Campbell Biology in Focus (2nd Edition)
2nd Edition
ISBN: 9780321962751
Author: Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, Jane B. Reece
Publisher: PEARSON
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Textbook Question
Chapter 21, Problem 2TYU
No two people are genetically identical, except for identical twins. The main source of
- A. new mutations that occurred in the preceding generation.
- B. genetic drift.
- C. the reshuffling of alleles in sexual reproduction.
- D. environmental effects.
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Students have asked these similar questions
A gene pool is
a. all of the genes in a single individual.
b. all of the genes in the gametes from a single individual.
c. all of the genes in a population of individuals.
d. the random mixing of genes during sexual reproduction.
Sexual reproduction provides an advantage to organisms because it increases the
A.
size of the genome of a species.
B.
genetic variability in a population.
C.
fitness of individual alleles of a gene.
D.
number of mutations during cell division.
Which of the following consequences of sexual reproduction is considered disadvantageous?
A. More rapid evolution.
B. Generation of novel genotypes.
C. Clearance of deleterious mutations.
D. Reduced relatedness.
Chapter 21 Solutions
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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- Of the following, which is the least plausible hypothesis for why natural selection has not eliminated genes for male homosexuality? a. Perhaps the relatives of a homosexual male have more than an average number of children. b. Homosexual people might spread their genes by helping their brothers and sisters rear their children. c. Maybe there is no gene for homosexuality. Instead, an environmental event produces an epigenetic effect that can be transmitted from one generation to the next. d. Some homosexual men have children.arrow_forwardWhich of the following scenarios does NOT describe an event that leads to the conceptions of twins? Select one: A. two eggs are fertilized by two sperm cells, resulting in a fraternal twin. B. High levels of FSH stimulate the maturation of three ovums. C. Two eggs are fertilized by one sperm cell, resulting in a monozygotic twin. D. One egg is fertilized by one sperm but divides into two zygotes, resulting in two babies of the same gender.arrow_forwardBinary fission is a form of asexual reproduction. What is an advantage of asexual reproduction when compared to sexual reproduction? a Asexual organisms are less likely to have mutations in their DNA than sexual organisms are. b An organism that reproduces asexually can reproduce much more quickly than an organism that reproduces sexually. c An asexual organism lives longer than an organism that reproduces sexually. d An organism that reproduces asexually is better equipped to respond to environmental changes than an organism that reproduces sexually.arrow_forward
- One of the key ingredients of evolution by natural selection is variation. Within a population, evolution by natural selection will occur if there is a selective advantage of one variation over another. What are the sources of variation in living populations? Select all that apply. a random mutations to DNA when DNA replicates in reproductive cells b environmental factors that may mutate DNA in gametes c mutations in somatic cells d crossing over during meiosisarrow_forwardIf you continue with biological studies in the future, you are most likely going to carry out fruit fly experiments. Drosophila melanogaster are used in genetics labs due to how inexpensive they are, how visible their traits are, and their high reproductive rate. In Drosophila, the gene for red and white eye colour is found on the X chromosome. The allele for red eyes (XR) is dominant to the allele for white eyes (Xr). You are asked to cross a pure breeding white-eyed female with a pure breeding red-eyed male. What are the genotypes of the individuals involved in this cross? XRXR XRXr XRX- XrXr XRY XrY Genotype of the parent male Answer Genotype of the parent female Answer Genotype of the male offspring Answer Genotype of the female offspring Answerarrow_forwardOne day while walking across campus, you see a female butterfly laying fertilized eggs, as shown in the image: 1. The adult butterfly is: a. Viviparous b. Ovoviviparous c. Oviparous d. None of these 2. Gender in the butterfly’s offspring will be determined by: a. Sex chromosomes, in which XX is female XY is male b. A single sex chromosome, in which XX is female and XO is male c. Haplodiploidy, in which an unfertilized egg develops into a female through ameiotic parthenogenesis. d. Hermaproditism e. c and d f. None of these 3. In the development of the butterfly, it has: a. A vermiform larva and a coarctate pupa that develops inside a puparium b. A eucephalus larva and an exarate pupa that develops inside an ootheca c. An eruciform larva and an obtect pupa that develops inside a chrysalis d. A scarabeiform larva and a eucephalus pupa that develops inside a cocoon of silk.arrow_forward
- Which of the following statements is false? A. Humans have 1 pair of sex chromosomes B. Humans have 46 chromosomes C. Sex chromosomes are considered a homologous pair D. Humans have 23 pairs of chromosomes E. Humans have 22 autosomesarrow_forwardWhich of the following statements accurately represents the difference between a gene and a locus? a. A gene is dominant, and a locus is recessive. b. A locus and a gene are essentially the same - there is no difference. c. A locus occurs in diploid cells, and a gene occurs in a haploid cell. d. A locus is a phenotype and a gene is a genotype.arrow_forwardWhich of the following statements regarding the Y chromosome in mammals is TRUE?A. The Y chromosome is less than half the size of the X chromosome.B.Y chromosomes are most often present in egg cells and are not found in sperm cells. C.Most female mammals have one Y chromosome. D. The Y chromosome contains no protein-coding genes.arrow_forward
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