However, for individuals who are unfamiliar with algebra, it takes some practice working problems before you get the hang of it. Below I have provided a series of practice problems that you may wish to try out. The frequency of the "a" allele. The frequency of the "A" allele. The frequencies of the genotypes "AA" and "Aa. Sickle-cell anemia is an interesting genetic disease. Normal homozygous individials SS have normal blood cells that are easily infected with the malarial parasite.
Thus, many of these individuals become very ill from the parasite and many die. Individuals homozygous for the sickle-cell trait ss have red blood cells that readily collapse when deoxygenated. Although malaria cannot grow in these red blood cells, individuals often die because of the genetic defect.
However, individuals with the heterozygous condition Ss have some sickling of red blood cells, but generally not enough to cause mortality. In addition, malaria cannot survive well within these "partially defective" red blood cells. Thus, heterozygotes tend to survive better than either of the homozygous conditions. There are students in a class. Ninety-six did well in the course whereas four blew it totally and received a grade of F. The frequency of the dominant allele.
The frequency of heterozygous individuals. Within a population of butterflies, the color brown B is dominant over the color white b. Given this simple information, which is something that is very likely to be on an exam, calculate the following: The percentage of butterflies in the population that are heterozygous. The fish are healthy and strong, all exactly the same except for the coloring.
Fishermen visit the lake, and catch 7 fish with red spots and 1 fish with no red spots, leaving 1 with red spots and 3 without red spots remaining in the lake. All the factors listed are factors that can change the genetic equilibrium of a population. Genetic drift is a random change in the frequency of alleles, as in this question—at first, there were more red-spotted fish than spotless fish a ratio , but once the random fishing took place, there were fewer red-spotted fish than spotless fish a ratio.
This selection by chance is genetic drift. Gene flow is the movement of alleles into or out of a population, generally due to patterns of migration. Migration is the physical departure or arrival of organisms between different populations or geographical locations. Natural selection is the increased prevalence of "favorable" traits and genes, and the decline in prevalence of "unfavorable" traits and genes.
Mutation is a genetic alteration that results in a new DNA sequence. Mutation is responsible for the creation of new alleles, traits, and phenotypes. Which of the following is not an application of the assumptions underlying Hardy-Weinberg equilibrium?
Hardy-Weinberg equilibrium describes no change in genotypic frequencies over multiple generations. This is not likely to be seen in nature due to multiple factors, but it can be a useful theory for scientists. Hardy-Weinberg equilibrium requires no immigration or emigration, a large population, random mating, and no spontaneous mutations all of which are virtually unavoidable in nature.
Natural selection would violate these conditions. Hardy-Weinberg equilibrium describes no change in the genotypic frequencies of a population. After one generation, assuming random mating, a closed system, a large population, and no random mutations, the genotypic frequencies of the population will not change. If you've found an issue with this question, please let us know. With the help of the community we can continue to improve our educational resources.
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Organisms entering or leaving the population must not change the gene pool frequencies. Correct answer: The population must be at carrying capacity. Explanation : Hardy-Weinberg equilibrium has a set of conditions that must be met in order for the population to have unchanging gene pool frequencies. Report an Error. Possible Answers: There is a large population of birds on an island.
Birds with black feathers prefer to mate with birds that have similarly colored feathers. Predators do not discriminate between members of the species with different colored feathers. The population is isolated on an island, and new birds are unable to fly to the island. Correct answer: Birds with black feathers prefer to mate with birds that have similarly colored feathers. Explanation : If a population is in Hardy-Weinberg equilibrium, there is no evolution taking place in the population.
Possible Answers: Mutation. Correct answer: Differentiation. Another factor that can upset this equilibrium is genetic drift, which occurs when allele frequencies grow higher or lower by chance and typically takes place in small populations. Gene flow, which occurs when breeding between two populations transfers new alleles into a population, can also alter the Hardy-Weinberg equilibrium.
Because all of these disruptive forces commonly occur in nature, the Hardy-Weinberg equilibrium rarely applies in reality. Therefore, the Hardy-Weinberg equilibrium describes an idealized state, and genetic variations in nature can be measured as changes from this equilibrium state. Hardy-Weinberg equilibrium. Further Exploration Concept Links for further exploration genotype allele natural selection evolution speciation dominant recessive allele frequency Hardy-Weinberg equation population bottleneck genetic drift gene flow.
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