NCERT Exemplar: Animal Kingdom

MULTIPLE CHOICE QUESTIONS

Q.1. In some animal groups, the body is found divided into compartments with serial repetition of at least some organs. This characteristic feature is called
(a) Segmentation
(b) Metamerism
(c) Metagenesis
(d) Metamorphosis
Ans. (b)
Explanation: Metamerism refers to the external and internal division of the body into a series of segments with repetition of some organs. This is clearly seen in earthworms (annelids) where segments show repeated organs and structures. True metameric segmentation is seen in  phyla: Annelida and modified metamerism is seen in Arthropoda and Chordata . Metamerism provides greater flexibility and allows specialisation of different body regions for distinct functions.

Q.2. Given below are types of cells present in some animals. Which of the following cells can differentiate to perform different functions?
(a) Choanocytes
(b) Interstitial cells
(c) Gastrodermal cells
(d) Nematocytes
Ans. (b)
Explanation: Interstitial cells are undifferentiated or totipotent cells that can give rise to other cell types and perform different functions. They are commonly found in some lower animals (for example, in cnidarians such as Hydra) where they help regenerate or replace specialised cells. By contrast, choanocytes are characteristic flagellated feeding cells of poriferans, gastrodermal cells line the gut in cnidarians, and nematocytes are specialised stinging cells of cnidarians.

Q.3. Which one of the following sets of animals share a four chambered heart?
(a) Amphibian, Reptiles, Birds
(b) Crocodiles, Birds, Mammals
(c) Crocodiles, Lizards, Turtles
(d) Lizards, Mammals, Birds
Ans. (b)
Explanation: Crocodiles, birds and mammals all possess a four-chambered heart (two atria and two ventricles), which allows complete separation of oxygenated and deoxygenated blood and supports a more efficient metabolic rate. In contrast, most fishes have a two-chambered heart; amphibians and many reptiles have a three-chambered heart (except crocodilians which have four chambers among reptiles).

Q.4. Which of the following pairs of animals has non glandular skin?
(a) Snake and Frog
(b) Chameleon and Turtle
(c) Frog and Pigeon
(d) Crocodile and Tiger
Ans. (b)
Explanation: Chameleon and turtle (both reptiles) have dry, scaly or keratinised skin that lacks cutaneous glands; it is therefore described as non-glandular. Amphibians such as frogs have moist glandular skin with mucous glands, while birds and mammals have other epidermal specialisations and may have glandular skin in places.

Q.5. Birds and mammals share one of the following characteristics as a common feature.
(a) Pigmented skin
(b) Pneumatic bones
(c) Viviparity
(d) Warm blooded
Ans. (d)
Explanation: Both birds and mammals are endothermic (warm-blooded or homeothermic) and are able to maintain a relatively constant high body temperature independent of the environment. Pneumatic bones are typical of many birds, viviparity is common in most mammals but not in birds, and pigmented skin is not a shared defining feature.

Q.6. Which one of the following sets of animals belong to a single taxonomic group?
(a) Cuttlefish, Jellyfish, Silverfish, Dogfish, Starfish
(b) Bat, Pigeon, Butterfly
(c) Monkey, Chimpanzee, Man
(d) Silkworm, Tapeworm, Earthworm
Ans. (c)
Explanation: Monkey, chimpanzee and man are all mammals and belong to the same taxonomic class Mammalia. The other sets mix animals from different phyla or classes (for example, jellyfish are cnidarians while cuttlefish are molluscs), so they do not form a single taxonomic group.

Q.7. Which one of the following statements is incorrect? 
(a) Mesoglea is present in between ectoderm and endoderm in Obelia.
(b) Exhibits radial symmetry Asterias
(c) Fasciola is a pseudocoelomate animal
(d) Taenia is a triploblastic animal
Ans. (c)
Explanation: Fasciola (a fluke) is an acoelomate - it lacks a body cavity between the gut and body wall. The mesoglea between ectoderm and endoderm is correct for some cnidarians like Obelia, Asterias (a starfish) exhibits radial symmetry as an adult (echinoderm), and Taenia (a tapeworm) is triploblastic (has three germ layers).

