Chapter 12 – Survival strategies : Adaption

Want to make your Geography revision faster and easier? The topic Survival Strategies and Adaptation is important for your WBBSE Class 10 exam. This page gives you important questions and answers in very simple English. All questions are selected from important topics and common exam patterns. With this, you can revise quickly, understand clearly, and score better marks in your Madhyamik exam.

Content Structure

  • 1. Multiple choice questions and answers (MCQs)
  • 2. Very short-type questions and answers
    • 2A. Fill in the blanks
    • 2B. True or false
    • 2C. Match the following
    • 2D. Single word questions and answers
  • 3. Short-type questions and answers
  • 4. Long-type questions and answers

1. Multiple choice questions and answers (MCQs)

1. Place where organism lives is known as-
(a) Habitat
(b) Nest
(c) Habit
(d) Dwelling place

Ans: (a) Habitat

2. The change of living body which helps them to survive in changed environment or habitat is known as-
(a) Evolution
(b) Adaption
(c) Mutation
(d) Modification

Ans: (b) Adaption

3. Among adaption and evolution which one first developed in organism?
(a) Adaption
(b) Evolution
(c) Both simultaneously
(d) Mutation

Ans: (a) Adaption

4. The respiratory organ of rohu fish is-
(a) Lungs
(b) Air bladder
(c) Gills
(d) Accessory respiratory organ

Ans: (c) Gills

5. How many fins are present in the rohu fish-
(a) Three
(b) Five
(c) Seven
(d) Three pairs

Ans: (b) Five

6. Which fins are paired in rohu fish?
(a) Anal fin
(b) Dorssal fin
(c) Pectoral and pelvic fins
(d) Anal and tall fins

Ans: (c) Pectoral and pelvic fins

7. Which organ does help rohu fish to feel pressure, depth of water and temperature?
(a) Air bladder
(b) Scales
(c) Skin
(d) Lateral skin

Ans: (d) Lateral skin

8. Which organ is responsible for maintaining buoyancy of rohu fish?
(a) Swim bladder
(b) Myotome muscle
(c) Air sacs
(d) Fins

Ans: (a) Swim bladder

9. Primary acquatic adaptation is found in-
(a) Whale
(b) Koi
(c) Magur
(d) Rohu fish

Ans: (d) Rohu fish

10. The main breathing organ of pigeon is-
(a) Air sacs
(b) Lungs
(c) Air bladder
(d) Accessary respiratory organ

Ans: (b) Lungs

11. Which of the following animal shows double repiration?
(a) Bird
(b) Snake
(c) Fish
(d) Both fish and bird

Ans: (a) Bird

12. Air sacs are ofund in –
(a) Rohu fish
(b) Pigeon
(c) Snake
(d) Whale

Ans: (b) Pigeon

13. How many air sacs are present in the respiratory system of pigeon?
(a) Five
(b) Nine
(c) Eight
(d) Ten

Ans: (b) Nine

14. Cactus belongs to –
(a) Hydrophyte
(b) Xerophytes
(c) Epiphyte
(d) Halophyte

Ans: (b) Xerophytes

15. Phylloclade of cactus is the fleshy leaf like structure which is formed by the modification of-
(a) Root
(b) Leaf
(c) Stem
(d) Flower

Ans: (c) Stem

16. Spines are the modified structure of leaf to check-
(a) Photosynthesis
(b) Transpiration
(c) Metabolism
(d) Respiration

Ans: (b) Transpiration

17. Which part of the cactus mainly performs photosynthesis?
(a) Root
(b) Stem
(c) Spine
(d) Both root and stem

Ans: (b) Stem

18. Leaves of cactus get modified into-
(a) Spines
(b) Tendrils
(b) Thorns
(d) Spines and tendrils

Ans: (a) Spines

19. In which of the following soil does the Sundari plants grow?
(a) Silty
(b) Clayey soil
(c) Saline soil
(d) Sandy soil

Ans: (c) Saline soil

20. Sundari belongs to-
(a) Xerophytes
(b) Hydrophytes
(c) Halophytes
(d) Epiphytes

Ans: (c) Halophytes

21. Physiology dry soil contains-
(a) No water
(b) Large amount of salty water
(c) Large amount of general soil water
(d) Small amount of water in soil

Ans: (d) Small amount of water in soil

22. The survival strategy of living organisms is-
(a) Reproduction
(b) Mutation
(c) Heredity
(d) Adaptation

Ans: (d) Adaptation

23. Who discovered the language of honeybee?
(a) Niko Tinbergen
(b) Konrad Lorenz
(c) Karl Von Frisch
(d) Jane Goodall

Ans: (c) Karl Von Frisch

24. In which animal. the size of RBC may increase up to 240 times of its normal size?
(a) Rat
(b) Human
(c) Chimpanzee
(d) Camel

