Phylum Aschelminthes NEET notes

Phylum Aschelminthes NEET Notes

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Phylum Aschelminthes is the group of roundworms: bilaterally symmetrical, triploblastic and pseudocoelomate animals with a complete gut. These NEET notes follow NCERT Class 11 Biology, Chapter 4 (Animal Kingdom) section 4.2.5 line by line and add labelled diagrams of Ascaris, circular life cycles, a disease chart, an NCERT checklist and 90 practice questions (30 MCQs, 30 assertion-reason and 30 match-the-pair).

Key points

  • Body is circular in cross-section, hence the name roundworms.
  • May be free-living, aquatic and terrestrial, or parasitic in plants and animals.
  • Organ-system level of organisation; bilaterally symmetrical, triploblastic and pseudocoelomate.
  • Complete alimentary canal with a well-developed muscular pharynx.
  • An excretory tube removes body wastes from the body cavity through the excretory pore.
  • Dioecious; females are often longer than males. Internal fertilisation; development direct or indirect.
  • Examples: Ascaris (Roundworm), Wuchereria (Filaria worm), Ancylostoma (Hookworm).

What is Aschelminthes? Phylum Aschelminthes (Roundworms)

Phylum Aschelminthes roundworm Ascaris showing circular transverse section
Why Phylum Aschelminthes are called roundworms: the transverse section is circular.

The phylum Aschelminthes is called roundworms, but they are not round on the outside. Then why are they called roundworms? When you take a transverse section of the worm, it is round, and that’s why they have this name. In other words, roundworms get their name from their cross-section.

So, what is Aschelminthes? NCERT puts it simply: the body of the aschelminthes is circular in cross-section, hence the name roundworms. They may be free-living, aquatic and terrestrial, or parasitic in plants and animals. The name comes from the Greek askos (cavity or bladder) and helminthes (worms), a reference to the fluid-filled body cavity.

Why Aschelminthes are called nematodes and roundworms

So, why Aschelminthes are called nematodes? The word comes from the Greek nema, meaning ‘thread’: most members are long, slender and thread-like, tapering at both ends. Nematodes form the largest and best-known class of the phylum, so the common members, such as Ascaris, hookworms and filarial worms, are all nematodes. They are called roundworms because the body is circular in transverse section, and threadworms because of their thread-like shape.

Difference between Aschelminthes and Nemathelminthes; are Aschelminthes and Nematoda the same?

Students often ask about the difference between Aschelminthes and Nemathelminthes. In NEET and NCERT usage the two names refer to the same phylum of roundworms. ‘Aschelminthes’ (cavity worms) highlights the pseudocoelom, while ‘Nemathelminthes’ (thread worms) highlights the thread-like body shape.

Name Meaning What it covers
Aschelminthes askos = cavity, helminthes = worms NCERT name; a broad grouping of pseudocoelomate worms (nematodes and, in older schemes, rotifers and related groups)
Nemathelminthes nema = thread, helminthes = worms Older synonym used in many textbooks for the same roundworm phylum
Nematoda nema = thread, eidos = form The roundworms proper (Ascaris, Wuchereria, Ancylostoma); a class in older schemes, a separate phylum in modern classification

Are Aschelminthes and Nematoda the same? Not exactly. For NEET you can treat roundworm, nematode and Aschelminthes as describing the same animals, because all the NCERT examples are nematodes. Strictly, though, Nematoda is one class within the broader Aschelminthes, which in older schemes also included Rotifera, Gastrotricha, Kinorhyncha and Nematomorpha.

General characteristics of the phylum Aschelminthes

General characteristics of the phylum Aschelminthes

  • They are mostly endoparasites (NCERT: they may be free-living, aquatic and terrestrial, or parasitic in plants and animals)
  • They are triploblastic and show bilateral symmetry
  • Tube within the tube body plan
  • Organ level system of organization (NCERT: organ-system level of body organisation)
  • Pseudocoelomate – unique characteristic of this phylum
  • Cuticle, syncytial epidermis
  • Complete alimentary canal – seen for the first time in this phylum (with a well-developed muscular pharynx)
  • Epidermal nervous system (a nerve ring around the pharynx with dorsal and ventral nerve cords running in the epidermal cords)
  • H-shaped excretory organ (Renette cell); an excretory tube removes body wastes from the body cavity through the excretory pore
  • Sensory structures are present (amphids and phasmids, papillae around the lips)
  • Unisexual. Sexual dimorphism (males are smaller with a curved tail end, and females are longer with a straight tail end)
  • Usually indirect development (NCERT: development may be direct, the young ones resemble the adult, or indirect)
  • No circulatory and no respiratory system (Table 4.2); respiration by diffusion through the body surface, often anaerobic in gut parasites
  • Body wall has only longitudinal muscles, so roundworms move with a whip-like, wriggling motion
  • Fertilisation is internal

NCERT checklist: Phylum Aschelminthes

Tick off every Phylum Aschelminthes point before your exam; every point from NCERT 4.2.5 and Table 4.2 is covered in these notes.

Body plan of Phylum Aschelminthes: symmetry and germ layers

Bilateral symmetry in Phylum Aschelminthes roundworm with median plane
Phylum Aschelminthes is bilaterally symmetrical: only one median plane gives mirror halves.

Roundworms are elongated, cylindrical, unsegmented and taper at both ends. They are bilaterally symmetrical: only the median (sagittal) plane divides the body into identical left and right halves. They follow the tube-within-tube body plan, in which the outer body wall surrounds an inner digestive tube with the body cavity in between.

