What is the definition of the term ''evolution'' and what are some of its key principles and mechanisms?

Evolution is a scientific theory explaining how life changes over time. It describes the process by which species of organisms develop and diversify through changes that occur over many generations.

The main principles of evolution are natural selection and genetic drift. Natural selection is the process whereby organisms that are better adapted to their environment are more likely to survive and reproduce, passing on their advantageous traits to the next generation. Genetic drift, on the other hand, refers to random changes in the frequency of different traits in a population due to chance events.

Another important mechanism of evolution is gene flow, which occurs when individuals from one population migrate to another, introducing new genetic traits into the population. Mutation is another key mechanism of evolution, as it creates new genetic variation by producing random changes in DNA.

Overall, the key principles and mechanisms of evolution work together to drive the process of natural selection, leading to the diversity of life that we see today.