Biod 171 Exam 2 Quizzes

Biod 171 Exam 2 Quizzes True or false: Genetic differences are always more important than environmental differences for determining phenotypic outcomes. false true Correct answer- false If Mendel bas ...

Biod 171 Exam 2 Quizzes True or false: Genetic differences are always more important than environmental differences for determining phenotypic outcomes. false true Correct answer- false If Mendel based his data only on two traits, and the genes influencing those traits were linked and located close together on the same chromosome, which of his laws would he not have been able to resolve? The Law of Segregation The Law of Independent Assortment Correct answer- The Law of Independent Assortment Which of the following types of inheritance violate Mendel's law of independent assortment? Sex linkage Linkage between alleles on the same chromosome Epistasis Mitochondrial inheritance Codominance Correct answer- Linkage between alleles on the same chromosome True or false: When studying phenotypic variations due to the environment, it is necessary to compare organisms with identical genotypes. In addition, it is necessary to use identical environments when studying variation in genotypes. true false Correct answer- true The differential reproductive success of individuals who carry a particular allele in a given environment is called ____________. fixation selection evolution migration genetic drift Correct answer- selection What kind of mutation has no effect on an organism's ability to survive or reproduce? an advantageous mutation a neutral mutation an adaptive mutation a deleterious mutation Correct answer- a neutral mutation Given equal probabilities of the birth of a boy or girl, what is the probability that a group of four siblings includes all boys? All girls? All boys or all girls? 1/16; 1/16; 1/64 1/8; 1/16; 3/8 1/16; 1/8; 3/8 1/16; 1/16; 1/8 Correct answer- 1/16; 1/16; 1/8 Choose one single BEST answer to complete this sentence. The frequency of recombination during meiosis is a function of: the distance between genes: the closer the genes are, the more frequent the recombination between them. the alleles on the genes; recombination happens less frequently among recessive alleles. whether or not the genes are sex-linked; Y chromosomes recombine much more frequently than do the autosomes. whether or not the genes are sex-linked; X chromosomes recombine much more frequently than do autosomes. the distance between genes: the farther apart the genes are, the more frequent the recombination between them. Correct answer- the distance between genes: the farther apart the genes are, the more frequent the recombination between them. In one set of experiments, Calvin Bridges crossed white-eyed female fruit flies with red-eyed males. Some of the offspring were white-eyed females. These individuals, he demonstrated, had the genotype ____________, which occurred because of ____________ during meiosis. (Hint: see Figure 17.6) XXO; independent assortment XXY; nondisjunction XXY; random segregation XXX; nondisjunction Correct answer- XXY; nondisjunction Hammer-head bats are a species of African fruit bats. During the breeding season, males gather in mating arenas, where they display to females who pass through and assess males before selecting individuals with which to mate. This is an example of ____________-sexual selection. inter intra Correct answer- inter On a hike through the forest, you notice a population of 100 flowering plants that all look identical (phenotypic clones). They span an area of approximately 100 square meters but there are other populations of this species nearby. You take some representatives from one corner of their distribution back to the lab, sequence their DNA and conclude that they are also genetic clones. True or false: This population can ONLY evolve through genetic drift. false true Correct answer- false Genetic drift has an especially significant effect in what kind of populations? populations with high genetic variability populations that are large populations that are small populations that are subject to natural selection populations that are migrating Correct answer- populations that are small Females are generally "choosier" than males about who they mate with. False True Correct answer- True What does it mean to say that an allele is "fixed" in the population? It has been repaired by typical mechanisms in the cell. It is an indication of no genetic variation at that locus in the population. It is an indication that locus cannot undergo mutation. It is an indication of high genetic variation at that locus in the population. It is an indication of low genetic variation at that locus in the population. Correct answer- It is an indication of no genetic variation at that locus in the population. One oak tree produces two kinds of leaves: large with shallow lobes and narrow with deep lobes. If this variation in leaf shape is based solely on the ecological condition of amount of sunlight exposure and there is no genetic difference between leaves that express either of the two forms, then this is: a gene by environment interaction the result of maternal inheritance the result of epistasis the result of a mutation the result of multiple alleles Correct answer- a gene by environment interaction A cattle breeder selects the largest males for breeding with the largest females. Assume that the trait for body size is heritable. This is an example of: Directional natural selection Directional artificial selection Disruptive selection Balancing selection Stabilizing selection Correct answer- Directional artificial selection What would you expect to decrease in frequency more rapidly in a population: a gene with no impact on survival or a gene with a negative impact on survival? Why? A gene with no impact on survival; decreasing its frequency is advantageous A gene with no impact on survival; decreasing its frequency is deleterious A gene with a negative impact on survival; decreasing its frequency is deleterious A gene with a negative impact on survival; decreasing its frequency is advantageous Correct answer- A gene with a negative impact on survival; decreasing its frequency is advantageous One type of natural selection is balancing selection. One scenario that can lead to balancing selection is when a heterozygote phenotype has a fitness advantage. Which of the following are reasonable predictions of balancing selection due to heterozygote advantage? Assume that after 10 generations under the balancing selection, the f(A1) = 0.5, where "A1" is one of two alleles of a given gene; "A2" is the other allele. The genotype, A1A2, will become fixed in the population. The f(A2) will increase, while the f(A1) will decrease. One of the two alleles will become fixed in the population. The f(A1A2) will increase, while the f(A1A1) and f(A2A2) will decrease. The f(A1) will remain roughly the same over the following generations. Correct answer- The f(A1) will remain roughly the same over the following generations. When a founder population colonizes a new habitat or when a population undergoes a bottleneck, genetic drift can dramatically change allele frequencies. This dramatic change happens because: The population size is very small During these dramatic events, only the strongest individuals can survive, which means that natural selection is acting very strongly Chance events happen more frequently after disasters, such as those that cause bottlenecks The decrease in population size must mean that some individuals can reproduce and others cannot, because of their phenotypes Genes drifted from one population to another, for example, from the mainland to an island population Correct answer- The population size is very small Please review lecture 8 before completing this question. In a population, a gene, Tough, has 2 alleles. "T" confers the dominant phenotype (tough), and individuals with the dominant phenotype produce, on average, 10 offspring. "t" confers the recessive phenotype (brittle), and individuals with the recessive phenotype produce, on average, 100 offspring. Given this we know that: None of these answers is valid, because we do not know the fitness of the heterozygote Stabilizing selection is happening Balancing selection is happening Directional selectio