Campbell Biology in Focus; Modified Mastering Biology with Pearson eText -- ValuePack Access Card -- for Campbell Biology in Focus (2nd Edition)
2nd Edition
ISBN: 9780134433776
Author: Lisa A. Urry, Michael L. Cain, Steven A. Wasserman
Publisher: PEARSON
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Chapter 21.4, Problem 3CC
Summary Introduction
To determine:
The type of natural selection (directional, disruptive or stabilizing) in situation where heterozygotes for a certain locus in a population have extreme phenotype that confers a selective advantage.
Introduction:
Natural selection is processes by which organisms are tend to adapt the environment and produce more offsprings of particular traits. Natural selection: are of 3 types (a) stabilizing selection; in which an average phenotype is favored, (b) directional selection; in which the change in the environment change the wide range of
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Stages of natural selection
What is the order of stages in natural selection?
Genetic variation exists between individuals of a population.
Individuals compete with each other for food,
water and mates, and to avoid predators.
Individuals with adaptive phenotypes compete better and
are more likely to survive and reproduce, at the expense of...
..individuals with less adaptive phenotypes and fewer
competitive characteristics, which die or reproduce less.
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Chp
Consider the roles of different types of selective pressure.
Part A: Compare and contrast sexual selection, artificial selection, and natural selection.
Part B: Give examples of traits that may be favored in sexual selection, artificial selection, and natural
selection. For each, explain if the trait would be favored by one type of selection but selected against by
another type of selection.
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Please answer fast
Which of the following are true about the logic we use to identify alleles under positive selection at a given locus?
Question 3 options:
Alleles under positive selection should occur at relatively high frequency.
An allele that occurs at relatively high frequency because of genetic drift is likely to be a "young allele," which means it arose by mutation relatively recently.
An allele that occurs at relatively high frequency because of positive selection is likely to be an "old allele," which means it arose by mutation relatively recently.
"Old alleles" are likely to be in linkage disequilibrium with nearby loci. "Young alleles" are likely to be in linkage equilibrium with nearby loci.
Consider what we now know about the tree of life. Which of the following statements are true?
Question 8 options:
Archaea is paraphyletic.
Archaea and bacteria together form a monophyletic clade.
There are three monophyletic domains of life: eukaryotes, archaea, and…
Chapter 21 Solutions
Campbell Biology in Focus; Modified Mastering Biology with Pearson eText -- ValuePack Access Card -- for Campbell Biology in Focus (2nd Edition)
Ch. 21.1 - Explain why genetic variation within a population...Ch. 21.1 - Of all the mutations that occur in a population,...Ch. 21.1 - Prob. 3CCCh. 21.2 - A population has 700 individuals, 85 of genotype...Ch. 21.2 - The frequency of allele a is 0.45 for a population...Ch. 21.2 - WHAT IF? A locus that affects susceptibility to a...Ch. 21.3 - In what sense is natural selection more...Ch. 21.3 - Distinguish genetic drift from gene flow in terms...Ch. 21.3 - WHAT IF? Suppose two plant populations exchange...Ch. 21.4 - What is the relative fitness of a sterile mule?...
Ch. 21.4 - Explain why natural selection is the only...Ch. 21.4 - Prob. 3CCCh. 21 - Natural selection changes allele frequencies...Ch. 21 - No two people are genetically identical, except...Ch. 21 - Sparrows With average-sized w1ngs survive severe...Ch. 21 - If the nucleotide variability of a locus equals...Ch. 21 - There are 25 individuals in population 1, all with...Ch. 21 - A fruit fly population has a gene with two...Ch. 21 - FOCUS ON EVOLUTION Using at least TWO examples,...Ch. 21 - Prob. 9TYUCh. 21 - SYNTHESIZE YOUR KNOWLEDGE This kettle lake formed...
