Concepts of variability-natural selection and environmental

Question

Using concepts of variability, natural selection and environmental pressure how does the synthetic theory elucidate the Darwinian natural selection?

Answer 1

Genetic variability happens from recombination of chromosomes throughout sexual reproduction and from DNA mutations in the gametes and germ cells. Such variability makes individuals who are carriers of some new phenotypical features compared to their ancestors. These individuals are submitted to the environmental pressure and can be more or less well-succeeded about survival or reproduction. Those best succeeded transmit their genetic patrimony to a larger number of the descendants raising the frequency of their genes in the population; those less well-succeeded tend to transmit their genes to the small number of descendants lessening the frequency of their genes in the population or even becoming extinct. This procedure is called natural selection.