What Is Life? A Guide to Biology with Physiology & LaunchPad for What is Life? A Guide to Biology with Physiology (Twelve Month Access)
4th Edition
ISBN: 9781319201821
Author: Jay Phelan
Publisher: W. H. Freeman
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Chapter 10, Problem 7MC
Summary Introduction
Introduction:
Stabilizing selection is one of the ways in which natural selection alters the allelic frequencies in a population.
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If the X3 allele is undergoing positive selection, what will be the likely end result?
A There will be no individuals that are X3X3
B All individuals will be X1X3 or X2X3 because of the heterozygote advantage.
C The variance of the trait will stay the same, but the mean value will increase.
D The frequency of X3 will increase and it could potentially become fixed in the population.
e The allele frequency of X1 and X2 will stay the same, but the allele frequency of X3 will increase.
Saying that a quantitative trait follows a continuum means thata. the numerical value for the trait increases with the age ofthe individual.b. environmental effects are additive.c. the phenotypes for the trait are continuous and do not fallinto discrete categories.d. the trait continuously changes during the life of an individual.
Stabilizing selection on a trait tends toa. make the trait more extreme.b. reduce variability in the trait.c. decrease the frequency of alleles associated with the trait.d. result in elaborate male ornaments.
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What Is Life? A Guide to Biology with Physiology & LaunchPad for What is Life? A Guide to Biology with Physiology (Twelve Month Access)
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Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, biology and related others by exploring similar questions and additional content below.Similar questions
- Which of the following is NOT true of stabilising selection a. it occurs when inidivuals with extreme trait values have lower fitness than those with intermediate trait values. b. it keeps the mean close (or moves it closer) to the optimum value c. it can result from opposing directional selection, such as when early flowering makes flowers susceptible to herbivores, but late flowering reduces the availability of pollinators. d. it does not improve the fitness of the population to the environment. e. it decreases the range of variation in the populationarrow_forwardA species of hummingbird feeds on nectar of a particular plant whose flowers form a long, skinny cup. Beak length is a heritable trait that varies among individual hummingbirds. The birds' beaks must be long enough to reach the nectar, but longer beaks are also heavier and make flying more costly in terms of energy. a. Which mode of selection is this hummingbird species experiencing? b. How does this mode of selection affect the mean and standard deviation over time?arrow_forwardA. Use the genotype frequencies, relative fitness, and the mean relative fitness to calculate the genotype frequencies expected to be found in the next generation Show your work, include 3 decimals. p2’ = 2pq’ = q2’ = B. Is natural selection acting in this population in this new environment?arrow_forward
- Assuming a population is in Hardy-Weinberg equilibrium, an increase in the frequency of the p(A) allele from 0.6 to 0.9 would result in which of the following outcomes? a. A decrease in the number of homozygous dominant individuals within the population b. A decrease in the number of homozygous recessive individuals within the population c. An increase in the number of homozygous recessive individuals within the population d. An increase in the number of heterozygotes within the population e. No change in genotypic frequency within the populationarrow_forwardIllustrate (Draw) the following using the punnett square method:arrow_forwardConsider a gene with two alleles, L and M, that exhibit complete dominance. The table below provides the relative fitnesses of the three genotypes in two populations. LL LM MM Population 1 0.8 0.3 0.3 Population 2 0.9 1.0 1.0 a. Which allele is dominant, and how do you know? b. Which allele will increase (in each population), and how do you know? c. In which population will the change in allele frequencies occur more quickly, and how do you know?arrow_forward
- Which of the following principles of selection are true for both the sickle cell and rock pocket mice examples? Check all that apply. (1 or more are correct). Group of answer choices A_The same genotype can have higher fitness in one environment, but lower fitness in another environment B-Some genotypes have higher fitness than other genotypes C-Some genotypes have lower fitness than other genotypesarrow_forwardA type of bird on an island makes nests in both tree roots and in tree branches at various heights from the ground. A ground snake invades the island and eats eggs or chicks from nests in tree roots and low tree branches. Part A: What type of selection is operating on the height at which the bird places its nest? A. Stabilizing B. Balancing C. Directional D. Disruptive What's the rationale? What effect will this selection have on the trait phenotype (height of nest)? Answer based on chart linkedarrow_forwardWhen calculating heritability in finch beak size using parent/offspring data, we find that 70 percent of the variation in the trait is due to genetics. What might explain the remainder of the variation? Select all that apply. A. nutrition B. color C. precipitation D. stress E. rarity F. temperaturearrow_forward
- Which of the following is the best definition of fitness? a. The ability to increase the number of alleles in a gene pool b. The ability to survive for a long time c. The ability of an individual to adapt to a changing environment d. The ability to produce many offspringarrow_forward. A farmer have 2000 cows. A total of 1500 of the cows are browh coated and the rest are white coated. Allele B for the brown coat is dominant, while allele b for the white coat is recessive: Assume that the population of the cows is at genetic equilibrium and bred randomly. Calculate the frequency for the dominant and recessive alleles of the population. i. Calculate the genotype frequencies in the F1 generation if the cows are left to breed randomly. ii. If the farmer adds another 1000 homozygous dominant brown cows into the populations, calculate the new dominant allele frequency. ii. iv. State three conditions for the Hardy Weinberg equilibrium to be achieved.arrow_forward1)You measure the effects of a single allele (A2) on fitness in two populations of the same plant species, Population X and Population Y. Population X lives at higher altitudes. The average excess of fitness of the A2 allele (aA2) in Population X is 1.21, and the average fitness of the population (w) is 1.0. Population Y lives at a lower altitude. The average excess of fitness of the A2 allele (aA2) in Population Y is -1.68 and the average fitness of the population (w) is 1.0 a) Which population is likely to experience faster evolution? Why? b) What do you predict will happen to the frequency of the A2 allele (pA2) in population X? c) What do you predict will happen to the frequency of the A2 allele (pA2) in population Y? d) Why do you think the average excess of fitness of the A2 allele is different in these two populations?arrow_forward
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