Living Science Biology Class 6 ICSE Solutions Chapter 4 Classification of Animals

ICSE Living Science Biology for Class 6 Solutions Chapter 4 Classification of Animals

Check Your Progress

Fill in the blanks.
Question 1.
………… do not have a backbone, while have it.
Answer:
Invertebrates do not have a backbone, while vertebrates have it.

Question 2.
Cnidarians have …………. symmetrical body.
Answer:
Cnidarians have radially symmetrical body.

Question 3.
………….. and live in the intestines of human beings and cattle.
Answer:
Tapeworm and liver fluke live in the intestines of human beings and cattle.

Question 4.
………….. are considered as friends of farmers.
Answer:
Earthworms are considered as friends of farmers.

Question 5.
Annelids have special organs of excretion called ………….
Answer:
Annelids have special organs of excretion called nephridia.

Practice Question 1.
live in the digestive tract of many vertebrates including human beings.
Answer:
Tapeworms live in the digestive tract of many vertebrates including human beings.

Practice Question 2.
Most arthropods have a tough outer body covering called .
Answer:
Most arthropods have a tough outer body covering called exoskeleton.

Check Your Progress

Fill in the blanks.
Question 1.
…………. have three pairs of jointed legs.
Answer:
Insects have three pairs of jointed legs.

Question 2.
Some …………. have two pairs of legs per segment.
Answer:
Some myriapods have two pairs of legs per segment.

Question 3.
A has an external coiled shell.

4. ………… is an example of a crustacean.
Answer:
Lobster is an example of a crustacean.

A. Tick the most appropriate answer.

Question 1.
The finger-like structures present around the mouth of cnidarians are called –
a. pseudopodia.
b. tentacles,
c. spines.
d. bristles.
Answer:
b. tentacles.

Question 2.
Organs of excretion in annelids are called –
a. gills.
b. nephridia.
c. suckers.
d. lungs.
Answer:
b. nephridia.

Question 3.
Annelids have a –
a. soft, unsegmented, bilaterally symmetrical body.
b. soft, cylindrical, segmented, bilaterally symmetrical body.
c. soft, segmented, bilaterally symmetrical body.
d. soft, segmented, laterally symmetrical body.
Answer:
c. soft, segmented, bilaterally symmetrical body.

Question 4.
Scorpions and spiders are –
a. crustaceans.
b. arachnids,
c. myriapods.
d. insects.
Answer:
b. arachnids.

Question 5.
The body temperature of warm-blooded animals –
a. keeps fluctuating0.
b. changes according to the temperature of the environment
c. does not change with the change in the temperature of the environment.
d. decreases when the temperature of the enviomment increases.
Answer:
c. does not change with the change in the temperature of the environment.

Question 6.
Bones with large air cavities are present in –
a. cnidnans.
b. fish.
c. annelids.
d. birds.
Answer:
d. birds.

Practice Question 1.
Milk ¡n the body of mammals is produced by –
a. sweat glands.
b. salivary glands.
c. mammary glands.
d. none of these
Answer:
e. mammazy glands.

B. Fill in the blanks.

Question 1.
The animals without a backbone whose body ¡s soft and often covered by a hard shell are ………….
Answer:
The animals without a backbone whose body is soft and often covered by a hard shell are molluscs.

Question 2.
Invertebrates with jointed legs belong to ………….
Answer:
Invertebrates with jointed legs belong to arthropods.

Question 3.
The backbone of vertebrates is made up of a number of small bones called ………….
Answer:
The backbone of vertebrates is made up of a number of small bones called vertebrae.

Question 4.
Fishes obtain oxygen from water through ………….
Answer:
Fishes obtain oxygen from water through gills

Question 5.
Vertebrates that spend a part of their life on land but lay their eggs In water are called –
Answer:
Vertebrates which spend a part of their life on land but reproduce in water are called amphibians.

C. Match the following.

Group	Characteristics
1. molluscs	a. feed milk to young ones, warm blooded
2. sponges	b. bag-like body with tentacles around the opening
3. flatworms	c. fins, gills and cold-blooded
4. mammals	d. body with large opening and many small pores all over
5. fish	e. jointed legs, exoskeleton
6. cnidarians	f. have only one opening
7. arthropods	g. hard shell, soft body
	h. cylindrical, unsegmented body with mouth at one end and anus at the posterior end

Answer:

Group	Characteristics
1. molluscs	a. feed milk to young ones, warm blooded
2. sponges	b. bag-like body with tentacles around the opening
3. flatworms	c. fins, gills and cold-blooded
4. mammals	d. body with large opening and many small pores all over
5. fish	e. jointed legs, exoskeleton
6. cnidarians	f. have only one opening
7. arthropods	g. hard shell, soft body
	h. cylindrical, unsegmented body with mouth at one end and anus at the posterior end

D. Differentiate between

1. flatworms and roundworms
2. insects and crustaceans
3. amphibians and Pisces
4. aves and mammals
5. radially symmertical and bilaterally symmetrical body
6. warm-blooded and cold-blooded animals.

