Reproductive fitness is less scary--it doesn't always mean "prevented from reproducing" * Imagine 20% of the population has adaptations that make them better s

Reproductive fitness is less scary--it doesn't always mean "prevented from reproducing" * Imagine 20% of the population has adaptations that make them better suited to mars--they keep their teeth, their bones are stronger, they do well in sports, they have more energy to take care of kids, so they have 1 extra kid on average. In one generation, that percentage is 30% and in one more it is 45%, one after that and it is the majority and heads toward 100%. What we'll be looking at is speciation. Also, evolution is at-work on our population as we speak--it doesn't take breaks.