Check your progress 1
Question 1
............... do not have a backbone, while ............... have it.
Answer
Invertebrate do not have a backbone, while vertebrate have it.
Question 2
Cnidarians have ............... symmetrical body.
Answer
Cnidarians have radially symmetrical body.
Question 3
............... and ............... live in the intestines of humans and cattle.
Answer
Planaria and liver fluke live in the intestines of humans and cattle.
Question 4
............... are considered as a farmer's friend.
Answer
Earthworms are considered as a farmer's friend.
Question 5
Annelids have special organs called ............... for excretion.
Answer
Annelids have special organs called nephridia for excretion.
Check your progress 2
Question 1
............... have paired appendages with many joints.
Answer
Arthropods have paired appendages with many joints.
Question 2
Arthropods have ............... eyes.
Answer
Arthropods have compound eyes.
Question 3
Most arthropods have a tough outer body covering called ............... .
Answer
Most arthropods have a tough outer body covering called exoskeleton.
Question 4
A snail belongs to the ............... phylum.
Answer
A snail belongs to the mollusca phylum.
Question 5
Echinoderms have a mouth on the ............... side and an anus on the ............... side.
Answer
Echinoderms have a mouth on the lower side and an anus on the upper side.
Check your progress 3A
Question 1
Vertebrates are animals without a backbone.
Answer
False
Corrected statement — Vertebrates are animals with a backbone.
Question 2
In fishes, fins are the organs of locomotion.
Answer
True
Question 3
Birds are cold blooded animals.
Answer
False
Corrected statement — Birds are warm blooded animals.
Question 4
Amphibians can only live on land.
Answer
False
Corrected statement — Amphibians can live on land as well as in water.
Question 5
Aves have horny beaks and do not have teeth.
Answer
True
Check your progress 3B
Question 1
Tick the statements that are true for mammals.
- They are warm-blooded animals.
- They breathe through gills.
- They give birth to babies.
- They have hair on their body.
Answer
- They are warm-blooded animals.
- They give birth to babies.
- They have hair on their body.
Tick the most appropriate answer
Question 1
Sponges are mostly found in
- distilled water
- sea water
- dirty water
- tap water
Answer
Sea water
Reason — Sponges are mostly found in sea water, only a few species are found in fresh water.
Question 2
Which one of the following is not a cnidarian?
- pin worm
- Hydra
- jellyfish
- sea anemone
Answer
pin worm
Reason — Hydra, jellyfish and sea anemone are cnidarians.
Question 3
The finger-like structures present around the mouth of cnidarians are called
- pseudopodia
- tentacles
- spines
- bristles
Answer
tentacles
Reason — The finger-like structures present around the mouth of cnidarians are called tentacles.
Question 4
Annelids have a
- soft, unsegmented, bilaterally, symmetrical body
- soft, cylindrical, segmented, bilaterally symmetrical body
- soft, segmented, bilaterally symmetrical body
- soft, segmented, laterally symmetrical body
Answer
soft, cylindrical, segmented, bilaterally symmetrical body
Reason — The body of annelids is soft, cylindrical, segmented and bilaterally symmetrical.
Question 5
Which of the following has nephridia for excretion?
- spider
- tapeworm
- earthworm
- shrimp
Answer
earthworm
Reason — Earthworm and leech have nephridia for excretion.
Question 6
Which of the following has an exoskeleton?
- octopus
- snail
- leech
- beetle
Answer
beetle
Reason — Beetle is an insect and has an exoskeleton.
Question 7
Scorpions and spiders are
- crustaceans
- arachnids
- myriapods
- insects
Answer
arachnids
Reason — Scorpions and spiders are arachnids, a subgroup of arthropoda.
Question 8
The body temperature of warm-blooded animals
- keeps fluctuating
- changes according to the temperature of the environment.
- does not change with the change in the temperature of the environment
- decreases when the temperature of the environment increases.
Answer
does not change with the change in the temperature of the environment
Question 9
Which of the following is an amphibian?
- turtle
- salamander
- alligator
- crocodile
Answer
Salamander
Reason — Salamander is an amphibian while turtle, alligator and crocodile are reptile.
Question 10
Bones with large air cavities are present in
- cnidarians
- fish
- annelids
- birds
Answer
birds
Reason — Birds have air cavities in their bones to make their body light.
Question 11
............... have four-chambered heart.
- Amphibians
- Mammals
- Fish
- Reptiles
Answer
Mammals
Reason — Mammals have four-chambered heart while amphibians and most of reptiles have three-chambered heart. Fishes have two chambered heart.
