Final answer:
Favorable mutations are rare genetic changes that lead to beneficial effects on an organism's ability to survive and reproduce, playing a crucial role in evolution. Examples include the CCR5-Δ32 mutation, conferring HIV resistance, and mutations that led to insecticide resistance in mosquitoes and darker coloration in peppered moths, improving survival.
Step-by-step explanation:
Favorable mutations are typically the rare genetic changes that lead to a positive effect on an organism's fitness, in terms of its ability to survive and reproduce within its environment. Beneficial mutations are crucial to the process of evolution, as they contribute to the genetic variation within populations. An increase in fitness means that these mutations are likely to become more prevalent over time through the process of natural selection.
Of the various types of mutations, beneficial mutations may lead to the creation of new proteins that help organisms adapt to environmental changes. For example, the CCR5-Δ32 mutation gives resistance to HIV in individuals who carry this mutation. This specific mutation is more commonly found in people of European descent, illustrating how a beneficial mutation can become more common in certain populations.
It is important to note that most mutations are either neutral, having no significant effect on the organism, or deleterious, which can harm an organism's fitness. Nonetheless, the rare beneficial mutations that do occur can have a substantial impact on an organism's survival and success in reproduction. The mutation that conferred insecticide resistance in mosquitoes and the mutation for black coloration in peppered moths during the Industrial Revolution are examples of advantageous genetic changes that improved survival.