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Bio Exam 1

50 Questions
Biology Quizzes & Trivia
Questions and Answers
  • 1. 
    Which of the following is a true statement concerning genetic variation?
    • A. 

      It is created by the direct action of natural selection.

    • B. 

      It arises in response to changes in the environment

    • C. 

      It must be present in a population before natural selection can act upon the population.

    • D. 

      It tends to be reduced by the processes involved when diploid organisms produce gametes.

    • E. 

      A population that has a higher average heterozygosity has less genetic variation than one with a lower average

  • 2. 
    In the formula for determining a population’s genotype frequencies, the 2 in the term 2pq is necessary because  
    • A. 

      The population is diploid.

    • B. 

      Heterozygotes can come about in two ways.

    • C. 

      The population is doubling in number.

    • D. 

      Heterozygotes have two alleles.

  • 3. 
    During an individual oganism’s lifetime, which of these is most likely to help the organism respond properly to changes in its environment?
    • A. 

      Microevolution

    • B. 

      Change in allele or gene frequency

    • C. 

      Change in gene expression

    • D. 

      Change in average heterozygosity

  • 4. 
    Which of the following types of reproductive barriers separates a pair of species that could interbreed except that one mates at dusk and the other at dawn?
    • A. 

      Temporal isolation

    • B. 

      Habitat isolation

    • C. 

      Behavioral isolation

    • D. 

      mechanical isolation

    • E. 

      Gametic isolation

  • 5. 
    Evolution
    • A. 

      Must happen, due to organisms’ innate desire to survive.

    • B. 

      Must happen whenever a population is not well-adapted to its environment

    • C. 

      Can happen whenever any of the conditions for Hardy-Weinberg equilibrium are not met.

    • D. 

      Requires the operation of natural selection.

    • E. 

      Requires that populations become better suited to their environments.

  • 6. 
    Over time, the movement of people on Earth has steadily increased. This has altered the course of human evolution by increasing
    • A. 

      Nonrandom mating

    • B. 

      Geographic isolation.

    • C. 

      Genetic drift.

    • D. 

      Gene flow

  • 7. 
    During breeding season, one should expect female house finches to prefer to mate with males with the brightest red feathers. Which of the following terms are appropriately applied to this situation?
    • A. 

      Sexual selection

    • B. 

      Mate choice

    • C. 

      Intersexual selection

    • D. 

      All of the above

    • E. 

      Only A and B

  • 8. 
    Which of the following statements best summarizes evolution as it is viewed today?
    • A. 

      It represents the result of selection for acquired characteristics.

    • B. 

      It is synonymous with the process of gene flow.

    • C. 

      It is descent of humans from present-day great apes

    • D. 

      It is the differential survival and reproduction of the most-fit phenotypes.

  • 9. 
    Which of the following is most likely to produce an African butterfly species in the wild whose members have one of two strikingly different color patterns?
    • A. 

      Artificicial selection

    • B. 

      Directional selection

    • C. 

      Stabilizing selection

    • D. 

      Disruptive selection

    • E. 

      Sexual selection

  • 10. 
    Which of the following must exist in a population before natural selection can act upon that population?
    • A. 

      Genetic variation among individuals

    • B. 

      Variation among individuals caused by environmental factors

    • C. 

      Sexual reproduction

    • D. 

      Three of the responses are correct

    • E. 

      Two of the responses are correct

  • 11. 
    Frequently, a group of related species will each have a unique courtship ritual that must be performed correctly for both partners to be willing to mate. Such a ritual constitutes a_________ , _________ reproductive barrier.
    • A. 

      Mechanical . . . postzygotic

    • B. 

      Behavioral . . . prezygotic

    • C. 

      Mechanical . . . prezygotic

    • D. 

      Temporal . . . prezygotic

    • E. 

      Gametic . . . postzygotic

  • 12. 
    The recessive allele that causes phenylketonuria (PKU) is harmful, except when an infant’s diet lacks the amino acid phenylalanine. What maintains the presence of this harmful allele in a populations gene pool?
    • A. 

      Heterozygote advantage

    • B. 

      Stabilizing selection

    • C. 

      Diploidy

    • D. 

      Balancing selection

  • 13. 
    The largest unit within which gene flow can readily occur is a
    • A. 

      Population

    • B. 

      Species

    • C. 

      Genus

    • D. 

