Factual Questions 1 Which would NOT be evidence to support the view that genes are on chromosomes A That chromosomes consist of a polymer of nucleotides linked together by alternating phosphates and sugars B That both genes and chromosomes sort independently into gametes C That both alleles and homologous chromosomes segregate into different gametes D That Down syndrome correlates with an extra chromosome 21 E Inheritance of a form of color blindness correlates with the inheritance of one X chromosome in males 5 Epistasis describes A when one gene affects the expression of another gene B the ability of a single gene to affect multiple phenotypic traits C when a heterozygote individual has a phenotype intermediate between those of the two types of homozygotes D when a heterozygote exhibits phenotypes for both its alleles 6 Which information can be used to determine which of two alleles for a gene is dominant i which phenotype promoted by these alleles is most common in the population ii which phenotype promoted by these alleles is expressed in heterozygotes iii which phenotype promoted by these alleles is more critical for survival in a given environment 2 After telophase I of meiosis the chromosomal makeup of each daughter cell is A haploid and the chromosomes are each composed of two chromatids B diploid and the chromosomes are each composed of a single chromatid C haploid and the chromosomes are each composed of a single chromatid D tetraploid and the chromosomes are each composed of two chromatids E diploid and the chromosomes are each composed of two chromatids A i only B ii only C iii only D i and ii E i ii and iii 7 An individual s fitness is BEST measured by A its relative contribution to the gene pool of the next generation B its ability to compete with other individuals for key resources C its resistance to disease and parasites D its ability to survive relative to other individuals E how early it can begin to reproduce 3 Which statement about inheritance of genes is incorrect A Genotype refers to the alleles for a gene present in an individual B Alternate forms of genes are called alleles C Individuals with the same phenotype can have different genotypes D Only two alleles can exist for a given gene in a population E A single gene can influence multiple phenotypes 8 Which was NOT part of Darwin s explanation of natural selection A Organisms commonly produce more offspring than can possibly survive B Mutations can create new versions of genes C Variation exists within each species D Members of a species compete with each other for food and space E Offspring that are most fit have traits best suited to the environment 4 In the Hardy Weinberg equation the 2 in the term 2pq is necessary because A the population is doubling in number B heterozygotes can form in two ways C heterozygotes have two alleles D the population is diploid 1 9 Which is likely to have the smallest impact on allele frequencies of a population in two generations A mutations B natural selection C genetic drift D immigration 13 In the pedigree shown above individuals with the solid symbols display a rare genetic trait caused by a dominant allele at an autosomal locus The probability that a child indicated by the question mark will have the disease is A 75 B 50 C 0 D 25 E 100 10 Which would generally REDUCE the likelihood of speciation A immigration and emigration B genetic drift C geographic isolation D natural selection E genetic variation in populations Concept Application Questions 11 Which of the following does NOT contribute to genetic variation among offspring A Independent assortment of sister chromatids during metaphase II B Independent assortment of homologous chromosomes during metaphase I C Crossing over during prophase I D Random fertilization 14 A man with blood type A whose father was blood type O married a woman of blood type B whose mother was blood type O What are the possible blood types of their offspring A A B AB or O B Only AB C Only AB or O D Only A or B E Only A B or AB 12 In corn the trait for tall plants T is dominant to the trait for dwarf plants t and the trait for colored kernels C is dominant to the trait for white kernels c In a particular cross of corn plants the probability of an offspring being tall is 0 5 and the probability of a kernel being colored is 0 75 15 Feather colour in budgies is determined by two different genes that affect the pigmentation of the feathers Y B is green yyB is blue and yybb is white Two blue budgies were paired for life Over many years they produced 22 offspring five of which were white What are the most likely genotypes for the parents A yyBb and yyBb B yyBB and yyBB C yyBB and yyBb D yyBB and yybb E yyBb and yybb Which of the following most probably represents the parental genotypes A TtCc x ttCc B TtCc x TtCc C TtCc x ttcc D TTCc x ttCc E TTCc x TtCC 2 16 What is the probability of having an offspring showing recessive traits for all five genes produced from the following cross 19 Which statement about genetic drift is FALSE A It is not influenced by the phenotype of an individual B It decreases the average variation in a population C It is more common on small islands than on large continents D It is dependent on the kind of genotype an individual possesses E It can produce changes that have positive or negative effects on the fitness of an individual AaBbccddEe X AabbCcddEe A 1 64 B 1 4 C 9 16 D 1 128 E 0 17 Which statement regarding the logistic growth equation is correct dN r K N maxN dt K 20 Which is NOT required for the size of a given trait to evolve by natural selection A Individuals with larger traits live longer B The size of the trait varies among individuals in the population C There is a relationship between the size of the trait and the reproductive success of the bearer of the trait D The size of the trait has a genetic basis A The intrinsic growth rate r of a population is considered to be constant but K can vary over time B At K dN dt 1 C For a given population the value of K does not change over time D Populations experience the most rapid growth as they approach K E When K is reached environmental resources are fully depleted 18 A population of butterflies has two alleles for wing spot colour The red allele is fully dominant to the white allele In a population of 200 diploid butterflies known to be in Hardy Weinberg equilibrium there are 18 white spotted butterflies What percentage of the population is heterozygous A 9 B