Triploblastic germ layers ectoderm mesoderm endoderm in Aschelminthes
Phylum Aschelminthes is triploblastic, with three germ layers.

They are triploblastic: ectoderm, mesoderm and endoderm are all present. Revise how these criteria work in the basis of classification of the animal kingdom.

Pseudocoelom: the body cavity of Phylum Aschelminthes

Pseudocoelom of Aschelminthes compared with acoelomate and coelomate cross-sections
Pseudocoelom of Phylum Aschelminthes compared with acoelom and true coelom.

In Aschelminthes the body cavity is not lined by mesoderm; instead, the mesoderm is present as scattered pouches in between the ectoderm and endoderm. Such a body cavity is called a pseudocoelom, and roundworms are the NCERT example of pseudocoelomates. Flatworms in Phylum Platyhelminthes are acoelomate, while annelids onwards have a true coelom. The fluid in the pseudocoelom acts as a hydrostatic skeleton and helps distribute food and wastes.

T.S. of Ascaris: labelled diagram

Labelled transverse section of female Ascaris showing cuticle, muscles, pseudocoelom and nerve cords
T.S. of female Ascaris, the type example of Phylum Aschelminthes.
  • Cuticle: tough, non-living outer layer that resists the host’s digestive enzymes.
  • Epidermis: syncytial (cell boundaries not distinct), thickened into dorsal, ventral and two lateral cords.
  • Muscles: only longitudinal muscles, arranged in four quadrants.
  • Pseudocoelom: fluid-filled cavity containing the intestine and reproductive organs.
  • Lateral lines: carry the excretory canals; dorsal and ventral cords carry nerve cords.

Body systems in Phylum Aschelminthes

Digestive system

Complete digestive tract of Ascaris from mouth with three lips to anus
Complete alimentary canal in Phylum Aschelminthes (Ascaris), mouth to anus.

The alimentary canal is complete, with a mouth and an anus, and has a well-developed muscular pharynx used to suck food. In Ascaris, the mouth is surrounded by three lips, and the intestine is a simple, non-muscular tube that absorbs digested food from the host. A complete gut first appears in Phylum Aschelminthes.

Excretory system

H-shaped excretory system of Ascaris with lateral canals and excretory pore
H-shaped excretory system of Ascaris (Phylum Aschelminthes).

An excretory tube removes body wastes from the body cavity through the excretory pore. In Ascaris, two lateral excretory canals joined by a transverse canal form an H-shaped system that opens by a ventral excretory pore near the anterior end. Many free-living nematodes have a gland-like renette cell instead. Roundworms are mainly ammonotelic.

Nervous system and sense organs

A circum-pharyngeal nerve ring gives off dorsal and ventral nerve cords that lie in the epidermal cords. Sense organs include papillae on the lips, amphids (chemoreceptors at the front end) and phasmids (near the tail).

Respiration and circulation

Members of Phylum Aschelminthes have no special respiratory or circulatory organs (NCERT Table 4.2). Gases diffuse through the body surface, and intestinal parasites such as Ascaris respire largely anaerobically. The pseudocoelomic fluid circulates materials.

Reproduction in Phylum Aschelminthes and sexual dimorphism

Male and female Ascaris: male smaller with curved tail and penial spicules, female longer and straight
Sexual dimorphism in Phylum Aschelminthes: male vs female Ascaris.

In Phylum Aschelminthes, sexes are separate (dioecious), i.e., males and females are distinct, and the phylum shows clear sexual dimorphism. Often females are longer than males. In Ascaris, the female is 20–40 cm long with a straight tail end, while the male is 15–30 cm long with a ventrally curved tail bearing a pair of penial spicules used during copulation. Fertilisation is internal and development may be direct (the young ones resemble the adult) or indirect, through larval stages. Like most invertebrates, roundworms are oviparous; see oviparous, viviparous and ovoviviparous animals.

Life cycle of Ascaris

Circular life cycle of Ascaris lumbricoides with migration through liver, heart and lungs
Ascaris life cycle (Phylum Aschelminthes): one host (human), infection by swallowing embryonated eggs.

Ascaris lumbricoides is monogenetic: the whole life cycle is completed in one host, the human. A female lays about two lakh eggs a day, which pass out with the faeces. In moist soil a larva develops inside the egg, and the embryonated egg is the infective stage. When eggs are swallowed with contaminated food or water, larvae hatch in the intestine, bore into the gut wall and migrate through the liver, heart and lungs. From the lungs they are coughed up and swallowed, and mature into adults in the small intestine. Heavy infection causes ascariasis, with abdominal pain, indigestion and intestinal blockage.

Life cycle of Wuchereria (filarial worm)

Life cycle of Wuchereria bancrofti between human and Culex mosquito
Wuchereria (Phylum Aschelminthes) life cycle: human and female Culex mosquito.

Wuchereria bancrofti, the filaria worm, lives in human lymph vessels and lymph nodes. Females release microfilariae, which circulate in the blood, especially at night. A female Culex mosquito picks them up while biting; the larvae develop in the mosquito into the infective stage and are passed to a new human at the next bite. Blocking of lymph vessels causes chronic swelling of the legs or scrotum, called filariasis or elephantiasis.

Examples of Phylum Aschelminthes and diseases

Examples of Phylum Aschelminthes: Ascaris, Wuchereria, Ancylostoma and Enterobius with diseases
Common examples of Phylum Aschelminthes and the diseases they cause.

