HARDY-WEINBERG AND GENETIC EQUILIBRIUM Ch pp Warm-up 2/24: Make a double bubble (or Venn diagram) comparing and contrasting convergent and divergent evolution. Make sure to include at a minimum: Homologous Structures Analogous Structures Adaptive radiation Co-evolution Artificial Selection Environment Embryology Biogeography Vestigial Structures Phenotype Genotype Common Ancestor

 Analogous Structures  Biogeography  Environment  Co-evolution  Phenotype  Genotype ConvergentBothDivergent  Artificial Selection  Adaptive radiation  Homologous Structures  Embryology  Vestigial Structures  Common Ancestor

Variation of Traits in a Population  In a population, organisms tend to show small variations of a trait  Bell Curve – shows that whereas a few fish are very short and a few are very long, most are of average length.  Variations are caused by mutations, genetic recombination, and random-pairing of alleles

WHAT CAUSES THESES VARIATIONS? 1. Mutations- Random change in DNA passed to offspring 2. Recombination- reshuffling of genes during Meiosis a) Independent assortment b) crossing over 3. Random pairing of gametes

The Gene Pool Gene Pool = the total genetic information stored in a population Adapting to new selection factors can only use existing genes found in the population Allele Frequency = the number of a certain allele in the population / the total number of all alleles The phenotype frequencies can change between generations but allele frequencies that create the phenotypes generally do not change very much between generations A population is the smallest level evolution can work on, changing the genetic composition of the population over time.

The Gene Pool  Gene Pool- genetic variation stored in population  Each allele exists at a certain frequency - gene frequency

Hardy-Weinberg Genetic Equilibrium States that genotype frequencies remain the same from generation to generation unless acted upon by an outside influence Makes the following assumptions for a theoretical non-evolving population: 1) No Net Mutations – alleles remain the same 2) Individuals neither enter nor leave the population – no immigration/emigration 3) Large population – ideally infinitely large 4) Random mating 5) Selection does NOT occur – no natural or artificial selection at work Keep in mind this is theoretical!!! These rules generally allow us to determine the source of a population’s change

Homework  Quiz: Friday & VOCAB Due Friday  Evidence For Evolution Packet  Vestigial Structures & Homologous Structures p 3-5: Due Thursday  Embryology p Due Monday (2/29)  Evidence For Evolution Flipbook  Page #3 Due Thursday  Pages #4-5 Due Friday  Pages # 6-7 Due Tuesday (3/1)

Flipbook Due Friday Quiz Friday & HW Read p Do p320 #1-5 Both Due Mon.

Superposition Biogeography Phylogeny/ phylogenic tree Adaptive Radiation Allele frequency Gene pool Hardy-Weinberg genetic equilibrium Flipbook Due Friday Quiz Friday & HW Read p Do p320 #1-5 Both Due Mon.