Chapter 27: The Origin and Diversification of Eukaryotes

b. Choanoflagellates

62. Members of which group are thought to be the closest relatives of the animals? a. Euglenozoans b. Choanoflagellates c. Stramenopiles d. Alveolates e. Chlorophytes

b. highly diverse and not necessarily closely related to one another.

1. The many organisms designated as "protists" or "microbial eukaryotes" are a. closely related to the bacteria. b. highly diverse and not necessarily closely related to one another. c. part of a monophyletic clade. d. all unicellular. e. all microscopic.

e. chlorophytes

10. The _______ include the only microbial eukaryotes that contain the full complement of photosynthetic pigments characteristic of plants. a. choanoflagellates b. parabasalids c. cilians d. red algae e. chlorophytes

e. All of the above

11. In terms of their nutritional mode, microbial eukaryotes are a. autotrophs. b. absorptive heterotrophs. c. ingestive heterotrophs. d. Both a and b e. All of the above

e. All of the above

12. Microbial eukaryotes are found in which of the following habitats? a. Marine habitats b. Freshwater aquatic habitats c. The body fluids of other organisms d. Damp soil e. All of the above

c. None of the microbial eukaryotes are parasites.

13. Microbial eukaryotes are ecologically and evolutionarily important for many reasons. Which of the following is not true of this group? a. Multicellular groups evolved from microbial eukaryotes. b. Photosynthetic microbial eukaryotes play a major role in the energy balance of the living world. c. None of the microbial eukaryotes are parasites. d. Saprobic microbial eukaryotes are among the important decomposers and thus play a major role in the nutrient cycles of the living world. e. Many microbial eukaryotes have highly differentiated bodies, even though they consist of only one cell.

a. Protists are found only in aquatic habitats.

14. Which of the following statements about the diversity of protists is false? a. Protists are found only in aquatic habitats. b. Protists have many different metabolic lifestyles. c. Protists use pseudopods or cilia to locomote. d. Several groups of protists use contractile vacuoles to rid themselves of excess water. e. All of the above are true; none is false.

d. Pseudopod

15. Which of the following structures is not associated with movement or feeding in Paramecium? a. Food vacuole b. Oral groove c. Cilium d. Pseudopod e. Both b and c

b. Ciliate B has a greater solute concentration than ciliate A.

16. Two different species of ciliate are placed in a solution with an unknown solute concentration. Ciliate A has a contractile vacuole firing rate of 5 per minute; ciliate B has a contractile vacuole firing rate of 12 per minute. Which of the following is a reasonable conclusion based on these observations? a. Ciliate A has a greater solute concentration than ciliate B. b. Ciliate B has a greater solute concentration than ciliate A. c. The solution has a greater solute concentration than ciliate A. d. The solution has a greater solute concentration than ciliate B. e. No conclusions can be made unless we know the solute concentration of the solution.

a. decreases to aid in digestion, and then increases as digestion is completed.

17. When organic material is digested in a food vacuole, the pH in the vacuole a. decreases to aid in digestion, and then increases as digestion is completed. b. increases to aid in digestion, and then decreases as digestion is completed. c. stays the same during and after digestion. d. stays the same during digestion, and then increases as digestion is completed. e. None of the above

b. Diatoms

18. Which of the following groups of protists secretes an external "shell" of silica (silicon dioxide)? a. Paramecium b. Diatoms c. Red algae d. Euglenids e. Amoebozoans

d. diatoms

19. The _______, members of the phytoplankton, perform as much photosynthesis as all of Earth's rainforests. a. radiolarians b. stramenopiles c. dinoflagellates d. diatoms e. None of the above

a. uncertain, or at most weakly supported.

2. The evolutionary relationship among the five major groups of protists is a. uncertain, or at most weakly supported. b. strongly supported by morphological data. c. strongly supported by genomic data. d. Both b and c e. None of the above

c. dinoflagellates

20. Some _______ live endosymbiotically with coral and contribute to "coral bleaching"? a. radiolarians b. stramenopiles c. dinoflagellates d. diatoms e. None of the above

c. apicomplexans.

21. Plasmodium, the organism that causes malaria, is a member of the a. alveolates. b. stramenopiles. c. apicomplexans. d. choanoflagellates. e. None of the above

d. are found inside red blood cells.

