BIOL 112 Chapter 23: Chapter 23 The Evolution of Populations

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amberbeetle316

31 Jul 2016

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Evolution impacts entire population, not just single individuals. Microevolution- change in allele frequencies in a population over generations. factors that can change allele frequency: genetic drift, gene ow, natural selection. Generic variation- differences among individuals in the composition of their genes or other dna sequences. Can be measured through: number of heterozygous loci and dna differences in introns and exons. Neutral variation- point mutation in a non-coding region -> they do not create an advantage or disadvantage. Large scale changes in chromosomes are found to be harmful but sometimes can be bene cial to an organism. Gene duplication with no effect can accumulate over generation, becoming more harmful. Rna mutates more than dna (rna doesn"t have a repair mechanism) crossing over, independent assortment and fertilization allow successful genetic variation within a population. Hardy weinberg equation represents a population that"s not evolving and can also be sued to estimate the percentage of a population that has a speci c disease.

Related Questions

You are an ecologist studying a population ofgerbils that can be found in nature with 3 different colors. Anindividual gerbil can be, dark brown, medium brown, or lightbrown. There are 2 alleles for this gene B and b. Thecolor trait is determined by incomplete dominance. This is a casewhere one allele is not dominant over the other but insteadheterozygous individuals show an intermediate phenotype. In thiscase of incomplete dominance Dark brown individuals are homozygousBB, medium brown individuals are heterozygous Bb, and light brownindividuals are homozygous bb. You spend a night trapping andcatch.

10 Dark brown gerbils
10 Medium brown gerbils
10 Light brown gerbils

What is the gene pool in thispopulation?
What is the gene frequency in thispopulation?

Explain how genetic drift could alter thegene frequency in a population. Use your data from the geneticdrift experiment to support your answer.

lavendercockroach31

Q1. What are alleles?Different forms of the same gene.Different genes.The different characteristics of an organism.Genes found only in humans.Q2. If you add up the frequency of homozygotes + the frequency of heterozygotes for one gene (i.e. at one locus) in a population, what number do you get?Q3. People who are heterozygous for the sickle-cell allele:Are susceptible to malaria but not sickle-cell anemia.Are susceptible to sickle-cell anemia but not malaria.Are not susceptible to either sickle-cell anemia or malaria.Are susceptible to both sickle-cecell anemia and malaria.Q4. In the case study in this lab, which genotype is represented by "2pq" in the Hardy-Weinberg equation?Homozygous HbAHomozygous HbSHeterozygous HbA/HbSNo specific genotypeQ5. Suppose that, in an isolated village, the proportion of individuals that have sickle-cell anemia is 0.1 (or 1 of every 10 people). What proportion of the population should be sickle-cell carriers, according to Hardy-Weinberg expectations?Q6. When you simulated the elimination of malaria at the beginning of the lab, once the allele frequencies stabilized, what was the frequency of the HbA allele?Q7. When you investigated regional differences, what was the frequency (over many generations) of the HbS allele in the village in the "slightly wet" part of Africa?Q8. What is the number of deaths due to sickle-cell anemia in a region without mosquitoes expected to be?Very lowVery highModerateRelated to the frequency of malaria allelesQ9. As long as there are multiple alleles of a gene in a population, why will the frequencies of the alleles always change over time?Because natural selection changes all allele frequencies in populations over time.Because genetic drift causes random fluctuations of allele frequencies in populations.Because diseases will eliminate some of the alleles, generating fluctuations in their frequencies.Because allele frequencies fluctuate before the alleles eventually become fixed.Q10. Imagine a huge population with a gene that has ten functionally equivalent, neutral alleles. A small but genetically representative group of individuals from the big population is transported to an island, forming a small population. Which of the statements below best describes what will likely happen over time, and why?Because natural selection doesn't act on neutral alleles, the frequencies in the two populations should remain the same over time.Genetic drift will cause one allele to first become fixed in the island population, and later to become fixed in the original, large population.Genetic drift will result in the allele frequencies of the two populations diverging over time, with alleles being lost sooner in the island population.The allele frequencies of the two populations will change similarly due to a combination of genetic drift natural selection.

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BIOL 112 Chapter 23: Chapter 23 The Evolution of Populations

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