Saturday, March 9, 2019

Organisms and populations: Previous Year Questions Part 2


2013 MARCH
1.     Read the statements below and identify the mode of interaction between the species. (2)

a.     Tiger eating deer
b.     Butterfly feeding pollen
c.     Human liver fluke feed on snail
d.     Lice on humans
e.     Orchid attached to a tree
f.      Mycorrhizal association of fungi and roots of higher plants
g.     Sparrow eating seed
h.     Egrets foraging close to cattle
2.     In summer we use air conditioners and in winter we use heaters. Here homeostasis is accomplished by artificial means. Explain four ways by which other living organisms cope with the situation. (2)
2013 SAY
1.     Many desert plants have adaptations to prevent loss of water from their body. Mention any two adaptations to minimize water loss from plant body. (2)
2.     The size of a population is not static. Which of the following leads to decrease in population? (1)
        1) Natality & Mortality          2) Mortality & Emigration
        3) Mortality & Immigration 4) Natality & Immigration
3.     Some type of Orchids lives on the branches of mango trees. The relationship between mango tree and Orchid is an example of (1)
1) Mutualism                        2) Predation         
3) Commensalism               4) Parasitism
2014 MARCH
1.     The density of population in a given habitat increase or decrease due to different reasons. Name two factors responsible for increase in population in a given area. (1)
2.     Adaptations are the attributes of the organism that enables it to survive and reproduce in its habitat. Give the adaptations of
a.     Cactus plant in desert                 b.   Kangaroo rat in desert                  c.   Seals in polar region. (3)
2014 SAY
1.     Observe the diagram:
Define the following terms:       
a) Natality                      b) Mortality           
c) Emigration                 d) Immigration
2.     Response of organisms to abiotic stress involves different methods. Explain any 2 such responses with suitable examples. (2)
2015 MARCH
1.     Sucker fish and shark live in close association is a classic example of commensalism. What is commensalism? (Score: 1)
2.     Desert plants like Opuntia are able to grow in extreme conditions. Suggest any two adaptations of this plant. (Score: ½ + ½ = 1)
3.     With regard to population growth rate, when responses are limiting the plot is logistic. Verhulst - Pearl Logistic growth is represented by the equation  dN/dt=rN K-N/K what are
(a) r                 (b) K                                       (Scores: 1+ 1 = 2)
2015 SAY
1.     Observe the equation.
dN/dt=rN K-N/K
a.     Which type of growth curve does it represents?                                                                    (Score: ½)
b.     What do the following notations represent?
                              i.        N     ii.   r       iii.   K      (1½)


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