ORGANISMS & POPULATION: ASSIGNMENT

CLASS-XII

ASSIGNMENT

ORGANISMS & POPULATION

 

Q.(1)    Name the interaction in each of the following:

            (a)  Ascaris worms living in the intestine of humans.

            (b)  Sucker fish lives attached to the shark.

            (c)  Wasp pollinating fig inflorescence.

            (d)  Ticks live on the skin of dogs.

 

Q.(2)   (a)  Explain giving reasons why the tourist visiting Rohtang pass or Mansarovar are advised to resume normal ‘active life’ only after a few days of reaching there.

           (b)  It is impossible to find small animals in the polar region. Give reasons.

 

Q.(3)   If marine fish is placed in a fresh water aquarium, will the fish be able to survive? Why or why not?

           Ans.:- A marine fish kept in fresh water will not be able to survive for long because

1.  Water will enter its body due to endosmosis.
2. It has water drinking habit that causes excess water to enter the body.
3. It does not have salt absorbing mechanism of fresh water fishes.
                                     
   Exception: Migratory fish are exception to the above. They have hormone controlled mechanisms to connect them from salt recreating and water drinking marine form to non drinking and salt absorbing fresh water forms. Eg. Hilsa, salmon.
    
   Q.(4)   Most living organisms cannot survive at Temperature above 4 How are some `                microbes able to live in habitats with temperatures exceeding 10c.
    
   Q.(5)   Distinguish between the following:
               (a)  Hibernation and Aestivation
               (b)  Ectotherms  and Endotherms.
    
   Q.(6)   Define   (a)  Population  (b) Community  (c) Mutualism (d) Camouflage
                (e) Commensalism.
    
   Q.(7)   List any three characteristics of a population.
    
   Q.(8)   Explain brood parasitism with the help of an example.
    
   Q.(9) Why is Rhizobium categorised as a symbiotic bacterium’? How does it act
                as biofertilizer?
    
   Q.(10)  Define phenotypic adaptation. Give an example.
    
   Q.(11)  Why are coral reefs not found in the regions of west Bengal to Andra 
                  Predesh but are found in Tamil Nadu on the east coast of India.
    
   Q.(12)  Define zero population Growth.  Draw an age pyramid for the same.
    
   Q.(13)  Explain age pyramids of human population.
    
   Q.(14)  The predators help to maintain species diversity. Explain with the help of
                 an example.
    
   Q.(15)  How Prickly Pear Cactus when introduced in Australia created havoc?
                 How the havoc was combat?
    
   Q.(16)  Distinguish between
                  (a)  Camonflage and Mimicry
                  (b)  Mimicry and Acclimatisation.
    
    
   sQ.(17)  Give reasons:
                   (a) Mango trees cannot grow in temperate countries.
                   (b)  Agnathic organisms face water related problems.