According to the proposed definition of Darwin, evolution is any change in the allele frequencies of inherited traits in a population that occurs from one generation to the next. Evolution is any change in the trait and characteristics of any species for the sole purpose of improving his adaptive capacity, thus heightening his chances for survival. In the case of the flinches that Charles Darwin have observed, they have adapted to their natural environment by simply altering their beaks, evolving them to suite the available food supply in the area that they live. Same species, but different beaks, all for the purpose of survival.
Define evolution be sure to include in your definition what actually evolves.
Describe the principles of natural selection.