Fill in the blanks
Question 1
Animals without a backbone whose body is soft and often covered by a hard shell are called ............... .
Answer
Animals without a backbone whose body is soft and often covered by a hard shell are called mollusca.
Question 2
Invertebrates with jointed legs belong to the ............... phylum.
Answer
Invertebrates with jointed legs belong to the arthropods phylum.
Question 3
Fish obtain oxygen from water through ............... .
Answer
Fish obtain oxygen from water through gills.
Question 4
Vertebrates that spend a part of their life on land but reproduce in water are called ............... .
Answer
Vertebrates that spend a part of their life on land but reproduce in water are called amphibians.
Question 5
............... are warm-blooded animals and have hair on their body.
Answer
Mammals are warm-blooded animals and have hair on their body.
Write true or false. Correct the false statements.
Question 1
Arthropods have a soft outer covering called endoskeleton.
Answer
False
Corrected Statement — Arthropods have a rigid outer covering called exoskeleton.
Question 2
A tapeworm is a flatworm that lives in the human intestine.
Answer
True
Question 3
A centipede is an insect.
Answer
False
Corrected Statement — A centipede is a myriapod.
Question 4
Fish have fins, scales and they breathe through gills.
Answer
True
Question 5
Reptiles lay eggs with a hard shell and are warm-blooded animals.
Answer
False
Corrected Statement — Reptiles lay eggs with a leathery waterproof shell and are cold-blooded animals.
Differentiate between
Question 1
flatworms and roundworms
Answer
| Sl. No. | Flatworms | Roundworms |
|---|---|---|
| 1. | Flatworms belong to phylum Platyhelminthes. | Roundworms belong to phylum Nematoda. |
| 2. | The body is thin and flattened or leaf-like or ribbon-like. | The body is cylindrical, narrow, unsegmented and bilaterally symmetrical. |
| 3. | They have only one opening, for intake of food and excretion. | They have two openings — mouth for intake of food and anus for excretion. |
| 4. | They show sexual and asexual reproduction. | They reproduce sexually. |
| 5. | They are hermaphrodite. | Male and female exist separately. |
Question 2
arthropoda and mollusca
Answer
| Sl. No. | Arthropoda | Mollusca |
|---|---|---|
| 1. | Body of Arthropoda is segmented. | Body of Mollusca is unsegmented. |
| 2. | Arthropoda have jointed legs. | Mollusca do not have jointed legs. |
| 3. | Arthropoda have exoskeleton. | Mollusca have coiled shell. |
| 4. | For example — spider and ant. | For example — octopus and snail. |
Question 3
radially symmetrical body and bilaterally symmetrical body
Answer
| Sl. No. | Radially symmetrical body | Bilaterally symmetrical body |
|---|---|---|
| 1. | It means that the body can be divided vertically into two equal halves along any plane passing through the central point. | It can be divided into two identical halves only through one plane. |
| 2. | Coelenterates have a radially symmetrical body. | Flatworms have bilaterally symmetrical body. |
Question 4
amphibians and pisces
Answer
| Sl. No. | Pisces | Amphibians |
|---|---|---|
| 1. | Pisces are aquatic. | Amphibians can live on both land and water. |
| 2. | Body of Pisces is smooth and slimy and is covered with scales for protection. | Amphibians have thin, moist skin which may be smooth or rough. |
| 3. | In Pisces, limbs are modified into fins. | Amphibians have two pairs of limbs. |
| 4. | Pisces have gills to breath. | Amphibians breathe through lungs on land and through their moist skin in water. |
| 5. | Pisces have two chambered heart. | Amphibians have three chambered heart. |
Question 5
aves and mammals
Answer
| Sl. No. | Aves | Mammals |
|---|---|---|
| 1. | Aves lay eggs. | Mammals give birth to babies. |
| 2. | Aves have feathers on body. | Mammals have hairs on their body. |
| 3. | Aves have light bones with air cavities. | Mammals have solid bones. |
| 4. | Aves do not produce milk. | Mammals produce milk and suckle their young ones. |
| 5. | Aves do not have teeth. | Mammals have teeth. |
Question 6
warm-blooded and cold blooded animals
Answer
| Sl. No. | Warm-blooded animals | Cold-blooded animals |
|---|---|---|
| 1. | Body temperature of warm-blooded animals remains constant and is not affected by the temperature of their surroundings. | Body temperature of cold-blooded animals changes with the temperature of their surroundings. |
| 2. | For example: Mammals and Birds | For example: Fish and Reptiles |
Match the following
Question 1
| Sl. No. | Column A | Column B |
|---|---|---|
| 1. | molluscs | feed milk to young ones, warm-blooded |
| 2. | sponges | bag-like body with tentacles around the opening |
| 3. | flatworms | fins, gills and cold-blooded |
| 4. | mammals | body with large opening and many small pores all over |
| 5. | fish | hard shell, soft body |
| 6. | cnidarians | soft body without a body cavity and one opening only |
| 7. | arthropods | jointed legs, exoskeleton |
| 8. | cylindrical, unsegmented body with mouth at one end and anus at the posterior end |
Answer
| Sl. No. | Column A | Column B |
|---|---|---|
| 1. | molluscs | hard shell, soft body |
| 2. | sponges | body with large opening and many small pores all over |
| 3. | flatworms | soft body without a body cavity and one opening only |
| 4. | mammals | feed milk to young ones, warm-blooded |
| 5. | fish | fins, gills and cold-blooded |
| 6. | cnidarians | bag-like body with tentacles around the opening |
| 7. | arthropods | jointed legs, exoskeleton |
Find the odd one out. Give reasons.