Examples of Phylum Aschelminthes

  • Trichinella: Trichina worm
  • Trichuris: whipworm
  • Ascaris: common roundworm
  • Wuchereria: Filarial worm
  • Ancylostoma: Hookworm – it is a blood-sucking endoparasite
  • Enterobius: Pinworm
  • Loa: Eye worm
Worm Common name Disease Site / how infected
Ascaris lumbricoides Roundworm Ascariasis Small intestine; eggs in food/water
Wuchereria bancrofti Filaria worm Filariasis (elephantiasis) Lymphatics; bite of female Culex
Ancylostoma duodenale Hookworm Ancylostomiasis (anaemia) Small intestine; larvae enter through skin of bare feet
Enterobius vermicularis Pinworm Enterobiasis (anal itching) Large intestine; eggs swallowed, common in children
Trichinella spiralis Trichina worm Trichinosis Muscles; undercooked pork
Trichuris trichiura Whipworm Trichuriasis Large intestine
Loa loa Eye worm Loiasis Under the skin and eye; deer-fly bite

Some members of Phylum Aschelminthes are plant parasites, such as Meloidogyne (root-knot nematode), and many, like Caenorhabditis elegans, are free-living in soil.

Classes of Phylum Aschelminthes (older classification)

  • Nematoda (Gr. nema = thread): true roundworms with cuticle and pseudocoelom, e.g. Ascaris, Wuchereria, Ancylostoma.
  • Nematomorpha (horsehair worms): larvae parasitic in insects, adults free-living, e.g. Gordius.
  • Rotifera (wheel animalcules): microscopic, with a ciliated crown (corona), e.g. Rotaria.
  • Gastrotricha: microscopic, ventrally ciliated, e.g. Chaetonotus.
  • Kinorhyncha: tiny marine worms with a spiny, retractile head, e.g. Echinoderes.

Exam tip: Modern classification splits Phylum Aschelminthes and treats these classes as separate phyla. NEET follows NCERT, where Aschelminthes means roundworms.

Phylum Aschelminthes in NCERT Table 4.2 and comparison with neighbouring phyla

Feature Platyhelminthes Aschelminthes Annelida
Level of organisation Organ & organ-system Organ-system Organ-system
Symmetry Bilateral Bilateral Bilateral
Coelom Absent Pseudocoelomate Coelomate
Segmentation Absent Absent Present
Digestive system Incomplete Complete Complete
Circulatory system Absent Absent Present (closed)
Respiratory system Absent Absent Absent
Distinctive features Flat body, suckers Often worm-shaped, elongated Body segmentation like rings
Sexes Mostly hermaphrodite Separate (dioecious) Dioecious or monoecious

Explore the phyla: Phylum Porifera · Phylum Coelenterata (Cnidaria) · Phylum Ctenophora · Phylum Platyhelminthes · all Animal Kingdom notes. Practise with 40 NEET sample test papers and more NEET Biology notes.

Flip cards: Phylum Aschelminthes recall

Tap a card to flip it.

Why ‘roundworms’?tap to flip
Circular in cross-section
Body cavitytap to flip
Pseudocoelom
Guttap to flip
Complete, muscular pharynx
Excretiontap to flip
Excretory tube → excretory pore
Sexestap to flip
Separate; females longer
Filaria wormtap to flip
Wuchereria; vector Culex
Hookwormtap to flip
Ancylostoma; enters through skin
Pinwormtap to flip
Enterobius

Phylum Aschelminthes: Common doubts

What is Aschelminthes?

Aschelminthes is the phylum of roundworms: bilaterally symmetrical, triploblastic, pseudocoelomate animals with organ-system organisation and a complete gut, whose body is circular in cross-section.

Why are Aschelminthes called roundworms?

Because their body is circular in transverse section.

Why are Aschelminthes called nematodes?

From the Greek nema, meaning thread: most are slender and thread-like, and the main class of the phylum is Nematoda.

What is the difference between Aschelminthes and Nemathelminthes?

For NEET they are the same roundworm phylum. Aschelminthes (cavity worms) refers to the pseudocoelom; Nemathelminthes (thread worms) refers to the thread-like shape.

Are Aschelminthes and Nematoda the same?

Not strictly. Nematoda is the main class of Aschelminthes; older schemes also put rotifers and a few small groups in Aschelminthes. All NCERT examples are nematodes.

Do roundworms have a circulatory system?

No. NCERT Table 4.2 lists circulatory and respiratory systems as absent.

How does Ascaris infect humans?

By swallowing embryonated eggs in contaminated food or water.

Which mosquito spreads filariasis?

The female Culex mosquito transmits Wuchereria.

Phylum Aschelminthes: 30 NEET MCQs

Q1. Aschelminthes are called roundworms because their body is

  1. (a) flattened dorsoventrally
  2. (b) circular in cross-section
  3. (c) segmented into rings
  4. (d) radially symmetrical

Q2. The level of body organisation in Aschelminthes is

  1. (a) cellular
  2. (b) tissue
  3. (c) organ
  4. (d) organ-system

Q3. The body cavity of Ascaris is

  1. (a) true coelom
  2. (b) pseudocoelom
  3. (c) haemocoel
  4. (d) absent

Q4. In a pseudocoelomate, the mesoderm is

  1. (a) absent
  2. (b) lining the body cavity fully
  3. (c) present as scattered pouches between ectoderm and endoderm
  4. (d) only around the gut

Q5. Which is NOT a feature of Aschelminthes?