      Hybrid

    • E. 

      Phylum

  • 14. 
    Natural selection changes allele frequencies because some _________ survive and reproduce more successfully than others.
    • A. 

      Alleles

    • B. 

      Loci

    • C. 

      Gene pool

    • D. 

      Species

    • E. 

      Individuals

  • 15. 
    No two people are genetically identical, except for identical twins. The main source of genetic variation among human individuals is
    • A. 

      New mutations that occurred in the preceding generation.

    • B. 

      Genetic drift due to the small size of the population.

    • C. 

      Reshuffling of alleles in sexual reproduction.

    • D. 

      Geographic variation within the population.

    • E. 

      Environmental effects.

  • 16. 
    Sexual dimorphism is most often a result of
    • A. 

      Pansexual selection.

    • B. 

      Stabilizing selection.

    • C. 

      Intrasexual selection

    • D. 

      Intersexual selection

    • E. 

      Artificial selection

  • 17. 
    Which of the various species concepts distinguishes two species based on the degree of genetic exchange between their gene pools?
    • A. 

      Phylogenetic

    • B. 

      Ecological

    • C. 

      Biological

    • D. 

      Morphological

  • 18. 
    Dog breeders maintain the purity of breeds by keeping dogs of different breeds apart when they are fertile. This kind of isolation is most similar to which of the following reproductive isolating mechanisms?
    • A. 

      Reduced hybrid fertility

    • B. 

      Hybrid breakdown

    • C. 

      Mechanical isolation

    • D. 

      Habitat isolation

    • E. 

      Gametic isolation

  • 19. 
    Which of the following would a biologist describe as microevolution?
    • A. 

      The formation of new species

    • B. 

      The extinction of species

    • C. 

      Dramatic biological changes, such as the origin of flight, within a taxon

    • D. 

      The generation of biodiversity

    • E. 

      A change in allele frequencies within the gene pool of a population

  • 20. 
    Two species of frogs belonging to the same genus occasionally mate, but the offspring fail to develop and hatch. What is the mechanism for keeping the two frog species separate?
    • A. 

      The postzygotic barrier called hybrid inviability

    • B. 

      The postzygotic barrier called hybrid breakdown

    • C. 

      The prezygotic barrier called hybrid sterility

    • D. 

      Gametic isolation

  • 21. 
    According to the concept of punctuated equilibrium, the “sudden” appearance of a new species in the fossil record means that
    • A. 

      The species is now extinct.

    • B. 

      Speciation occurred instantaneously.

    • C. 

      Speciation occurred in one generation.

    • D. 

      Speciation occurred rapidly in geologic time.

    • E. 

      The species will consequently have a relatively short existence, compared with other species

  • 22. 
    Speciation
    • A. 

      Occurs at such a slow pace that no one has ever observed the emergence of new species.

    • B. 

      Occurs only by the accumulation of genetic change over vast expanses of time.

    • C. 

      Must begin with the geographic isolation of a small, frontier population. must begin with the geographic isolation of a small, frontier population.

    • D. 

      And microevolution are synonymous.

    • E. 

      Can involve changes to a single gene.

  • 23. 
    Which of the following statements about speciation is correct?
    • A. 

      The goal of natural selection is speciation.

    • B. 

      When reunited, two allopatric populations will interbreed freely if speciation has occurred.

    • C. 

      Natural selection chooses the reproductive barriers for populations.

    • D. 

      Prezygotic reproductive barriers usually evolve before postzygotic barriers.

    • E. 

      Speciation is a basis for understanding macroevolution.

  • 24. 
    In order for speciation to occur, what must be true?
    • A. 

      The number of chromosomes in the gene pool must change.

    • B. 

      Changes to centromere location or chromosome size must occur within the gene pool.

    • C. 

      Large numbers of genes that affect a single phenotypic trait must change.

    • D. 

      Large numbers of genes that affect numerous phenotypic traits must change.

    • E. 

      At least one gene, affecting at least one phenotypic trait, must change.

  • 25. 
    Sea urchins release their gametes into the water without courtship. Which of these reproductive isolation mechanisms might operate for sea urchin species?
    • A. 

      Behavioral isolation

    • B. 

      Gametic isolation

    • C. 

      Habitat isolation

    • D. 

      Mechanical isolation

  • 26. 
    Which of the following types of reproductive barriers separates a pair of moth species that could interbreed except that the females’ mating pheromones are not attractive to the males of the other species?
    • A. 

