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Chapter 3

Classification of Animals

Class 7 - Concise Biology Selina



Objective Type Questions

Question 1(i)

Identify the aquatic animal with scaly skin which breathe with gills:

  1. Rohu
  2. Tortoise
  3. Sparrow
  4. Rat

Answer

Rohu

Reason — Rohu is a fish.

Question 1(ii)

Identify the bird which cannot fly:

  1. Peacock
  2. House sparrow
  3. Ostrich
  4. Pigeon

Answer

Ostrich

Reason — Ostrich is a flightless bird.

Question 1(iii)

Identify the animal which is not an Arthropod:

  1. Prawn
  2. Butterfly
  3. Earthworm
  4. Spider

Answer

Earthworm

Reason — Earthworm is classified under Annelids.

Question 1(iv)

Which of the following organisms is not an invertebrate ?

  1. Round worm
  2. Butterfly
  3. Sea anemone
  4. Lizard

Answer

Lizard

Reason — Lizards belong to Class Reptilia and are vertebrates.

Question 1(v)

Liver fluke belongs to :

  1. Nematoda
  2. Platyhelminthes
  3. Annelida
  4. Cnidaria

Answer

Platyhelminthes

Reason — Liver fluke belongs to Platyhelminthes.

Question 1(vi)

Which of the following structures is not found in the body of birds ?

  1. Teeth
  2. Scales
  3. Beak
  4. Claws

Answer

Teeth

Reason — Birds have jaws provided with horny beak but have no teeth.

Question 1(vii)

The locomotory structures of Echinoderms are :

  1. Tentacles
  2. Jointed legs
  3. Fins
  4. Tube feet

Answer

Tube feet

Reason — Echinoderms move with the help of tube feet.

Question 1(viii)

Radial symmetry can be found in :

  1. Coelenterata
  2. Platyhelminthes
  3. Echinodermata
  4. Both (1) and (3)

Answer

Both (1) and (3)

Reason — Both Coelenterata and Echinodermata have radially symmetrical bodies.

Question 1(ix)

Which class of vertebrates have animals with dry and scaly skin ?

  1. Aves
  2. Amphibia
  3. Reptilia
  4. Pisces

Answer

Reptilia

Reason — Reptiles have dry and scaly skin.

Question 1(x)

What is the main distinguishing feature of arachnids ?

  1. Six legs
  2. Segmented body
  3. Nephridia
  4. Four pairs of legs

Answer

Four pairs of legs

Reason — Arachnids have four pairs of jointed legs.

Question 2

Name one example each of an animal which shows the following characteristics:

  1. Fixed animal with a pore-bearing body
  2. Star-shaped body
  3. Can live in water as well as on land
  4. Has a flattened ribbon-like body

Answer

  1. Fixed animal with a pore-bearing body — Sponge

  2. Star-shaped body — Starfish

  3. Can live in water as well as on land — Frog

  4. Has a flattened ribbon-like body — Tapeworm

Question 3

Match the animals given under column A with their respective classification group given under column B.

Sl.
No.
Column AColumn B
1.SpongeAmphibia
2.SnailReptilia
3.ButterflyEchinodermata
4.ToadMollusca
5.LizardArthropoda
6.StarfishPorifera

Answer

Sl.
No.
Column AColumn B
1.SpongePorifera
2.SnailMollusca
3.ButterflyArthropoda
4.ToadAmphibia
5.LizardReptile
6.StarfishEchinodermata

Question 4

Categorise the following animals under their appropriate columns of classfication:

ANIMALS :

DogGrasshopperRatScorpionToad
ButterflyLizardTurtleFrogBatSnailHoney beePigeonLiverflukeLeechCattleSnakeRohuParrotAscarisEarthwormCowRabbitMonkeyElephant

Answer

CLASSIFICATION :

WORMSMOLLUSCSFISHESAMPHIBIANSREPTILESBIRDSMAMMALS
EarthwormSnailRohuFrogLizardPigeonDog
LiverflukeToadSnakeParrotCattle
LeechTurtleRat
AscarisRabbit
Monkey
Bat
Elephant
Cow
  • Butterfly, Grasshopper, Honeybee and Scorpion are Arthropods.

Question 5

Animals cannot prepare their own food. What scientific name is given to such organisms.

Answer

The scientific name for such organisms is Heterotrophs.

Question 6

Identify the phylum/ class with the help of the following clues and give one example of each.

  1. Body is covered by a slimy and slippery skin.
  2. Body bears many tiny pores.
  3. Body has jointed legs.
  4. Animals swim with the help of fins.
  5. Body has special excretory organs called nephridia.

