In a study of genetic variation of the Graceland gene, a researcher finds that there are...
In a study of genetic variation of the Graceland gene, a researcher finds that there are two alleles in a population. In a large sample (500 individuals), the frequency of heterozygotes is 0.63. You monitor the population and determine that all requirements for the Hardy-Weinberg principle have been satisfied. You come back after 500 generations have past and observe that the frequency of heterozygotes is still 0.63. You conclude that the population is experiencing selection. Which type of selection is the population most likely experiencing?
Homework Answers
Answer: Stabilizing selection
Explanation: Since there is no change in the average phenotypic
range (i.e. the frequency of the heterozygotes), it must be
stabilizing selection.
Natural selection is the driving force of evolution. Alleles that provide a selective advantage to the prevailing environmental conditions are selected and non-adaptive/deleterious alleles are subsequently eliminated from the population. There are three types of natural selection.
1. Stabilizing selection: It is also known as centripetal selection. It operates in a stable environment and eliminates individuals at the two ends of the phenotypic distribution. It preserves individuals with the average phenotypic distribution. It is not a driving force of speciation. However, it eliminates deleterious genotypes from the population. Ex: A greater mortality rate is observed in babies when the birth weight is higher or lesser than the average weight.
2. Directional selection: It is also known as phyletic evolution or anagenesis. It operates in a gradually changing environment. It eliminates individuals with one end of the phenotypic distribution and preserves individuals with the other/opposite end of the phenotypic distribution. The average value of the phenotype is gradually shifted to either of the ends. It is a good driving force of speciation. Ex: Mosquitoes with high DDT resistance are selected over less resistant strains.
3. Disruptive selection: It is also known as centrifugal selection or adaptive radiation. It operates in heterogeneous environmental conditions. It eliminates individuals with the average phenotypic value and selects individuals with either end of the phenotypic distribution. The phenotypes are moved away from the starting average value. It is a major driving force of speciation. Ex: Evolution of different species of finches on the Galapagos islands.
Add Answer to:
In a study of genetic variation of the Graceland gene, a
researcher finds that there are...
1. You are studying a color polymorphism in a population of soapberry bugs. A single gene...
1. You are studying a color polymorphism in a population of soapberry bugs. A single gene controls color variation; individuals with at least 1 copy of the R allele at this locus are red while individuals of the rr genotype are white. You know that this population satisfies the conditions for Hardy-Weinberg Equilibrium, and that 64% of the population shows the red phenotype. What is the frequency of the R allele? Show your work. 2. Male Trinidadian guppies use bright...
1. Which of the following mutations could create a frameshift and change the sequence of a...
1. Which of the following mutations could create a frameshift and change the sequence of a protein? 1. A back mutation 2. Deletion of a base 3. Insertion of a base 4. A base substitution of C for A I 2. Which of the following is NOT common to ALL forms of speciation? Select one: a. Formation of a new species b. None, all of these are common to all forms of speciation c. Ecological isolation d. Limited gene flow...
Page 2 7. In a species of non-poisonous butterfly species are avoided by predatory birds: individuals...
Page 2 7. In a species of non-poisonous butterfly species are avoided by predatory birds: individuals that are intermediate closely match either of the two poisonous species are readily eaten by predators. This isanampe tropical butterfly, individuals that resemble one or the other of two poisonous in appearance and do not a. directional selection b. stabilizing selection c. disruptive selection d. genetic drift e. gene flow 8. An evolutionary process that reduces among-population genetic variation genetic variation is: but increases...
1. You are studying a population of sandblossoms (Linanthus parryae) that has individuals with blue and...
1. You are studying a population of sandblossoms (Linanthus parryae) that has individuals with blue and white flowers. The allele for white flowers (A) is dominant to the allele for blue flowers (a). In the population you survey, 91 out of 100 individuals have white flowers. Based on this information: a. Calculate the frequency of the A and a alleles. b. Calculate the numbers of each genotype. 2. A population of snapdragons (Antirrhinum hispanicum) has two additive alleles for flower...
2.3 Problem 3 The Hardy-Weinberg equation is useful for predicting the percent of a hu- man...
2.3 Problem 3 The Hardy-Weinberg equation is useful for predicting the percent of a hu- man population that may be heterozygous carriers of recessive alleles for certain genetic diseases. Phenylketonuria (PKU) is a human metabolic dis- order that results in mental retardation if it is untreated in infancy. In the United States, one out of approximately 10.000 babies is born with the disor- der. Approximately what percent of the population are heterozygous carriers of the recessive PKU allele? If you...
1. Fixation of Dominant Alleles Start with a population that has a gene with two alleles (A and a...
1. Fixation of Dominant Alleles Start with a population that has a gene with two alleles (A and a) with classical Mendelian dominance that are at equal frequency (p0.5. q 0.5). Assume this first generation is at hardy Weinberg equilibrium. Calculate the genotype frequencies AA- a. Aa b. Now assume some environmental change that makes the recessive phenotype completely unfit (fitness- 0). Calculate the allele frequencies and genotype frequencies in the second generation. (Hint: Your calculations might be easier if...
1. Which of the following is FALSE? A. If a genetic disease reduces fertility and the...
1. Which of the following is FALSE? A. If a genetic disease reduces fertility and the allele that causes the disease offers no other advantage, the allele will likely eventually disappear, due to natural selection. B. Natural selection does not favor individuals who are homozygous for the sickle-cell allele, because these individuals typically die before they are old enough to reproduce. C. Individuals who are heterozygous HbA/HbS are protected from malaria, and this is why sickle-ce disease persists in wetter,...
