Final answer:
Microevolution refers to small-scale evolutionary changes within a species, such as the development of pesticide-resistant mosquitoes due to a change in allele frequencies over generations, without leading to the creation of a new species.
Step-by-step explanation:
An example of microevolution is the development of pesticide-resistant mosquitoes. Specifically, when a pesticide that kills most mosquitoes is widely used, a few may survive due to a random mutation that makes them resistant to the pesticide. These resistant mosquitoes then reproduce, passing on the resistance trait, and soon, the majority of the mosquito population in the area displays this new trait. This is microevolution because a change in allele frequency within the species occurs over time, but it does not result in the creation of a new species, as the resistant mosquitoes are still capable of reproducing with non-resistant mosquitoes.
Microevolution is distinct from macroevolution, which refers to evolution that occurs at a larger scale and can lead to the formation of new species. It's important to note that microevolution is not about the size of the organism but rather the scale of genetic changes within a population or species.
The peppered moth is another classic example often cited in biology textbooks; it demonstrates evolutionary change through a shift in population's allele frequencies, reflecting small-scale evolution or microevolution.