Answer:
1. Flatworms and roundworms
Flatworms :
a. They are also called as Platyhelminthes.
b. They have flat ribbon like bodies.

Roundworms :
a. They are also called as Nemathelminthes.
b. They have cylindrical bodies.

2. Insects and crustaceans
Insects :
a. Body of insects is divided into three regions-head, thorax and abdomen.
b. Most of them have three pairs of legs.
c. Most of them have wings.
d. e.g. Housefly, butterfly.

Crustaceans :
a. Head and thorax are fused in crustaceans.
b. They have many number of jointed legs.
c. Wings are absent.
d. e.g. Crab, lobster.

3. Amphibians and pisces
Amphibians :
a. They can live both on land and in water.
b. Body of amphibians is covered with slimy- with scales.
c. They breathe through lungs and skin.
d. e.g. Frogs, toad.

Pisces :
a. They live in water.
b. Their body is covered slippery skin.
c. They breathe through gills.
d. e.g. Shark, sea-horse.

4. Aves and mammals
Aves :
a. Their body is covered with feathers.
b. Forelimbs are modified into wings to fly.

Mammals :
a. They have hair on their body.
b. Forelimbs exist as hand, paw or hooves.

2. Insects and crustaceans
Insects :
a. Body of insects is divided into three regions-head, thorax and abdomen.
b. Most of them have three pairs of legs.
c. Most of them have wings.
d. e.g. Housefly, butterfly.

Crustaceans:
a. Head and thorax are fused in crustaceans.
b. They have many number of jointed legs.
c. Wings are absent.
d. e.g. Crab, lobster.

3. Amphibians and pisces
Amphibians :
a. They can live both on land and in water.
b. Body of amphibians is covered with slimy- with scales.
c. They breathe through lungs and skin.
d. e.g. Frogs, toad.

Pisces :
a. They live in water.
b. Their body is covered slippery skin.
c. They breathe through gills.
d. e.g. Shark, sea-horse.

4. Aves and mammals
Aves :
a. Their body is covered with feathers.
b. Forelimbs are modified into wings to fly.
c. They have a homy beak with no teeth.
d. They lay eggs.
e. They have mammary glands i.e. they suckle their babies.
f. They have hollow bones.

Mammals :
a. They have hair on their body.
b. Forelimbs exist as hand, paw or hooves.
c. They have a mouth with teeth.
d. They give birth to young ones.
e. They don’t have mammary glands.
f. They have solid bones.
g. e.g. Crow, parrot. & e.g. Humans, dog.

5. Radially symmertical and bilaterally symmetrical body
Radially symmertical :
a. It is a body that can be divided vertically into two equal halves along any plane passing through the central point.
b. Examples: Starfish, jellyfish, Hydra, corals, etc. Body

Bilaterally symmetrical :
a. It is a body that can be divided into two equal halves only through one plane.
b. Examples: Tapeworm, insects, lizard, humans, etc.

6. Warm-blooded and cold-blooded animals
Warm-blooded :
a. The temperature of the body of warm-blooded animals remains constant and does not change with the temperature of their surroundings.
b. Examples: Birds, humans, dogs, etc.

cold-blooded animals:
a. The temperature of the body of cold-blooded animals changes with the temperature of their surroudings
b. Examples : reptiles, fish, frogs, etc.

E. State if the following statements are true or false. Correct the statement if it is false.

Question 1.
A tapeworm is a flatworm that lives in the human intestine.
Answer:
True.

Question 2.
Arthropods have a soft, outer covering called endoskeleton.
Answer:
False : Arthropods have a tough, outer covering called exoskeleton.

Question 3.
Insects belong to class amphibia.
Answer:
False : Insects belong to class arthropoda.

Question 4.
Fish have fins, scales and they breathe through gills.
Answer:
True.

Question 5.
Reptiles have a wet skin. They lay eggs that have a hard shell
Answer:
False: Reptiles have a scaly skin. They lay eggs that have a leathery shell.

