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Climate change has caused a slight rise in the average temperature in the Andes Mountains in South America. Predict what might happen to hair length in llama populations over time. Type of Selection? How will the graph change?. CATALYST. Shaved Alpacas.
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Climate change has caused a slight rise in the average temperature in the Andes Mountains in South America. Predict what might happen to hair length in llama populations over time. Type of Selection? How will the graph change? CATALYST Shaved Alpacas
Evolution = changes in the relative frequencies of alleles in the gene pool of a population Defining Evolution: Genetics
How do we decide if a population is evolving? THE HARDY-WEINBERG EQUILBRIUM!
THE HARDY-WEINBERG EQUILBRIUM! For a given gene there are two alleles – A and a Frequency of A = p Frequency of a = q p + q = 1
THE HARDY-WEINBERG EQUILBRIUM! All the sperm in the population a A A All the eggs in the population a Frequency of genotypes of offspring:
THE HARDY-WEINBERG EQUILBRIUM AS A NULL HYPOTHESIS For a locus with two alleles (A and a) in a population at risk from an infectious disease, 16 people had the genotype AA, 92 had the genotype Aa, and 12 had the genotype aa. Is this population evolving?
OTHER USES OF H-W EQUILIBRIUM: DETERMINING THE # of HETEROZYGOTES Black skin is recessive to pink
OTHER USES OF H-W EQUILIBRIUM: DETERMINING THE # of HETEROZYGOTES
Your turn to practice! THE HARDY-WEINBERG EQUILBRIUM!
THE HARDY-WEINBERG EQUILBRIUM! • 5 assumptions: • No natural selection! • No genetic drift! • No gene flow! • No mutation • No nonrandom mating!
GENETIC DRIFT Genetic Drift =
GENETIC DRIFT : Founder Effect Afrikaner population of South Africa descended from a few Dutch colonists. Today, they have an unusually high frequency of the gene that causes Huntington’s Disease.
GENETIC DRIFT: Bottleneck Effect Pingelap Atol, South Pacific 1775 Typhoon and Famine
GENETIC DRIFT: Bottleneck Effect Survivors included 1 individual with a mutation on gene CNGB 3 Individuals who are homozygous recessive are colorblind Frequency of allele worldwide < 1% Frequency of allele in Pingelap Atol is > 20%!
GENE FLOW Gene Flow =
GENE FLOW – Inhibiting Fitness Gene flow inhibits bent grass populations growing next to copper mines from evolving
GENE FLOW – Spreading Fitness Worldwide spread of insecticide resistance in Culex pipiens
MUTATION – How does it impact fitness? How important is it?
NONRANDOM MATING – Sexual Selection! A peacock’s tail…an adaptation? Why or why not?