3. 1. Variation 2. Selection 3. Heredity 2

4.  Variation exists in all populations  (Siblings look similar…but not identical)  Causes of variation  Mutations  Sexual recombination ▪ (mixing of parents traits)  Meiosis ▪ (remember crossing over?) 3

5.  Malthus – There are limits to the sizes of populations  Going to run out of SOME resource ▪ Food, water, room, etc…  “Struggle for”  More individuals produced than can survive  Not everyone gets to live & reproduce 4 existence

6.  What are the two types of selection? 1. Artificial Selection  Humans pick for certain traits 2. Natural Selection  Nature selects for certain traits  Traits that are most beneficial for an organism  Trait that would allow an organism to eat different kinds of food…  Trait that would make an organism have more offspring…

7.  Some  Some traits are passed down from parent to child  Acquired (gained) traits are not passed down reproduce  (Those with the best traits are more likely to survive to reproduce) reproduction  (Its all about the reproduction)  Reproduce and pass on your better genes or go extinct! 6

8.  The new offspring should have most of the characteristics of the surviving parents  (How is the information passed down?)  (DNA!) 7

9. 1. Variation Some lions will be faster and stronger than others 2. Selection The fastest and strongest lions are more likely to eat & survive longer Longer survival = more reproduction 3. Heredity Surviving lions will have faster and stronger cubs 8