F. Find the odd one out Give reasons.

Question 1.
ant, cockroach, spider, dragonfly
Answer:
spider : spider is odd one out because it is an arachnid whereas rest three are insects.

Question 2.
frog, shark, seahorse, carp
Answer:
frog: frog is an amphibian while other three are fishes.

Question 3.
snail, oyster, earthworm, octopus
Answer:
earthworm: earthworm is an annelid whereas rest three are molluscs.

Question 4.
snake, alligator, eel, turtle
AnswerP
eel: eel is a fish whereas the other three animals are reptiles.

Question 5.
sea urchin, starfish, brittle star, jellyfish
Answer:
jellyfish : jellyfish belongs to Cnidarians whereas the rest three are echinoderms.

Question 6.
jellyfish, Hydra, sea anemone, butterfly
Answer:
butterfly : butterfly is an insect whereas rest three are Cnidarians.

G. Answer the following in short.

Question 1.
What are invertebrates ?
Answer:
Invertebrates are animals without a backbone, e.g. Insects, worms.

Question 2.
What do you mean by radially symmetrical body ?
Answer:
Radially symmetrical body is the body that can be divided into two identical halves along any plane, e.g. Star fish, jelly fish.

Question 3.
Name the special organs of excretion in annelids ?
Answer:
Annelids have a special organ of excretion called nephridia.

Question 4.
What is an exoskeleton ? How is it different from a backbone ?
Answer:
Exoskeleton is a tough outer covering of an animal body. e.g. Crab, lobster have exoskeletons.

Exoskeleton:

• It is a rigid external covering of the body that provides support and protection to the body.
• It is present in invertebrates.
• Examples : Crab, lobster, spiders, scorpions, etc.
• It is in the form of shell, or scales or feathers, etc.

Backbone:

• It is an internal skeleton (endoskeleton) that provides support and protection to the body.
• It is present in vertebrates.
• Examples: Humans, fish lions, dogs, etc.
• It is made up of number of vertebral joined to form a vertebral column.

Question 5.
Write two examples of myriapods.
Answer:
Centipede and Millipede

Question 6.
How are the bones of birds different from those of other vertebrates ?
Answer:
The bones of birds have large air cavities (are hollow) and hence are light. This enables them to fly. On the other hand,
bones of other vertebrates are dense and solid and form a heavy skeleton.

Practice Question 1.
Give two examples of Platyhelminthes.
Answer:
Two examples of Platyhelminthes are tapeworms and liver fluke.

H. Answer the following in detail.

Question 1.
Write a short note on annelids.
Answer:
Annelids are invertebrates which include segmented worms. They are found in moist soil and pond water. They have a soft, cylindrical and bilaterally symmetrical body. Their body surface is marked into ring-like compartments called segments which help in movement. They have a special organ of excretion called nephridia. Examples: Leech and earthworm.

Question 2.
Name the different classes of arthropods. Write one characteristic feature of each class.
Answer:
Arthropods are inverteberates with joined legs, segmented body and bilaterally symmetrical body which is divided into head, thorax and abdomen. Anthropods are further classified into –

• Arachnids – They have fused head and thorax, four pairs of legs, hard exoskeleton, no wings and antennae. Examples : Scorpions and spiders.
• Crustaceans – They have fused head and thorax, appendages on all segments, variable number of jointed legs and two pairs of antennae extending from the head. Examples: lobsters and shrimps.
• Myriapods – Body divided into large number of segments and have two pairs of legs per segment (example: millipede) or one pair of legs per segment (Example : centipede). Number of legs may vary from 20 to 200.
• Insects – Their body is divided into head, thorax and abdomen. They have three pairs of legs, two pairs of wings (some have one pair or none) and a pair of antennae. Examples : ants and butterflies.

Question 3.
Write two characteristics each of
a. birds
b. amphibians
c. reptiles
d. mammals
Answer:
Two characteristics of:

a. Birds :

• They are warm blooded animals with feathers on their body.
• They have homy beak and do not have teeth.

b. Amphibians:

• They are animals which can live both on land and in water.
• They breathe through lungs and skin.

c. Reptiles :

• They are land animals with dry scaly skin on their body.
• They breathe through lungs.

d. Mammals:

• They are warm blooded animals with hair on their body.
• They give birth to babies and are the only animals that produce milk for nourishing their young ones.

Question 4.
List two notable characteristic of birds that are not found in any other group of animals ?
Answer:
The most notable characteristic of birds which is not found in any other group of animals is the presence of feathers. They are the only animals on earth which have a backbone as well as feathers which cover their entire body.
Also, their skeleton is light as their bones have air cavities and are hollow. They also have beaks with no teeth.