Ans: (d) Camel

25. A plant growing in physically dry soil is-
(a) Cactus
(b) Pea plant
(c) Mango
(d) Sundari

Ans: (a) Cactus

26. A plant having root-buttresses is-
(a) Watermelon
(b) Mango
(c) Garan
(d) Cactus

Ans: (c) Garan

27. Which of the following absorbs the gas of swim bladder of bony fishes? [Madhyamik 17]
(a) Anterior chamber
(b) Rete mirabile
(c) Gastric gland
(d) Red gland

Ans: (d) Red gland

28. The main hydrostatic organ of fish is-
(a) Lateral line sense organ
(b) Operculum
(c) Air bladder
(d) Fin

Ans: (c) Air bladder

29. This animal which has water-conserving system in the body is-
(a) Horse
(b) Cow
(c) Camel
(d) Chimpanzee

Ans: (c) Camel

30. The animal having eyelids lined by long eyelashes, is-
(a) Dog
(b) Cat
(c) Fox
(d) Camel

Ans: (d) Camel

31. The sole of foot is padded with thick soft muscle in-
(a) Donkey
(b) Horse
(c) Buffalo
(d) Camel

Ans: (d) Camel

32. The skin of the animals living in desert area is-
(a) Very thin
(b) Thin
(c) Very thick
(d) Moderately thick

Ans: (c) Very thick

33. The plant which is adapted to physiologically dry soil is-
(a) Cactus
(b) Lotus
(c) Pine
(d) Sundari

Ans: (d) Sundari

34. Decide for which of the following purpose bees demonstrate waggle dance- [Madhyamik 20]
(a) Inform other worker bees about the direction and the distance of the source of food from the bee hive
(b) Selecting place for the construction of the new bee hive
(c) Avoid attack by probable enemy
(d) Search for reproductive mates

Ans: (a) Inform other worker bees about the direction and the distance of the source of food from the bee hive

35. Which of the following takes part in waggle dance?
(a) Worker bees
(b) King bee
(c) Queen bee
(d) Drones

Ans: (a) Worker bees

36. Identify the animal who communicates information with other members of its own group through specific dancing pattern regarding the source of food. [Madhyamik 19]
(a) Chimpanzee
(b) Cockroach
(c) Peacock
(d) Honey bee

Ans: (d) Honey bee

37. The materials which are difficult for the plants to collect from physiologically dry soil, are-
(a) CO2 and water
(b) Minerals and water
(c) CO2 and minerals
(d) Water and O2

Ans: (b) Minerals and water

38. The organ that help fishes in aquatic locomotion are-
(a) Lateral line sense organ
(b) Gills
(c) Fins
(d) Venous heart

Ans: (c) Fins

39. Which of the following plants is not a halophyte?
(a) Sundari tree
(b) Geona tree
(c) Garan tree
(d) Cactus

Ans: (d) Cactus

40. Which of the following is not a flight muscle of pigeon?
(a) Pectoralis major
(b) Pectoralis minor
(c) Myotome
(d) Coracobrachialis

Ans: (c) Myotome

41. ‘Waggle’ means-
(a) Circle
(b) Wobble
(c) Angle
(d) Swim

Ans: (b) Wobble

42. Air sacks are present in-
(a) Seals
(b) Pigeons
(c) Whales
(d) Dolphins

Ans: (b) Pigeons

43. Myotome muscles are present in-
(a) Snake
(b) Pigeon
(c) Human
(d) Fish

Ans: (d) Fish

44. The animal having nucleus in RBC is-
(a) Man
(b) Mice
(c) Camel
(d) Bird

Ans: (d) Bird

45. In fish, the organ that helps it to move in different depths of water is-
(a) Fins
(b) Air bladder
(c) Tail
(d) Scales

Ans: (b) Air bladder

46. The stem of cactus is called –
(a) Rhizome
(b) Underground stem
(c) Phyllode
(d) Phylloclade

Ans: (d) Phylloclade

47. The plants growing in desert are known as-
(a) Xerophytes
(b) Hydrophytes
(c) Mesophytes
(d) Epiphytes

Ans: (a) Xerophytes

48. An example of morphological adaptation is-
(a) Air sacks of pigeon
(b) Hibernation in frog
(c) Camel reserve fat in hump
(d) Production of sweat to cool the body