  1. (a) Triploblastic
  2. (b) Bilateral symmetry
  3. (c) Metameric segmentation
  4. (d) Complete alimentary canal

Q6. The alimentary canal of roundworms is

  1. (a) incomplete, with one opening
  2. (b) complete, with a well-developed muscular pharynx
  3. (c) absent
  4. (d) blind sac with gastrovascular cavity

Q7. In Aschelminthes, body wastes are removed from the body cavity through

  1. (a) flame cells
  2. (b) nephridia
  3. (c) the excretory pore by an excretory tube
  4. (d) Malpighian tubules

Q8. Sexes in Aschelminthes are

  1. (a) always united
  2. (b) separate (dioecious)
  3. (c) absent
  4. (d) changing with season

Q9. Which statement about Ascaris is correct?

  1. (a) Males are longer than females
  2. (b) Females are often longer than males
  3. (c) Both sexes are equal in size
  4. (d) Only females exist

Q10. Fertilisation in roundworms is

  1. (a) external
  2. (b) internal
  3. (c) absent
  4. (d) by budding

Q11. Development in Aschelminthes is

  1. (a) only direct
  2. (b) only indirect
  3. (c) direct or indirect
  4. (d) absent

Q12. Wuchereria is commonly called

  1. (a) Hookworm
  2. (b) Filaria worm
  3. (c) Pinworm
  4. (d) Whipworm

Q13. Ancylostoma is commonly called

  1. (a) Roundworm
  2. (b) Hookworm
  3. (c) Tapeworm
  4. (d) Liver fluke

Q14. Which system is absent in Aschelminthes according to Table 4.2?

  1. (a) Digestive
  2. (b) Circulatory
  3. (c) Excretory
  4. (d) Nervous

Q15. The distinctive feature listed for Aschelminthes in Table 4.2 is

  1. (a) Body with pores and canals
  2. (b) Often worm-shaped, elongated
  3. (c) Comb plates
  4. (d) Water vascular system

Q16. Aschelminthes may be

  1. (a) only free-living
  2. (b) only parasitic
  3. (c) free-living, aquatic and terrestrial, or parasitic in plants and animals
  4. (d) only marine

Q17. Number of germ layers in roundworms is

  1. (a) one
  2. (b) two
  3. (c) three
  4. (d) four

Q18. Symmetry in Aschelminthes is

  1. (a) radial
  2. (b) biradial
  3. (c) bilateral
  4. (d) asymmetrical

Q19. Which figure in NCERT shows the roundworm male and female?

  1. (a) Fig. 4.8
  2. (b) Fig. 4.10
  3. (c) Fig. 4.12
  4. (d) Fig. 4.14

Q20. The first phylum with a complete digestive tract is

  1. (a) Platyhelminthes
  2. (b) Aschelminthes
  3. (c) Ctenophora
  4. (d) Annelida

Q21. Elephantiasis is caused by

  1. (a) Ascaris
  2. (b) Wuchereria
  3. (c) Enterobius
  4. (d) Taenia

Q22. The vector of Wuchereria is

  1. (a) Anopheles
  2. (b) Aedes
  3. (c) female Culex
  4. (d) housefly

Q23. Infective stage of Ascaris for man is

  1. (a) adult worm
  2. (b) embryonated egg
  3. (c) microfilaria
  4. (d) cysticercus

Q24. Hookworm larvae usually enter the human body

  1. (a) through bare skin of feet
  2. (b) by mosquito bite
  3. (c) through eating pork
  4. (d) through inhalation

Q25. Body wall muscles of Ascaris are

  1. (a) only circular
  2. (b) only longitudinal
  3. (c) circular and longitudinal
  4. (d) absent

Q26. The epidermis of Ascaris is

  1. (a) cellular ciliated
  2. (b) syncytial
  3. (c) absent
  4. (d) chitinous

Q27. Male Ascaris can be identified by

  1. (a) straight tail
  2. (b) curved tail with penial spicules
  3. (c) larger size
  4. (d) vulva near front

Q28. Enterobius vermicularis is

  1. (a) Pinworm
  2. (b) Eye worm
  3. (c) Guinea worm
  4. (d) Whipworm

Q29. Which pair is correctly matched?

  1. (a) Loa – Eye worm
  2. (b) Trichuris – Hookworm
  3. (c) Trichinella – Pinworm
  4. (d) Ascaris – Filaria

Q30. Aschelminthes differ from Annelida in having

  1. (a) bilateral symmetry
  2. (b) pseudocoelom and no segmentation
  3. (c) triploblastic body
  4. (d) complete gut

Phylum Aschelminthes: 30 Assertion-Reason questions

Options for every question: (a) Both A and R are true and R is the correct explanation of A. (b) Both A and R are true but R is not the correct explanation of A. (c) A is true but R is false. (d) A is false but R is true.

Q1. Assertion (A): Aschelminthes are called roundworms.
Reason (R): Their body is circular in cross-section.

  1. (a) Both A and R true; R explains A
  2. (b) Both A and R true; R does not explain A
  3. (c) A true, R false
  4. (d) A false, R true

Q2. Assertion (A): Ascaris is a pseudocoelomate.
Reason (R): Its mesoderm is present as scattered pouches between ectoderm and endoderm.

  1. (a) Both A and R true; R explains A
  2. (b) Both A and R true; R does not explain A
  3. (c) A true, R false
  4. (d) A false, R true

Q3. Assertion (A): Roundworms have a complete alimentary canal.
Reason (R): They have both mouth and anus.

  1. (a) Both A and R true; R explains A
  2. (b) Both A and R true; R does not explain A
  3. (c) A true, R false
  4. (d) A false, R true

Q4. Assertion (A): Aschelminthes show organ-system level of organisation.
Reason (R): They are diploblastic.

