How does selective advantage influence allele frequencies?

How does selective advantage influence allele frequencies?

• A. Alleles that increase survival or reproduction become more common over generations.
• B. Alleles always remain at the same frequency.
• C. Alleles with harmful effects rise in frequency.
• D. Only neutral mutations are inherited.

Answer: (A)

Natural selection shifts allele frequencies in a population: alleles that improve survival or reproduction tend to become more common over generations. When individuals carrying a beneficial allele survive longer or have more offspring, they pass that allele on to more of the next generation. Over many generations, the frequency of that advantageous allele increases in the population, and the population can become better adapted to its environment. The other statements aren’t consistent with how evolution works. Frequencies don’t stay fixed just by themselves; advantageous alleles rise in frequency, while harmful ones tend to decline because those carrying them have fewer offspring. Neutral mutations can be inherited, but their frequencies can drift or change due to random sampling, not because they are favored by selection.

Natural selection shifts allele frequencies in a population: alleles that improve survival or reproduction tend to become more common over generations. When individuals carrying a beneficial allele survive longer or have more offspring, they pass that allele on to more of the next generation. Over many generations, the frequency of that advantageous allele increases in the population, and the population can become better adapted to its environment.

The other statements aren’t consistent with how evolution works. Frequencies don’t stay fixed just by themselves; advantageous alleles rise in frequency, while harmful ones tend to decline because those carrying them have fewer offspring. Neutral mutations can be inherited, but their frequencies can drift or change due to random sampling, not because they are favored by selection.