1. Question: Use genetics to explain variation in a population

2. http://www.npr.org/templates/story/story.php?storyId=18393850

4. Lamarck- inheritance of acquired characteristics first to suggest that species change over time, just had the wrong explanation Charles Lyell- (geologist) first to explain that the Earth had changed over time- published just before Darwin left on his voyage Thomas Malthus- (economist) explained that if human populations kept growing, resources would become scarce. *just like nature*

5. Darwin’s conclusions were based on his observations AND the ideas of other scientists. 1859: Published his book, The Origin of Species which outlined his observations and his ideas. Book received with mixed feelings.

6. Natural Variation- Species naturally have different characteristics which leads to variation in the species (now known to be due to DNA) Implications Survival of the “fittest” adaptations lead to different types of “fitness”, allowing for better survival **Fitness = ability to PASS ON GENES survival reproduction

7. Environmental Change If a species adapts to its environment, then the environment changes, the species must change or go extinct. Those that survive have the traits that will be passed on Finite Resources Competition for resources causes only the strongest to pass on their traits, leading to a stronger population over time

8. Overproduction- species have more offspring than they expect to survive. Due to sexual reproduction/meiosis, some of the offspring have better combinations of traits. different combinations of genes are passed on resulting in genetic diversity Species today look differently than species in past, because different genes have been passed on. asexual reproduction  little evolution because no new combinations of genes are made

9. What Darwin couldn’t explain… mutation rates! remember- mutations happen as a random event- some are good, but more are not a good mutation may allow a species to survive better than the rest of the species if that trait passes on, THAT IS EVOLUTION

10. Genetic Variation Think of all of the traits humans have… The more different traits are out there, the greater the chance that one of those traits will allow a species to survive environmental changes Think about an Asian Tiger- if we only have 50 left, what is the problem?

11. Bacteria antibiotics  antibiotic resistant bacteria humans and the plague- those that survived had a genetic mutation may lead to HIV/AIDS immunity!HIV/AIDS immunity