1. VARIATION Variation - heritable differences of a genetic trait
Within populations, individuals may vary in observable traits
Ex: Peppered Moth
In most populations, traits will typically follow a bell curve shape
Most individuals in the middle of the traits; lesser individuals at the extremes
New variations in populations are often caused by mutations

2. NATURAL SELECTION
Natural Selection - Organisms with traits that are favorable to the environment will reproduce at a higher rate
4 Types of Natural Selection:
- Stabilizing Directional Disruptive Sexual
Stabilizing Selection: individuals with an average form of a trait have the highest fitness
Ex: Large lizards: seen easily; eaten first
Small lizards: slow; eaten first
Medium sized lizards are the most fit since they can hide easily and be fast enough to escape predators

3. NATURAL SELECTION
Directional Selection: Organisms with a more extreme variation of a trait will be most fit
Ex: Giraffe with long neck during a drought
Disruptive Selection: Organisms with either extreme variation are more fit
Ex: Limpets are a marine animal that live in the shallow waters on rocks. The rocks are light or dark colors…

4. NATURAL SELECTION
Sexual Selection: selection based on mating preference
Intrasexual: males fighting other males and winner gets to mate with female
Ex: Elephant Bull Seal
Intersexual: attracting a mate
Ex: Peacock
Frigate bird

5. NATURAL SELECTION