1. Hardy-Weinberg equilibrium if p = frequency of allele A q = frequency of allele a p + q = 1, ( p + q ) 2 = 1 p 2 + 2pq + q 2 = 1 if only law of probability affects the frequency w/ which gametes combine to form new individuals

2. Bisexual population Large population Random mating No mutation Migration ~ 0 Natural selection does not affect the locus

3. A population that is in Hardy-Weinberg equilibrium will experience no change in either genotype frequency or allele frequency If one or more of the conditions is violated, genotype frequency and allele frequency will change

4. Example If only 6% of the population displays pale eyes (recessive gene e). What is the frequency of genotype Ee in this population? q 2 = 0.06 ---> q = 0.24 p + q = 1 ---> p = 0.76 Ee = 2pq = 2(0.76)(0.24) = 0.36

5. Genetic variation Cline – a measurable, gradual change over a geographical region in the average of some phenotype character Ecotype – abrupt changes in the phenotype characters within a species, which often reflect abrupt changes in local environment

6. Geographic isolates – semi-isolated populations prevented by some extrinsic barriers from a free flow of genes Genetic polymorphism – the existence within a species or population of different forms of individuals

7. Maintenance of balanced polymorphism (vs. transitional or directional polymorphism) heterosis diversifying evolution frequency-dependent selection selective forces operating in different directions within different patches of a fine mosaic in the population

8. Stabilizing, directional, diversifying or disruptive evolution Speciation Allopatric speciation Sympatric speciation

10. Isolation mechanism Pre-zygotic: habitat, temporal, ethological, mechanical Post-zygotic hybrid inviability or weakness hybrid sterility F 2 breakdown

11. Reduction in variation inbreeding, bottlenecks, founder effect, genetic drift genetic drift - random shifts in allele frequencies

12. Effect of small populations More demographic variation, inbreeding depression, genetic drift → higher risk of extinction Minimum viable population size the threshold # of individuals that will ensure the persistence of subpopulation in a viable state for a given time interval

13. Effective population size (Ne) the size of a genetically idealized population with which an actual population can be equated genetically, Ne = N, if equal sex ratio equal probability of mating constant dispersal rate progeny per family randomly distributed

14. unequal sex ratio Ne = 4 Nm˙Nf / (Nm + Nf ) population fluctuation 1 / Ne = (1 / t )(1/N 1 + 1/N 2 + … + 1/N t ) non-random progeny distribution N k Ne = ----------------------------------------- (N/N-1)˙V k /k˙(1+F) + (1-F)

15. Effect of continental drift Distribution/radiation of monotremes and marsupials

16. Extinction and its causes Natural causes: climatic changes and stochastic event Human disturbance habitat alteration over-exploitation exotic species diseases and other factors