In this chapter Darwin set out to answer the question of how adaptations arise. His explanation was that adaptations result from what he called the “struggle for existence”. He wrote: “Owing to this struggle for life, any variation, however slight and from whatever cause proceeding, if it be in any degree profitable to an individual of any species, in its infinitely complex relations to other organic beings and to external nature, will tend to the preservation of that individual, and will generally be inherited by its offspring. The offspring, also, will thus have a better chance of surviving, for, of the many individuals of any species which are periodically born, but a small number can survive. I have called this principle, by which each slight variation, if useful, is preserved, by the term of Natural Selection…”
Illustration: The diversity of bird beaks is a prime example of adaptation to different life habits.
No comments:
Post a Comment