Q.8. Which one of the following statements is incorrect?
(a) In cockroaches and prawns excretion of waste material occurs through malpighian tubules.
(b) In ctenophores, locomotion is mediated by comb plates.
(c) In Fasciola, flame cells help in excretion
(d) Earthworms are hermaphrodites and yet cross fertilization take place among them.
Ans. (a)
Explanation: Statement (a) is incorrect because cockroaches excrete wastes via Malpighian tubules, whereas prawns (crustaceans) use green glands (antennal glands) for excretion. The other statements are correct: ctenophores move by comb plates, Fasciola (a platyhelminth) uses flame cells (protonephridia) for excretion/osmoregulation, and earthworms are hermaphrodites that typically reproduce by cross-fertilisation.

Q.9. Which one of the following is oviparous?
(a) Platypus
(b) Flying fox (Bat)
(c) Elephant
(d) Whale
Ans. (a)
Explanation: The platypus (a monotreme, class Prototheria) is oviparous - it lays eggs despite being a mammal. Monotremes are primitive mammals that retain several reptilian features such as egg-laying; they also have mammary glands but lack true teats. Examples include Ornithorhynchus (duck-billed platypus) and echidnas.

Q.10. Which one of the following is a non-poisonous snake?
(a) Cobra
(b) Viper
(c) Python
(d) Krait
Ans. (c)
Explanation. Python is a non-venomous constrictor snake; it kills prey by constriction rather than by venom. Cobras (Naja), vipers (Vipera) and kraits (Bungarus) are venomous snakes. Note: King Cobra (Ophiophagus hannah) is a venomous species and is notable for some nesting behaviour, but it is not a non-venomous snake.

Q.11. Match the following list of animals with their level of organisation.

Choose the correct match showing division of labour with animal example.
(a) i-B, ii-C, iii-D, and iv-A 
(b) i-B, ii-D, iii-C, and iv-A 
(c) i-D, ii-A, iii-B, and iv-C 
(d) i-A, ii-D, iii-C, and iv-B 
Ans. (c)
Explanation.

Q.12. Body cavity is the cavity present between body wall and gut wall. In some animals the body cavity is not lined by mesoderm. Such animals are called
(a) Acoelomates
(b) Pseudocoelomates
(c) Coelomates
(d) Haemocoelomates
Ans. (b)
Explanation. Animals in which the body cavity is not lined by mesoderm are called pseudocoelomates (e.g., Ascaris).
Acoelomates lack a body cavity completely and are represented by Platyhelminthes.
Coelomates possess a true coelom lined by mesoderm (e.g., Annelida, Arthropoda, Mollusca, Chordata).

Q.13. Match the column A with column B and choose the correct option.

(i) A-(ii), B-(iii), C-(v), D-(iv), E-(i)

(ii) A-(ii), B-(v), C-(iii), D-(iv), E-(i)

(iii) A-(i), B-(iii), C-(v), D-(iv), E-(ii)

(iv) A-(i), B-(v), C-(iii), D-(iv), E-(ii)

Ans. (c)
Explanation. 

VERY SHORT ANSWER TYPE QUESTIONS

Q.1. Identify the phylum in which adults exhibit radial symmetry and larva exhibit bilateral symmetry.
Ans. In Phylum Echinodermata, adults show radial symmetry whereas their larvae are bilaterally symmetrical.

Q.2. What is the importance of pneumatic bones and air sacs in Aves?
Ans. Pneumatic bones are hollow bones that make the skeleton lighter, aiding flight. Air sacs form part of the respiratory system in birds; they improve the efficiency of gas exchange and assist in reducing body density, which also helps flight and buoyancy.

Q.3. What is metagenesis? Mention an example which exhibits this phenomenon.
Ans. Metagenesis, or alternation of generations, is the regular alternation between two different forms or generations in the life cycle of an organism (for example, a sessile polyp and a free-swimming medusa). Obelia is a classic example that shows alternation between polyp and medusa forms.

Q.4. What is the role of feathers?
Ans. Feathers provide insulation, help to keep the body light and aerodynamic for flight, and are also used in display and protection.

Q.5. Which group of chordates possess sucking and circular mouth without jaws?
Ans. Cyclostomes (jawless fishes such as lampreys and hagfishes) have a circular, sucking mouth without jaws.

