What happens if genotypes have unequal fitness?

When genotypes have unequal fitness, it leads to natural selection, a fundamental mechanism of evolution. Natural selection favors certain alleles that confer advantages in survival and reproduction, causing those alleles to increase in frequency within the population over time. This change in allele frequencies is a direct result of the differential survival and reproduction rates of individuals based on their genotypes.

As a result, some alleles may become more common, while others may be reduced or even eliminated from the gene pool, indicating that allele frequencies are indeed not static but dynamic and subject to change. This process contributes to the evolution of species as they adapt to their environments or face different selective pressures.

In contrast, the other options do not reflect the consequences of unequal fitness among genotypes. For example, constant allele frequencies suggest a lack of changes in the population, which contradicts the influence of natural selection. Fixation of all alleles would imply a lack of genetic diversity and ignore the nuances of selective pressures. Lastly, stating that no genetic drift occurs ignores the role of random sampling effects that can affect allele frequencies independently of natural selection. Therefore, recognizing that allele frequencies will change over time due to unequal fitness aligns with fundamental principles of evolutionary biology.