Question 1
ant, cockroach, spider, dragonfly
Answer
Spider
Reason — Spiders are classified under arachnida while others are insect.
Question 2
snake, alligator, eel, turtle
Answer
Eel
Reason — Eel is a fish while others are reptiles.
Question 3
frog, shark, seahorse, carp
Answer
frog
Reason — Frog is amphibian while shark, seahorse and carp are classified under class pisces
Question 4
sea urchin, starfish, brittle star, jellyfish
Answer
jellyfish
Reason — Jellyfish is a cnidarian but others are echinoderms.
Question 5
snail, oyster, earthworm, octopus
Answer
Earthworm
Reason — Earthworm is annelid while others are molluscs.
Question 6
jellyfish, Hydra, sea anemone, butterfly
Answer
butterfly
Reason — Butterfly is an arthropod (insect) while others are cnidarians.
Answer the following in short
Question 1
What are invertebrates?
Answer
The animals that do not have a back bone or vertebral column are called invertebrates.
Question 2
What do you mean by radially symmetrical body?
Answer
A radially symmetrical body is a body that can be divided vertically into two equal halves along any plane passing through the central point.
Question 3
What are the special organs of excretion in annelids?
Answer
Nephridia are the special organs of excretion in annelids.
Question 4
What is an exoskeleton? How is it different from the backbone?
Answer
A rigid external covering of the body found in some invertebrates that provides support and protection to their body is called an exoskeleton. It is different from backbone in the following ways:
- Exoskeleton is present outside the body while backbone is present inside the body.
- Exoskeleton is shell like or chitinous covering above the body present in some invertebrates but backbone is bony structure found inside the body of vertebrates.
Question 5
Which class of animals can live both on land and in water? Give two examples.
Answer
Animals of class Amphibia can live both on land and in water. Two examples of amphibians are salamander and frog.
Question 6
Write three most important features of birds.
Answer
Three most important features of birds are:
- Their skeleton is very light because their bones have large air cavities. They have horny beaks and no teeth.
- They are the only animals whose body is covered with feathers.
- Their forelimbs are modified into wings and hind limbs are adapted for walking, perching or swimming.
Answer the following in detail
Question 1
Name the different classes of arthropods. Write two examples of each class.
Answer
Arthropoda are classified into following four subgroups or classes:
- Arachnida — Examples: scorpions, spiders
- Crustacea — Examples: lobsters, shrimps
- Myriapods — Examples: centipedes, millipedes
- Insect — Examples: ants, beetles
Question 2
Write two characteristics each of
a. birds.
b. amphibians.
c. reptiles.
Answer
a. Two characteristics of bird are:
- Their skeleton is very light because their bones have large air cavities. They have horny beaks and no teeth.
- They are the only animals whose body is covered with feathers.
b. Two characteristics of amphibians are:
- They breathe with lungs on land, and through their moist skin in water.
- They are cold-blooded animals.
c. Two characteristics of reptiles are:
- Their skin is covered with horny epidermal scales.
- They breathe through lungs.
Question 3
How do fish exchange gases?
Answer
Fish has special breathing organ called gills. The gills have numerous thin blood capillaries. Fish takes in water through the mouth and this water passes through the gills. The capillaries absorb the oxygen that is dissolved in the water and release the carbon dioxide in the water. In this way the fish exchange gases.
Question 4
How are the bones of birds different from those of other vertebrates?