Ans: (a) Air sacks of pigeon

49. A physiological adaptation is-
(a) Air sacks of pigeon
(b) Pneumatophore of Sundari tree
(c) Thorn of cactus
(d) Air bladder of rohu fish

Ans: (a) Air sacks of pigeon

50. Which of the following helps an animal to survive and reproduce?
(a) Evolution
(b) Behaviour
(c) Migration
(d) Reproduction

Ans: (d) Reproduction

2. Very short-type questions and answers

2A. Fill in the blanks

1. Adaption that occurs due to living in new habitat is called ___________ adaption. (Secondary)
2. Adaption that occurs due to living in old habitat is called ____________ adaption. (Primary)
3. Adaption is the cause of ____________. (Evolution)
4. To experience less resistance during swimming the body of fishes become ____________ shaped. (Streamlined)
5. The V shaped muscles of fishes are known as ____________ muscles. (Myotome)
6. __________ ___________ is known as hydrostatic organ of fishes. (Air bladder)
7. Rohu is an ___________ animal. (Aquatic)
8. Gills are an adaptive character of _________________ animal. (Aquatic)
9. Modification of ____________ limbs from wings. (Forelimbs)
10. Presence of feathers is the characteristic adaptive feature of __________. (Birds)
11. The respiratory organ of bird are provided with ___________ ____________. (Air sacs)
12. As lotus lives in water, thus it is ____________. (Hydrophyte)
13. Transpiration rate of lotus is _____________. (High)
14. Large number of air cavities are present in _________ of the lotus. (Stem)
15. As major part of lotus plant remains submerged the transpiration rate is ____________. (Low)
16. Cactus belong to _______ because they grow in ________ habitat. (Xerophytes, dry)
17. In Opuntia the stem becomes flat, fleshy green and is called ____________. (Phylloclade)
18. Leaves of Opuntia is modified into ______________. (Spines)
19. Leaves are modified into spines to check ______________. (Transpiration)
20. Stomata in the leaf of cactus is present in _____________ epideris. (Lower)
21. Sundari plant generally grows in ____________ soil. (Saline)
22. Sundari plant is ______________ because it grows in saline soil. (Halophyte)
23. Example of a mangrove species is __________. (Sundari)
24. Which one is the adaptive feature of Opuntia ____________. (Phylloclade)
25. In Sundari leaves stomata are restricted to the __________ epidermis. (Lower)
26. Vegetation in a saline habitat is called ______________ vegetation. (Halophytic)
27. Which feature is not present in Heritiera _____________. (Spines)
28. Halophytic adaptation is found in ____________. (Sundari)
29. Phylloclade is the modification of ____________. (Stem)
30. Gills are an adaptative character of ___________. (Aquatic animals)
31. Fish can swim at different levels in water with the help of _______________. (Air bladder)
32. Lung is provided with __________ in pigeon. (Air sacs)
33. The leaves of cactus are modified into ___________. (Spines)
34. While flying __________ shaped body of pigeon facilities it to overcome aerial resistance. (Streamlined)
35. The V shaped ________ muscles at two lateral sites of the body help fishes in swimming. (Myotome)
36. The air bladder of rohu fish is an example of ___________ adaptation. (Physiological)
37. While flying the ___________ of pigeon help to supply extra energy. (Air sacs)
38. Excessive saline soil of coastal area is called __________ dry soil. (Physiologically)
39. Bee dance is performed only by the __________ bees. (Worker)
40. The ___________ of Sundari trees help it in absorbing atmospheric oxygen for respiration. (Pneumatophores)
41. The red blood cells of camel can expand up to _______ times of their normal size. (240)
42. Sundari is a perennial ___________. (Tree)
43. cactus grow in desert land, therefore these are called _________ plants. (Xerophytic)
44. The body cells of ________ contain mucilage, hence these plants are capable of conserving excess water. (Xerophytes)
45. The animals which inhabit in aquatic environment since their origin are called ___________ aquatic animals. (Primary)

2B. True or false

1. Air bladder of fish helps it in respiration. (False)
2. Pigeon has 13 air sacs associated with the lungs. (False)
3. It source of food is 100 meters away, honeybees perform circular dance. (True)
4. Xerophytic adaptation is seen in pigeons. (False)
5. Pneumatophores are seen in Sundari trees. (True)
6. Flying squirrel is a primary volant animal. (False)
7. Rohu fish is a primary aquatic animal. (True)
8. Air bladder of fish helps it in respiration. (False)
9. The leaf of cactus is modified into spine for the reduction of the rate of transpiration. [Madhyamik 20] (True)
10. The shape of the course of ‘waggle dance’ movement of honeybees is like English numerical ‘B’. (False)
11. The RBCs of camel are small and oval in shape. (True)
12. Rete mirabile is present in air bladder of fish. (True)

