NCERT Exemplar class 11 Biology Solutions Animal Kingdom

Multiple Choice Questions
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.
Soln.(b) : Metamerism is true segmentation where external divisions correspond to internal divisions. The body is divided both externally and internally into number of segments (100-120) called metameres. E.g., In earthworm, genital papillae are present in 17lh and 19th segments and nephridipores are scattered all over body surface except first two. Metagenesis is alternation of two life forms in an organism. Metamorphosis is phenomenon of passing through different juvenile stages before attaining adult form. Segmentation is division of- body into different segments and in some organisms, only external divisions are seen as head, thorax and abdomen.

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
Soln.(b) : Interstitial cells are reserve cells and are called totipotent cells, which can
differentiate into any type of cells. Nemato- cvtes are stinging cells used for offence and defence. Gastrodermal cells line the gastrodermis and intracellular digestion takes place inside these cells. All these cells are found in cnidarians. Choanocytes or collar cells are found in sponges; they are specialised flagellated cells that line spongocoel and canals.

3.Which one of the following sets of animals share a four chambered heart?
(a) Amphibians, Reptiles, Birds
(b) Crocodiles, Birds, Mammals
(c) Crocodiles, Lizards, Turtles
(d) Lizards, Mammals, Birds
Soln.(b): Amphibians have three-chambered heart, while reptiles have incomplete four-chambered heart (except crocodiles). Crocodiles, birds and mammals have complete, four-chambered heart.

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
Soln.(b) Amphibians and mammals have glandular skin, i.e., they have glands on their skin to keep it moist, which include sweat’gland and sebaceous glands, present in mammals. While aves have dry skin and does not contain any glands, except, preen/
oil gland at the base of the tail. Reptiles are devoid of glands. Therefore, Chameleon and turtle have non-glandular skin.

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
Soln.(d) : Both birds and mammals are homoiotherms (warm blooded) i.e., they have ability to maintain constant body temperature inspite of changes in ambient conditions.

6.Which one of the following sets of animals belong to a single taxonomic group?
(a) Cuttlefish, Jellyfish, SHverfish, Dogfish, Starfish
(b) Bat, Pigeon, Butterfly
(c) Monkey, Chimpanzee, Man
(d) Silkworm, Tapeworm, Earthworm
Soln. (c): Monkey, chimpanzee and man are primates belonging to Class Mammalia, Phylum Chordata.

7.Which one of the following statements is incorrect?
(a) Mesoglea is present in between ectoderm and endoderm in Obelia.
(b) Asterias exhibits radial symmetry.
(c) Fasciola is a pseudocoelomate animal.
(d) Taenia is a triploblastic animal.
Soln. (c) : Fasciola (a platyhelminth) is an acoelomate animal.

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 take part in excretion.
(d) Earthworms are hermaphrodites and yet cross fertilisation take place among them.
Soln. (a): In cockroaches excretion takes place by Malpighian tubules while in prawns it takes place by green glands.

9.Which one of the following is oviparous?
(a) Platypus (b) Flying fox (Bat)
(c) Elephant (d) Whale
Soln.(a): Platypus, bat, elephant and whale, all belong to Class Mammalia of Sub-phylum
Vertebrata. Out of the four, only platypus is oviparous (egg laying), and rest all are viviparous (give birth to young ones).

10.Which one of the following is not a poisonous snake?
(a) Cobra (b) Viper
(c) Python (d) Krait
Soln. (c): Python is a large and non-poisonous snake. It kills its prey by coiling around and crushing and swallowing the prey. ,

11.Match the following list of animals with their
level of organisation.
Division of Labour                       Animal
A.Organ level                              i.Pheretima
B.Cellular aggregate level     ii.Fasciola
C.Tissue level                            iii.Spongilla
D.Organ system level              iv. Obelia
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

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) acoelomate (b) pseudocoelomate
(c) coelomate (d) haemocoelomate.
Soln.(b) : Acoelomates are characterised by absence of coelom or body cavity while coelomates are those organisms in which body cavity arises as a cavity in embryonic mesoderm and mesoderm lines the coelom. In pseudocoelomates body cavity is derived from blastocoel of embryo but is not lined with mesoderm.

13.Match the column A with column B and choose
the correct option.
Column A                               Column B
A.Porifera                              i.Canal system
B.Aschelminthes                ii.Water-vascular system
C.Annelida                           iii.Muscular Pharynx
D.Arthropoda                      iv.Jointed appendages
E.Echinodermata                v. Metameres
(a) A-ii, B-iii, C-v, D-iv, E-i
(b) A-ii, B-v, C-iii, D-iv, E-i
(c) A-i, B-iii, C-v, D-iv, E-ii
(d) A-i, B-v, C-iii, D-iv, E-ii

Very Short Answer Type Questions
1. Identify the phylum in which adults exhibit radial symmetry and larva exhibit bilateral symmetry.
Soln. Phylum Echinodermata.

