Final answer:
Selection changes allele frequencies, violates the Hardy-Weinberg principle, and can occur at any phase, leading to evolutionary changes in a population's genome through mechanisms such as natural selection and genetic drift, including the founder effect.
Step-by-step explanation:
The statement is true; selection changes allele frequencies and is indeed a violation of the Hardy-Weinberg (HW) principle. Natural selection is one of the evolutionary forces that act upon populations causing changes in allele frequencies over time. Though the Hardy-Weinberg principle provides a framework for understanding what a non-evolving population would look like, in reality, populations are subject to various forces that lead to evolution, including natural selection, genetic drift, and the founder effect. These forces can cause significant changes in a population's genome and occur at any phase during the life of a population.
Natural selection tends to increase the frequency of alleles that confer advantageous traits, leading to adaptive evolutionary changes. Genetic drift, which can occur in any sized population but is more pronounced in smaller populations, leads to changes in alleles frequencies purely by chance. The founder effect is a type of genetic drift that occurs when a few individuals from a larger population colonize a new area, leading to a new population with different allele frequencies than the original population. All of these factors contribute to the ongoing evolutionary process in natural populations.