Part 2, Chapter 12 Summary

Darwin could not conceptualize divergence happening quickly. He was certain it took thousands of generations to become noticeable. However, this has been proven false. As early as 1963, a study of South American fruit flies showed a change to a new species in only five years. Because these flies were not watched very carefully, the researchers do not know when the change occurred, or how long the change took to complete within that five years. Many hypothesize that the original species of flies became infected with a bacteria, which caused them to change, but it also suggests that this type of infection could affect any species currently alive in a similar way.

Adaptations are usually small variations in a species that create a new way of life and become more relevant the more the change occurs during the future generations. A study...