The article states that “trichromacy originally evolved for picking out the most nutritious leaves.” I teach high school students to avoid this kind of statement in regard to evolution. The trait arose by accident (nicely explained in the article) and then became more abundant in the population because it conferred an advantage on the organisms that possessed it (natural selection). I know that’s a lot to say, but my experience in teaching evolution has shown me that misunderstandings in this area run deep.

Will Warren
Colchester High School
Colchester, Vt.