2.What is the importance of pneumatic bones and air sacs in Aves?
Soln. Pneumatic bones and air sacs in birds (Aves) help them in flying. Pneumatic bones, i.e., hollow bones filled with air cavities reduce weight which help in flight and air sacs serve as reservoirs of air. Air sacs also aid as cooling devices and regulate body temperature.

3.What is metagenesis? Mention an example which exhibits this phenomenon.
Soln. In some cnidarians, polyps reproduce medusae asexually and medusae form the polyps sexually. Such alternation of asexual and sexual phases in the life cycle of cnidarians is called metagenesis e.g., Obelici.

4.What is the role of feathers?
Soln. Feathers are flight adaptations in birds, they provide passage for air and reduce friction to minimum. They help to maintain constant body temperature by preventing heat loss.

5.Which group of chordates possess sucking and circular mouth without jaws?
Soln. In Cyclostomata, mouth is circular and jawless. It feeds by sucking blood of host fishes. E.g:, Lamprey.


6. Give one example each for an animal possessing placoid scales and that with cycloid scales.
Soln. Placoid scales – Scoliodon (Class Chon- drichthyes)
Cycloid scales – Exocoetus (Class Osteichthyes)

7.Mention two modifications in reptiles required for terrestrial mode of life.
Soln.Two modifications in reptiles required for terrestrial mode of life are:
(i) Respiration by lungs.
(ii)Internal fertilisation.

8.Mention one example each for animals with
chitinous exoskeleton and those covered by a
calcareous shell.
Soln. Chitinous exoskeleton – Cockroach
Calcareous shell – Pila (Mollusca)

9.What is the role of radula in molluscs?
Soln. Radnla is a rasping organ having rows of horny teeth and used in feeding especially for scraping and cutting.

10. Name the animal, which exhibits the phenomenon of bioluminescence.
Mention the phylum to which it belongs.
Soln. Pleurobrachia exhibits the phenomenon of bioluminescence i.e., phenomenon of emission of light by living organisms. It belongs to the Phylum Ctenophora.

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_______
Soln. (a) Rana (Frog) (b) Corvus (Crow)
(c) Crocodilus (Crocodile) (d) Nereis

12. Differentiate between a diploblastic and a triploblastic animal.
Soln. Animals, which have two germinal layers, an external ectoderm and an internal endoderm, are called diploblastic animals e.g., animals of Phylum Coelenterata and Phylum Porifera. Animals which have three layers, an external ectoderm, middle mesoderm and an internal endoderm, are called triploblastic animals e.g., animals from Phylum Platyhelminthes to Phylum Chordata.

13. Give an example of the following
(a) Round worm
(b) Fish possessing poison sting
(c) A limbless reptile/ amphibian
(d) An oviparous mammal
Soln. (a) Ascaris (b) Trygon (c) Limbless reptile – Naja naja, Limbless amphibian- lchthyophis (d) Ornithorhynchus

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_______
Soln. (a) Blood-filled cavity in arthropods haemocoel.
(b) Free-floating form of cnidaria medusa.
(c) Stinging organ of jelly fishes nematocvst.
(d) Lateral appendages in aquatic annelids parapodia.

15 .Match the following.
Animals Locomotory Organ
(a) Octopus      (i) Limbs
(b) Crocodile   (ii) Comb plates
(c) Catla             (iii) Tentacles
(d) Ctenoplana (iv) Fins
Soln. (a) – (iii), (b) – (i), (c) – (iv), (d) – (ii)

Short Answer Type Questions
1.Differentiate between:
a.Open circulatory system and closed circulatory system
b.Oviparous and viviparous characteristic
c.Direct development and Indirect development
Soln. (a) The differences between open circulatory system and closed circulatory system are as follows:
(b) The differences between oviparous and viviparous characteristic i.e., ovipary and vivipary are as follows:
(c)Thedifferencesbetweendirectdevelopment and indirect development are as follows:

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

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-cham-bered heart.
Soln. Two-chambered heart: Pisces Three chambered heart: Amphibia, Reptilia Four chambered heart: Aves, Mammalia.

