Evolution

In the book, Life's Grandeur, Stephen Jay Gould goes into detail why the most common misconception of Evolution by Natural Selection. That is the misconception that evolution progresses from lesser forms, to more advanced, complex forms. Indeed Charles Darwin disliked the term evolution as it carries with it exactly this connotation. Instead he preferred the term, Descent by Modification. When you look at the principles behind Darwin's great idea the reasons for his objection become apparent. There are just three simple propositions:

1. organisms tend to produce more offspring than can possibly survive
   
2. off-spring vary among themselves and not identical to their parents
   
3. off-spring inherit at least some of these variations
   

That is it. The remainder is about following the consequences of these principles. Darwin deduced that, given the above, then those organisms best able to adapt to their local environment will tend to have an advantage. That advantage helps their offspring survive. Even if the environment remains static, the population is not. Since there is population pressure when more offspring are produced than the environment can sustain. Resources are finite, leading to increased competition between and within groups of organisms.

Gould comes in refuting the popular misconception of evolutionary progress. Instead he prefers the description, “descent with modification”. His point is subtle but powerful: a population will have a variation of behaviours and adaptations. Over time members of a population will cluster around the mean, since any subgroup that excels will slowly grow in number which influences the mean.