1. Evolution of Populations 2010

2. The Modern Synthesis Population genetics integrates Darwinian evolution and Mendelian Genetics Important terms in population genetics: Population: group of individuals of same species Species: groups of populations that are capable of interbreeding and producing fertile offspring in nature Gene pool: total aggregate of genes in a population

3. Hardy – Weinberg Theorem Gene pool of non-evolving population States that the frequency of alleles and genotypes in a population’s gene pool remain constant unless acted upon by agents other than Mendelian segregation and recombination of alleles. p+q = 1 Hardy Weinberg Equilibrium: p 2 + 2pq + q 2 = 1 P 2 = Frequency of RR phenotype 2pq -= Frequency of Rr phenotype q 2= Frequency of rr phenotype

4. Conditions that must be met: 1. Very large population size. 2.No migration 3.No net mutations 4.Random mating 5.No natural selection Do you that any natural populations are in Hardy- Weinberg equilibrium?

5. Microevolution Generation to generation change in the population’s frequency of alleles 2 main causes: genetic drift – change due to chance, small populations & natural selection Other causes -

6. Bottleneck Effect Drastically reduced population sizes Small population size may not be representative of original gene pool Reduction in genetic variablility

7. The Founder Effect Occurs when a few individuals colonize an isolated habitat from a larger population

8. Gene Flow Genetic exchange through migration – gain or loss of alleles

9. Mutation Substitutes one allele for another

10. Selection Types

11. Sexual Selection

12. Speciation – Biological Species Concept Prezygotic Barriers: habitat isolation, behavioral isolation, temporal isolation, mechanical isolation, gametic isolation Postzygotic Barriers: reduced hybrid viability, reduced hybrid fertility, hybrid breakdown

13. Types of Speciation Allopatric: geographic barriers, disruption of gene flow Sympatric: genetic causes – polyploid (plants), other genetic factors

14. Tempo of Evolution Darwin – gradual continual rate Punctuated equilibrium model: spurts of rapid change followed by periods of relatively little change (Ex. Species exists for 5 million years but most morphological changes in 50,000 yrs – just 1%).

15. Phylogenies Many lines of evidence compiled Biogeographical, fossil, morphological similarities (homologous not analogous structures), genetic evidence

16. Categories of Evolution Convergent evolution - acquisition of the same biological trait in unrelated lineages. Leads to analogous structures

18. Parallel evolution is the development of a similar trait in related, but distinct, species descending from the same ancestor, but from different cladesclades

19. Divergent evolution - accumulation of differences between groups which can lead to the formation of new species, usually a result of diffusion of the same species adapting to different environments

21. Major Lineages of Life 3 domains: Bacteria, Eukaryota, Arachae