22. The gametocytes of the malaria-causing organism Plasmodium, a. develop into merozoites. b. inhabit the salivary glands of Anopheles mosquitoes. c. are the infective stage obtained from the insect vector. d. are found inside red blood cells. e. give rise to zygotes within the mammalian circulatory system.

e. All of the above

23. Which of the following is a sexual reproductive process common to organisms in the Protista (microbial eukaryotes) group? a. Binary fission b. Multiple fission c. Budding and spore formation d. Union of gametes e. All of the above

a. The macronucleus is involved in genetic recombination.

24. Which of the following statements about the micronucleus and macronucleus is false? a. The macronucleus is involved in genetic recombination. b. The micronucleus is a typical eukaryotic nucleus. c. Multiple copies of macronuclear genes are commonly found. d Transcription and translation involve genes found mostly in the macronucleus. e. The micronucleus and macronucleus are unique to ciliates.

c. Cytokinesis

25. Which of the following processes is not part of conjugation in Paramecium? a. Meiosis b. Mitosis c. Cytokinesis d. Fusion of haploid nuclei e. Breakdown of some micronuclei

c. contains many copies of the genetic information.

26. Paramecia contain two types of nuclei: a large macronucleus and as many as 80 micronuclei. The micronuclei are typical eukaryotic nuclei, essential for genetic recombination. The macronucleus a. is important in sexual recombination (conjugation). b. contains several micronuclei. c. contains many copies of the genetic information. d. contains DNA that is not transcribed. e. contains DNA that is transcribed but not translated.

b. haploid; gametes

27. In the alternation of generations, the gametophyte generation is _______ and produces _______. a. haploid; spores b. haploid; gametes c. diploid; spores d. diploid; gametes e. haploid or diploid; spores

c. Only the haploid organism may also reproduce asexually.

28. Some algae demonstrate the phenomenon of alternation of generations, by which a multicellular, diploid, spore-producing organism gives rise to a multicellular, haploid, gamete-producing organism. Which of the following statements about alternation of generations is false? a. The haploid and diploid organisms may or may not differ morphologically. b. The haploid and diploid organisms differ genetically. c. Only the haploid organism may also reproduce asexually. d. Haploid gametes can produce new organisms only by fusing with other gametes. e. Diploid sporophytes may undergo meiosis to produce haploid spores.

d. conjugation.

29. Paramecia have an elaborate sexual behavior in which they line up against each other and fuse. This is followed by an extensive reorganization and exchange of nuclear material. The entire process is called a. isogamous reproduction. b. alternation of generations. c. sexual reproduction. d. conjugation. e. None of the above

b. Microbial eukaryotes

3. Which of the following are not monophyletic? a. Diplomonads b. Microbial eukaryotes c. Animals d. Red algae e. Eukarya

c. It is a reproductive process.

30. Which of the following statements about the process of conjugation is false? a. Micronuclei disintegrate. b. Meiosis takes place. c. It is a reproductive process. d. Mitosis takes place. e. It is a sexual process of genetic recombination.

b. heteromorphic.

31. A eukaryotic organism that undergoes alternation of generations in which different generations do not resemble each other morphologically is referred to as a. homomorphic. b. heteromorphic. c. isomorphic. d. anisomorphic. e. gametophytic.

c. All species of Ulva are isogamous.

32. Which of the following statements about the life cycle of the green alga Ulva is false? a. Ulva has an isomorphic life cycle. b. The sporophyte and gametophyte can be differentiated only microscopically. c. All species of Ulva are isogamous. d. Individual gametophytes produce only sperm or only eggs—never both. e. The diploid sporophyte produces flagellated spores.

a. The sporophyte and the gametophyte look virtually identical.

33. The common sea lettuce, Ulva lactuca, is said to have an isomorphic life cycle. Which of the following statements about this species is true? a. The sporophyte and the gametophyte look virtually identical. b. The diploid and haploid stages of the life cycle are morphologically different from each other. c. The male and female gametes are different sizes. d. All of the above e. None of the above

e. female gametes are larger than male gametes.

34. In species that are anisogamous, a. both male and female gametes are very large. b. both male and female gametes are microscopic in size. c. male and female gametes are the same size. d. male gametes are larger than female gametes. e. female gametes are larger than male gametes.

a. multicellular haploid

35. A haplontic life cycle includes _______ individuals that form gametes. a. multicellular haploid b. multicellular diploid c. unicellular haploid d. unicellular diploid e. None of the above

a. Alveolates

36. Which of the following groups includes the dinoflagellates? a. Alveolates b. Green algae c. Red algae d. Stramenopiles e. Euglenozoans

a. coral.

