Worksheet Solutions: Classification of Animals | Biology Class 7 ICSE PDF Download

Part A — Multiple Choice Questions 

Q1. In which kingdom do prokaryotic, single-celled organisms with a nucleoid (no true nucleus) belong?

(a) Protista

(b) Monera

(c) Fungi

(d) Plantae
Answer: (b) Monera
Explanation: Members of Monera (such as bacteria) are single-celled and lack a nuclear membrane; their DNA lies in a nucleoid region.

Q2. The tiny “false feet” that help Amoeba move and capture food are called

(a) Cilia

(b) Flagella

(c) Pseudopodia

(d) Hyphae
Answer: (c) Pseudopodia
Explanation: Amoeba pushes out parts of its cell membrane and cytoplasm to form pseudopodia, used for movement and surrounding food.

Q3. In bread mould, the round structure at the tip that holds spores is the

(a) Mycelium

(b) Hypha

(c) Sporangium

(d) Capsule
Answer: (c) Sporangium
Explanation: Thread-like hyphae form a network (mycelium). Erect hyphae develop sporangia at the tips, which release spores.

Q4. Which statement correctly distinguishes algae and fungi?

(a) Both have chlorophyll and make food

(b) Algae lack chlorophyll; fungi have chlorophyll

(c) Algae have chlorophyll (make food); fungi lack chlorophyll (feed on dead matter)

(d) Both are animals
Answer: (c)
Explanation: Algae are photosynthetic (chlorophyll present). Fungi are saprophytes; they absorb nutrients from dead and decaying material.

Q5. Plants that bear seeds not enclosed in fruits (often in cones) are

(a) Angiosperms

(b) Ferns

(c) Mosses

(d) Gymnosperms
Answer: (d) Gymnosperms
Explanation: Gymnosperms produce naked seeds (no fruit). Angiosperms have seeds inside fruits.

Part B: Short Answer Type Questions

Q6. State two differences between invertebrates and vertebrates.
Answer:

• Presence of backbone: Invertebrates do not have a backbone (example: worm, snail). Vertebrates have a backbone made of bones called vertebrae (example: fish, dog, human).

• Size and complexity: Invertebrates are usually small and simple in body structure, while vertebrates are larger and more complex, with advanced systems like brain, heart, and lungs.

Explanation: This difference is important because the backbone supports the body and protects the spinal cord in vertebrates, while invertebrates rely on other structures like shells or outer coverings for support.

Q7. Write two features of Cnidaria with examples.
Answer:

• They have a sac-like body with only one opening (mouth), which is used for both taking food and removing waste.

• Their mouth is surrounded by tentacles, which help them catch small animals and also assist in movement.
  Examples: Hydra, Jellyfish, Sea anemone.

Explanation: The simple body of cnidarians shows how early animals evolved ways to feed and protect themselves using tentacles.

Q8. What are arthropods? Name any two examples.
Answer:

• Arthropods are animals that have jointed legs and an external covering (exoskeleton) made of a tough substance called chitin.

• Their body is usually divided into three parts – head, thorax, and abdomen.
  Examples: Ant, Crab, Butterfly, Spider.

Explanation: Arthropods are the largest group of animals on Earth, making up more than 70% of all known species. Their jointed legs make them good at crawling, flying, or swimming.

Q9. How does an amoeba move and capture its food?
Answer:

• Amoeba moves with the help of pseudopodia (meaning “false feet”), which are temporary finger-like extensions of its body.

• When food (like a tiny plant or organism) comes nearby, amoeba surrounds it using pseudopodia. The food is then trapped in a food vacuole inside the cell.

• Inside the vacuole, digestive juices break down the food into simpler form, which is absorbed into the cytoplasm.

Explanation: Amoeba is a good example of how even a single-celled organism can perform all life processes like movement, feeding, digestion, and growth.

Q10. Mention two adaptations of fishes for living in water.
Answer:

• Streamlined body: The narrow shape at both ends of the body allows the fish to swim smoothly in water with little resistance.

• Gills for breathing: Fishes do not have lungs like humans. They breathe by passing water over their gills, which take in oxygen dissolved in water.

Explanation: These features show how fishes are perfectly adapted to their aquatic environment and cannot survive outside water.

Part C: Long Answer Type Questions

Q11. Explain the main features of Amphibians with examples.
Answer:

1. Meaning of the group: Amphibians are animals that can live both in water and on land. The word “amphibian” means “double life.”

2. Body covering: Their skin is slimy and slippery (moist) and does not have scales. The moist skin helps them when they are in water.

3. Breathing: They can breathe through their lungs on land, and their skin also helps in breathing (especially when they are in water).

4. Reproduction: Amphibians lay eggs in water. The young ones hatch in water first.

5. Life cycle change (metamorphosis): The young ones (like tadpoles of frogs) live in water and later change their body form to become adults that can live on land as well. This change is called metamorphosis.

6. Examples: Frog, Toad.

Examples: Frog, Toad, Salamander.

Explanation: Amphibians are important in classification because they are the “link” between aquatic animals like fishes and land animals like reptiles.

Q12. Describe the characteristics of mammals.
Answer:

1. Body covering: Mammals have hair or fur on their bodies which helps to keep them warm.

2. Feeding the young: Female mammals have mammary glands that produce milk to feed their babies. This is a key feature of mammals.

3. Birth: Most mammals give birth to young ones (not eggs).
   (Note: A very small number of mammals are exceptions, but at your level, remember most give birth to babies.)

4. Ears: Mammals have external ears that are clearly seen outside the head.

5. Limbs: They usually have four limbs for different activities—walking, running, swimming, or flying (like bats).

6. Examples: Cow, Dog, Deer, Camel, Lion, Tiger, Elephant, Rat, Humans.

Explanation: Mammals are the most advanced animals, showing features like parental care, intelligence, and the ability to adapt to all types of environments (land, air, water).

Q13. Compare any three classes of invertebrates with their features and examples.

A. Porifera (Sponges)

1. Habitat: Mostly aquatic (marine and fresh water).

2. Body plan: Body has many tiny pores all over to draw in water, and one large opening to send it out.

3. Movement: They are fixed to rocks or the bottom; they do not move from place to place.

4. Examples: Sponge, Sycon.

B. Annelida (Segmented Worms)

1. Body plan: Body is made up of many rings or segments.

2. Breathing: The soft, moist body wall helps in breathing.

3. Excretion: They have special organs called nephridia for removing wastes.

4. Examples: Earthworm, Leech.

C. Arthropoda (Jointed-legged Animals)

1. Body plan: Body often divided into head, thorax, and abdomen and covered by a tough outer layer (exoskeleton).

2. Movement: Have jointed legs for walking, crawling, flying, or swimming.

3. Diversity: This is the largest group of animals and includes many classes (insects, spiders, crabs, etc.).

4. Examples: Ant, Housefly, Butterfly, Spider, Crab.