Question 5.
Why are mammals regarded as the most advanced animals ?
Answer:
Mammals are regarded as the most advanced animal because they are the most recently evolved vertebrates who have the most advanced, complex brain, are the only animals that produce milk for their young ones and give birth to babies.

Question 6.
How will you classify animals according to the food they eat ?
Answer:
On the basis of food they eat, animals are classified as –
1. Herbivores – They eat only green plants as food. Examples : cow, goat, etc.
2. Carnivores – They eat only the flesh of other animals as food. Examples : tiger and lion, etc.
3. Omnivores – They eat both plants as well as the flesh of other animals as food.
Examples : bear, crow, man, etc.

Practice Question 1.
List four characteristics of reptiles.
Answer:
Four characteristics of reptiles are :
a. They are cold blooded vertebrates.
b. They have dry skin covered with scales.
c. They lay eggs that have leathery shells.
d. They breathe through lungs.
e. g. : Lizard, crocodile.

Practice Question 2.
How do fish exchange gases ?
Answer:
Fish exchange gases in water through gills. Gills enable the fish to obtain oxygen dissolved in the water.

Practice Question 3.
You are asked to classify an animal in the correct group. The animal has a soft body and arm-like tentacles. You dissect the animal and find that it has an internal shell. Is the animal a cnidarian or a mollusc ? Explain your answer.
Answer:
The animal is a mollusc because although both molluscs and cnidarians have soft bodies and tentacles but only molluscs have shells (internal or external) and cnidarians don’t.

Practice Question 4.
How do warm-blooded and cold-blooded animals differ?
Answer:
Warm blooded animals are those animals whose body temperature remain same and is not affected by the
temperature of their surroundings, e.g. Birds, Humans. Cold blooded animals change their body temperature with the change in the temperature of their surroundings, e.g. Fish, reptiles.

I. Classify the given animals into different categories indicated.

Question 1.
Jellyfish, liver fluke, pin worm, As car is, tapeworm, Hydra, sea anemone into cnidarians, Platyhelminthes and Nemathelminthes.
Answer:
Cnidarians – Jelly fish, Hydra, sea anemone.
Platyhelminthes – Liver fluke, tapeworm.
Nemathelminthes – P inworm, Ascaris.

Question 2.
Crab, millipede, butterfly, ant, scorpion, centipede, spider, lobster, moth, prawn into arachnids, crustaceans, myriapods and insects.
Answer:
Arachnids – Scorpion, spider.
Crustaceans – Crab, lobster, prawn.
Myriapods – Millipede, centipede.
Insects – Fly, ant, moth.

J. Give reasons for the following.

Question 1.
What happens to the body temperature of a fish when the temperature of water drops ?
Answer:
Since fish are cold blooded animals, the temperature of their body also drops when the temperature of water drops.

Question 2.
Why do adult amphibians tend to stay near water ?
Answer:
Adult amphibians tend to stay near water because they have
to return to water to reproduce and they always lay their eggs in water, e.g. frog.

K. Given below are groups of animals, and their characteristics features. One of the features is incorrect. Identify it.
1. Porifera : porous animals, have tentacles, fixed to surface
2. Amphibia : cold blooded, lungs in adults, scaly skin
3. Aves : cold blooded, wings, feathers, bones with large air spaces
4. Pisces : live in water, scaly skin, warm blooded, fins for swimming
Answer:

L. Each animal drawn below is an invertebrate. Fill in the characteristics of each one.
Answer:

Practice Question 1.
Each animal drawn below is an invertebrate. Fill in the characteristics of each one.
Answer:
Group to which it Belongs :
Protista
Where it lives : Every where mostly in water Two other members of the same group :
Paramecium euglena One characteristic feature of the group : They are made up of a single cell
Group to which it Belongs :Poriferans
Where it lives : Salty sea water
Two other members of the same group : Sycon,Spongilla
One characteristic feature
of the group : Have pores all over the body
Group to which it Belongs : Arachnids
Where it lives : Any warm habitat
Two other members of the same group: Scorpions, ticks One characteristic feature of the group : Have four pairs of legs
Group to which it Belongs : Cnidarians
Where it lives : Marine water Two other members of the same group : Hydra, Sea Anemone One characteristic feature of the group : Tentacles are used to capture prey Group to which it Belongs :
Molluscs Where it lives : Mostly in water
Two other members of the same group : Octopus, squid One characteristic feature of the group: Soft body with an external hard shell

Living Science Biology Class 6 ICSE Solutions