Textbook Question
Natural selection changes allele frequencies because some _________ survive and reproduce better than others.
a. Alleles
b. Loci
c. Species
d. Individuals
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Ch. 23 - The Evolution of Populations
Urry11th EditionCampbell BiologyISBN: 9789357423311
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Table of contents
- Ch. 1 - Evolution, the Themes of Biology, and Scientific Inquiry8
- Ch. 2 - The Chemical Context of Life8
- Ch. 3 - Water and Life6
- Ch. 4 - Carbon and the Molecular Diversity of Life9
- Ch. 5 - The Structure and Function of Large Biological Molecules9
- Ch. 6 - A Tour of the Cell6
- Ch. 7 - Membrane Structure and Function6
- Ch. 8 - An Introduction to Metabolism6
- Ch. 9 - Cellular Respiration and Fermentation10
- Ch. 10 - Photosynthesis7
- Ch. 11 - Cell Communication7
- Ch. 12 - The Cell Cycle10
- Ch. 13 - Meiosis and Sexual Life Cycles10
- Ch. 14 - Mendel and the Gene Idea14
- Ch, 15 - The Chromosomal Basis of Inheritance7
- Ch. 16 - The Molecular Basis of Inheritance9
- Ch. 17 - Gene Expression: From Gene to Protein9
- Ch. 18 - Regulation of Gene Expression10
- Ch. 19 - Viruses6
- Ch. 20 - DNA Tools and Biotechnology8
- Ch. 21 - Genomes and Their Evolution8
- Ch. 22 - Descent with Modification: A Darwininan View of Life6
- Ch. 23 - The Evolution of Populations5
- Ch. 24 - The Origin of Species6
- Ch. 25 - The History of Life on Earth6
- Ch. 26 - Phylogeny and the Tree of Life7
- Ch. 27 - Bacteria and Archaea8
- Ch. 28 - Protists7
- Ch. 29 - Plant Diversity I: How Plants Colonized Land7
- Ch. 30 - Plant Diversity II: The Evolution of Seed Plants7
- Ch. 31 - Fungi5
- Ch. 32 - An Overview of Animal Diversity4
- Ch. 33 - An introduction to Invertebrates6
- Ch. 34 - The Origin and Evolution of Vertebrates7
- Ch. 35 - Vascular Plant Structure, Growth, and Development8
- Ch. 36 - Resource Acquisition and Transport in Vascular Plants8
- Ch. 37 - Soil and Plant Nutrition10
- Ch. 38 - Angiosperm Reproduction and Biotechnology8
- Ch. 39 - Plant Responses to Internal and External Signals8
- Ch. 40 - Basic Principles of Animal Form and Function8
- Ch. 41 - Animal Nutrition7
- Ch. 42 - Circulation and Gas Exchange7
- Ch. 43 - The Immune System6
- Ch. 44 - Osmoregulation and Excretion6
- Ch. 45 - Hormones and the Endocrine System8
- Ch. 46 - Animal Reproduction8
- Ch. 47 - Animal Development8
- Ch. 48 - Neurons, Synapses, and Signaling6
- Ch. 49 - Nervous Systems8
- Ch. 50 - Sensory and Motor Mechanisms5
- Ch. 51 Animal Behavior6
- Ch. 52 - An Introduction to Ecology and the Biosphere7
- Ch. 53 - Population Ecology10
- Ch. 54 - Community Ecology9
- Ch. 55 - Ecosystems and Restoration Ecology8
- Ch. 56 - Conservation Biology and Global Change6
Chapter 23, Problem 3
If the nucleotide variability of a locus equals 0%, what is the gene variability and number of alleles at that locus?
a. gene variability = 0%; number of alleles = 0
b. gene variability = 0%; number of alleles = 1
c. gene variability = 0%; number of alleles = 2
d. gene variability > 0%; number of alleles = 2
Verified step by step guidance1
Understand the concept of nucleotide variability: It refers to the proportion of nucleotide sites that are different among individuals in a population. A 0% nucleotide variability means there is no variation at the nucleotide level at that locus.
Recognize the relationship between nucleotide variability and gene variability: Gene variability is the proportion of loci that are polymorphic (having more than one allele) in a population. If nucleotide variability is 0%, it implies that there is no polymorphism at the nucleotide level, leading to 0% gene variability.
Consider the number of alleles: If there is no nucleotide variability, it means all individuals have the same nucleotide sequence at that locus, indicating only one allele is present.
Evaluate the options: Based on the understanding that 0% nucleotide variability leads to 0% gene variability and only one allele, identify the correct option.
Select the correct answer: The option that states gene variability is 0% and the number of alleles is 1 is the correct choice.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Nucleotide Variability
Nucleotide variability refers to the degree of variation in the nucleotide sequences at a specific locus within a population. A 0% nucleotide variability indicates that there is no variation in the nucleotide sequences among individuals at that locus, meaning all individuals have identical sequences at that position.
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05:35
Nucleotides
Gene Variability
Gene variability measures the diversity of alleles present at a particular gene locus within a population. If nucleotide variability is 0%, it implies that there is no genetic variation at the nucleotide level, leading to 0% gene variability, as there are no different alleles present at that locus.
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07:36Variables
Number of Alleles
The number of alleles at a locus refers to the different versions of a gene that exist within a population. When nucleotide variability is 0%, it means there is only one allele present at that locus, as all individuals have the same nucleotide sequence, resulting in no genetic diversity at that position.
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06:36Allele Frequencies
Related Practice
Textbook Question
No two people are genetically identical, except for identical twins. The main source of genetic variation among humans is
a. New mutations that occurred in the preceding generation.
b. Genetic drift.
c. The reshuffling of alleles in sexual reproduction.
d. Environmental effects.
Textbook Question
There are 25 individuals in population 1, all with genotype AA, and there are 40 individuals in population 2, all with genotype aa. Assume that these populations are located far from each other and that their environmental conditions are very similar. Based on the information given here, the observed genetic variation most likely resulted from
a. Genetic drift.
b. Gene flow.
c. Nonrandom mating.
d. Directional selection.
Textbook Question
A fruit fly population has a gene with two alleles, A1 and A2. Tests show that 70% of the gametes produced in the population contain the A1 allele. If the population is in Hardy-Weinberg equilibrium, what proportion of the flies carry both A1 and A2?
a. 0.7
b. 0.49
c. 0.42
d. 0.21