Can you explain how evolution and biodiversity are related?
Natural selection can only eliminate biological variations that are not as well adapted to the changing environmental conditions. Natural selection can not create biodiversity.
If there is sufficient biodiversity when an environmental change occurs some variations may be adapted to the changing environment. These variation will survive while natural selection, selects the poorly adapted variations for extinction. Those biodiversity will lead to a change in the population.
These variations must exist before natural selection can occur. Darwinian evolution had no answer for the source of the new unique variations. De Vrie's mutations were thought to be the answer. Modern biochemistry and knowledge of DNA have shown that mutations are always the result of a loss of information.
Evolution or changes in species may result from natural selection working with biodiversity to select well adapted variations to environmental changes. Darwinian evolution has no explanation for where biodiversity comes from.