Answer

  1. Amphibia
    Example — Frogs

  2. Porifera
    Example — Sponge

  3. Arthropoda
    Example — Crabs

  4. Pisces
    Example — Rohu

  5. Annelida
    Example — Earthworms

Question 7

Given below are sets of four terms. Choose the odd one and write the category of the remaining terms :

  1. Jellyfish, Dogfish, Sea anemone, Hydra
  2. Electric ray fish, Dogfish, Starfish, Shark
  3. Myriapoda, Mammalia, Arachnida, Crustacea
  4. Turtle, Tortoises, Crocodiles, Frog
  5. Sucker, Tube feet, Muscular foot, Fins

Answer

  1. Odd one — Dogfish
    Category of the remaining terms — Coelenterata

  2. Odd one — Starfish
    Category of the remaining terms — Pisces

  3. Odd one — Mammalia
    Category of the remaining terms — Arthropoda

  4. Odd one — Frog
    Category of the remaining terms — Reptiles

  5. Odd one — Fins
    Category of the remaining terms — Locomotory structures in invertebrates

Question 8

Correct the following statements by changing the first/ last word only :

  1. Amphibians breathe through lungs and gills.
  2. Slimy scales are found on the body of reptiles.
  3. Fins are covered and protected by an operculum.
  4. Ascaris is a segmented flatworm.
  5. Insects have four pairs of jointed legs.

Answer

  1. Amphibians breathe through lungs and skin.
  2. Slimy scales are found on the body of fish.
  3. Gills are covered and protected by an operculum.
  4. Ascaris is an unsegmented roundworm.
  5. Arachnids have four pairs of jointed legs.

Short Answer Questions

Question 1

Name the following:

  1. Eight phyla of Invertebrates
  2. Five classes of Vertebrates
  3. Four classes of Arthropoda
  4. Three main regions of the body of Arthropods
  5. Three flightless birds

Answer

  1. Porifera, Cnidaria, Platyhelminthes, Nematoda, Annelida, Arthropoda, Mollusca, and Echinodermata.
  2. Pisces, Amphibia, Reptilia, Aves, and Mammalia.
  3. Crustacea, Myriapoda, Insecta, and Arachnida.
  4. Head, Thorax, and Abdomen.
  5. Ostrich, Penguin, and Kiwi.

Question 2

Define the terms given below :

  1. Heterotrophs
  2. Locomotion
  3. Invertebrates
  4. Vertebrates
  5. Mammals

Answer

  1. Heterotrophs — Heterotrophs are organisms that cannot produce their own food and obtain nutrients by consuming other organisms.

  2. Locomotion — Most animals move from one place to another mainly in search of food or shelter. Such a movement is called locomotion.

  3. Invertebrates — The animals that do not have a back bone are called invertebrates.

  4. Vertebrates — Animals with a backbone (vertebral column) are called vertebrates.

  5. Mammals — Mammals are animals that gives birth to young ones (babies), and feeds its young on milk from the mother's body. Mammals have body covered with hair, possess projecting external ears, have four limbs, and a tail (except humans).

Question 3

Write one important function of the following structures along with the group (phyla/ class) of animals in which they are found:

  1. Tentacles
  2. Nephridia
  3. Gills
  4. Muscular foot
  5. Mammary glands

Answer

  1. Tentacles — Tentacles are found in Cnidarians. These finger-like projections surrounding the mouth, called tentacles help in catching food and swimming.

  2. Nephridia — Nephridia are found in Annelids. Nephridia are special organs for excretion.

  3. Gills — Gills are found in Class Pisces. Gills help fishes breathe.

  4. Muscular foot — Muscular foot is found in Molluscs. Mulluscs move with the help of a muscular foot.

  5. Mammary glands — Mammary glands are found in mammals (females). Young ones suckle milk from mammary glands present in mothers.

Question 4

Give two examples of each of the following:

  1. Amphibians
  2. Segmented worms
  3. Reptiles
  4. Coelenterates
  5. Arthropods
  6. Flatworms

Answer

  1. Amphibians — Frog, Toad

  2. Segmented worms — Earthworm, Leech

  3. Reptiles — Lizard, Snake

  4. Coelenterates — Hydra, Jellyfish

  5. Arthropods — Prawn, Ant

  6. Flatworms — Tapeworm, Liverfluke

Question 5

Give names of two animals which are found as parasites inside the human intestine.

Answer

Two animals which are found as parasites inside the human intestine are Tapeworm and Roundworm.

Question 6(i)

Write one difference between Porifera and Coelenterata.

Answer

PoriferaCoelenterata
Body is porous, i.e., bear many tiny pores to draw water into the body cavity and one large pore to pass it out.The body is radially symmetrical i.e., the body can be divided into two identical halves along any plane.

Question 6(ii)

Write one difference between Arthropoda and Mollusca.

Answer

ArthropodaMollusca
Their body is divided into three regions — head, thorax and abdomen.Their body is soft and unsegmented.

Question 6(iii)

Write one difference between Invertebrates and Vertebrates.

Answer

InvertebratesVertebrates
The animals that do not have a back bone are called invertebrates.The animals that have a back bone are called vertebrates.

