Quote:
|
Quote by: Pooeypants Variations are caused by mutations. How else do variations come about? |
Exactly. There are several kinds of changes in a genome that are lumped as "mutations." Any change in the genome that wasn't there before produces genetic variability or genetic diversity. This is what makes a species adaptable in a changing environment.
Although it is constantly stated that mutations are rare, most people have a wrong idea of what that means. Even if we ignore the billions of cell divisions that produced the somatic cells in your body (and have not evolutionary importance), each individual inherits between 10 and 100 mutations from his/her parents.
Creationists love to claim that "most" mutations are harmful and therefore no evolution can ever take place. Of course, this is not correct. Most mutations have no effect whatsoever. Many are harmful, and a few are beneficial.
Evolution takes place because certain mechanisms tend to increase the genetic diversity in a population, while other mechanisms tend to reduce it.