Campbell Biology in Focus 3rd Edition Chapter 021 Quiz
Test Bank with Verified Answers 2023 GRADED A+
Microevolution correct answers Changes in allele frequency within a population over time. This is
caused by natural selection, genetic drift, and gene flow
Genetic Variation correct answers The differences in gene sequence or composition present between
the members of a population, causing different phenotypes to be shown. Gene variability can be
measured by the percentage of loci that are heterozygous, while molecular variability can also be
measured.
Molecular variability correct answers Variability between gene sequences of organisms. Little of this
results in phenotypic change, as most of DNA is noncoding, and exon variation is corrected by wobble.
Small gene changes can result in large phenotypic differences.
Phenotypic Variation correct answers As a phenotype is the combination of genotype and environment,
some elements of phenotype are not heritable. Only heritable characters contribute to the evolution of
populations over time.
Sources of Genetic Variation correct answers Genetic variation all comes from the formation of new
alleles by mutation, either by point mutation or chromosomal aberrations. Chromosomal aberrations
such as duplication can also provide a place for mutations to accumulate without harm. The rapid
reproduction of certain organisms can contribute to rapid production and proliferation of genetic
variation, while sexual reproduction causes unique gene combinations to occur by crossing over,
independent assortment, and random fertilization.
Population correct answers A group of individuals that are capable of interbreeding viably.
Gene pool correct answers All copies of every allele found within a population. If only one allele exists at
a locus, it is a fixed allele, with all individuals homozygous for it.
Allele frequency correct answers The total number of a specific allele divided by the total number of
alleles in a gene pool
Hardy-Weinberg Principle/Equilibrium correct answers A principle that states that in a population where
evolution is not occurring, allele and phenotype frequencies should remain constant over time. In a two-
allele scenario, equilibrium exists if the proportion of homozygous for allele
1:heterozygous:homozygous for allele 2 is (pp):(2pq):(qq), where p and q are the allele frequencies of
allele 1 and 2 respectively.
Conditions for Hardy Weinberg Equilibrium correct answers Hardy-Weinberg Equilibrium requires that
there be no mutation introducing new alleles, random mating, no natural selection, large size to avoid
genetic drift, and no gene flow. The principle can be used to test if any such changes are occurring, or
used to predict genotype frequencies in stable populations.
Test Bank with Verified Answers 2023 GRADED A+
Microevolution correct answers Changes in allele frequency within a population over time. This is
caused by natural selection, genetic drift, and gene flow
Genetic Variation correct answers The differences in gene sequence or composition present between
the members of a population, causing different phenotypes to be shown. Gene variability can be
measured by the percentage of loci that are heterozygous, while molecular variability can also be
measured.
Molecular variability correct answers Variability between gene sequences of organisms. Little of this
results in phenotypic change, as most of DNA is noncoding, and exon variation is corrected by wobble.
Small gene changes can result in large phenotypic differences.
Phenotypic Variation correct answers As a phenotype is the combination of genotype and environment,
some elements of phenotype are not heritable. Only heritable characters contribute to the evolution of
populations over time.
Sources of Genetic Variation correct answers Genetic variation all comes from the formation of new
alleles by mutation, either by point mutation or chromosomal aberrations. Chromosomal aberrations
such as duplication can also provide a place for mutations to accumulate without harm. The rapid
reproduction of certain organisms can contribute to rapid production and proliferation of genetic
variation, while sexual reproduction causes unique gene combinations to occur by crossing over,
independent assortment, and random fertilization.
Population correct answers A group of individuals that are capable of interbreeding viably.
Gene pool correct answers All copies of every allele found within a population. If only one allele exists at
a locus, it is a fixed allele, with all individuals homozygous for it.
Allele frequency correct answers The total number of a specific allele divided by the total number of
alleles in a gene pool
Hardy-Weinberg Principle/Equilibrium correct answers A principle that states that in a population where
evolution is not occurring, allele and phenotype frequencies should remain constant over time. In a two-
allele scenario, equilibrium exists if the proportion of homozygous for allele
1:heterozygous:homozygous for allele 2 is (pp):(2pq):(qq), where p and q are the allele frequencies of
allele 1 and 2 respectively.
Conditions for Hardy Weinberg Equilibrium correct answers Hardy-Weinberg Equilibrium requires that
there be no mutation introducing new alleles, random mating, no natural selection, large size to avoid
genetic drift, and no gene flow. The principle can be used to test if any such changes are occurring, or
used to predict genotype frequencies in stable populations.
