Some individuals have genes that increase their chances for survival and reproduction. These individuals are more likely to reproduce and pass on their genes, causing their genes to become more common in the next generation.
Explanation:
The basic idea of natural selection is that environmental conditions determine how well the characteristics of organisms contribute to the survival and reproduction of the organism; organisms that do not have these traits may die before reproduction or be less fertile. As long as environmental conditions remain the same or close enough for these traits to remain adaptive, these traits will become more common in populations. The loss of an ecological niche of a species or overcrowding as a result of an increase in abundance can significantly alter the adaptive characteristics required for survival. In this case, and also in any environment where survival is determined more by ecology than secondary sex characteristics, ecological choice takes place.