  1. (a) Both A and R true; R explains A
  2. (b) Both A and R true; R does not explain A
  3. (c) A true, R false
  4. (d) A false, R true

Q5. Assertion (A): Roundworms are dioecious.
Reason (R): Males and females are distinct.

  1. (a) Both A and R true; R explains A
  2. (b) Both A and R true; R does not explain A
  3. (c) A true, R false
  4. (d) A false, R true

Q6. Assertion (A): In Ascaris, females are often longer than males.
Reason (R): Male has a curved posterior end.

  1. (a) Both A and R true; R explains A
  2. (b) Both A and R true; R does not explain A
  3. (c) A true, R false
  4. (d) A false, R true

Q7. Assertion (A): Fertilisation in Aschelminthes is external.
Reason (R): Sexes are separate.

  1. (a) Both A and R true; R explains A
  2. (b) Both A and R true; R does not explain A
  3. (c) A true, R false
  4. (d) A false, R true

Q8. Assertion (A): Aschelminthes lack a circulatory system.
Reason (R): Pseudocoelomic fluid distributes materials.

  1. (a) Both A and R true; R explains A
  2. (b) Both A and R true; R does not explain A
  3. (c) A true, R false
  4. (d) A false, R true

Q9. Assertion (A): Aschelminthes are segmented.
Reason (R): They are often worm-shaped and elongated.

  1. (a) Both A and R true; R explains A
  2. (b) Both A and R true; R does not explain A
  3. (c) A true, R false
  4. (d) A false, R true

Q10. Assertion (A): Wuchereria causes elephantiasis.
Reason (R): It blocks lymphatic vessels.

  1. (a) Both A and R true; R explains A
  2. (b) Both A and R true; R does not explain A
  3. (c) A true, R false
  4. (d) A false, R true

Q11. Assertion (A): Filariasis is transmitted by Anopheles.
Reason (R): Wuchereria lives in lymphatics.

  1. (a) Both A and R true; R explains A
  2. (b) Both A and R true; R does not explain A
  3. (c) A true, R false
  4. (d) A false, R true

Q12. Assertion (A): Ascaris life cycle is monogenetic.
Reason (R): It requires no intermediate host.

  1. (a) Both A and R true; R explains A
  2. (b) Both A and R true; R does not explain A
  3. (c) A true, R false
  4. (d) A false, R true

Q13. Assertion (A): Ancylostoma causes anaemia.
Reason (R): It is a blood-sucking endoparasite.

  1. (a) Both A and R true; R explains A
  2. (b) Both A and R true; R does not explain A
  3. (c) A true, R false
  4. (d) A false, R true

Q14. Assertion (A): Ascaris shows whip-like movement.
Reason (R): Its body wall has only longitudinal muscles.

  1. (a) Both A and R true; R explains A
  2. (b) Both A and R true; R does not explain A
  3. (c) A true, R false
  4. (d) A false, R true

Q15. Assertion (A): Roundworms are bilaterally symmetrical.
Reason (R): They are triploblastic.

  1. (a) Both A and R true; R explains A
  2. (b) Both A and R true; R does not explain A
  3. (c) A true, R false
  4. (d) A false, R true

Q16. Assertion (A): Development in Aschelminthes may be direct.
Reason (R): In direct development the young ones resemble the adult.

  1. (a) Both A and R true; R explains A
  2. (b) Both A and R true; R does not explain A
  3. (c) A true, R false
  4. (d) A false, R true

Q17. Assertion (A): Aschelminthes have a well-developed muscular pharynx.
Reason (R): The pharynx helps in sucking food.

  1. (a) Both A and R true; R explains A
  2. (b) Both A and R true; R does not explain A
  3. (c) A true, R false
  4. (d) A false, R true

Q18. Assertion (A): Excretory tube removes wastes through excretory pore.
Reason (R): Aschelminthes have flame cells.

  1. (a) Both A and R true; R explains A
  2. (b) Both A and R true; R does not explain A
  3. (c) A true, R false
  4. (d) A false, R true

Q19. Assertion (A): Cuticle protects Ascaris in the host intestine.
Reason (R): Cuticle resists digestive enzymes of the host.

  1. (a) Both A and R true; R explains A
  2. (b) Both A and R true; R does not explain A
  3. (c) A true, R false
  4. (d) A false, R true

Q20. Assertion (A): Aschelminthes are all parasitic.
Reason (R): Some roundworms are free-living in soil and water.

  1. (a) Both A and R true; R explains A
  2. (b) Both A and R true; R does not explain A
  3. (c) A true, R false
  4. (d) A false, R true

Q21. Assertion (A): Aschelminthes are acoelomates.
Reason (R): Their body cavity is not lined by mesoderm.

  1. (a) Both A and R true; R explains A
  2. (b) Both A and R true; R does not explain A
  3. (c) A true, R false
  4. (d) A false, R true

Q22. Assertion (A): Respiratory organs are absent in roundworms.
Reason (R): Gas exchange occurs through the body surface or anaerobically.

  1. (a) Both A and R true; R explains A
  2. (b) Both A and R true; R does not explain A
  3. (c) A true, R false
  4. (d) A false, R true

Q23. Assertion (A): Roundworms are also called nematodes.
Reason (R): Nema means thread.

  1. (a) Both A and R true; R explains A
  2. (b) Both A and R true; R does not explain A
  3. (c) A true, R false
  4. (d) A false, R true

Q24. Assertion (A): Enterobius infection is common in children.
Reason (R): Eggs are spread by contaminated fingers.

