Final answer:
Convergent evolution is an example that supports the theory of evolution by showing how different species can independently develop similar traits as a result of natural selection.
Step-by-step explanation:
To understand how a specific example supports the theory of evolution by natural selection, consider the phenomenon of convergent evolution. This is when species not closely related, independently evolve similar traits as a result of having to adapt to similar environments or ecological niches. Despite their different ancestors, both have developed wings for flight. This highlights the principle of natural selection, where similar environmental pressures result in similar adaptations, even when the involved species have different ancestral lines.
Mutations are changes in the genetic mutations that introduce new alleles into a population's gene pool and can result in new traits. Over time, some traits prove advantageous for survival and reproduction in a given environment, leading to an increase in frequency of those traits within the population through natural selection.