ORGANISMS AND POPULATIONS
2010 MARCH
1. Given below is a table which shows the
interspecific interaction. ‘+’ sign indicates beneficial, ‘-‘ sign indicates
detrimental and ‘0’ indicates neutral.
a. Fill in the blanks.
|
Species
A
|
Species
B
|
Interaction
|
|
-
|
-
|
Competition
|
|
0
|
-
|
……………………
|
|
+
|
0
|
……………………
|
b.
Name the
interactions where one species is benefited and the other is detrimental (2)
2. Given below a schematic representation
with circles and squares which shows four factors/processes influence the
population density.
a. Write the positive factors in circles and
negative factors in squares. (2)
2010 SAY
1. Snakes change their body temperature with
changes in external temperature, but human beings not. Organisms may be classed
according to above character with explanation. (2)
2. Density of a population in a given
habitat during a given period fluctuates due to changes in 4 basic processes-
Natality, Mortality, Immigration & Emigration.
a. Differentiate Natality and Mortality.
b. Differentiate Immigration &
Emigration. (2)
3. Two students, Unni and Kannan studied
inter-specific interactions between different species. They made a table
assigning a ‘+’ for beneficial interaction, ‘-‘ for detrimental and ‘0’ for
neutral interaction. Can you help them by naming the interaction between
species in different cases? Write one example for each interaction.
|
Case
number
|
Species
A
|
Species
B
|
|
1
|
+
|
+
|
|
2
|
-
|
-
|
|
3
|
+
|
-
|
|
4
|
+
|
0
|
2011 MARCH
1.
Given above is the bar diagram showing
age structure of three different populations. Observe the diagram carefully and
answer the following questions.
a. Select the stable population.
b. Compare the nature of population growth
in A, B and C. (3½)
2011 SAY
1. Population interactions:
|
Case
|
Species x
|
Species y
|
Species z
|
|
1
|
+
|
+
|
0
|
|
2
|
0
|
-
|
+
|
|
3
|
-
|
+
|
-
|
Where ‘+’ beneficial interaction
‘-‘ detrimental interaction
‘0’ neutral interaction
Observe
the interactions of populations of 3 species as shown in the table. Name the
interactions between: (3)
a. Species x and species y in case 1
b. Species y and species z in case 2
c. Species x and species z in case 3
d. Species y and species z in case 1
2. Mohammed and his family left to Dubai
from Kozhikode on March, 2009. In Kozhikode they are referred as …………. After
2009. How it affects Kozhikode population? (1)
2012 MARCH
1. Interspecific
interaction arises from the interaction of populations of two different
species. If we assign + for beneficial, - for detrimental and 0 for neutral
interactions, copy and complete the following chart.
2012 SAY
1.
Students
involved in nature club activity found some inter-specific interactions between
organisms in a garden area. They made a table of interaction giving ‘+’ for
beneficial interaction, ‘-‘ for detrimental and ‘0’ for neutral interaction. (4)
Species
A Species B
i. + +
ii. - -
iii. + 0
iv. - 0
a. Give name of interaction in each case.
b. Explain how parasitism differs from
predation.
c. Give the significance of species
interaction.