Biological Science
5th Edition
ISBN: 9780321743671
Author: Scott Freeman
Publisher: PEARSON
expand_more
expand_more
format_list_bulleted
Concept explainers
Question
Chapter 27, Problem 11TYU
Summary Introduction
To review:
Whether the phenomenon of increased gene flow among humans (occurring due to intermarriage among different ethnic groups and regions of world), is increasing or decreasing the racial differences.
Introduction:
Gene flow is the movement of individuals from one area to another. This results in altered gene frequency, thus disturbing the Hardy Weinberg equilibrium.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solutionStudents have asked these similar questions
Dunkers are part of a religious group which originated from 27 families that emigrated from
Germany to the USA in the XVIIIth century. Dunkers only mary between themselves. The frequency
of the M allele in the MN blood group system is 0.65 among Dunkers while it is 0.54 in both German
and American populations.
a) How can you explain this observation ? Is this due to genetic drift, natural selection, or
inbreeding?
The remote South Atlantic island of Tristan da Cunha was first colonized in 1818 by exactly 20 people, 12 men and 8 women. It’s reasonable to assume that the starting genetic variation in the population was high – the men were all English while the women were primarily of African descent- so we’ll say that heterozygosity was 0.5. The breeding sex ratio in this starting population was 1:1 (which each woman having children with only a single man). Let’s also assume that the generation time across this time interval has been constant at 20 years.
1a. If these conditions held constant – what would the expected heterozygosity be in the population today (2018 to deal with a clean integer value for generations)?
1b. In 1884 the population had grown to 106 when disaster struck the island. Of the 19 adult men on the island, 15 were in the same fishing boat that capsized, leaving only 4 adult men alive on the island. These desperate times may have changed the sex ratio of the breeding population…
background: Lizards often have bright coloration and in some species there is variation in coloration within populations. For the sake of simplicity, let’s assume that color is genetically determined by a single gene with two alleles that interact in a codominant fashion: r+r+ = red, r+r- = yellow, r-r- = white.
Imagine there is a large population of these lizards where 1 in 200 lizards have the white coloration, 30 are yellow and the rest are red. A tsunami sweeps through the population! Although no lizards died, 10 random lizards were swept to a nearby island. One of these individuals is white while the rest were yellow. Over time, these individuals remain stuck on the island and form a new population. Eventually, 80% of this population has the white coloration. Assume that color does not affect fitness in either population.
question: At the time of the founding of the smaller population, (when 1/10 were white, the rest yellow), what was the chance of fixation of the r- allele via…
Chapter 27 Solutions
Biological Science
Ch. 27 -
1. What distinguishes a morphospecies?
a. It has...Ch. 27 - 2. Which of the following describes vicariance?
a....Ch. 27 - The biological species concept can be applied only...Ch. 27 - True or False? Gene flow increases the divergence...Ch. 27 - 5. When the ranges of two different species meet,...Ch. 27 - 7. QUANTITATIVE If one species (2n = 10) crosses...Ch. 27 - Prob. 15TYPSSCh. 27 - Prob. 16TYPSSCh. 27 - Prob. 3TYKCh. 27 -
