Arizona State University (ASU) BIO181 General Biology I Exam 2 Practice

Mutations are fundamental to the process of evolution because they introduce genetic variation within a population. Genetic variation is essential for natural selection to occur, as it provides the raw material upon which evolutionary forces can act. By creating new alleles or changes in the genetic code, mutations can result in new traits that may be beneficial, neutral, or even harmful. When a mutation leads to a trait that enhances an organism's fitness in its environment, that trait can become more common in the population over generations through the mechanism of natural selection. Conversely, if a mutation is disadvantageous, it may be reduced or eliminated over time. This process of mutation and selection helps populations adapt to their environments, ultimately driving the evolutionary process. In contrast, the other choices do not accurately describe the role of mutations in evolution. For example, mutations are not always harmful; many are neutral or beneficial. Furthermore, mutations contribute to, rather than reduce, genetic variation within populations. Lastly, while some mutations may lead to the elimination of non-advantageous traits, this is not their primary contribution to evolution, which is the introduction of variation that can be acted upon by selection.