      Temporal isolation

    • B. 

      Habitat isolation

    • C. 

      Behavioral isolation

    • D. 

      Mechanical isolation

    • E. 

      Gametic isolation

  • 27. 
    A trend toward the decrease in the size of plants on the slopes of mountains as altitudes increase is an example
    • A. 

      A cline

    • B. 

      A bottleneck

    • C. 

      Relative fitness

    • D. 

      Genetic drift

    • E. 

      Geographic variation

  • 28. 
     Speciation without geographic isolation is called _________ speciation.
    • A. 

      Sympatric

    • B. 

      Allopatric

    • C. 

      Incomplete

    • D. 

      Diversifying

    • E. 

      Punctuated

  • 29. 
    The geographic isolation of a population from other members of the species and the subsequent evolution of reproductive barriers between it and the parent species describes _________ speciation.
    • A. 

      Punctuated

    • B. 

      Phylogenetic

    • C. 

      Sympatric

    • D. 

      Allopatric

    • E. 

      Biogeographic

  • 30. 
    Most polyploid species arise from
    • A. 

      A single diploid parent plant.

    • B. 

      A single triploid parent plant.

    • C. 

      Single tetraploid parent plant.

    • D. 

      The hybridization of two parent species and subsequent chromosome duplications.

    • E. 

      The hybridization of a diploid and a tetraploid parent species.

  • 31. 
    Charles Darwin was the first person to propose
    • A. 

      That evolution occurs.

    • B. 

      A mechanism for how evolution occurs.

    • C. 

      That Earth is older than a few thousand years.

    • D. 

      A mechanism for evolution that was supported by evidence.

    • E. 

      That population growth can outpace the growth of food resources.

  • 32. 
    Sparrows with average-sized wings survive severe storms better than those with longer or shorter wings,illustrating
    • A. 

      The bottleneck effect

    • B. 

      Disruptive selection.

    • C. 

      Frequency-dependent selection

    • D. 

      Neutral variation

    • E. 

      Stabilizing selection

  • 33. 
    Darwin found that some of the species on the Galápagos islands resembled species of the South American mainland
    • A. 

      Less than they resembled animals on ecologically similar but distant islands

    • B. 

      More than they resembled animals on ecologically similar but distant islands.

    • C. 

      Less than they resembled animals in Europe.

    • D. 

      Less than they resembled animals from Australia.

    • E. 

      Very closely; in most cases, the species from the mainland and the islands were identical.

  • 34. 
    The emergence of many diverse species from a common ancestor that finds itself in a new environment is called
    • A. 

      Adaptive radiation

    • B. 

      Gradualism

    • C. 

      Disruptive selection

    • D. 

      Allopatric speciation

    • E. 

      Hybridization

  • 35. 
    Given a population that contains genetic variation, what is the correct sequence of the following events, under the influence of natural selection? 1. Well-adapted individuals leave more offspring than do poorly adapted individuals. 2. A change occurs in the environment. 3. Genetic frequencies within the population change. 4. Poorly adapted individuals have decreased survivorship.
    • A. 

      2--4--1--3

    • B. 

      4--2--1--3

    • C. 

      4--1--2--3

    • D. 

      4--2--3--1

    • E. 

      2--4--3--1

  • 36. 
    Which of the following statement about Darwin following the voyage of HMS Beagle is incorrect?
    • A. 

      Darwin thought individuals varied

    • B. 

      Darwin thought the Earth was a few thousand years old

    • C. 

      Darwin thought fossils in a given area were similar to extant species in the same area

    • D. 

      Darwin thought organisms were capable of producing many offspring

    • E. 

      Darwin thought few offspring of a pair survived

  • 37. 
    If two modern organisms are distantly related in an evolutionary sense, then one should expect that
    • A. 

      They live in very different habitats.

    • B. 

      They should share fewer homologous structures than two more closely related organisms.

    • C. 

      Their chromosomes should be very similar.

    • D. 

      They shared a common ancestor relatively recently.

    • E. 

      They should be members of the same genus.

  • 38. 
    Rocky Mountain juniper (Juniperus scopulorum) and one-seeded juniper (J. monosperma) have overlapping ranges. If pollen grains (which contain sperm cells) from one species are unable to germinate and make pollen tubes on female ovules (which contain egg cells) of the other species, then which of these terms are applicable 1. sympatric species   2. prezygotic isolation   3. postzygotic isolation   4. allopatric species   5. habitat isolation  
    • A. 

