EBK CAMPBELL BIOLOGY IN FOCUS
2nd Edition
ISBN: 8220101459299
Author: Reece
Publisher: PEARSON
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Question
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.
Genes for adaptive char acteristics are more likely to be inherited.
The number of individuals with the adaptive phenotype increases.
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Chp
do explain.
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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Chapter 21 Solutions
EBK CAMPBELL BIOLOGY IN FOCUS
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_forwardGive typed full explanationarrow_forwardsolve this please, the 1st problem. with explanationarrow_forward
- Phenotypic 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_forwardWhen 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_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
- Need help with the question below ?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
- 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…arrow_forward12arrow_forward#20arrow_forward
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