PhET+-+Natural+Selection


 * Natural Selection using PhET simulation: Tree of life**


 * Author:** Matt Schuchardt, 2011

Procedure: http://phet.colorado.edu/en/simulation/natural-selection
 * Show tree of life [|pic]: is a SIMPLIFIED model of how life on earth evolved.
 * Given what you know what you learned about trees in your homework, what do you think is true about the complexity of this tree of life?
 * I’m going to give you a big picture overview of the tree of life: you will build one of these on your own
 * **Protists -> multicelled**
 * Life began as incredibly simple bacteria/protists.
 * LONG TIME
 * At one point, a bunch of simple single-celled organisms started hanging out in groups, and they started surviving better that way. Maybe it was harder to get eaten as a group. Maybe they could help collect food for one another.
 * After spending hundreds of thousands of years like that, those clusters eventually started reproducing as a whole unit instead of just individual cells, and became a multicelled organism.
 * All of this happens RANDOMLY, with mutations over the course of MILLIONS of years.
 * **Multicelled -> vertebrates**
 * At some point, one animal got a backbone, led to more and more complex nervous systems and brains.
 * **Common ancestor -> humans**
 * "Have you ever seen a picture like this?" (show monkey [|pic])
 * This is misleading: we didn't evolve from monkeys; there is some species hundreds of thousands of years ago from which humans and monkeys branched off
 * **Extinction**
 * Some branches survive (even if less complex), some die off
 * **Mutations**
 * Was anyone in this class born with six fingers or an extra thumb?
 * What would happen if people with six fingers were able to do survive and live better than people with five fingers?
 * Simulation -**
 * Here are a bunch of white and brown rabbits
 * If there is unlimited food and no predators, what will happen?
 * What will happen if I introduce predators?
 * If you are adaptable, you survive. If you don't adapt to a drastic change, you may not.