Q.6. Give one example each for an animal possessing placoid scales and that with cycloid scales.
Ans. Cycloid scales: Labeo, Catla
Placoid scales: Pristis, Trygon

Q.7. Mention two modifications in reptiles required for terrestrial mode of life.
Ans. 1. Body covered by dry, cornified (keratinised) skin with epidermal scales or scutes to reduce water loss.
2. Cleidoic (amniotic) eggs that permit development on land by providing protection and a controlled internal environment for the embryo.

Q.8. Mention one example each for animals with chitinous exoskeleton and those covered by a calcareous shell.
Ans. The body of arthropods (for example, cockroach) is covered by a chitinous exoskeleton. Molluscs (for example, Pila) typically have a body protected by a calcareous shell.

Q.9. What is the role of radula in molluscs?
Ans. The radula is a file-like, rasping organ used in feeding; it scrapes or cuts food particles before ingestion.

Q.10. Name the animal, which exhibits the phenomenon of bioluminescence. Mention the phylum to which it belongs.
Ans. Bioluminescence (the ability to emit light) is well marked in members of Phylum Ctenophora (comb jellies). Examples include Pleurobrachia, Ctenoplana, Beroe, Coeloplana and Velamen.

Q.11. Write one example each of the following in the space provided.
(a) Cold blooded animal ______
(b) Warm blooded animal ______
(c) Animal possessing dry and cornified skin ______
(d) Dioecious  animal ______
Ans.
Examples:
(a) Cold blooded animal: an amphibian - Frog
(b) Warm blooded animal: a mammal - Human
(c) Animal possessing dry and cornified skin: a reptile - Lizard
(d) Dioecious animal: Ascaris (Aschelminthes), sexes separate

Q.12. Differentiate between a diploblastic and a triploblastic animal.
Ans. 
Diploblastic: Animals having two germ layers (ectoderm and endoderm).
Example: Cnidaria and Ctenophora
Triploblastic: Animals having three germ layers (ectoderm, mesoderm, endoderm).
Example: From Platyhelminthes to Chordata

Q.13. Give an example of  the following
(a) Round worm
(b) Fish possessing poison sting
(c) A limbless reptile/ amphibian
(d) An oviparous mammal
Ans.
Examples:
(a) Roundworm: Ascaris
(b) Fish possessing poison sting: Trygon (sting ray)
(c) A limbless reptile/amphibian: Ichthyophis (a limbless amphibian)
(d) An oviparous mammal: Ornithorhynchus (duck-billed platypus)

Q.14. Provide appropriate technical term in the space provided.
(a) Blood-filled cavity in arthropods ______.
(b) Free-floating form of cnidaria ______.
(c) Stinging organ of jelly fishes ______.
(d) Lateral appendages in aquatic annelids ______.
Ans. Provide appropriate technical term in the space provided.
(a) Blood-filled cavity in arthropods: Haemocoel
(b) Free-floating form of cnidaria: Medusa
(c) Stinging organ of jelly fishes: Nematocyst
(d) Lateral appendages in aquatic annelids: Parapodia

Q.15. Match the following:

Ans.

SHORT ANSWER TYPE QUESTIONS

Q.1. Differentiate between:
(a) Open circulatory system and closed circulatory system
(b) Oviparous and viviparous characteristic
(c) Direct development and Indirect development
Ans. 
(a) Open Circulatory System and Closed Circulatory System:

(b) Oviparous and Viviparous:

(c) Direct Development and Indirect Development:

Q.2. Sort out the animals on the basis of their symmetry (radial or bilateral) coelenterates, ctenophores, annelids, arthropods, and echinoderms.
Ans. Coelenterates: Radial
Ctenophores: Radial
Annelids: Bilateral
Arthropods: Bilateral
Echinoderms: Radial (adult)

Q.3. There has been an increase in the number of chambers in heart during evolution of vertebrates. Give the names of the class of vertebrates having two, three or four-chambered heart.
Ans. Two-chambered heart: Chondrichthyes and Osteichthyes (fishes)
Three-chambered heart: Amphibia and most Reptilia (except crocodilians)
Four-chambered heart: Aves and Mammalia

Q.4. Fill up the blank spaces appropriately.

Ans.
A = Malpighian Tubule/ coxal glands/ antennal glands/ green glands
B = Open
C = Annelida
D = Mollusca
E = Feather like gills
F = Kidney

Q.5. Match  the following

Ans.