5. Why is “reinforcement" an appropriate name for...
Knowledge Booster
Learn more about
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
- In the Paraguayan Easter Atlantic Forest, a mating between a homozygous black yaguarundi and a homozygous blond yaguarundi will produce all brown yaguarundi offspring. When these brown F₁ yaguarundies are mated, their offspring consists of 2 white, 31 black, 154 brown, and 17 blond yaguarundies. A) Name what genetic interaction or ratio (depending on the ratio expected) may be occurring in this population? B) What are the observed and expec phenotypic ratios for these F2 progeny? C) Use a Chi-squared analysis to test your hypothesis (set a = 0.05). Be sure to report all values used in your comparisons (p-values, critical values, alpha value, df, etc), your hypothesis, and show your work.arrow_forwardShort eyelashes are dominant to extra-long eye lashes. In a large, randomly mating population with no forces acting to change gene frequencies, 1600 people out of 10000 have extra-long eye lashes. a)What is the number of people in the population who are expected to be heterozygous? Show your calculation below. b) Would the frequency of the extra-long lash allele increase, decrease, or remain the same if long-lashed individuals preferentially mated with each other and no one else? Explain.arrow_forwardIn Africa we find albinism in around 1 in every 5,000 individuals. This is puzzling, because albinism may reduce survival, for instance due to increased risk of skin cancer. What evolutionary mechanism (natural selection, mutation, genetic drift, or gene flow) is a viable explanation for the consistent observation of a few children born with albinism each generation and why?arrow_forward
- You are studying a population of penguins in Antarctica. Your DNA analysis of this population reveals that for the feather color pattern gene, 35 individuals are homozygous dominant, 35 individuals are heterozygous, and 30 individuals are homozygous recessive. After observing this population for several years, you repeat your DNA study and find that the current generation of penguins has 15 individuals that are homozygous dominant, 10 individuals that are heterozygous, and 75 individuals that are homozygous recessive. Which of the following hypotheses for this data would be supported by this data based on your understanding of Hardy-Weinberg equilibrium? This population of penguins is maintaining Hardy-Weinberg equilibrium due to its large population size. The penguins are randomly choosing mates, which has led to Hardy-Weinberg equilibrium. The penguins are very isolated, which is preventing gene flow from affecting Hardy-Weinberg equilibrium. The recessive phenotype in…arrow_forwardA preserve contains the last population of the very rare desert pupfish which is only found in one pool. There are two color forms of this pupfish, one is silver and one is black and the color is inherited. The color forms are equally successful in surviving and having offspring over the long term but the frequency of the two forms varies greatly from generation to generation. Which evolutionary force is causing the fluctuation in frequency?arrow_forwardLets say there exists a gene in the United States that comes in two alleles, the dominant A and the recessive a. The allele frequency of the dominant allele is 60% and the allele frequency of the recessive allele is 40% The population in genotyped and its found in the United States there are 36% Homozygous Dominant folk, 48% Homozygous Recessive folk, and 16% Homozygous recessive folk. Do you think there is any fitness advantage to any of these genotypes? Why or why not? View keyboard shortcutsarrow_forward
- The following table provides phenotypic data for a population of mammoths living in cold environments based on fossil and DNA evidence. Based on this data and your knowledge of natural selection, which explanation best explains the trends seen in the data? Individuals with thicker fur had a survival advantage in the cold environment, allowing these individuals to reproduce more often and create more offspring. Individuals within this population of mammoths tend to only mate with individuals that have thick fur. This population of mammoths appear to be in Hardy-Weinberg equilibrium since no allele frequencies are changing over time. Individuals with thick fur migrated into the population of mammoths, increasing the proportion of these individuals.arrow_forwardThere are three genotypes for flower colour in Barberton Daisies. DD = Red; Dd = Orange; dd = yellow. The allelic frequency of f(D) = p = 0.634. Scientists observed 2 red, 18 orange and 2 yellow flowers in a field of Barberton Daisies. How many yellow daisies would you have expected in this population if the population was randomly mating, large and not affected by mutation, migration or natural selection?arrow_forwardIf a particular population of diploid individuals is in equilibrium and contains 16% homozygous dominant individuals, 48% heterozygotes, and 36% homozygous recessive individuals, what is the frequency of the recessive allele in this population?arrow_forward
