Q23 of 50 Page 1

(i) What is primary productivity? Why does it vary in different types of eco-systems?

(ii) State the relation between gross and net primary productivity.


(i) Primary productivity is the amount of biomass which is the organic matter produced by the plants in a fixed time. Primary productivity depends on various factors such as:


1) Amount of light, water, temperature and water etc.


2) It depends upon the availability of nutrients.


3) The type of ecosystem.


4) The type of environment.


ii) The relation between gross and net primary productivity is:


Net primary productivity (Pn) = Gross primary productivity (Pg) - Respiration (R)


Hence,


Pn = Pg - R


More from this chapter

All 50 →
20

A cross between a normal couple resulted in a son who was haemophilic and a normal daughter. In course of time, when the daughter was married to a normal man, to their surprise, the grandson was also haemophilic.

(a) Represent this cross in the form of a pedigree chart. Give the genotypes of the daughter and her husband.


(b) Write the conclusion you draw of the inheritance pattern of this disease.


 22

Draw a labelled diagram of the sectional view of a human seminiferous tubule (six parts to be labelled)

 30

Explain the ovarian and uterine events that occur during a menstrual cycle in a human female, under the influence of Pituitary and Ovarian hormones respectively.
OR

(a) Why does endosperm development precede embryo development in angiosperm seeds? State the role of endosperm in mature albuminous seeds.


(b) Describe with the help of three labelled diagrams the different embryonic stages that include mature embryo of dicot plants.


 3

How is repetitive / satellite DNA separated from bulk genomic DNA for various genetic experiments?