Evolutionary mechanisms are the processes that drive the changes in species over time. These include natural selection, where organisms better adapted to their environment tend to survive and reproduce more successfully. This means that traits that help with survival are passed on to future generations, leading to gradual changes in a species, such as the peppered moth adapting to its environment during the Industrial Revolution. Another important mechanism is genetic drift, which refers to random changes in the frequency of traits in a population. This can happen due to chance events, especially in small populations, where certain traits may become more common or disappear entirely. Together, these mechanisms explain how species like Darwin's finches evolve and adapt to their unique environments.