- In a certain population, a previously neutral, homozygous recessive gene (aa) becomes lethal through changed environmental circumstances. The frequency of the recessive allele (q) was 0.5 before the environmental changes. (i) What was the genotype distribution when the recessive genotype was not selected against / selectively neutral? (ii) What will be the allelic frequency after one generation in the altered generation? Assume random mating among the breeding population. (iii) What will be the genotype frequency of the progeny breeding population?arrow_forwardUnder the above conditions of reproductive discrimination against those with attached earlobes, if the population in this next generation is still 500,000 people, then the new genotypic frequencies will be: Homozygous dominants, unattached ear lobes: 0.34 Heterozygotes, unattached ear lobes: 0.48 Homozygous recessives, attached ear lobes: 0.18 What will be the allele frequencies for L and l in this generation? Did the frequency of the recessive allele (l), as compared to its frequency calculated in Part B, increase or decrease because of its deleterious effects on fitness? Does the possession of the recessive allele kill those who possess it? If those with attached ear lobes continue to be only half as successful in securing mates in each successive generation, what will happen to the frequency of the recessive allele in this population?arrow_forwardDistinct species that are able to interbreed in nature are said to “hybridize,” and their offspring are called “hybrids.” The gray oak and the Gambel oak can mate to produce fertile hybrids in regions where they co-occur. However, the gene flow in nature is sufficiently limited that, overall, the two species remain phenotypically distinct. If the hybrid offspring survive well and reproduce to the extent that there is a large population of hybrid individuals that breed between themselves but do not interbreed with either of the two original parent species (the gray and the Gambel), which of the following would you say most likely led to the new hybrid species?(a) prezygotic reproductive barriers (b) sympatric speciation (c) allopatric speciation (d) postzygotic reproductive barriers (e) none of the abovearrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
- Human Anatomy & Physiology (11th Edition)BiologyISBN:9780134580999Author:Elaine N. Marieb, Katja N. HoehnPublisher:PEARSONBiology 2eBiologyISBN:9781947172517Author:Matthew Douglas, Jung Choi, Mary Ann ClarkPublisher:OpenStaxAnatomy & PhysiologyBiologyISBN:9781259398629Author:McKinley, Michael P., O'loughlin, Valerie Dean, Bidle, Theresa StouterPublisher:Mcgraw Hill Education,
- Molecular Biology of the Cell (Sixth Edition)BiologyISBN:9780815344322Author:Bruce Alberts, Alexander D. Johnson, Julian Lewis, David Morgan, Martin Raff, Keith Roberts, Peter WalterPublisher:W. W. Norton & CompanyLaboratory Manual For Human Anatomy & PhysiologyBiologyISBN:9781260159363Author:Martin, Terry R., Prentice-craver, CynthiaPublisher:McGraw-Hill Publishing Co.Inquiry Into Life (16th Edition)BiologyISBN:9781260231700Author:Sylvia S. Mader, Michael WindelspechtPublisher:McGraw Hill Education
Human Anatomy & Physiology (11th Edition)
Biology
ISBN:9780134580999
Author:Elaine N. Marieb, Katja N. Hoehn
Publisher:PEARSON
Biology 2e
Biology
ISBN:9781947172517
Author:Matthew Douglas, Jung Choi, Mary Ann Clark
Publisher:OpenStax
Anatomy & Physiology
Biology
ISBN:9781259398629
Author:McKinley, Michael P., O'loughlin, Valerie Dean, Bidle, Theresa Stouter
Publisher:Mcgraw Hill Education,
Molecular Biology of the Cell (Sixth Edition)
Biology
ISBN:9780815344322
Author:Bruce Alberts, Alexander D. Johnson, Julian Lewis, David Morgan, Martin Raff, Keith Roberts, Peter Walter
Publisher:W. W. Norton & Company
Laboratory Manual For Human Anatomy & Physiology
Biology
ISBN:9781260159363
Author:Martin, Terry R., Prentice-craver, Cynthia
Publisher:McGraw-Hill Publishing Co.
Inquiry Into Life (16th Edition)
Biology
ISBN:9781260231700
Author:Sylvia S. Mader, Michael Windelspecht
Publisher:McGraw Hill Education
GCSE Biology - Adaptations #79; Author: Cognito;https://www.youtube.com/watch?v=tC-u8xcZYSM;License: Standard Youtube License