1. Put your homework out on your desk.. I am going to check it!
Biology March 20, 2013
Bellringer: --Grab the notes sheet… THEN
Look at your list of adaptations from Build-A-Beast. Identify one of each that you used:
Chemical-
Physical-
Behavioral Objectives:
Population Evolution Notes
QUIZ FRIDAY!!! HW: Analyze populations…
Over… Notes Monday, reading last night, Notes Today!
TEST TUESDAY!!!
You will get a review sheet tomorrow!
Put your homework out on your desk.. I am going to check it!

2. Evolution of
Populations

3. A group of individuals of the same species living in the same area.
Population
A group of individuals of the same species living in the same area.

4. Species
Group of similar organisms that can breed and produce fertile offspring

5. Speciation Process by which a new species is formed
How does Speciation occur?

6. The combined genetic information of all of the members of a population
Gene Pool
The combined genetic information of all of the members of a population

7. GENETIC DRIFT
PROCESS IN WHICH GENE FREQUENCIES WITHIN A POPULATION CAN CHANGE BY CHANCE – NATURAL SELECTION NOT INVOLVED.

8. GENETIC DRIFT CHANCE OCCURRANCES INCLUDE :
- 1 INDIVIDUAL PRODUCES MORE OFFSPRING THAN OTHERS JUST BY CHANCE
- PART OF A POPULATION IS DESTROYED IN A DISASTER (EARTHQUAKE, FLOOD, ETC)
- EXAMPLE - NORTHERN ELEPHANT SEAL
1890 POPULATON < 20 DUE TO HUNTING. THE SURVIVORS WERE JUST THE LUCKY ONES.

10. The Bottleneck Effect
Population bottlenecks occur when a population’s size is reduced for at least one generation.
Can reduce genetic variation very quickly, even if only for one generation!

11. Founder’s Effect
A founder effect occurs when a new colony is started by a few members of the original population.
This small population size means that the colony may have:
reduced genetic variation from the original population.
a non-random sample of the genes in the original population.

14. GENE FLOW Migration
THE EXCHANGE OF GENES BETWEEN 2 OR MORE POPULATIONS
THE GREATER THE GENE FLOW, THE LESSER THE GENETIC DIFFERENCES BETWEEN THE POPULATIONS
THE LESSER THE GENE FLOW, THE GREATER THE DIFFERENCES.

15. Sources of Genetic Variation
Mutation
Gene Shuffling

16. A change in the DNA of an organism
Mutation
A change in the DNA of an organism

17. Mutation
Might affect the phenotype of the organism
Might affect the organism’s ability to survive and reproduce (fitness)

18. Gene Shuffling Rearranging of genes during reproduction
Occurs in organisms that reproduce Sexually

19. Gene Shuffling cont.
In humans, gamete formation can result in 8.4 million different gene combinations.

20. Natural Selection acts on Phenotypes!
Natural Selection determines which genes will be passed on to the next generation

21. Natural Selection can affect the genotype and phenotype of a population

22. Natural Selection and Phenotype
Natural Selection can affect the distribution of phenotypes in 3 ways:
Directional Selection
Stabilizing Selection
Disruptive Selection

23. Directional Selection
Individuals at one end of curve have an advantage (more fit).
Over time, the curve will move in one direction.

26. Disruptive Selection
Individuals at the upper and lower end of the curve have an advantage (more fit)
Eventually, the curve splits into both directions

29. Stabilizing Selection
Individuals in the middle of the curve have an advantage
The curve stays narrow and in the same place