ORGANISMS AND POPULATIONS
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)