Darwin and His Theory of 
    Evolution by Natural Selection
  Evolution- changes in the 
   characteristics of groups of 
   organisms over time 
  Charles Darwin was the first to 
   propose a feasible 
   mechanism for evolution. It 
   is called natural selection. 
  Evolution by Natural Selection is a theory. 
      What is a scientific theory?
  Scientific Theory- an idea that is strongly 
  supported by evidence. It is generally accepted 
  and used to explain many observations.
  *Remember: The word “theory” in everyday 
  language and in scientific language mean very 
  different things. 
  In everyday language, people use the word 
  theory to mean a hypothesis or an educated 
  guess. 
   Natural Selection- 
   differential success in 
   survival and 
   reproduction of 
   individuals with 
   different phenotypes 
   (physical 
   characteristics) 
   resulting from 
   interactions with their 
   environments
  Conditions Needed for Natural Selection: VISTA
  1. Variation
  There are a variety of forms of traits or 
    phenotypes. 
         Conditions Needed for Natural Selection: VISTA
    2. Inheritance 
    ● Only traits that are determined by an organism’s 
      genes will be passed to the next generation.