BIO 3102 Study Guide - Chromosome, Ernst Mayer, Speciation

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peartortoise481

11 Jul 2014

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Incorporation of mendellian genetics in natural philosophy: natural selection had no mechanism,multiplication of species is the way we get new species. By incorporating mendellian genetics we are able to explain the holes in darwin"s theories: no change in frequency no evolution. Changes in allele frequencies in a population cause evolution: 2 of every allele and they express a phenotype which is different of a genotype. Mendel sorted all this out before meiosis and mitosis: hardy and wineburg study heredity and apply mathematical probability to it, using hardy and wineburg principle they are able to see if there is a change in allele frequency. Change and variation which occurs in a population: evolution. Genetic soo strong u end up with genetic fixation. Fixation b1 allele gets fixed in the population while the other is lost through generations. You will get the bell curve for most traits in a population.

Related Questions

In 1908 Hardy and Weinberg published papers showing that the binomial or multinomial could be applied in genetics to predict the frequencies of genotypes when allele frequencies where known. The formal algebraic proof of this Hardy-Weinberg Equilibrium Law assumes that there is no mutation in the population. This assumption is necessary, because a. organisms reproduce sexually and litter or family sizes vary. b. populations will exhibit random sampling changes in allele frequency. c. populations are not infinite and the Hardy-Weinberg proof is only a very crude approximation when natural selection is acting. d. populations are not closed and reproduce both sexually and asexually so an infinite size population is required to preserve genetic variation. e. allowing alleles to change would alter their frequencies.

amethystcrab894

Hardy and Weinberg (one a genetics expert and the other a mathematician) independently demonstrated that the alleles within populations may be stable under certain conditions. If the allele frequency is variable, they will change, and evolution is possible. If the allele frequencies are stable, will evolution be possible? THINK about this... by definition, evolution will NOT occur when the allele frequencies are stable.

1) What are the assumptions for STABLE allele frequencies for a population from one generation to the next?

2) Next, what occurs if any of these assumptions do not hold true (another words...the assumption do NOT apply)?

3) From the list of assumptions, select one (only ONE) and describe how it may/may not apply to a ânatural populationâ (this where things get very cool...)

purpleduck821

Consider two populations of guppies living in a tropical stream. One is upstream of a waterfall, and the other is downstream. In both populations, homozygous individuals have either blue or red stripes, depending on the allele they carry: R for the red allele and B for the blue. RB heterozygotes have purple stripes.

In the downstream population only, there are crayfish that feed on the guppies. Because the crayfish can't see red colors, the red-striped guppies have higher fitness than blue or purple. Comparison to the upstream population, where there are no crayfish, indicates that the selection coefficient on purple and blue guppies is 0.25.

The current frequency of the R allele is 0.64. Your job is to calculate the percent change in allele frequency that occurs in the next generation due to crayfish predation. To do this you should:

a) Use the Hardy-Weinberg principle to determine expected genotype frequencies in the generation without selection

b) Determine the relative fitness of each genotype

c) Calculate the genotype frequencies in the new population following selection.

d) Find the percent change in allele frequency of the resistant R allele.

cerisesquirrel57

BIO 3102 Study Guide - Chromosome, Ernst Mayer, Speciation

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