1. Evolution http://cercopan.wildlifedirect.org/files/2008/03/forest.jpg http://www.softpedia.com/screenshots/Monkeys-Free-Screensaver_2.jpg http://www.the-reel-mccoy.com/movies/2000/images/dinosaur1.jpg http://gopaultech.com/files/2008/02/bacteria.jpg

2. Evolutionary Mechanisms: Microevolution Genetic Variation Natural Selection Genetic Drift Speciation vs.

3. Evolutionary Mechanisms: Macroevolution Evolutionary trends in an area Evolution above the species level Mass Extinctions

4. Types of Selection Natural Selection acts on variation in a population Stabilizing Selection Favors the average individual

5. Types of Selection continued Directional Selection Disruptive Selection Favors one of the extreme forms of a trait Favors individual with either of two forms of a trait Eliminates the intermediate form of the trait over time

7. Speciation Evolution of a new species Species= a group of organisms that can interbreed naturally and produce viable, fertile offspring Limitations to a species concept?

8. Factors Contributing to Speciation Small population size Founder effect Bottleneck effect Isolation Geographic isolation  Organisms are separated by a physical barrier  Results in allopatric speciation

9. More Factors Contributing to Speciation  Behavior patterns and/or physical characteristics prevent reproduction Reproductive Isolation- Simpatric Speciation Seasonal Mechanical Prevention of gamete fusion

10. More Factors Contributing to Sympatric Speciation Ecological Isolation  Populations require different habitats Adaptive Radiation  One ancestral species evolves into an array of species that occupy different niches

11. Speed of Speciation Gradualism Species develop through gradual buildup of new adaptations Accumulation of lots of little changes

12. Speed of Speciation (cont.) Punctuated Equilibrium Speciation occurs quickly in rapid bursts with long periods of stability in between Usually a result of environmental changes <-->