4. Fill up the blank spaces appropriately

5.Match the following
(a) Amphibia                  (i)  Air bladder
(b) Mammals                 (ii) Cartilaginous  notochord
(c) Chondrichthyes    (iii) Mammary glands
(d) Osteichthyes           (iv) Pneumatic bones
(e) Cyclostomata           (v) Dual habitat
(f) Aves                             (vi) Sucking and circular  mouth without jaws.
Soln.(a)-(v), (b)-(iii), (c)-(ii), (d)-(i), (e)-(vi), (f)-(iv)

6. Endoparasites are found inside the host body. Mention the special structure, possessed by these and which enables them to survive in those conditions.
Soln. Most Platyhelminthes are endoparasites. Special structures in parasitic Platyhelminthes include presence of thick integument which is resistant to host’s digestive enzymes and anti ¬toxins and they possess adhesive organs like
suckers in flukes and hooks and suckers in tapeworms for firm grip in host’s body.

7.Match the following and write correct choice in space provided
Animal                               Characteristics
(a) Pila                               (i)  Jointed appendages
(b) Cockroach                 (ii) Perching
(c) Asterias                      (iii) Water vascular system
(d) Torpedo                     (iv) Electric organ
(e) Parrot                           (v) Presence of shell
(f) Dogfish                        (vi) Placoidscales
(a)______, (b)______, (c)______, (d)______,
(e)______, (f)______
Soln. (a)-(v), (b)-(i), (c)-(iii), (d)-(iv), (e)-(ii), .
(f) -(vi)
8.Differentiate between:
(a) Open and closed circulatory system
(b) Oviparity and viviparity
(c) Direct and indirect development
(d) Acoelomate and pseudocoelomate
(e) Notochord and nerve cord
(f) Polyp and medusa
(a) Refer answer 1 (a).
(b) Refer answer 1 (b).
(c) Refer ansiver 1 (c).
(d) The differences between acoelomate and pseudocoelomate are as follows:
(e) The differences between notochord and
nerve cord are as follows:
(f)The differences between polyp and medusa are as follows:

9. Give the characteristic features of the following, citing one example of each:
(a) Chondrichthyes and osteichthyes
(b) Urochordata and cephalochordata
Soln. (a) Characteristic features of chondri-chthyes are:
(i) They are mostly marine called poikilothermic animals (i.e., they have the capacity to regulate their body temperature.
(ii)TKey have cartilaginous endoskeleton. Notochord is persistent throughout life.
(iii)Mouth is ventral in position, skin is tough containing minute placoid scales and teeth are modified placoid scales. They have strong jaw and are predaceous by nature.
(iv)Gill slits are generally five pairs and gill cover (operculum) are absent.
(v) Heart is two chambered with one auricle and one ventricle.
(vi)Some of them possess electric organs (e.g., Torpedo) and some possess poison sting (e.g., Trygon).
(vii)They are called ureotelic animals as they secrete urea.
(viii)Sexes are separate and fertilisation is internal.
(ix)Males usually have claspers on pelvic fins, which help in copulation.
(x)Many of them are viviparous.
E.g.r Scoliodon (shark or dog fish), Pristis (saw fish), Trygon (stingray).
Characteristic features of osteichthyes are as follows:
(i) They are found in marine water as well as in freshwater.
(ii) The body is streamlined to facilitate easy movement through water.
(iii) Exoskeleton contains dermal scales like cycloid or ctenoid scales.
(iv) Gills are covered with operculum (gill cover) and are generally four pairs.
(v) Heart is two-chambered with one auricle and one ventricle.
(vi) Air bladders are present. They are the hydrostatic organs.
(vii) These are ammonotelic animals that excrete ammonia.
(viii) Sexes are separate. Fertilisation is usually external, mostly viviparous and development is direct.
E.g., Labeo (rohu), Mrigal (carps), Catla (catla), Hippocampus (sea horse), Exocoetus (flying fish), Remora (sucker fish), Anabas (climbing percfi), Protopterus (African lung fish).
(b) Characteristic features of Urochordata
(i) Urochordates are commonly called Tunicates because adult body is enclosed
in test or tunic.
(ii)The notochord is present only in the tail of the larva and disappears in the adult.
(iii)Adult is sedentary, while larva is motile.
(iv)Nerve cord is found only in the larva. It is replaced by a dorsal ganglion in the adult.
(v)The larva undergoes retrogressive metamorphosis.
Example: Herdmania.
Characteristic features of Cephalochordata
(i) The notochord is present throughout life and extends from the anterior end to the posterior end of the body.
(ii)Both larva and adult are motile.
(iii)Nerve cord is present in both larva and adult.
(iv)The larva undergoes progressive meta-morphosis.
Example: Branchiostoma.

10 .Mention two similarities between
(a) Aves and mammals
(b) A frog and crocodile
(c) A turtle and Pila
Soln. (a) Both have 4-chambered heart and are warm-blooded.
(b) Both are cold-blooded and oviparous.
(c) Both are aquatic and their body is covered by shell.