Answer
Birds have different adaptations in their body that help them to fly. Their bones are hollow with large air cavities in them which makes them light. Such bones are known as pneumatic bones. This keeps the body of birds light and makes it easy for them to fly. Other vertebrates either have solid bones or their bones are filled with bone marrow.
Question 5
What is the most notable characteristic of birds that is not found in any other group of animals?
Answer
Birds are the only animals whose body is covered with feathers.
Identify the odd one out
Question 1
Given below is a table consisting of different groups of animals and their characteristics features. Some of the features are incorrect. Identify the odd one out in each.
| Sl. No. | Group | Characteristic features | Odd one out |
|---|---|---|---|
| 1. | Porifera | porous animals, have tentacles, fixed to surface | |
| 2. | Pisces | live in water, scaly skin, warm blooded, fins for swimming | |
| 3. | Amphibia | cold blooded, lungs in adults, scaly skin | |
| 4. | Aves | cold blooded, wings, feathers, bones with large air cavities |
Answer
| Sl. No. | Group | Characteristic features | Odd one out |
|---|---|---|---|
| 1. | Porifera | porous animals, have tentacles, fixed to surface | have tentacles |
| 2. | Pisces | live in water, scaly skin, warm blooded, fins for swimming | warm blooded |
| 3. | Amphibia | cold blooded, lungs in adults, scaly skin | scaly skin |
| 4. | Aves | cold blooded, wings, feathers, bones with large air cavities | cold blooded |
Complete the table
Question 1
Look at the pictures and complete the table.
Answer
| Animal | Group to which it belongs | Where it lives | Two other members of the same group | One characteristic feature of the group |
|---|---|---|---|---|
 | Nematoda | freshwater, marine and terrestrial environment, lives in intestine as parasite | pinworm, whipworm | unsegmented cylindrical body |
 | Annelida | moist soil, pond water | Polychaete, leech | segmented body |
 | Mollusca | freshwater, marine and terrestrial environment | octopus, squid | soft, unsegmented body with an outer hard shell |
 | Arthropoda (insect) | air and land | ant, housefly | compound eyes |
 | Arthropoda (arachnida) | terrestrial | cockroach, scorpions | four pairs of jointed limbs |
 | Echinodermata | Marine water | brittle star, sea urchin | Mouth on lower side and anus on upper side |
 | Arthropoda (crustacean) | Marine and Fresh water | lobsters, shrimps | Jointed legs |
 | Amphibia | land and water | toad, salamander | Thin, moist skin which may be smooth or rough |
 | Aves | land and air | crow, sparrow | Body covered with feathers |
 | Reptiles | terrestrial | snake, turtle | Dry skin covered with scales |
Classify the given animals
Question 1
Classify the given animals into different categories indicated:
jellyfish, liver fluke, pinworm, Ascaris, tapeworm, Hydra, sea anemone into Cnidarians, Platyhelminthes and Nematoda.
Answer
| Cnidarians | Platyhelminthes | Nematoda |
|---|---|---|
| jellyfish | liver fluke | pinworm |
| Hydra | tapeworm | ascaris |
| sea anaemone |
Question 2
Classify the given animals into different categories indicated:
crab, millipede, fly, ant, scorpion, centipede, spider, lobster, moth, prawn into Arachnids, Crustaceans, Myriapods and Insects.
Answer
| Arachnids | Crustaceans | Myriapods | Insects |
|---|---|---|---|
| scorpion | lobster | millipede | fly |
| spider | prawn | centipede | ant |
| crab | moth |
Question 3
Classify the given animals into different categories indicated:
seahorse, turtle, mouse, dog, shark, alligator, lion, crocodile, eel, pomfret, snake into Pisces, Reptiles and Mammals.
Answer
| Pisces | Reptiles | Mammals |
|---|---|---|
| seahorse | turtle | mouse |
| shark | alligator | lion |
| eel | snake | dog |
| pomfret | crocodile |
Think and answer
Question 1
This 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? Which group does this animal belong to?
Answer
The animal is a mollusc as it has a soft body and arm-like tentacles and also an internal shell. It belongs to the Invertebrates group.
Question 2
What happens to the body temperature of a fish when the temperature of water drops?
Answer
Fish is a cold-blooded animal. It means it changes its body temperature according to the change in temperature of the environment. So, the body temperature of a fish will decrease when the temperature of water drops.
Question 3
Why do adult amphibians tend to stay near water?
Answer
Amphibians require water to complete their life cycle. Adult amphibians tend to stay near water to lay their eggs in water.