2C. Match the following

Left columnRight column
1. Modification of leaves into spinesA. Adaptation of sundari tree
2. Presence of air sacsB. Adaptation of camel
3. Small over RBCC. Adaptation of honey bees
4. Dance to indicate the direction of source of foodD. Adaptation of cactus
5. Presence of pneumatophoresE. Adaptation of pigeon
6. Use of medical plantsE. Adaptation of garan
F. Adaptation of chimpanzee

Ans:

Left columnRight column
1. Modification of leaves into spinesD. Adaptation of cactus
2. Presence of air sacsE. Adaptation of pigeon
3. Small oval RBCB. Adaptation of camel
4. Dance to indicate the direction of source of foodC. Adaptation of honey bees
5. Presence of pneumatophoresA. Adaptation of sundari tree
6. Use of medicinal plantsF. Adaptation of chimpanzee

2D. Single word questions and answers

1. Mention one example each from aquatic plant and aquatic animal.
Ans: An aquatic plant is Lotus, which grows and lives in water. An aquatic animal is Fish, which lives in water and breathes through gills.

2. Name an animal with primary aquatic adaptation and mention one of its adaptive features.
Ans: Fish has primary aquatic adaptation. One adaptive feature is the presence of gills for breathing in water.

3. Name an animal with secondary aquatic adaptation and mention one adaptive feature.
Ans: Whale has secondary aquatic adaptation. One adaptive feature is its streamlined body which helps in swimming.

4. What is locomotary organ of fish?
Ans: Fins are the locomotory organs of fish.

5. Name a fish which does not contain swim bladder?
Ans: Shark does not contain a swim bladder.

6. Name two fishes in which additional breathing organ is present.
Ans: Anabas and Clarias have additional breathing organs.

7. Name the organ of flight in bird.
Ans: Wings are the organs of flight in birds.

8. Mention the number of air sacs present in pigeon.
Ans: A pigeon has nine air sacs.

9. What is the name of wing feathers?
Ans: Wing feathers are called remiges.

10. What are rectrices?
Ans: Rectrices are tail feathers of birds. They help the bird to change direction and keep balance during flight.

11. Why lotus leaves have waxy covering?
Ans: Lotus leaves have a waxy covering to prevent water from sticking to the leaf and to protect the leaf from rotting in water.

12. What are xerophytes?
Ans: Xerophytes are plants that grow in dry and desert regions.

13. What is it called when the stem is modified to function as leaf?
Ans: When the stem is modified to function like a leaf, it is called a phylloclade.

14. Why the leaves of cactus are modified into spine?
Ans: The leaves of cactus are modified into spines to reduce loss of water by transpiration.

15. Why is the epidermis of phanimanasa covered with thick cuticle?
Ans: The thick cuticle prevents excess loss of water.

16. Why is the stem of phanimanasa flat and green?
Ans: The stem is flat and green to perform photosynthesis.

17. What is phylloclade? Give an example.
Ans: Phylloclade is a flattened green stem which performs photosynthesis. Example: Opuntia

18. What kind of structure are the spines of cactus?
Ans: The spines of cactus are modified leaves.

19. What are halophytes?
Ans: Halophytes are plants that grow in saline soil containing excess salt.

20. Name the vegetation found in the soil which contains excess salt in water.
Ans: Mangrove vegetation is found in soil containing excess salt in water.

21. To which group of plants does cactus belong?
Ans: Cactus belongs to the group of plants called xerophytes.

22. Why do the leaves of cactus modify into spines?
Ans: The leaves of cactus are modified into spines to reduce the rate of transpiration and prevent loss of water.

23. Mention one morphological adaptation of cactus to prevent transpiration. [Madhyamik 17]
Ans: The leaves are modified into spines, which helps to prevent transpiration.

24. In which plant do you find phylloclade?
Ans: Phylloclade is found in Opuntia (cactus).

25. The leaves of cactus modify into spines. In that case which organ helps it in photosynthesis?
Ans: In cactus, the green stem helps in photosynthesis.

26. Which part of cactus grows elaborately to absorb water?
Ans: The root system of cactus grows elaborately to absorb water.

27. What do you call the changes that occur in organisms to adjust themselves to the changing environment?
Ans: The changes that occur in organisms to adjust themselves to the changing environment are called adaptations.

28. What do you call the adaptation that occurs in organisms to adapt themselves in the environment of their origin?
Ans: This type of adaptation is called primary adaptation.