  1. (a) Both A and R true; R explains A
  2. (b) Both A and R true; R does not explain A
  3. (c) A true, R false
  4. (d) A false, R true

Q25. Assertion (A): Hookworm infection can be prevented by wearing footwear.
Reason (R): Hookworm larvae penetrate the skin.

  1. (a) Both A and R true; R explains A
  2. (b) Both A and R true; R does not explain A
  3. (c) A true, R false
  4. (d) A false, R true

Q26. Assertion (A): Trichinosis is caused by eating undercooked pork.
Reason (R): Larvae of Trichinella encyst in pig muscles.

  1. (a) Both A and R true; R explains A
  2. (b) Both A and R true; R does not explain A
  3. (c) A true, R false
  4. (d) A false, R true

Q27. Assertion (A): Platyhelminthes and Aschelminthes both have complete gut.
Reason (R): Both are bilaterally symmetrical.

  1. (a) Both A and R true; R explains A
  2. (b) Both A and R true; R does not explain A
  3. (c) A true, R false
  4. (d) A false, R true

Q28. Assertion (A): Table 4.2 lists Aschelminthes as pseudocoelomate.
Reason (R): They show segmentation.

  1. (a) Both A and R true; R explains A
  2. (b) Both A and R true; R does not explain A
  3. (c) A true, R false
  4. (d) A false, R true

Q29. Assertion (A): Ascaris eggs need soil to become infective.
Reason (R): Larva develops inside egg in moist soil.

  1. (a) Both A and R true; R explains A
  2. (b) Both A and R true; R does not explain A
  3. (c) A true, R false
  4. (d) A false, R true

Q30. Assertion (A): Aschelminthes have tissue level organisation.
Reason (R): They show germ layers.

  1. (a) Both A and R true; R explains A
  2. (b) Both A and R true; R does not explain A
  3. (c) A true, R false
  4. (d) A false, R true

Phylum Aschelminthes: 30 Match the pair questions

Q1. Match Column I with Column II.

Column I Column II
A. Ascaris i. Pinworm
B. Wuchereria ii. Filaria worm
C. Ancylostoma iii. Roundworm
D. Enterobius iv. Hookworm
  1. (a) A-ii, B-iii, C-i, D-iv
  2. (b) A-iii, B-ii, C-iv, D-i
  3. (c) A-ii, B-iv, C-i, D-iii
  4. (d) A-i, B-iv, C-iii, D-ii

Q2. Match Column I with Column II.

Column I Column II
A. Trichinella i. Eye worm
B. Trichuris ii. Common roundworm
C. Loa iii. Trichina worm
D. Ascaris iv. Whipworm
  1. (a) A-iv, B-ii, C-i, D-iii
  2. (b) A-iv, B-i, C-iii, D-ii
  3. (c) A-ii, B-iii, C-i, D-iv
  4. (d) A-iii, B-iv, C-i, D-ii

Q3. Match Column I with Column II.

Column I Column II
A. Wuchereria i. Trichinosis
B. Ancylostoma ii. Elephantiasis
C. Enterobius iii. Anaemia
D. Trichinella iv. Anal itching
  1. (a) A-i, B-iii, C-iv, D-ii
  2. (b) A-iii, B-i, C-ii, D-iv
  3. (c) A-i, B-iv, C-ii, D-iii
  4. (d) A-ii, B-iii, C-iv, D-i

Q4. Match Column I with Column II.

Column I Column II
A. Body cavity i. Pseudocoelom
B. Symmetry ii. Bilateral
C. Germ layers iii. Triploblastic
D. Organisation iv. Organ-system
  1. (a) A-iv, B-i, C-iii, D-ii
  2. (b) A-i, B-iv, C-ii, D-iii
  3. (c) A-iv, B-i, C-ii, D-iii
  4. (d) A-i, B-ii, C-iii, D-iv

Q5. Match Column I with Column II.

Column I Column II
A. Digestive system i. Complete
B. Circulatory system ii. Absent
C. Respiratory system iii. Absent
D. Segmentation iv. Absent
  1. (a) A-iv, B-iii, C-ii, D-i
  2. (b) A-i, B-iii, C-ii, D-iv
  3. (c) A-iii, B-i, C-iv, D-ii
  4. (d) A-ii, B-i, C-iv, D-iii

Q6. Match Column I with Column II.

Column I Column II
A. Platyhelminthes i. Diploblastic
B. Aschelminthes ii. Pseudocoelomate
C. Annelida iii. Coelomate
D. Ctenophora iv. Acoelomate
  1. (a) A-ii, B-iv, C-iii, D-i
  2. (b) A-iv, B-ii, C-i, D-iii
  3. (c) A-iii, B-ii, C-i, D-iv
  4. (d) A-iv, B-ii, C-iii, D-i

Q7. Match Column I with Column II.

Column I Column II
A. Cuticle i. Protects from enzymes
B. Syncytial epidermis ii. Whip-like movement
C. Longitudinal muscles iii. Cell boundaries absent
D. Pseudocoelomic fluid iv. Hydrostatic skeleton
  1. (a) A-iv, B-iii, C-i, D-ii
  2. (b) A-iii, B-ii, C-i, D-iv
  3. (c) A-i, B-iii, C-ii, D-iv
  4. (d) A-iii, B-iv, C-i, D-ii

Q8. Match Column I with Column II.