Q.6. Endoparasites are found inside the host body. Mention the special structure, possessed by these and which enables them to survive in those conditions.
Ans. The life cycles of endoparasites are often complex and they show special adaptations for a parasitic lifestyle. Their morphology and anatomy are frequently simplified, while reproductive capacity is emphasised. Adaptations include:
1. Loss or reduction of unnecessary sense organs.
2. Reduction or loss of digestive structures (many absorb nutrients directly from the host).
3. Very high reproductive capacity to ensure transmission to new hosts.
4. Presence of adhesive organs or suckers (e.g. hooks, suckers) to attach securely to the host.

Q.7. Match the following and write correct choice in space provided

a. ______, b. ______, c. ______ d. ______, e. ______, f. ______
Ans.

Q.8. Differentiate between:
(a) Give the characteristic features of the following citing one example culatory system
(b) Oviparity and viviparity
(c) Direct and indirect development
(d) Aceolomate and pseudocoelomate
(e) Notochord and nerve cord
(f) Polyp and medusa
Ans. 
(a) The circulatory system may be of two types:

Open circulatory system: Blood is pumped into open spaces (sinuses) and directly bathes tissues.
Example: Arthropoda, Mollusca
Closed circulatory system: Blood flows through vessels (arteries, veins, capillaries).
Example: Annelida, Chordata

(b) Oviparous animals lay eggs which develop outside the mother's body; viviparous animals give birth to live young that developed within the mother.
(c) Direct development: An embryo develops into a juvenile or adult form without a distinct larval stage. Indirect development: Development includes a larval stage that differs markedly from the adult and usually undergoes metamorphosis.
(d) Acoelomate: No body cavity is present between gut and body wall; tissues fill the space (e.g. Platyhelminthes).
Pseudocoelomate: Body cavity (pseudocoel) is present but not fully lined by mesoderm (e.g. Aschelminthes).
(e) Notochord: A dorsal, stiff rod-like structure of mesodermal origin that provides skeletal support in chordates (present at least in embryonic stages). Nerve cord: A dorsal hollow tube of ectodermal origin that forms the central nervous system in chordates.
(f) Polyp: A sessile, tubular form (e.g. Hydra, Adamsia) with mouth and tentacles directed upwards. Medusa: An umbrella-shaped, free-swimming form (e.g. Aurelia, common jellyfish) with mouth and tentacles hanging down.

Q.9. Give the characteristic features of the following citing one example of each 
(a) Chondrichthyes and ostichthyes 
(b) Urochordata and cephalochordata
Ans. 
(a) Chondrichthyes - Cartilaginous fishes with streamlined bodies and a cartilaginous endoskeleton. Mouth usually ventral; notochord may persist; gill slits are separate and lack a bony operculum. Skin bears placoid scales; teeth are modified placoid scales. Many species lack an air bladder and must swim to maintain buoyancy. Examples: Scoliodon (dogfish), Pristis (sawfish), Carcharodon (great white shark), Trygon (sting ray).
Osteichthyes: Bony fishes with a bony endoskeleton, usually covered with cycloid or ctenoid scales. Gills are covered by an operculum; many have an air bladder that regulates buoyancy. Examples: marine - Exocoetus (flying fish), Hippocampus (seahorse); freshwater - Labeo (rohu), Catla, Clarias (magur).
(b) Urochordata and Cephalochordata are protochordates (marine). In Urochordata the notochord is present only in the tail of the larval stage and is usually lost in adults (e.g. Ascidia, Salpa, Doliolum). In Cephalochordata the notochord extends from head to tail and persists throughout life (e.g. Branchiostoma also called Amphioxus or lancelet).

Q.10. Mention two similarities between
(a) Aves and mammals
(b) A frog and crocodile
(c) A turtle and pila
Ans. Similarities between aves and mammals
(i) Both are homeothermic (warm-blooded).
(ii) Both have a four-chambered heart.
(b) Similarities between frog and crocodile
(i) Both are poikilothermic (cold-blooded).
(ii) Both lay eggs (oviparous) in typical cases.
(c) Similarities between turtle and Pila
(i) Both are poikilothermic (cold-blooded).
(ii) Both are oviparous (lay eggs).