29. What do you call the adaptation that occurs in organisms to adapt themselves in the environment other than their site of origin?
Ans: This type of adaptation is called secondary adaptation.

30. What do you call the two separate types of adaptations that occur in organisms living in two different environment?
Ans: This type of adaptation is called double adaptation.

31. Who carried out extensive research on honeybees to find out their language?
Ans: Karl Von Frisch carried out extensive research on the language of honeybees.

32. Name a desert mammal.
Ans: Camel is a desert mammal.

33. Which animals use thin sticks to collect termites from termite mounds?
Ans: Chimpanzees use thin sticks to collect termites from termite mounds.

34. Which chemical plays an important role in controlling the behaviour of honeybees?
Ans: Pheromone plays an important role in controlling the behaviour of honeybees.

35. Which animal can absorb water with its skin?
Ans: Frog can absorb water through its skin.

36. How many paired and unpaired air sacs are present in pigeon?
Ans: In pigeon, there are four pairs and one unpaired air sac.

37. Name an animal with secondary volant adaptation.
Ans: Flying squirrel shows secondary volant adaptation.

38. Name an animal with primary volant adaptation.
Ans: pigeon shows primary volant adaptation.

39. Which fin of a fish helps to change its direction?
Ans: The pectoral fins help the fish to change its direction.

40. Name an animal with secondary aquatic adaptation.
Ans: Whale is an animal with secondary aquatic adaptation.

41. Name an animal with primary aquatic adaptation.
Ans: Rohu fish is an animal with primary aquatic adaptation.

42. Name two plants with pneumatophores.
Ans: Sundari and Garan plants have pneumatophores.

43. Mention one adaptation feature of Sundari plants?
Ans: Sundari plants have pneumatophores, which help in respiration.

44. How many air sacs are associated with the lungs of pigeon?
Ans: Nine air sacs are associated with the lungs of pigeon.

45. In which year did Karl Von Frisch receive the Nobel Prize for discovering the language of bee dance?
Ans: Karl Von Frisch received the Nobel Prize in 1973.

46. Name a plant with stilt roots.
Ans: Maize is a plant with stilt roots.

47. What is phylloclade?
Ans: Phylloclade is a modified stem which becomes green and performs photosynthesis.

48. Which portion of air bladder produces gas?
Ans: The red gland of the air bladder produces gas.

49. What is pneumathode?
Ans: Pneumatophores are special breathing roots found in mangrove plants.

50. Which animal discharges concentrated urine to conserve body fluid?
Ans: Camel discharges concentrated urine to conserve body fluid.

3. Short-type questions and answers

1. What is adaption?
Ans: Adaptation is the special structural, physiological or behavioural change by which an organism becomes fit to survive in its environment.

2. What is primary adaption?
Ans: Primary adaptation is the adaptation of an organism to the environment in which it originally lives and completes its life activities.

3. What is secondary adaption?
Ans: Secondary adaptation is the adaptation developed by an organism to live in an environment different from its original habitat.

4. What is the aim of adaption?
Ans: The aim of adaptation is to help an organism survive, grow and reproduce successfully in its environment.

5. What is double adaption? Give a suitable example.
Ans: Double adaptation is the adaptation of an organism to live in two different environments.
Example: Frog, which lives both on land and in water.

6. What is convergent adaption?
Ans: Convergent adaptation is the development of similar adaptive features in different organisms living in similar environments.

7. What is divergent adaption?
Ans: Divergent adaptation is the development of different adaptive features in organisms having a common origin but living in different environments.

8. Which fish does not possess air bladder?
Ans: Shark does not possess an air bladder.

9. What do you mean by hydrostatic organs?
Ans: Hydrostatic organs are special structures which help aquatic animals to maintain buoyancy and body balance in water, for example the air bladder of fishes.

10. How many air sacs are present in pigeon?
Ans: Nine air sacs are present in pigeon.

11. What are xerophytes?
Ans: Xerophytes are plants that grow in dry or desert areas and show special features to prevent loss of water.

12. What are halophytes?
Ans: Halophytes are plants which grow in saline soil containing a large amount of salt.

13. What are mesophytes?
Ans: Mesophytes are plants which grow in ordinary soil where water is available in adequate amount.

14. What are the xerophytic organisms?
Ans: Xerophytic organisms are plants and animals which live in dry regions and show special features to save water.

15. What is phylloclade?
Ans: Phylloclade is a modified stem which becomes flat, green and leaf-like to perform photosynthesis.