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- Recall that the Hardy-Weinberg model makes the following assumptions: No mutations Extremely large population No gene flow No selection You score flower colour in a very large natural population where flower colour is a co-dominant trait where white and red are homozygotes (CWCW and CRCR) and pink are heterozygotes (CWCR). Taking your observed phenotypes and genotypes, you apply the Hardy-Weinberg principle and find an excess of homozygous individuals (that is, individuals with either white or red flowers). Give two plausible explanations for this excess of homozygotes in the natural population.arrow_forwardExercse 2 #1 - In what populations do we see the high frequencies (above 80%) of the allele associated with lighter pigmentation? O Chinese O African O Japanese O Bangladeshi V French O Mongolian V Italian V German O Indian O Turkish Indonesian Question 2 Exercse 2 #4 - Why might some light-skinned populations, such as the Japanese, be missing the F374 allele? O Some populations, such as Japanese, are only light-skinned because they avoid tanning. O This allele does not cause depigmentation. O There have been multiple, different mutations that have produced light skin in different populations. The sampling of Japanese in this study probably did not capture the true incidence of the F374 allele in the population.arrow_forwardPhenotypic trait (2) Phenotypic trait (z) Phenotypic trait (z) Identify the type of selection indicated by the three graphs. O A = stabilizing selection; B = directional selection; C = disruptive selection O A = directional selection; B = disruptive selection; C = stabilizing selection O A = directional selection; B = stabilizing selection; C = disruptive selection O A = disruptive selection; B = stabilizing selection; C = directional selection houanbay Kouenbe Kouerbelarrow_forward
- When we take, say, 100 individuals of a species of beetle from the wild and place them in a new environment that is not so different that they are unable to thrive but different enough so that they are experiencing a new selective regime, say, a lower temperature, what typically happens? A - Sexual selection causes some larvae to be able to survive in the cooler temperatures and other individuals to be unable to survive because they need warmer temperatures. B - We are unable to measure phenotypic selection, presumably because we do not have much variation among individuals for how they handle temperature. C - The founder event assures us that the new population will be strictly representative of the source population (especially if we took all the 100 from the same location rather that from throughout the range of the species). D - The population evolves to be tolerant of the lower temperature; it can do this because of latent variation already in the 100 founding individuals. E -…arrow_forward> Within a certain population, there are exactly 2 alleles at the T locus: T and t. Among the entire population, 30% of the alleles are T. If this population is in Hardy Weinberg equilibrium, what proportions (or percentages, however, you want to express it) will be TT, Tt, and tt? Show work. In a population, there are 75 TT individuals, 25 Tt individuals, and 250 tt individuals. What are the frequencies of T and t? Show work. What are the "expected" numbers of each genotype? Show work. Ís this population in Hardy Weinberg equilibrium? (don't do Chi², just compare your answer in a) b) c) part b io actual and it should be obvious.) ) Assume that, in a population of deer, two alleles exist for eye color. BB deer have blue eyes, Bb deer have purple eyes, and bb deer have red eyes. Out of a population of 1000 deer, 490 have blue eyes. You took notes on the amount of red and purple eyed deer, but your notebook fell in the mud and those numbers are obscured. However, if the population is in…arrow_forwardThe MN blood group is of interest to population geneticists because (a) people with genotype MN cannot receive blood transfusions from either MM or NN people (b) the MM, MN, and NN genotype frequencies can be observed directly and compared with calculated expected frequencies (c) the M allele is dominant to the N allele (d) people with the MN genotype exhibit frequency-dependent selection (e) people with the MN genotype exhibit heterozygote advantagearrow_forward
- Imagine a population in which the survival of A1A1 homozygotes is 80 percent as great as that of A1A2 heterozygotes, while the survival of A2A2 homozygotes is 95 percent that of the heterozygotes. What is p, the frequency of the A2 allele, at equilibrium? Now suppose the population has reached this equilibrium, but that the environment then changes so that the relative fitnesses of A1A1, A1A2, and A2A2 become 1.0, 0.95, and 0.90. What will p be in the adults after one generation of selection in the new environment?arrow_forwardsolve G-M but make sure you read previous statements if needed ( ragoon/ Rat Is same )Sample A has been allowed to breed randomly for many generations. At a particular gene locus, there are two alleles, and one is dominant to the other. After several generations, 64% of the animals have the phenotype associated with the dominant allele. Population A is in Hardy-Weinberg Equilibrium.a) In Colony A, what is the estimated frequency of the recessive allele and heterozygous genotype? Sample B has been studied for many generations. The slope of the regression line describing the relationship between the number of whiskers in an offspring and the average number of whiskers of both parents is 0.50.b)What is the heritability (h2) of abdominal bristle number in Sample B? c) Suppose that the mean whisker number in Sample B is 26 and suppose that the researcher chooses rats for breeding such that the mean whisker number of breeding individuals is 36. What would you expect the mean number of…arrow_forwardWhat are two reasons why a selection limit is reached in which artificial selection no longer has an effect?arrow_forward
- Bjork and Pitnick (2006) investigated sexual selection in Drosophila melanogaster. Which of the following is an accurate conclusion that can be made from their results below? [Note that the open circles and dotted line represent data collected from females and the closed circles and solid line represents data collected from males.] 200 - 150 100 50 1 2 4 5 Number of mates (mating success) O a. Sexual selection is stronger on females than males. O b. Males have a weaker Bateman gradient than females. O C. Females likely invest more in the reproductive process. O d. Males likely exhibit parental rather than females. Number of offspring (reproductive success)arrow_forward. The inability to taste phenylthiocarbamide (PTC) is due to a recessive allele and is inherited autosomally. If this particular trait in a population involves only two alleles in a dominant/recessive relationship (namely, taster, T; and nontaster, t) and that the population is in Hardy-Weinberg equilibrium. Calculate the frequency of allele T if the phenotypic frequency of individuals who can taste PTC is approximately 0.7 (Give your answer in decimal number with 2 decimal places).arrow_forwardCalculate the rate of genetic change in feed conversion in a pig population given the following : Heritability of feed conversion (h2) = 0.35 Phenotypic standard deviation (αp) = 0.2 kg/kg Accuracy of male selection = 0.8 Accuracy for female selection = 0.5 Intensity of male selection (im) = -2.4 Intensity of female selection (if) = -1.5 Generation interval for males (Lm) = 1.8 years Generation interval for females (Lf) = 1.8 yearsarrow_forward
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