Q.11. Name
(a) A limbless animal
(b) A cold blooded animal
(c) A warm blooded animal
(d) An animal possessing dry and cornified skin
(e) An animal having canal system and spicules
(f) An animal with cnidoblasts
Ans. 
(a) A limbless animal: Ichthyophis
(b) (b) Cold-blooded animal: Frog
(c) A warm blooded animal: Macaca (monkey)
(d) Animal possessing dry and cornified skin: Lizard
(e) An animal having canal system and spicules: Euspongia (bath sponge)
(f) An animal with cnidoblasts: Hydra.

Q.12. Give an example for each of the following
(a) A viviparous animal
(b) A fish possessing a poison sting
(c) A fish possessing an electric organ
(d) An organ, which regulates buoyancy
(e) Animal, which exhibits alternation of generation
(f) Oviparous animal with mammary gland
Ans.
(a) A viviparous animal: Panthera leo (lion)
(b) A fish possessing a poison sting: Trygon (sting ray)
(c) A fish possessing an electric organ: Torpedo (electric ray)
(d) An organ which regulates buoyancy: Air bladder
(e) Animal which exhibits alternation of generation: Obelia
(f) Oviparous mammal with mammary glands: Echidna (a monotreme; similar to platypus in being egg-laying)

Q.13. Excretory organs of different animals are given below. Choose correctly and write in the space provided.

a. ______, b. ______, c. ______ d. ______, e. ______, f. ______
Ans.

LONG ANSWER TYPE QUESTIONS

Q.1. Give three major differences between chordates and non-chordates and draw a schematic sketch of a chordate showing those features.
Ans. Animals in Phylum Chordata are primarily distinguished by the presence, at some stage of life, of: (1) a dorsal hollow nerve cord, (2) a notochord (a flexible supporting rod), and (3) paired pharyngeal gill slits. In addition, chordates typically have a post-anal tail and show bilateral symmetry, triploblastic organisation and a closed circulatory system. Non-chordates (all other animal phyla) lack this combination of features.

Q.2. What is the relationship between germinal layers and the formation of body cavity in case of coelomate, acoelomates and pseudocoelomates?
Ans. Presence or absence of a body cavity (between body wall and gut wall) is important in classification. In coelomates the body cavity (coelom) is fully lined by mesoderm on both sides (examples: annelids, molluscs, arthropods, echinoderms, chordates). In pseudocoelomates the body cavity (pseudocoel) is not completely lined by mesoderm; the mesoderm is present as scattered pouches and the cavity is often derived from the blastocoel (example: Aschelminthes). In acoelomates the body cavity is absent and the region between gut and body wall is filled with mesodermal tissue (example: Platyhelminthes).

Q.3. Comment upon the habitats and external features of animals belonging to class, amphibia and reptilia.
Ans. Class Amphibia: Amphibians (Greek: amphi = both, bios = life) live both in water and on land during different phases of life. Most have two pairs of limbs; body divided into head and trunk; tail present in some species. Skin is moist and generally without scales; it aids in cutaneous respiration and must remain moist. Eyes have eyelids and there is usually a tympanum (external hearing structure). Examples include Rana (frog), Bufo (toad), Hyla (tree frog), Salamandra (salamander) and Ichthyophis (limbless amphibian).

Class Reptilia: Reptiles are primarily terrestrial; their skin is dry and covered by cornified (keratinised) epidermal scales or scutes which reduce water loss. They typically lack external ear openings (a tympanum may be present) and most have two pairs of limbs when present. Reptiles lay cleidoic eggs and exhibit adaptations for life on land. Examples include Testudo (tortoise), Chelone (turtle), Chameleon, Calotes (garden lizard), and Crocodilus (crocodile).

Q.4. Mammals are most adapted among the vertebrates. Elaborate.
Ans. Mammals show a high degree of adaptive success and occupy diverse habitats: polar regions, deserts, mountains, forests, grasslands and aquatic environments. Key adaptations include:

1. Presence of hair for insulation and sensory functions.

2. Skin with sweat and sebaceous glands; mammary glands that secrete milk for nourishing young.

3. Differentiated teeth (heterodont dentition) and strong jaws suited to varied diets.

4. Four-chambered heart and efficient lungs for high metabolic activity.

5. Endothermy (homeothermy) allowing maintenance of a constant body temperature.

6. Internal fertilisation, usually viviparous reproduction and direct development. Limbs are adapted in different groups for walking, running, climbing, burrowing, swimming or flying. These features together make mammals well adapted to exploit many ecological niches.