16. What are the modifications that take place in the opuntia stem to check transpiration?
Ans: The stem of Opuntia becomes flat and green, is covered with thick cuticle, and bears sunken stomata to reduce transpiration.

17. Why is the stem of Opuntia flat?
Ans: The stem of Opuntia is flat to carry out photosynthesis, because its leaves are changed into spines.

18. What is the utility of transformation of leaves of phylloclade into spiny structure?
Ans: The spiny leaves reduce loss of water by transpiration and protect the plant from grazing animals.

19. In which plant is phylloclade seen?
Ans: Phylloclade is seen in Opuntia.

20. What do you know about mangrove vegetation and mangrove plants?
Ans: Mangrove vegetation is found in saline and marshy coastal areas. Mangrove plants have special breathing roots called pneumatophores, which help them to take in oxygen from air.

21. What is physiologically dry soil?
Ans: Physiologically dry soil is soil where water is present but plants cannot absorb it due to excess salt.

22. What are the differences between primary and secondary adaption?
Ans:

Primary adaptationSecondary adaptation
It develops in the original habitat of an organism.It develops when an organism lives in a new habitat.
Present from the early stage of life of the organism.Develops later due to change of habitat.
Example: Fish showing aquatic features.Example: Whale showing aquatic features.

23. What are the purposes of adaption?
Ans: Adaptation helps organisms to survive, obtain food, protect themselves and reproduce in their environment.

24. What is volant animal and volant adaption?
Ans: Volant animals are animals which have the ability to fly, like birds. Volant adaptation refers to the special features like wings, strong flight muscles and hollow bones, which help animals in flying.

25. What are air sacs?
Ans: Air sacs are thin-walled, air-filled structures connected with the lungs of birds. They help in continuous respiration and also reduce body weight during flight.

26. What are xerophytes? write two adaptive features.
Ans: Xerophytes are plants which grow in dry or desert areas.
Two adaptive features of xerophytes are:

  • Presence of a thick cuticle to reduce loss of water.
  • Leaves modified into spines to check transpiration.

27. What are hydrophytes? Give two examples of hydrophytes?
Ans: Hydrophytes are plants which grow and live in water. Examples of hydrophytes are Lotus and Hydrilla.

28. What type of plant is cactus? Mention the name of three xerophytic plants?
Ans: Cactus is a xerophytic plant because it grows in dry regions. Three examples of xerophytic plants are Cactus, Opuntia and Aloe.

29. What are the physiological adaptive modifications of cactus?
Ans: Cactus shows several physiological adaptations to survive in dry conditions. It shows very low transpiration, stores large amount of water in its body, and performs special type of photosynthesis which helps to reduce water loss.

30. Why the leaves of cactus are modified into spine?
Ans: The leaves of cactus are modified into spines to reduce loss of water by transpiration and also to protect the plant from grazing animals.

31. What is phylloclade?
Ans: Phylloclade is a modified green stem that performs the function of photosynthesis.

32. What are halophytes? Give two examples.
Ans: Halophytes are plants which grow in saline soil containing excess salt. Examples of halophytes are Mangrove and Rhizophora.

33. What do you mean by physiologically dry soil?
Ans: Physiologically dry soil is soil which contains water, but plants cannot absorb the water due to presence of excess salt.

34. What are pneumatophores? Where is it found?
Ans: Pneumatophores are special breathing roots which grow upward from the soil and help the plant to take in oxygen from air. They are found in mangrove plants.

35. Name a plant, which is adapted to grow in physiologically dry soil and mention two adaptive features.
Ans: Mangrove plant is adapted to grow in physiologically dry soil.
Two adaptive features are:

  • Presence of pneumatophores for respiration.
  • Ability to remove excess salt from the plant body.

36. What is acclimatisation?
Ans: Acclimatisation is the temporary adjustment of an organism to changes in temperature, humidity or altitude. These changes are not inherited by the next generation.

37. What is ethology?
Ans: Ethology is the branch of biology which studies animal behaviour under natural conditions.

38. Distinguish between adaptation and evolution.
Ans:

AdaptationEvolution
It is a short-term change that helps an organism to survive in a particular environment.It is a long-term gradual change that occurs over many generations.
It occurs in individual organisms or a species.It occurs in a population over a long period of time.
It mainly helps in survival of organisms.It may lead to the formation of new species.

39. “Adaptation is the change of shape, physiological functions and behaviour of organism” – justify with two examples. [Madhyamik 20]
Ans: Adaptation includes changes in body structure, physiological function and behaviour.