Question 6(iv)

Write one difference between Platyhelminthes and Nematoda.

Answer

PlatyhelminthesNematoda
Their body is thin and flat.Their body is rounded and unsegmented.

Long Answer Questions

Question 1

Draw a neat diagram of a fish and label the five kinds of fins, operculum and mouth. Answer the following questions :

  1. Name the phylum and the class to which fishes belong.
  2. What is the one advantage of their specific body shape ?
  3. Do they breathe through nostrils ? If not, mention the role of nostrils.
  4. Mention the breathing and locomotory structures in fishes.
  5. Give any two examples of fishes.

Answer

Diagram of fish is given below

Draw a neat diagram of a fish and label the five kinds of fins, operculum and mouth. Answer the following questions : Concise Biology Solutions ICSE Class 7.
  1. Fishes belong to Class Pisces of Phylum Chordata.

  2. Their streamlined body, which is narrow at both ends help reduce water resistance, allowing for more efficient and faster swimming.

  3. Fishes do not breathe through nostrils, but through gills. Fish nostrils are used to detect chemicals in the water, aiding in finding food, identifying potential mates, and detecting danger.

  4. Fishes breathe through the gills. The locomotory structures in fishes are their fins, which help in swimming.

  5. Two examples of fishes are — Rohu and Catla.

Question 2

Given alongside are the figures of two organisms. Study the organisms and answer the following questions :

Given alongside are the figures of two organisms. Study the organisms and answer the following questions : Concise Biology Solutions ICSE Class 7.
  1. Name the organisms [A] and [B].
  2. Label the guidelines 1 and 2.
  3. Do they belong to the same phylum ? If yes, name the phylum.
  4. What are the two important functions of part 1 ?
  5. Mention the mode of reproduction shown in figure [B]. Is it a kind of asexual or sexual reproduction ?

Answer

  1. Organism [A] is Sea-anemone, and Organism [B] is Hydra.

  2. The guidelines 1 and 2 show:
    1 → Tentacles
    2 → Mouth

  3. Yes, they both belong to the same Phylum, i.e. Cnidaria of Invertebrates.

  4. Two important functions of Tentacles are:

    1. Tentacles help in catching food.
    2. Tentacles help in swimming.
  5. We can see budding in Hydra, which is a form of asexual reproduction. This process involves the development of a new individual from an outgrowth or bud on the parent's body.

Question 3

The figure given alongside represents an animal. Study the same and answer the following questions :

The figure given alongside represents an animal. Study the same and answer the following questions : Concise Biology Solutions ICSE Class 7.
  1. Name the animal and write the phylum to which it belongs.
  2. Mention the locomotory structure of the animal.
  3. What kind of symmetry is found in the body of this animal ?
  4. Write a suitable habitat where animals of this phylum are found.
  5. Mention one characteristic feature of the body of this animal.

Answer

  1. The given figure shows a Starfish. It belongs to phylum Echinodermata.

  2. The locomotory structure present in Starfish are Tube feet.

  3. Starfish are radially symmetrical.

  4. Echinoderms are mainly found in marine habitat.

  5. Starfish body is rough, spiny and radially symmetrical.

Question 4

Given alongside is the figure of an animal. Study the same and answer the following questions :

Given alongside is the figure of an animal. Study the same and answer the following questions : Concise Biology Solutions ICSE Class 7.
  1. Name the animal.
  2. Write the phylum and class to which this animal belongs.
  3. Mention one distinguishing feature of this phylum.
  4. Give two more examples of organisms belonging to this phylum.
  5. Are these animals cold-blooded or warm-blooded ? Explain.

Answer

  1. The animal shown in the given figure is Rabbit.

  2. Rabbit belongs to Class Mammalia of Phylum Chordata.

  3. A key distinguishing feature of the phylum Chordata is the presence of a backbone (vertebral column).

  4. Two more examples of organisms belonging to Phylum Chordata are — Tiger and Elephant.

  5. Rabbits, like all mammals, are warm-blooded (endothermic), meaning they can regulate their body temperature internally.

Question 5

Give three characteristic features of Amphibians which help to differentiate them from fishes.

Answer

Three characteristic features of Amphibians which help to differentiate them from fishes are:

  1. They can live in water as well as on land.
  2. They breathe through lungs and skin.
  3. Body is covered by a slimy and slippery skin

Question 6

Why fishes are said to have a streamlined body? Name their respiratory organs.

Answer

The fishes have streamlined body which means that their body is narrow at both ends. This helps them to swim by minimizing the resistance of water.

The respiratory organ of fish is gills.

Question 7

Give two characteristic features of birds which enable them to fly. Name any two birds which cannot fly.

Answer

Two characteristic features of birds which enable them to fly are:

  1. Their bones are hollow and light which make their body light.
  2. They have wings to fly.

Two birds which cannot fly are Ostrich and Kiwi.

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