The Living Organisms and their surroundings ( By Dharmendra Sir )


 




A. VERY SHORT ANSWER QUESTIONS: Answer in one word

1. Name one terrestrial habitat which is dry and hot.
Ans. Desert

2. Name one organ of the grassland herbivore which helps it to follow the movement of a predator.
Ans. Ears

3. name an aquatic animal which breathes- in through nostrils.
Ans. Whale

4. What is the reaction of a living organisms to a stimulus called?
Ans. Response

5. What is the opening and closing of guard cells regulating the water level in leaves called?
Ans. Hydrotropism

B. SHORT-ANSWER QUESTIOS: ANSWER IN 10-15 WORDS

Q 1. What is meant by the term habitat? Name the three main habitats in our biosphere.
Ans. A natural place for a living organism to live, survive, breed and flourish is called habitat. Three main habitats in our biosphere are:
 (1) Terrestrial habitat (2) Aquatic habitat (3) Arboreal habitat

Q 2. What is hibernation? Give an example.
Ans. A long summer or winter sleep of certain animals is called hibernation. Example-Frog.

Q 3. Write two characteristics which the camel has adapted to survive in deserts.
Ans. (1) Its limbs contain large pads which help it to move on hot slippery sand.
         (2) The hump of camel is a reservoir of food in the form of fat.

Q 4. What are the common features found in mountain animals.
Ans. (1) The animals of these regions are usually white or light coloured.
         (2) They have thick skin or fur to protect them from cold.

Q 5. What is meant by excretion? Name two products excreted by trees.
Ans. The process by which a living body throws out the waste products produced inside the body is called excretion. Two products excreted by tress are latex and gum.

C. LONG ANSWER TYPE QUESTIONS: Answer in 20-25 words

Q 1. Distinguish between aquatic and terrestrial habitats.
Ans.
 

Aquatic habitat

Terrestrial habitat

The organisms that live, grow and propagate in water are called aquatic habitat.

Ex- Oceans, Sea, Rivers etc.

The organisms that live, grow and propagate on land are called terrestrial habitat.

 Ex- Desert, grassland etc.


Q 2. How do desert plants adapt themselves to the conditions in the desert?
Ans. The following adaptations are found in desert plants:
           (1) Their leaves are reduced to scales or spines which reduce the loss of water by                 transpiration.
        (2) The leaves bear sunken stomata to reduce the rate of transpiration.
        (3) The thick cuticle is found on the stem and leaves for the prevention loss of water.

Q 3. Why do all living beings need food? Why are the green plants called autotrophs?
Ans. All livings beings need food to stay alive, grow and get energy to perform various activities. Green plants are called autotrophs because they make their own food by the process photosynthesis.

Q 4. Describe breathing. In what way is the exhaled air different from the inhaled air.
Ans. The process of inhaling and exhaling air is called breathing. The exhaled air is different from the inhaled air in following way:

 

Oxygen

Carbon dioxide

Inhaled air

21%

0.03%

Exhaled air

16%

4%


D.TICK THE ODD-ONE OUT GIVING REASON

1. Grassland, Mountain, Ocean, Desert
Ans. Ocean because it is aquatic habitat and rest others are terrestrial habitat.

2. Lotus, Opuntia, Hydrilla, Vallisneria
Ans. Opuntia because it is a xerophyte plant and rest others are hydrophytes.

3. Monkey, Yak, Snake, Lion
Ans. Yak because it is mountain animal and rest others are animals of grassland.

4. Phototropism, Geotropism, Hydrotropism, Flying
Ans. Flying because it is a type of locomotion of animals and rest others are the movement of plants.

5. Cactus, Acacia, Jujube (Ber), Hydrilla
Ans. Hydrilla because it is a hydrophyte and rest others are xerophytes.

E. DEFINE THE FOLLOWING TERMS

1. Nasticism: Movement of a plant neither in the direction nor away from the stimulus is called nasticism. Example- Touch me not plant.

2. Autotrophs: The organisms which make their own food themselves are called autotrophs. Ex-Green plants.

3. Hydrophytes: The aquatic plants of fresh water are called hydrophytes. They may be free floating, rooted, and floating or submerged. Ex- Lotus, Hydrilla etc.

4. Adaptation: The tendency of an organism to develop certain specific features which improve the chance of its survival in the environment in which it lives is known as adaptation.

5. Arboreal organisms: The organisms that use trees for their activities are known as arboreal organisms. Ex- All birds

HOTS: HIGHER ORDER THINKING SKILLS  

1. Do all aquatic animals breathe oxygen dissolved in water?
Ans. No, all aquatic animals do not breathe oxygen dissolved in water. They have lungs on the place of gills and they breathe-in air through nostrils or blowholes. They come on water surface time to time for breathing. Example Dolphins and whales.

2. Why is camel called “ship of desert”?
Ans. Camel is called the “ship of desert” because it is the only means of transport found in desert. The body of a camel has undergone various adaptations such as padded feet, presence of hump, absence of sweat glands etc. that help it to survive in the hot and dry conditions of the deserts. 

3. The animal which hibernate eat a lot before going for a long sleep. Why?
Ans. The animals which hibernate eat a lot before going for a long sleep and store it in their body because they don’t eat anything during that time but their body need energy for survival which the get from the stored food.

4. Why are the animals living on mountains have thick skin or fur on their body?
Ans. The animals living on mountains have thick skin or fur on their body to protect them from cold.


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