  1. Change in shape: The body of fish is streamlined, which helps it to move easily in water.
  2. Physiological change: Camel produces concentrated urine, which helps to conserve water in desert conditions.

40. What is the relation between behaviour and evolution?
Ans:

BehaviourEvolution
Behaviour helps organisms to survive in their environment.Evolution is the gradual change of organisms over generations.
Useful behaviours help organisms to find food and avoid danger.Such useful behaviours are selected by nature.
Helpful behaviours are passed on to the next generation.Over time, this leads to evolution of the species.

41. What are the primary aquatic animals?
Ans: Animals which have lived in water from their origin are called primary aquatic animals.

42. Which plants are called xerophytes?
Ans: Plants that grow in dry or desert areas and show special adaptations to prevent water loss are called xerophytes, for example cactus.

43. Who are called secondary aquatic animals?
Ans: Animals that originally lived on land but later adapted to live in water are called secondary aquatic animals, such as whale and dolphin.

44. Describe any two adaptations in Sundari plant for tolerance of salt. [Madhyamik 19]
Ans: Sundari plant shows the following salt-tolerant adaptations:

  1. Salt excretion: Excess salt is removed from the plant body through special glands.
  2. Thick leaves: Thick and leathery leaves reduce water loss and help in salt tolerance.

45. What are the two adaptive significance of air sacs of pigeon? [Madhyamik 18]
Ans:

  1. Air sacs supply extra oxygen during flight.
  2. They reduce the body weight, making flight easier.

46. What are the roles of swim bladder in the aquatic adaptation of rohu fish? [Madhyamik 18]
Ans:

  1. Swim bladder helps the fish to float at different depths of water.
  2. It maintains balance and buoyancy of the fish.

47. Who are called primary volant animals?
Ans: Animals which have the natural ability to fly and whose forelimbs are modified into wings are called primary volant animals, such as birds.

48. Define physiological adaptation and give example.
Ans: Physiological adaptation refers to changes in the internal body functions that help an organism to survive. Example: Camel produces concentrated urine to conserve water.

49. Why is Sundari tree called the “looking glass tree”?
Ans: Sundari tree is called the looking glass tree because the lower surface of its leaves is shiny, reflecting light like a mirror.

50. Mention two adaptive features of camel.
Ans:

  • Camel passes concentrated urine, helping it to conserve water.
  • Camel has a hump which stores fat for use during scarcity of food and water.

4. Long-type questions and answers

1. What is adaption? What are the relation between adaption and evolution?
Ans: Adaptation is the special structural, physiological or behavioural change by which an organism becomes fit to survive in a particular environment.

AdaptationEvolution
Adaptations help organisms to survive in a changing environment.Evolution is the gradual change in organisms over many generations.
Useful adaptations are passed on from one generation to the next.Such inherited adaptations accumulate over time.
Adaptations begin as small changes.Accumulation of these changes leads to new forms or species.
Adaptation acts as a driving force.Evolution is the final result of long-term adaptations.

2. What do you mean by primary and secondary adaptions? What is the aim of adaption?
Ans: Primary adaptation is the adaptation of an organism to the environment in which it originally lives and completes its life activities. Example: Fish living in water.
Secondary adaptation is the adaptation developed by an organism to live in an environment different from its original habitat. Example: Whale, which is aquatic but belongs to land mammals.

Aim of adaptation:

  • To help organisms survive in their environment
  • To obtain food and shelter
  • To protect from enemies
  • To reproduce successfully
  • To maintain continuity of species

3. What is a volant animal? How many types of volant animals are there and what are these? Describe any three adaptive features of pigeon related to flight.
Ans: Volant animals are animals which have the ability to fly. There are two types of volant animals. The first type is primary volant animals, such as birds (pigeon), which can fly naturally. The second type is secondary volant animals, such as bats, which have acquired the power of flight.

Pigeon shows several adaptations related to flight. The forelimbs are modified into wings, which help in flying. The body of pigeon is light in weight because the bones are hollow and filled with air. The presence of air sacs helps in respiration and also reduces body weight, making flight easier.

4. Mention the role of wings and air sacs in the flight of birds.
Ans:

Role of WingsRole of Air Sacs
Wings are modified forelimbs of birds.Air sacs are thin-walled air-filled sacs connected with the lungs.
Wings help in lifting the body upward during flight.Air sacs help in continuous supply of oxygen.
They push air backward and downward to move the bird forward.They take part in double respiration in birds.
Wings help in changing direction while flying.Air sacs help in reducing body weight of birds.
Wings help in maintaining balance in air.They help in maintaining body balance during flight.
Wings help in landing safely on the ground or branches.Air sacs help in regulating body temperature during flight.

