Hypothesis If the type of the food available changes, then the frequency of beak types will change, because birds with beaks more suited to the available food will be more successful over time.
For many species, there are often regional differences in their genes, although most of the time this differences aren't noticeable in their outward appearance.
Back in the 1800's. There were 2 variations of moths. 1 with white and 1 with black. The black colored moths could blend in the with the coal mines to hide from predators.