37. Dinoflagellates are common endosymbionts of a. coral. b. fungi. c. other dinoflagellates. d. tertiary endosymbionts. e. None of the above

b. Algae

60. Which of the following are not unikonts? a. Fungi b. Algae c. Animals d. Choanoflagellates e. Slime molds

d. Sponges

61. Which of the following organisms are not considered microbial eukaryotes? a. Diatoms b. Algae c. Slime molds d. Sponges e. Giant kelp

c. Air sacs below the plasma membrane

38. Which of the following characteristics represents the synapomorphy of the alveolates? a. The presence of peptidoglycan between membranes of an important organelle b. Rows of tubular hairs on the longer of two unequally sized flagella c. Air sacs below the plasma membrane d. A fully parasitic lifestyle e. External shells of calcium carbonate

c. Chromalveolates

39. Which of the following groups may not be monophyletic? a. Opisthokonts b. Plantae c. Chromalveolates d. Stramenopiles e. Excavates

c. Excavates

4. Which clade of eukaryotes includes groups that do not have mitochondria? a. Chromalveolates b. Plantae c. Excavates d. Rhizaria e. Unikonts

d. apicomplexans

40. Perhaps the best-known _______ are the malarial parasites of the genus Plasmodium. a. turbellarians b. mastigophorans c. dinoflagellates d. apicomplexans e. poriferans

b. Dinoflagellates

41. Which of the following include species that form large toxic "blooms" in the ocean? a. Foraminiferans b. Dinoflagellates c. Kinetoplastids d. Paramecium e. Euglena

c. Stramenopiles

42. Which of the following groups contains multicellular brown algae and giant kelps? a. Diplomonads b. Chlorophytes c. Stramenopiles d. Alveolates e. Euglenozoans

c. Floridean starch is the main photosynthetic storage product.

43. Which of the following statements does not apply to diatoms? a. The cell walls are often impregnated with silicon. b. During mitosis, the top and bottom of the cell become the tops of the two new cells. c. Floridean starch is the main photosynthetic storage product. d. Zygotes are formed by gametes that lack cell walls. e. They can show bilateral or radial symmetry.

b. Rows of tubular hairs on the longer of two unequally sized flagella

44. Which of the following represents the synapomorphy of the stramenopiles? a. The presence of peptidoglycan between membranes of an important organelle b. Rows of tubular hairs on the longer of two unequally sized flagella c. Air sacs below the plasma membrane d. A fully parasitic lifestyle e. External shells of calcium carbonate

e. oomycetes

45. The _______ include the water molds and their terrestrial relatives, such as the downy mildews. a. parabasalids b. apicomplexans c. red algae d. euglenoids e. oomycetes

c. they have multiple nuclei enclosed in a single plasma membrane.

46. Some oomycetes are coenocytes, which means that a. they have a single nucleus enclosed in a single plasma membrane. b. their cytoplasm is pigmented. c. they have multiple nuclei enclosed in a single plasma membrane. d. their reproductive cells have no flagella. e. they have multiple flagella on their nonreproductive cells.

b. Storage of the products of photosynthesis as floridean starch

47. Which of the following is not a characteristic of the brown algae? a. Leaflike growths called thalli b. Storage of the products of photosynthesis as floridean starch c. A specialized holdfast that aids in attachment to a surface d. The presence of the carotenoid fucoxanthin in their chloroplasts e. Multicellularity

e. All of the above

48. The algal microbial eukaryote groups differ from one another in terms of their a. principal photosynthetic storage product. b. body plan (unicellular or multicellular). c. lack of or possession of flagella. d. principal photosynthetic pigments. e. All of the above

a. phycoerythrin

49. The presence of _______ in the chloroplasts of red algae gives them their characteristic color. a. phycoerythrin b. fucoxanthin c. -carotene d. chrysolaminarin e. chlorophyll b

b. Plantae

5. Which clade of eukaryotes includes groups that produce chlorophyll a and b? a. Chromalveolates b. Plantae c. Excavates d. Rhizaria e. Unikonts

b. red algae

50. Algal life cycles show extreme variation. Members of only one group, the _______, do not have flagellated motile cells in at least one of the stages. a. alveolates b. red algae c. euglenozoans d. diplomonads e. ciliates

d. chlorophytes.

