1. MECHANISMS FOR EVOLUTION

2. Objectives State the Hardy-Weinburg theorem
Write the Hardy-Weinburg equation and be able to use it to calculate allele and genotype frequencies
List the conditions that must be met to maintain Hardy Weinburg equilibrium

3. VOCABULARY POPULATION SPECIES GENE POOL GENE FLOW BOTTLENECK EFFECT
FOUNDER EFFECT
HETEROZYGOTE ADVANTAGE
HYBRID VIGOR
STABILIZING SELECTION
DIRECTIONAL SELECTION
DIVERSIFYING SELECTION
SEXUAL DIMORPHISM

4. POPULATION SPECIES GENE POOL
Localized group belonging to the same species
SPECIES
Naturally breeding group of organisms that produce fertile offspring
GENE POOL
Total aggregate of genes in a population at any one time
Most species are not evenly distributed over a geographic range. Individuals are more likely to breed with others from their population center

5. HARDY – WEINBURG THEOREM
Describes a NON-EVOLVING population
In the absence of other factors the segregation and recombination of alleles during meiosis and fertilization will not alter the overall genetic make-up of a population
The gene pool will remain constant unless acted upon by outside agents. No evolution!

6. Imagine an isolated wildflower population with the following characteristics
Diploid with both pink and white flowers
Pink is dominant A and white is recessive a
There are 480 pink flowers and 20 white
320 are AA
160 are Aa
(p + q)2 = 1
p + q = 1
p2 + 2pq +q2 = 1

7. p2 = frequency of AA 2pq = frequency of Aa q2 = frequency of aa
Calculate q2 first
There are 1000 alleles
AA x 2/plant = 640
Aa x 1/plant = 160
800
aa x 2/plant = 40
Aa – 160 x 1/plant =160
200
Frequency of A = 80% and a = 20%

8. Condition for Hardy-Weinburg
Large population
No net mutation
Isolated population
Random mating
No natural selection

9. MICROEVOLUTION LEADS TO MACROEVOLUTION

10. CAUSES OF MICROEVOLUTION
GENETIC DRIFT
BOTTLENECK EFFECT
FOUNDER EFFECT

11. Bottleneck
Population bottlenecks occur when a population's size is reduced for at least one generation. Because genetic drift acts more quickly to reduce genetic variation in small populations, undergoing a bottleneck can reduce a population's genetic variation by a lot, even if the bottleneck doesn't last for very many generations. 

12. An example of a bottleneck
Northern elephant seals have reduced genetic variation probably because of a population bottleneck humans inflicted on them in the 1890s. Hunting reduced their population size to as few as 20 individuals at the end of the 19th century. Their population has since rebounded to over 30,000 — but their genes still carry the marks of this bottleneck: they have much less genetic variation than a population of southern elephant seals that was not so intensely hunted.

13. Founders
Founder effects 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. An example of Founders Effect
 the Afrikaner population of Dutch settlers in South Africa is descended mainly from a few colonists. Today, the Afrikaner population has an unusually high frequency of the gene that causes Huntington's disease, because those original Dutch colonists just happened to carry that gene with unusually high frequency. This effect is easy to recognize in genetic diseases, but of course, the frequencies of all sorts of genes are affected by founder events.

15. GENE FLOW – genetic exchange between populations due to migration
Mutation – a new mutation that is transmitted in a gamete can immediately change the gene pool
NONRANDON MATING
Breed with other members of the “neighborhood” promotes inbreeding
Assortative mating – mate with others like themselves
NATURAL SELECTION

16. Variation within Populations
Most heritable variation is measured by
Quantitative characters (vary along a continuum ie. Height) are polygenetic
Discrete characters (pink or white) are located on a single gene
Polymorphism – two or more forms of a discrete character are represented in a population

17. GEOGRAPHICAL VARIATION
A cline is a graded change in some trait along a geographical axis.

18. MODES OF SELECTION