QUESTION 4 1 points Save Answer One metric of genetic diversity in a population is heterozygosity,...
QUESTION 4 1 points Save Answer One metric of genetic diversity in a population is heterozygosity, i.e., the frequency of heterozygotes. For the marker(s) that are not in Hardy-Weinberg equilibrium, does the difference between Ho and He indicate increased or decreased heterozygosity for those markers? Increased heterozygosity Decreased heterozygosity QUESTION 5 2 points Save Answer Select all the mechanisms of evolution that could explain the deviations from H-W expected frequencies for those markers, based on the difference in heterozygosity? Selection...
In the gene pool of a population with 132 individuals, a fixed allele for a particular...
In the gene pool of a population with 132 individuals, a fixed allele for a particular genetic locus has a frequency of Select one: O a. 1 O b. More information is needed to determine this. O c. 0.75 O d.o O e. 0.5 Which of the following does not have the ability to alter allele frequencies? Select one: O a. gene flow O b. inbreeding O c. genetic drift O d. natural selection O e. All of these have...
Climate change is a threat to the existence of many species.
QUESTION 2 Climate change is a threat to the existence of many species. Which of the following limits to natural selection hinders the adaptation of species to the new climate conditions? The developmental plans of plants and animals are too complex. They cannot cope with the warmer temperatures. Mutations happen so frequently that beneficial alleles change before natural selection can substantially increase their frequency Many species not have gene variants in their gene pool that are beneficial in higher temperatures. Climate change happens so...
1. Which of the following mutations could create a frameshift and change the sequence of a protein? 1. A back mutation 2. Deletion of a base 3. Insertion of a base 4. A base substitution of C for A I 2. Which of the following is NOT common to ALL forms of speciation? Select one: a. Formation of a new species b. None, all of these are common to all forms of speciation c. Ecological isolation d. Limited gene flow...
Page 2 7. In a species of non-poisonous butterfly species are avoided by predatory birds: individuals that are intermediate closely match either of the two poisonous species are readily eaten by predators. This isanampe tropical butterfly, individuals that resemble one or the other of two poisonous in appearance and do not a. directional selection b. stabilizing selection c. disruptive selection d. genetic drift e. gene flow 8. An evolutionary process that reduces among-population genetic variation genetic variation is: but increases...
2.3 Problem 3 The Hardy-Weinberg equation is useful for predicting the percent of a hu- man population that may be heterozygous carriers of recessive alleles for certain genetic diseases. Phenylketonuria (PKU) is a human metabolic dis- order that results in mental retardation if it is untreated in infancy. In the United States, one out of approximately 10.000 babies is born with the disor- der. Approximately what percent of the population are heterozygous carriers of the recessive PKU allele? If you...
1. Fixation of Dominant Alleles Start with a population that has a gene with two alleles (A and a) with classical Mendelian dominance that are at equal frequency (p0.5. q 0.5). Assume this first generation is at hardy Weinberg equilibrium. Calculate the genotype frequencies AA- a. Aa b. Now assume some environmental change that makes the recessive phenotype completely unfit (fitness- 0). Calculate the allele frequencies and genotype frequencies in the second generation. (Hint: Your calculations might be easier if...
QUESTION 4 1 points Save Answer One metric of genetic diversity in a population is heterozygosity, i.e., the frequency of heterozygotes. For the marker(s) that are not in Hardy-Weinberg equilibrium, does the difference between Ho and He indicate increased or decreased heterozygosity for those markers? Increased heterozygosity Decreased heterozygosity QUESTION 5 2 points Save Answer Select all the mechanisms of evolution that could explain the deviations from H-W expected frequencies for those markers, based on the difference in heterozygosity? Selection...
In the gene pool of a population with 132 individuals, a fixed allele for a particular genetic locus has a frequency of Select one: O a. 1 O b. More information is needed to determine this. O c. 0.75 O d.o O e. 0.5 Which of the following does not have the ability to alter allele frequencies? Select one: O a. gene flow O b. inbreeding O c. genetic drift O d. natural selection O e. All of these have...
Most questions answered within 3 hours.
-
Choose all that are true:
A)
A FileReader object can be passed to BufferedReader or Scanner...
asked 1 minute from now -
a sample of the labor costs per hour to assemble a product has a
mean of...
asked 2 minutes ago -
Research taking place at Stanford University has been a
consistent force in the development of Silicon...
asked 3 minutes ago -
what evidence is there that mitochondria and chloroplasts
originated from ancient prokaryotes and why?
asked 7 minutes ago -
A Mg|Mg2+ ||
Ni2+|Ni galvanic cell
is constructed in which the standard cell voltage is
2.12...
asked 8 minutes ago -
An organization's routine purchase changes when a supplier
discontinues a product. In such a situation, which...
asked 19 minutes ago -
Like Jupiter's moon Europa, Saturn's moon Enceladus is high on
our list for exploration. List and...
asked 22 minutes ago -
Problem 9-21
(Algorithmic) (LO. 2, 3)
Taylor, age 16, is a
dependent of her parents. For...
asked 32 minutes ago -
An egg is thrown nearly vertically upward from a point near the
cornice of a tall...
asked 29 minutes ago -
Find a map online of major or minor tectonic plates, and choose
one of interest to...
asked 46 minutes ago -
5. Explain why direct antigen activation of CTLs and B cells is
more important than APC-initiated...
asked 52 minutes ago -
Seaborgium (Z= 106) can be synthesized by the bombardment of
249Cf with 16O. If four (4)...
asked 59 minutes ago