      1 and 2

    • B. 

      2 and 4

    • C. 

      1,3,and 6

    • D. 

      2,4,and 5

    • E. 

      1,2,5,and 6

  • 39. 
    Evolutionary trees are properly understood by scientists to be
    • A. 

      Theories

    • B. 

      Hypothesies

    • C. 

      Guesses

    • D. 

      Dogmas

    • E. 

      Facts

  • 40. 
    . Broccoli, cabbages, and brussels sprouts all descend from the same wild mustard and can still interbreed. These varieties were produced by
    • A. 

      Speciation

    • B. 

      Artificial selection

    • C. 

      Natural selection

    • D. 

      Genetic drift

    • E. 

      Inheritance of acquired characteristics

  • 41. 
    Which of the following best expresses the concept of natural selection?
    • A. 

      Differential reproductive success based on inherited characteristics

    • B. 

      Inheritance of acquired characteristics

    • C. 

      Change in response to need

    • D. 

      A process of constant improvement, leading eventually to perfection

    • E. 

      Survival of the fittest

  • 42. 
    Which of the following represents a pair of homologous structures?
    • A. 

      The wing of a bat and the scales of a fish

    • B. 

      The wing of a bat and the flipper of a whale

    • C. 

      The antennae of an insect and the eyes of a bird

    • D. 

      The feathers of a bird and the wing membrane of a bat

    • E. 

      The wing of a bat and the wing of a butterfly

  • 43. 
    Genetic drift resulting from a disaster that drastically reduces population size is called
    • A. 

      Natural selection

    • B. 

      Gene flow

    • C. 

      The bottleneck effect

    • D. 

      Nonrandom mating

    • E. 

      The founder effect

  • 44. 
    You are confronted with a box of preserved grasshoppers of various species that are new to science and have not been described. Your assignment is to separate them into species. There is no accompanying information as to where or when they were collected. Which species concept will you have to use?
    • A. 

      Biological

    • B. 

      Phylogentic

    • C. 

      Ecological

    • D. 

      Morphological

  • 45. 
    Which of the following is not an observation or inference on which natural selection is based?
    • A. 

      There is heritable variation among individuals

    • B. 

      Poorly adapted individuals never produce offspring

    • C. 

      Species produce more offspring than the environment can support

    • D. 

      Individuals whose characteristics are best suited to the environment generally leave more offspring than those whose characteristics are less well suited

    • E. 

      Only a fraction of an individual’s offspring may survive

  • 46. 
    Although each of the following has a better chance of influencing gene frequencies in small populations than in large populations, which one most consistently requires a small population as a precondition for its occurrence?
    • A. 

      Mutation

    • B. 

      Nonrandom mating

    • C. 

      Genetic drift

    • D. 

      Natural selection

    • E. 

      Gene flow

  • 47. 
    Which of the following represents an idea that Darwin learned from the writings of Thomas Maithus?
    • A. 

      Technological innovation in agricultural practices will permit exponential growth of the human population into the foreseeable future.

    • B. 

      Populations tend to increase at a faster rate than their food supply normally allows

    • C. 

      Earth changed over the years through a series of catastrophic upheavals.

    • D. 

      The environment is responsible for natural selection

    • E. 

      Earth is more than 10,000 years old.

  • 48. 
    The original source of all genetic variation is
    • A. 

      Natural selection

    • B. 

      Sexual reproduction

    • C. 

      Independent assortment

    • D. 

      Recombination

    • E. 

      Mutation

  • 49. 
    Natural selection is based on all of the following except
    • A. 

      Genetic variation exists within populations

    • B. 

      The best-adapted individuals tend to leave the most offspring

    • C. 

      Individuals who survive longer tend to leave more offspring than those who die young

    • D. 

      Populations tend to produce more individuals than the environment can support

    • E. 

      Individuals adapt to their environments and, thereby, evolve

  • 50. 
    A high proportion of the cats on Key West have extra toes (polydactyly). What is the most likely explanation?
    • A. 

      High rate of mutation

    • B. 

      Founder effect

    • C. 

      Bottle neck effect

    • D. 

      Directional selection for extra toes

    • E. 

      Sexual selection