1. Daily Warm-up February 3rd
Describe an example of analogous structures and how you would know that they were analogous.
HW:
-Read 21.1 and 21.2
Turn in:
-Nothing

2. Microevolution
Evolution on the smallest scale
Within a population

3. Genetic Variation and Evolution
NEED genetic variation to have evolution
How do you get it?
Mutations
Altering gene number or position
Rapid reproduction
Sexual reproduction
Crossing over
Fertilization
Independent assortment

4. Genetics of a Population
Gene pool- all copies of all alleles of all genes
Each allele has a frequency in a population
If there are 500 individuals, how many alleles will they have for a particular gene?

5. Allele Notations
When there is a locus with two alleles: p= dominant allele p2 = dominant homozygous genotype q= recessive allele q2 = recessive homozygous genotype 2pq= frequency of heterozygous genotype ***Sum of all allele frequencies must=1

6. Hardy-Weinberg equilibrium
Hypothetical situation
serves as null hypothesis
non-evolving population
REMOVE all agents of evolutionary change
no genetic drift (very large population size )
no gene flow (no migration in or out)
no mutation (no chemical change to DNA)
random mating (no sexual selection)
no natural selection (equal survival)
It is unlikely that all the conditions for Hardy-Weinberg equilibrium will be met
Allelic frequencies change
Populations evolve
Tested by applying the Hardy-Weinberg

7. So, if….
Evolution: change in the genetic composition of a population over time
Then, a population that meets the Hardy-Weinberg principle is not evolving.
Can use the Hardy-Weinberg principle to test whether or not a population is evolving.

8. H-W Equations Allele frequency: Genotype frequency: p+q=1
p is dominant allele and q is recessive allele
Genotype frequency:
p2 + 2pq + q2 =1
***If in H-W, most populations will have as values***

9. Solving Hardy-Weinberg equations
1. ALWAYS start with the recessive genotype
2. Calculate recessive allele frequency
Square root
3. Plug and chug
Remember, none of the frequencies should be over 1.