5. What is adaption? What are the adaptions ovserved in cactus?
Ans: Adaptation is the special change in structure, function or behaviour by which an organism becomes fit to live in its environment. Cactus is a xerophytic plant and shows several adaptations to live in dry desert conditions. The leaves are modified into spines, which reduce loss of water by transpiration. The stem is flat, green and fleshy, and it performs photosynthesis in the absence of leaves. The stem is covered with a thick cuticle, which prevents water loss. Stomata are sunken, which further reduces transpiration. The fleshy stem also stores water for use during long dry periods.

6. Why xerophytic adaptions are found in hydrophytes?
Ans: Xerophytic adaptations are found in some hydrophytes because their floating leaves remain exposed to air and sunlight. As a result, water is lost from the upper surface of the leaves by evaporation, to prevent excessive loss of water, the leaves develop a waxy coating. Stomata are present only on the upper surface of the leaves to control transpiration. Thus, xerophytic adaptations help hydrophytes to survive in such conditions.

7. What is Sundari plant? Mention why the adaptations of Sundari plant are a mixture of xerophytes and terrestrial plants. Discuss the adaptive characters of Sundari plant.
Ans: Sundari plant is a mangrove plant found in saline and marshy coastal areas, especially in river deltas. The adaptations of Sundari plant are a mixture of xerophytic and terrestrial adaptations because it grows in saline soil containing excess water and salt. Although water is present in plenty, it cannot be absorbed easily due to the presence of salt. The plant behaves as if it is growing in dry soil. Sundari plant shows several adaptive characters. It has pneumatophores, which help in respiration by absorbing oxygen from air. The leaves have a thick cuticle, which reduces loss of water. The plant can remove excess salt from its body. The strong root system helps the plant to remain fixed in soft muddy soil. The leaves are leathery, which helps to reduce transpiration.

8. what is the importance of air sacks in pigeons? Write down the role of air bladder in rohu fish in maintaining body balance in winter. [Madhyamik 20]
Ans: Importance of air sacs in pigeons

  1. Air sacs are thin-walled air-filled sacs connected with the lungs of pigeons.
  2. Air sacs supply extra oxygen during flight.
  3. They make the body light in weight, which helps in flying.
  4. They help in continuous respiration.
  5. They help in regulating body temperature during flight.

Role of air bladder in rohu fish during winter

  • The air bladder is a hydrostatic organ of rohu fish.
  • This helps the fish to maintain body balance and remain at a suitable depth without much effort.
  • In winter, rohu fish goes to deeper water where temperature is suitable.
  • The air bladder regulates the amount of gas inside it.

9. Mention the physlogical adaption of camel. [Madhyamik 18]
Ans: Camel shows several physiological adaptations to live in desert conditions.

  1. Camel passes highly concentrated urine, which reduces loss of water.
  2. It produces very dry faeces, helping in water conservation.
  3. Camel can tolerate a large rise in body temperature, reducing sweating.
  4. The red blood cells of camel are oval in shape and can expand, helping it to survive dehydration.
  5. These physiological adaptations help camel to survive in hot and dry deserts.

10. Describe the diagram how honeybees pass massage to the members of the hive about the source of food. [Madhyamik 17]
Ans: Honeybees communicate information about the source of food by performing special dances inside the hive. This behaviour was discovered by Karl Von Frisch.

Types of dance

  1. Round dance
    • Performed when the food source is near the hive (within about 100 m).
    • It tells other bees that food is nearby.
  2. Waggle dance
    • Performed when the food source is far away.
    • The dance is figure-of-eight (8-shaped).
    • It gives information about the direction and distance of the food source.

Thus, by dancing, honeybees pass messages to other worker bees about food.

11.Give example of ways chimpanzees solve their problems intelligently for procuring food and preventing disease. [Madhyamik 18]
or, Explain how do the chimpanzee hunt termites for food. [Madhyamik 19]
or, How chimpanzee break open the hard shells for eating the nuts? [Madhyamik 20]
Ans: Chimpanzees show intelligent behaviour while collecting food and protecting themselves.

  1. Hunting termites: Chimpanzees use thin sticks or grass stems and insert them into termite mounds. Termites stick to the tool, which the chimpanzee then eats.
  2. Breaking hard nuts: Chimpanzees use stones as hammer and anvil to break open hard shells of nuts.
  3. Preventing disease: Chimpanzees eat certain medicinal leaves to kill intestinal worms and remain healthy.

These examples prove that chimpanzees have intelligent problem-solving ability.

Related Links

WB 10 all notes