How do monkey flowers near mines show that natural selection causes evolution?
2 Answers
Monkey flowers growing in areas around copper mines are almost entirely of a variant which is copper tolerant.
Explanation:
Copper is toxic to most plants however copper tolerance has been found to occur as a natural phenomenon with certain species.
Some of the copper extracted from copper mines ends up leaching into the soil. Most of the monkey flowers could not survive but the few that contained the copper tolerance would grow and reproduce.
Monkey flowers show that changing environments cause natural selection within existing variations.
Explanation:
Monkey flowers have numerous possible variations. One ( or some) of these variations have genetic variations that allows them to live in normally toxic levels of copper.
Copper is a toxin to most varieties of Monkey Flowers. In fact copper is a toxin to most living things. The existing genetic variation allows for adaptive evolution in the survival of the flowers that contain that genetic variation.
A classic example of adaptive evolution is the peppered moth in England. In the pre industrial revolution the white variation was the dominate form of the peppered moth while a black form existed but was rare. During the industrial revolution with large amounts of black coal dust, the black form of the peppered moth became dominate while the white form became rare. When the post industrial resulted in clean air, the white form again became dominate and the black form rare.
Both of these are example of adaptive evolution where existing variations better suited to the new environment survive while other forms do not. ( Note these are examples of adaptive evolution but not Darwinian evolution creating new forms.)
