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The Hardy-Weinberg Principles Changing Populations.

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Presentation on theme: "The Hardy-Weinberg Principles Changing Populations."— Presentation transcript:

1 The Hardy-Weinberg Principles Changing Populations

2 Evolution Evolution is caused by the changing of populations.

3 Changing Populations Populations change at the genetic level. To get the population to change the gene pool must change.

4 Gene Pool Gene pool- all of the alleles in a population Ex. 500 Flowers (show incomplete dominance) 320 RR (red) 160 Rr (pink) 20 rr (white)

5 Allele Frequency Allele frequency is the proportion of each allele found in the gene pool. p = one allele (dominant) q = the other allele (recessive) Ex. What would the allele frequency be for “R” and “r” in the wild flower population?

6 Hardy-Weinberg Equation This equation shows the frequency of each genotype we would expect to see based on the allele frequencies in the population. p 2 + 2pq + q 2 = 1 Ex. What would the genotype proportions be in the flower population?

7 Hardy-Weinberg Equilibrium If the genotype frequencies in the actual population match the proportions in the equation, then the population is in Equilibrium and not evolving. Ex. Is the flower population Evolving? ****

8 5 conditions For a population to stay in equilibrium (not evolve) five things must be true. 1 No Mutations 2 Random Mating (no sexual selection) 3 No Natural Selection 4 No Gene flow 5 Very Large Population (no Genetic Drift) These five things change the proportion of genotypes or the allele frequencies

9 Example In a population of 300 Snakes 130 are homozygous dominant for black scales. 70 are homozygous recessive and have red scales. 100 are Heterozygous are have a checker board pattern. Is this population evolving?

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