Column I Column II
A. Excretory pore i. Removes wastes
B. Muscular pharynx ii. Copulation in male
C. Penial spicules iii. Sucking food
D. Vulva iv. Female genital opening
  1. (a) A-i, B-ii, C-iii, D-iv
  2. (b) A-i, B-ii, C-iv, D-iii
  3. (c) A-i, B-iii, C-ii, D-iv
  4. (d) A-ii, B-iii, C-iv, D-i

Q9. Match Column I with Column II.

Column I Column II
A. Wuchereria vector i. Undercooked pork
B. Ascaris infection ii. Skin of bare feet
C. Hookworm infection iii. Female Culex
D. Trichinella infection iv. Contaminated food/water
  1. (a) A-iii, B-iv, C-ii, D-i
  2. (b) A-ii, B-i, C-iii, D-iv
  3. (c) A-ii, B-iv, C-i, D-iii
  4. (d) A-iii, B-ii, C-i, D-iv

Q10. Match Column I with Column II.

Column I Column II
A. Male Ascaris i. Separate
B. Female Ascaris ii. Curved tail
C. Females iii. Often longer
D. Sexes iv. Straight tail
  1. (a) A-i, B-iii, C-iv, D-ii
  2. (b) A-ii, B-iv, C-iii, D-i
  3. (c) A-iv, B-iii, C-i, D-ii
  4. (d) A-ii, B-iii, C-iv, D-i

Q11. Match Column I with Column II.

Column I Column II
A. Direct development i. Internal
B. Indirect development ii. Dioecious
C. Fertilisation iii. Larval stage
D. Sexes iv. Young resemble adult
  1. (a) A-iv, B-iii, C-i, D-ii
  2. (b) A-i, B-iii, C-ii, D-iv
  3. (c) A-i, B-ii, C-iii, D-iv
  4. (d) A-iii, B-i, C-ii, D-iv

Q12. Match Column I with Column II.

Column I Column II
A. Nematoda i. Ascaris
B. Rotifera ii. Rotaria
C. Nematomorpha iii. Echinoderes
D. Kinorhyncha iv. Gordius
  1. (a) A-i, B-iv, C-ii, D-iii
  2. (b) A-iv, B-i, C-ii, D-iii
  3. (c) A-i, B-ii, C-iv, D-iii
  4. (d) A-ii, B-iv, C-i, D-iii

Q13. Match Column I with Column II.

Column I Column II
A. Askos i. False
B. Nema ii. Cavity
C. Helminthes iii. Thread
D. Pseudo iv. Worms
  1. (a) A-ii, B-iii, C-iv, D-i
  2. (b) A-iv, B-iii, C-i, D-ii
  3. (c) A-iii, B-ii, C-i, D-iv
  4. (d) A-i, B-ii, C-iv, D-iii

Q14. Match Column I with Column II.

Column I Column II
A. Porifera i. Organ-system level
B. Coelenterata ii. Cellular level
C. Aschelminthes iii. Organ level
D. Platyhelminthes iv. Tissue level
  1. (a) A-iii, B-i, C-iv, D-ii
  2. (b) A-iv, B-ii, C-iii, D-i
  3. (c) A-ii, B-iv, C-i, D-iii
  4. (d) A-i, B-iii, C-ii, D-iv

Q15. Match Column I with Column II.

Column I Column II
A. Fig. 4.10 i. Roundworm male and female
B. Fig. 4.3(b) ii. Pseudocoelom
C. Table 4.2 iii. Salient features
D. Section 4.2.5 iv. Phylum Aschelminthes
  1. (a) A-ii, B-iv, C-i, D-iii
  2. (b) A-i, B-ii, C-iii, D-iv
  3. (c) A-iii, B-ii, C-iv, D-i
  4. (d) A-iii, B-i, C-iv, D-ii

Q16. Match Column I with Column II.

Column I Column II
A. Microfilariae i. Blood of human
B. Adult Wuchereria ii. Lymphatics
C. Adult Ascaris iii. Small intestine
D. Enterobius adult iv. Large intestine
  1. (a) A-iii, B-ii, C-i, D-iv
  2. (b) A-ii, B-iv, C-iii, D-i
  3. (c) A-i, B-ii, C-iii, D-iv
  4. (d) A-ii, B-i, C-iii, D-iv

Q17. Match Column I with Column II.

Column I Column II
A. Ascaris larva path i. Infective stage
B. Ascaris eggs ii. Liver, heart, lungs
C. Embryonated egg iii. Passed in faeces
D. Adult iv. Small intestine
  1. (a) A-iv, B-i, C-ii, D-iii
  2. (b) A-ii, B-iv, C-i, D-iii
  3. (c) A-ii, B-iii, C-i, D-iv
  4. (d) A-i, B-iii, C-iv, D-ii

Q18. Match Column I with Column II.

Column I Column II
A. Flatworm gut i. Complete
B. Roundworm gut ii. Canal system
C. Sponge iii. Gastrovascular cavity
D. Cnidarian iv. Incomplete
  1. (a) A-ii, B-iii, C-iv, D-i
  2. (b) A-iv, B-iii, C-i, D-ii
  3. (c) A-iv, B-i, C-ii, D-iii
  4. (d) A-ii, B-iv, C-iii, D-i

Q19. Match Column I with Column II.

Column I Column II
A. Flame cells i. Platyhelminthes
B. Excretory tube ii. Aschelminthes
C. Nephridia iii. Annelida
D. Malpighian tubules iv. Arthropoda
  1. (a) A-iii, B-iv, C-ii, D-i
  2. (b) A-i, B-ii, C-iii, D-iv
  3. (c) A-ii, B-iii, C-iv, D-i
  4. (d) A-iv, B-i, C-iii, D-ii

Q20. Match Column I with Column II.

