reduce average fitness (Frank & Slatkin, 1992). Many evolutionists realized that the fundamental theorem about total evolutionary change in fitness is not totally correct and it is usually applicable under very special conditions (Edwards, 1994). This conceptual confusion realised the importance of being able to mathematically separate the selective versus non-selective components of evolutionary change (Grafen,
Natural selection follows inevitably from inherited variation in the ability to reproduce to pass their progeny from generation after generation. The systematic accumulation of chance variations is the only process that can lead to biological adaptations, thereby produced organisms that can live in extreme environments and on diverse energy sources (Nealson, 1999). When applied to natural evolution, question arises whether actual rates of adaptation are close to any limitation or whether actual genetic systems have evolved so as to improve the response to selection. Following Darwin and Wallace's proposal of adaptation by natural selection had emphasized that enough time had not been there since the formation of the earth …show more content…
Fitness may be decomposed into its genetical and environmental components that are captures the non-additive genotypic effects (such as dominance, epistasis, synergy and frequency dependence) as well as other more obviously environmental effects. The change in average fitness responsible to the action of natural selection is equal to the additive genetic variance of the trait (Fisher, 1930, 1941). The significance of this result was that as variances are non-negative, natural selection can only have an improving effect on fitness. Fisher (1930) represented the fundamental theorem as an explanation for the idea that individuals will adopt themselves to maximize their fitness (Grafen, 2002). Usually, the fundamental theorem is not concerned with total evolutionary changes that develop due to fitness rather explain only the action of natural selection (Price, 1972b). Non-selective change in fitness leads to mutation and changing associations between genes and fitness collectively called as deterioration of the environment by Fisher (1930) that owing to reduce average fitness (Frank & Slatkin, 1992). Many evolutionists realized that the fundamental theorem about total evolutionary change in fitness is not totally correct and it is usually applicable under very special conditions (Edwards, 1994). This conceptual confusion realised the importance of being able to mathematically separate the selective versus non-selective components of evolutionary change (Grafen,