51. Sea lettuce, Ulva lactuca, is a member of the green algae clade of a. charophytes. b. glaucophytes. c. coenocytes. d. chlorophytes. e. None of the above

a. Diplomonads

52. Which of the following organisms lack mitochondria? a. Diplomonads b. Choanoflagellates c. Red algae d. Euglenozoans e. Both b and c

c. Foraminiferans

53. _______ have created vast limestone deposits throughout the world. a. Radiolarians b. Dinoflagellates c. Foraminiferans d. Heliozoans e. None of the above

e. Both a and c

54. When some autotrophic Euglena are placed in the dark, they a. stop producing their photosynthetic pigment. b. produce an excess of photosynthetic pigment. c. begin feeding on organic material floating in the surrounding water. d. die. e. Both a and c

c. radiolarians

55. The _______ are marine microbial eukaryotes that secrete a glassy endoskeleton. a. algae b. protozoa c. radiolarians d. flagellates e. dinoflagellates

b. both have insect vectors for transmission to humans.

56. The microbial eukaryotes that are responsible for sleeping sickness and those that are responsible for malaria a. are both alveolates. b. both have insect vectors for transmission to humans. c. cause the same symptoms. d. both have gametocyte life stages. e. All of the above

b. Malaria

57. Which of the following diseases is not caused by the trypanosomes? a. African sleeping sickness b. Malaria c. Leishmaniasis d. Chagas' disease e. None of the above; all of these diseases are caused by trypanosomes.

c. radiolarians

58. The _______ are a group of protists that harbor photosynthetic endosymbionts that make them look greenish or golden in color. a. dinoflagellates b. plasmodial slime molds c. radiolarians d. diatoms e. corals

d. Both a and b

59. Which of the following groups uses pseudopods for locomotion? a. Radiolarians b. Amoebozoans c. Euglenids d. Both a and b e. Both a and c

e. Unikonts

6. Which clade of eukaryotes includes the choanoflagellates, whose bodies resemble cells found in sea sponges? a. Chromalveolates b. Plantae c. Excavates d. Rhizaria e. Unikonts

b. Haploid nuclei

63. Which of the following features is not a characteristic of the plasmodium of an acellular slime mold? a. Many nuclei enclosed in a single plasma membrane (coenocyte) b. Haploid nuclei c. Cytoplasmic streaming d. Mitosis without cytokinesis e. Formation of a sclerotium when conditions are unfavorable

a. Development of spores into myxamoebas

64. Which of the following events is not normally associated with the life cycle of a plasmodial slime mold? a. Development of spores into myxamoebas b. Formation of a sclerotium when conditions are adverse c. Active feeding by the plasmodium as it engulfs food particles d. Meiosis to form sporangiophores e. Fusion of swarm cells to form a diploid zygote

b. they have different numbers of nuclei within the plasma membrane.

65. The difference between acellular slime molds and cellular slime molds is that a. only cellular slime molds are motile. b. they have different numbers of nuclei within the plasma membrane. c. only acellular slime molds ingest food by endocytosis. d. only cellular slime molds ingest food by endocytosis. e. acellular slime molds prefer cool, moist habitats, whereas cellular slime molds prefer dry, hot conditions.

a. the onset of adverse conditions.

66. The signal responsible for the aggregation of myxamoebas is a. the onset of adverse conditions. b. alginic acid. c. phycoerythrin. d. actin. e. None of the above

e. aggregation of myxamoebas to form a slug or pseudoplasmodium.

67. In the cellular slime molds, the onset of adverse conditions causes a. aggregation of swarm cells to form a plasmodium. b. formation of sporangia. c. release of myxamoebas from fruiting bodies. d. the onset of cytoplasmic streaming. e. aggregation of myxamoebas to form a slug or pseudoplasmodium.

e. All of the above

7. Which of the following was an essential step in the evolution of eukaryotic cells? a. The development of a flexible cell surface b. The development of a cytoskeleton c. The development of a nuclear envelope d. The endosymbiotic acquisition of certain organelles e. All of the above

d. surface area-to-volume ratio.

8. The overall size that unicellular microbial eukaryotes can achieve is limited by their a. energy-producing potential. b. metabolism. c. mitochondria. d. surface area-to-volume ratio. e. Both a and b

b. secondary endosymbiosis, retaining the chloroplast from a red alga.

9. The photosynthetic stramenopiles obtained their chloroplasts, which are surrounded by three membranes, through a. primary endosymbiosis. b. secondary endosymbiosis, retaining the chloroplast from a red alga. c. secondary endosymbiosis, retaining the chloroplast from a chlorophyte. d. tertiary endosymbiosis. e. None of the above