Column I Column II
A. Amphids i. Dorsal and ventral
B. Phasmids ii. Around pharynx
C. Nerve ring iii. Posterior sense organs
D. Nerve cords iv. Anterior chemoreceptors
  1. (a) A-ii, B-i, C-iv, D-iii
  2. (b) A-iii, B-i, C-ii, D-iv
  3. (c) A-ii, B-iii, C-i, D-iv
  4. (d) A-iv, B-iii, C-ii, D-i

Q21. Match Column I with Column II.

Column I Column II
A. Ascaris i. Digenetic
B. Wuchereria ii. Monogenetic
C. Culex iii. Definitive host of filaria
D. Human iv. Vector
  1. (a) A-ii, B-iii, C-iv, D-i
  2. (b) A-ii, B-iii, C-i, D-iv
  3. (c) A-ii, B-i, C-iv, D-iii
  4. (d) A-iv, B-ii, C-iii, D-i

Q22. Match Column I with Column II.

Column I Column II
A. Meloidogyne i. Blood-sucking parasite
B. Caenorhabditis ii. Root-knot nematode
C. Ancylostoma iii. Free-living soil nematode
D. Loa iv. Eye worm
  1. (a) A-ii, B-iv, C-i, D-iii
  2. (b) A-ii, B-iii, C-i, D-iv
  3. (c) A-i, B-iii, C-iv, D-ii
  4. (d) A-i, B-ii, C-iv, D-iii

Q23. Match Column I with Column II.

Column I Column II
A. Ascaris disease i. Ancylostomiasis
B. Hookworm disease ii. Enterobiasis
C. Pinworm disease iii. Ascariasis
D. Whipworm disease iv. Trichuriasis
  1. (a) A-iii, B-i, C-ii, D-iv
  2. (b) A-ii, B-iv, C-iii, D-i
  3. (c) A-iii, B-ii, C-i, D-iv
  4. (d) A-ii, B-iii, C-i, D-iv

Q24. Match Column I with Column II.

Column I Column II
A. Body shape i. Often worm-shaped, elongated
B. Body in T.S. ii. Circular
C. Segmentation iii. None
D. Table 4.2 feature iv. Cylindrical, tapering
  1. (a) A-i, B-iii, C-ii, D-iv
  2. (b) A-ii, B-iv, C-iii, D-i
  3. (c) A-iv, B-iii, C-ii, D-i
  4. (d) A-iv, B-ii, C-iii, D-i

Q25. Match Column I with Column II.

Column I Column II
A. Ectoderm i. Intestine lining
B. Mesoderm ii. Muscles
C. Endoderm iii. Between gut and body wall
D. Pseudocoelom iv. Cuticle and epidermis
  1. (a) A-iv, B-ii, C-i, D-iii
  2. (b) A-ii, B-iii, C-iv, D-i
  3. (c) A-iii, B-ii, C-iv, D-i
  4. (d) A-iii, B-iv, C-ii, D-i

Q26. Match Column I with Column II.

Column I Column II
A. Annelida i. Flat, acoelomate
B. Aschelminthes ii. Comb plates
C. Platyhelminthes iii. Unsegmented, pseudocoelomate
D. Ctenophora iv. Segmented, coelomate
  1. (a) A-iii, B-ii, C-iv, D-i
  2. (b) A-i, B-iv, C-ii, D-iii
  3. (c) A-iv, B-iii, C-i, D-ii
  4. (d) A-i, B-ii, C-iii, D-iv

Q27. Match Column I with Column II.

Column I Column II
A. Ascaris male length i. About 2 lakh
B. Ascaris female length ii. 15–30 cm
C. Eggs per day iii. 20–40 cm
D. Lips around mouth iv. Three
  1. (a) A-ii, B-iii, C-i, D-iv
  2. (b) A-iii, B-iv, C-i, D-ii
  3. (c) A-iii, B-i, C-iv, D-ii
  4. (d) A-i, B-iii, C-iv, D-ii

Q28. Match Column I with Column II.

Column I Column II
A. Free-living aquatic i. Some nematodes in water
B. Terrestrial ii. Root-knot nematode
C. Plant parasite iii. Ascaris
D. Animal parasite iv. Soil nematodes
  1. (a) A-ii, B-iii, C-iv, D-i
  2. (b) A-i, B-ii, C-iii, D-iv
  3. (c) A-i, B-iv, C-ii, D-iii
  4. (d) A-iv, B-ii, C-iii, D-i

Q29. Match Column I with Column II.

Column I Column II
A. Bilateral symmetry i. Ctenophores
B. Radial symmetry ii. Many planes
C. Asymmetry iii. No plane
D. Biradial iv. One median plane
  1. (a) A-ii, B-iv, C-i, D-iii
  2. (b) A-iii, B-iv, C-i, D-ii
  3. (c) A-iv, B-iii, C-i, D-ii
  4. (d) A-iv, B-ii, C-iii, D-i

Q30. Match Column I with Column II.

Column I Column II
A. Respiration i. Nerve ring with cords
B. Circulation ii. Absent
C. Excretion iii. Excretory canals
D. Nervous system iv. Diffusion / anaerobic
  1. (a) A-ii, B-iv, C-i, D-iii
  2. (b) A-ii, B-iii, C-iv, D-i
  3. (c) A-iv, B-ii, C-iii, D-i
  4. (d) A-i, B-ii, C-iii, D-iv

Done with Phylum Aschelminthes? Next: continue to Annelida in our Animal Kingdom notes.

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