Unit 2: General Characteristics of Nematodes - Practice Quiz

1 What is the scientific study of nematodes called?

2 What does the term vermiform mean when describing a nematode?

3 What is a stylet in a plant-parasitic nematode?

4 Which body feature is characteristic of nematodes?

5 What type of body symmetry do nematodes possess?

6 Which structure forms the tough outer covering of a nematode?

7 What happens to the nematode cuticle during growth?

8 Which type of digestive system is found in most nematodes?

9 The fluid-filled body cavity of a nematode is called a:

10 How do nematodes mainly move?

11 Which genus is commonly known as the root-knot nematode?

12 Which plant is the principal host of Heterodera glycines, the soybean cyst nematode?

13 Which crop is commonly attacked by potato cyst nematodes of the genus Globodera?

14 Which genus is commonly called the lesion nematode?

15 The burrowing nematode Radopholus similis is an important pest of which crop?

16 Which feature most clearly distinguishes most plant-parasitic nematodes from free-living nematodes?

17 What do many free-living soil nematodes feed on?

18 How do bacterivorous nematodes contribute to soil fertility?

19 Why are nematode communities useful as indicators of soil health?

20 What is a common above-ground symptom of plant-parasitic nematode damage?

21 A nematode remains outside the root and inserts only its stylet into epidermal cells to feed. Which term best describes this feeding habit?

22 During examination of an infected root, a nematode is found moving through cortical tissues and producing elongated brown lesions. Which term most accurately describes it?

23 A plant shows little measurable yield reduction until the nematode population exceeds a particular density. What is this density commonly called?

24 A soil animal is unsegmented, bilaterally symmetrical, cylindrical, and tapered at both ends. Which additional feature would most strongly support its identification as a nematode?

25 Why can many nematodes increase in diameter but not increase greatly in cell number after reaching maturity?

26 A nematode is exposed to a chemical that prevents successful shedding of its old cuticle. Which process will be affected most directly?

27 A nematode specimen has a strong protrusible stylet with basal knobs. What biological function is this structure most likely to perform?

28 A researcher damages the amphids of a plant-parasitic nematode. Which behavior is most likely to be impaired?

29 Eggs of a plant-parasitic nematode hatch as second-stage juveniles. What most likely happened to the first-stage juveniles?

30 A sedentary endoparasitic female becomes swollen after establishing a permanent feeding site, while the male remains vermiform. What best explains this difference?

31 Tomato roots contain conspicuous galls, and swollen females are embedded in the root tissue. Which genus is the most likely cause?

32 A potato field contains spherical cysts attached to roots, and the nematode survives in soil for years without a host. Which genus is most consistent with these findings?

33 A banana plantation shows root necrosis, poor anchorage, and plant toppling. Microscopy reveals a migratory endoparasite in root lesions. Which genus is the strongest diagnosis?

34 A crop rotation replaces one cereal with another, but root-lesion symptoms continue because the nematode attacks both crops. Which genus is most likely involved?

35 A grapevine develops a viral disease, and dagger-shaped nematodes are recovered from soil around its roots. Which genus could have transmitted the virus?

36 Two nematodes are isolated from the same soil. One has a hollow stylet, while the other has a broad mouth containing structures suited for ingesting bacteria. What is the best interpretation?

37 After a field receives organic compost, bacterivorous nematodes increase rapidly but root damage does not. Why is this response reasonable?

38 A rise in bacterivorous nematodes is followed by increased mineral nitrogen in the soil. Which process best accounts for this pattern?

39 A soil food-web analysis finds many omnivorous and predatory nematodes with long life cycles. What does this most strongly suggest about the soil?

40 Plants infected by root-lesion nematodes develop more severe fungal root rot than plants exposed to either organism alone. Which explanation best fits this observation?

41 A nematode juvenile enters a root, migrates through cortical tissue while feeding, and leaves the root before completing development. Which terminology most precisely describes its parasitic strategy?

42 A swollen adult female remains attached to one feeding site, with her anterior region embedded in the root and most of her body exposed at the root surface. How should she be classified?

43 Which statement correctly distinguishes a nematode cyst from an egg mass?

44 A nematode increases substantially in diameter after feeding but possesses no circular body-wall muscles. Which mechanism best explains its ability to maintain body form and move?

45 Which combination is most consistent with the nematode body plan rather than that of an annelid?

46 An adverse season begins after a nematode has completed its first molt inside the egg. Which stage is commonly positioned to hatch and locate a host in many major plant-parasitic nematodes?

47 Microscopy reveals a protrusible stylet with basal knobs, a muscular median bulb, and posterior esophageal glands overlapping the intestine. Which functional interpretation is best supported?

48 A researcher disrupts the dorsal esophageal gland of an infective root-knot nematode juvenile without impairing stylet movement. Which process is most directly expected to fail?

49 Which observation most strongly indicates that an immobile, swollen female nematode has not ceased biologically active host manipulation?

50 A potato field shows patches of stunted plants. Lemon-shaped females occur on roots, and brown cysts containing eggs persist in soil. Which genus-host association is most likely?

51 A banana plantation has toppling plants, reddish-brown root lesions, and extensive cortical tunneling. Vermiform stages of both sexes are recovered from the lesions. Which genus best fits the evidence?

52 Which diagnostic pairing correctly links a nematode genus, its feeding behavior, and a representative host problem?

53 A vineyard has declining vines and transmission of a nepovirus. The vector is a large ectoparasitic nematode with a long odontostyle. Which genus is the strongest diagnosis?

54 A crop rotation replaces tomato with cotton, but severe root galling continues because the nematode population reproduces on both crops. Which feature most plausibly explains this failure?

55 A soil nematode possesses a narrow stylet, but no feeding behavior has been observed. Why is stylet presence alone insufficient to prove plant parasitism?

56 Two nematodes are extracted from the same rhizosphere. Specimen I has a bacterial-feeding stoma and rapidly colonizes enriched soil; specimen II has a knobbed stylet and reproduces only on living roots. Which classification is best supported?

57 Bacterivorous nematodes consume bacteria whose biomass has a lower nitrogen concentration than the nematodes require. What is the most likely immediate effect on plant-available nitrogen?

58 After repeated organic amendments, a soil sample becomes dominated by rapidly reproducing bacterivorous nematodes with low colonizer-persister values. What does this community shift most strongly indicate?

59 Plants infected simultaneously by a root-lesion nematode and a soilborne fungus develop more severe disease than plants challenged by either organism alone. Which mechanism best explains this interaction?

60 A root system contains many galls, yet only a small reduction in shoot growth occurs under high fertility. Which conclusion is scientifically most defensible?