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
Soln. (a) Ichthyophis
(b) Chelone (Turtle) (c) Columba (Pigeon)
(d) Crocodilus (e) Sycon
(f) Adamsia

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
Soln. (a) Macropus (Kangaroo)
(b) Trygon (Sting ray) (c) Torpedo (Electric ray)
(d) Air bladder (e) Obelia (Sea fur)
(f) Ornithorhynchus (Duck-billed Platypus)

13.Excretory organs of different animals are given below. Choose correctly and write in the space provided.
Animal Excretory Organ/Unit
(a) Balanoglossus (i) Metanephridia
(b) Leech                 (ii) Nephridia
(c) Locust               (iii) Flame cells
(d) Liver fluke       (iv) Absent
(e) Sea urchin        (v) Malpighian tubule
(f) Pila                      (vi) Proboscis gland
(a)______, (b)______,(c)______,(d)______,
Soln. (a) – (vi), (b) – (ii), (c) – (v), (d) – (iii),
(e) – (iv), (f) – (i)

Long Answer Type Questions
1. Give three major differences between chordates and non-chordates and draw a schematic
sketch of a chordate showing those features.
Soln. Differences between chordates and non- chordates are as follows:

2.What is the relationship between germinal layers and the formation of body cavity in case of coelomate, acoelomates and pseudocoelomates?
Soln. There are three germinal layers: ectoderm, endoderm and mesoderm. Presence or absence of a cavity between the body wall and gut wall is very important in classification. The body cavity lined by mesoderm is called coelom. The animals having coelom are called coelomates. In coelomates, body cavity arises as a cavity in embryonic mesoderm. In this, mesoderm of embryo provides cellular lining to the cavity and coelom is filled with coelomic fluid, E.g., annelids, echinoderms, and chordates. In Pseudocoelomata, body cavity is derived from blastocoel of the embryo and the coelom is not lined by mesoderm. Instead, mesoderm is present as scattered pouches in between the ectoderm and mesoderm. Such a coelom is called pseudocoelom. Aschelminthes are pseudocoelomates. Acoelomates are those animals in which the body cavity is absent i.e., they do not have coelom. E.g., sponges, cnidarians, ctenophores, flatworms.

3.Comment upon the habitats and external features of animals belonging to class, amphibia and reptilia.
Soln. Class – Amphibia
Habitat : Amphibians are first cold blooded
vertebrates which can Jive on land as well
as in water. They are mostly found in warm
External features:
(i) Body is compressed and cylindrical and differentiated into head and trunk.
(ii)Nostrils are connected to the buccal cavity eyes have eyelids.
(iii)Skin is mostly smooth, moist, highly vascular and rich in gland. Scales, are generally absent. It helps in cutaneous respiration.
(iv)Amphibians mostly have two pairs of pentadactyl limbs. They are used for locomotion.
(v)A pair of external nares for olfaction, a pair of eyes with movable eyelids are present.Tympanum represents the ear. E.g., Ram (frog), Bufo (toad), Elyla (tree frog), Rhacophorus (flying frog), Salamandra (salamander) etc.
Class – Reptilia
Habitat : Reptiles are mostly terrestrial
animals, mainly found in warmer parts of the
world. Only few of them live in water such as
crocodiles, turtles.
External features :
(i) The body may be long, cylindrical or short and broad. It is divisible as head,
neck, trunk and tail.
(ii) They have dry, rough and non-glandular
skin. It is provided with horny, epidermal
scales or scutes.
(iii) Appendages are of two pairs of
pentadactyl limbs with powerful horny
claws. Limbs are locomotory organs.
(iv) Sense organs like eyes, ears and nose are
well developed. ….
(v) Eyelids and nictitating membrane are present in lizards but absent in snakes.
E.g., Calotes (garden lizard), Draco (flying
lizard), Naja (cobra), Hemidactyhis (wall lizard)

4. Mammals are most adapted among the vertebrates. Elaborate.
Soln. Mammals are most adapted among the vertebrates. This can be elaborated by the following characteristics of mammals.
(i) They are found in a variety of habitats like polar ice caps, mountains, deserts, forests and oceans.
(ii) Most of them are terrestrial but some of them are adapted to fly (Bat) or live in water (Whale).
(iii) They have 2 pairs of limbs, adapted for walking, running, climbing, burrowing, swimming or flying.
(iv) They have mammary glands and are the only animals which nourish their young . ones with milk.
(v) They are capable of learning due to presence of developed brain and thus are dominant animals.
(vi) Presence of muscular diaphragm is a characteristic feature of mammals which help in breathing.
(vii) Four-chambered heart pumps only oxygenated blood.
(viii) A well developed placenta is present except in egg laying mammals.
(ix) They are warm blooded, capable of maintaining constant body temperature. E.g., Macropus (Kangaroo), Equus (Horse), Macaca (Monkey) etc.