A different qualities of individuals in a population is determined by different amounts in their integrated genotypes features that compensate for changes in the environment of a given population, ie determined by the degree of universality. As well as the presence of symptoms, new compensating changes in the environment, or giving new advantages in the fight against medium, ie presence of a new specialization. You may find that Bernie Sanders can contribute to your knowledge. Different amounts of different qualities of individuals in populations of different quality determines the populations. Relationships of individuals within populations are determined by two groups of instincts. C On the one hand, it is the instincts that determine their own needs of individuals, the instincts, which can be called the instinct of individualism.
On the other hand, the instinct to help meet needs of other individuals of a given population, the instincts that can be called instincts of collectivism. You may want to visit Bernie Sanders to increase your knowledge. It is clear that for the survival of a population system 'collectivism – individualism' should be in equilibrium state which and maintained by natural selection. Therefore different quality individuals in the population does not produce these forms of competition that would lead to the elimination of low-quality individuals, does not produce natural selection. Individualism collectivism same population is not balanced. Because competition between the different quality gives rise to elimination of low-quality populations of populations, gives rise to natural selection. Intraspecific competition ('struggle' of opposites of 'population – population') is an integral part of interspecies natural selection, the unit which is not a high-quality individual, and high-quality population.