Question Answers For All Chapters – General Science Class 7
The Living World : Adaptations and Classification
Use Your Brain Power!
1. Why does water trickle off lotus leaves?
Answer : Water trickles off lotus leaves because their surface is covered with a waxy layer, which makes them waterproof. This prevents water from staying on the leaf, allowing it to roll off easily.
2. Why don’t the leaves of these plants rot in water?
Answer : The leaves of aquatic plants do not rot in water because they have a waxy coating that prevents excess water absorption and decay. Also, they have air spaces that help them float and provide oxygen to the plant.
3. Why are their roots short and fibrous?
Answer : Aquatic plants have short and fibrous roots because they do not need to absorb much water from the soil. Their main function is to anchor the plant to the bottom of water bodies.
Exercise
1. Find My Match!
| ‘A’ Group | ‘B’ Group |
|---|---|
| (1) Lotus | (d) Adapted to live in water. |
| (2) Aloe | (c) Adapted to live in deserts. |
| (3) Cuscuta | (b) Haustorial roots for absorption of food. |
| (4) Venus flytrap | (a) Flower and leaves attract insects. |
2. Read the Paragraph and Answer the Following Questions
I am a penguin. I live in a polar region covered with snow. My abdomen is white. My skin is thick with a layer of fat underneath. My body is spindle-shaped. My wings are small. My toes are webbed. We live in flocks.
(a) Why is my skin white and thick and why is there a thick layer of fat underneath?
Answer : Your skin is white to help you blend in with the snowy surroundings, protecting you from predators. It is thick, and the fat layer underneath helps to keep your body warm in the freezing polar temperatures.
(b) Why do we live in flocks sticking close to each other?
Answer : Penguins live in flocks and stay close to each other to keep themselves warm and protect one another from cold winds.
(c) Which geographical region do I inhabit? Why?
Answer : Penguins inhabit the polar region, specifically Antarctica, because they are adapted to live in extremely cold environments covered with ice and snow.
(d) Which adaptations should you have to enable you to live permanently in the polar region? Why?
Answer : To live permanently in the polar region, one should have:
- Thick skin and a fat layer – To prevent heat loss and stay warm.
- White body color – To blend with the snowy surroundings for protection.
- Webbed feet – To help in swimming.
- Spindle-shaped body – To reduce resistance while swimming in water.
3. Who is Lying?
| Statement | Truth or Lie? | Correction |
|---|---|---|
| (a) Cockroach – I have five legs. | Lie | Cockroaches have six legs. |
| (b) Hen – My toes are webbed. | Lie | Hens do not have webbed feet; ducks do. |
| (c) Cactus – My fleshy, green part is a leaf. | Lie | In a cactus, the fleshy, green part is a stem, while the leaves are modified into thorns. |
4. Read each of the following statements. Write a paragraph about adaptation with reference to each statement.
(a) There is extreme heat in deserts.
Answer :
Desert plants and animals have special adaptations to survive in extreme heat. Plants like cactus have thick, fleshy stems to store water, and their leaves are modified into spines to reduce water loss. Desert animals like camels have humps to store fat, which provides energy when food is scarce. They also have long eyelashes to protect their eyes from sand.
(b) Grasslands are lush green.
Answer :
Grasslands have an abundance of tall grasses and shrubs that provide food for herbivores like deer and zebras. These animals have strong legs to run fast and escape predators. The grassland environment supports a balance between herbivores and carnivores.
(c) Insects are found in large numbers.
Answer :
Insects reproduce in large numbers to increase their chances of survival. Many insects, like butterflies and bees, are important for pollination. Some insects, like ants, live in colonies and work together for survival.
(d) We hide.
Answer :
Animals use camouflage to blend with their surroundings to escape from predators. For example, chameleons change their skin color, and tigers have stripes to hide in the forest.
(e) We have long ears.
Answer :
Animals in hot regions (like desert foxes) have long ears to help release body heat and keep them cool. Some animals, like rabbits, have long ears to detect predators easily.
5. Answer the Following
(a) Why is the camel called the ‘Ship of the Desert’?
Answer :
The camel is called the “Ship of the Desert” because it can walk easily on the hot sand due to its broad, padded feet. It can also store water and food in its hump, allowing it to survive without water for long periods.
(b) How can plants like cactus and acacia survive in deserts with scarce water?
Answer :
- Cactus: Stores water in its thick, fleshy stem and has spines instead of leaves to prevent water loss.
- Acacia: Has deep roots to absorb water from underground sources.
(c) What is the inter-relationship between adaptations of organisms and their surroundings?
Answer :
Organisms adapt to their surroundings to survive. Desert animals have special body structures to retain water, while aquatic animals have streamlined bodies to swim easily. This adaptation helps them to live and reproduce in their specific environments.
(d) How are organisms classified?
Answer :
Organisms are classified based on similar characteristics such as body structure, habitat, and mode of nutrition. They are grouped into:
- Kingdom – Broadest classification (e.g., Plants, Animals).
- Phylum – Grouped based on major traits (e.g., Vertebrates, Invertebrates).
- Class, Order, Family, Genus, and Species – These are further divisions that help in detailed classification.
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