Example Mechanism of evolution
1. As habitats change, populations of northern pine trees that were once separated can now exchange pollen. This exchange of genes between populations is allowing the previously isolated gene pools to mix. The mechanism of evolution is _______.
2. A sudden volcanic eruption kills many members of a population of elk. By chance, the individuals that remain do not have the same mix of genes as the original population. The mechanism of evolution is _______.
3. Although millions of prairie chickens once roamed the Midwest, their numbers dwindled to only 50 individuals in the 1990s. These few individuals have since produced a larger population. The genetic variation among the current population is quite low. The mechanism of evolution is _______.
4. Insecticide resistance among mosquitos is spreading around the world after mutations that originate in one population are spread to other populations through matings. The mechanism of evolution is ______.
5. Researchers discovered that female gray tree frogs prefer to mate with males who sound the longest mating calls. The mechanism of evolution is _______.
6. Tristan da Cunha is a remote island in the Atlantic Ocean. In 1814, 15 people formed a colony there, one of whom carried a rare gene for blindness. The frequency of this gene is now 10 times higher on the island than on the mainland from which the settlers arrived.