Biology Today — January 2018

SECTION - A

1. 
   

   Define standing crop and standing state.

   
   


2. 
   

   Write two different ways for the disposal of e-wastes.

   
   


3. 
   

Mammals

Y

X

Z

Reptiles

Name the labelled parts X, Y and Z in the pie chart (given
above) representing the global biodiversity of vertebrates
showing the proportionate number of species of major taxa.

4. Ecology is basically concerned with four levels of biological
   organisation. Name them.


5. In a pond, there were 40 lotus plants. If 10 lotus plants
   died in a week, reducing the current population to 30, then
   calculate the death rate of lotus population for the said
   period.
   SECTION - B


6. What type of interaction is seen between fig and wasp?

Explain.

7. Write any four measures that can control vehicular air
   pollution in cities.


8. Differentiate between in situ and ex situ conservation.
   OR
   State differences between net primary productivity and
   gross primary productivity.


9. Name the interaction in each of the following:
   (a) Calotropis producing highly poisonous chemicals
   (b) Pilot fish accompanies shark
   (c) Pluvianus enters the open mouth of crocodile
   (d) Association of Anabaena with Azolla


10. The pyramid of energy is always upright. Justify the
    statement.

SECTION - C

11. With the help of a flow chart, describe the phenomenon of
    biomagnification of DDT in an aquatic food chain.


12. David Tilman proved experimentally that stability of a
    community depends on its species richness. Explain.


13. Explain how does a primary succession start on a bare rock
    and reach a climax community.


14. Enumerate how human activities cause desertification.

GENERAL INSTRUCTIONS

(i) All questions are compulsory.

(ii) This question paper consists of five sections A, B, C, D and E. Section A contains 5 questions of one mark each, Section B contains

5 questions of two marks each, Section C contains 12 questions of three marks each, Section D contains 1 question of VBQ type with

four marks and Section E contains 3 questions of five marks each.

(iii) There is no overall choice. However, an internal choice has been provided in one question of 2 marks, one question of 3 marks and all the

three questions of 5 marks weightage. A student has to attempt only one of the alternatives in such questions.

(iv) Wherever necessary, the diagrams drawn should be neat and properly labelled.

Time Allowed : 3 hours Maximum Marks : 70

UNIT - V

• Organisms and Populations


• Ecosystem


• Biodiversity and Conservation


• Environmental Issues