Ecosystems, Populations and Biogeography - Ecology - Life Sciences Previous Year Questions

1

2007 · Life Sciences · Ecology · Ecosystems, Populations and Biogeography

Life Sciences (XL) 2007

Availability of free energy is maximum in which of the following trophic levels?

A

Producers

B

Decomposers

C

Herbivores

D

Secondary consumers

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2

2007 · Life Sciences · Ecology · Ecosystems, Populations and Biogeography

Life Sciences (XL) 2007

Which of the following statements are true on ecological point of view?
P   ‘Pyramid of numbers’ can sometimes be inverted
Q   Standing crop is not a reliable measure of productivity
R   Primary productivity should always be calculated on dry matter rather than on fresh biomass
S   The total solar energy trapped in the food material by photosynthesis is referred to as net primary production

A

P, Q

B

Q, R

C

R, S

D

P, R

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3

2008 · Life Sciences · Ecology · Ecosystems, Populations and Biogeography

Life Sciences (XL) 2008

Identify the correct statements P The second law of thermodynamics is also known as the law of conservation of energy Q 'Entropy' is a measure of the available energy resulting from transformations R The transfer of energy through the food chain of an ecosystem is termed as 'energy flow' S The second law of thermodynamics deals with the transfer of energy towards more available state

A

P, Q

B

P, R

C

Q, R

D

Q, S

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4

2009 · Life Sciences · Ecology · Ecosystems, Populations and Biogeography

Life Sciences (XL) 2009

Phagotrophs are

A

Organisms that feed on dead organic matter

B

Organisms that absorb dissolved organic matter

C

Organisms that ingest other organisms or particulate organic matter

D

Organisms that manufacture food from simple inorganic substances

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5

2009 · Life Sciences · Ecology · Ecosystems, Populations and Biogeography

Life Sciences (XL) 2009

Which of the following statements does NOT describe the characteristics of human population in industrialized countries ?

A

Relatively small family size

B

Relatively even age structure

C

Rapid reproduction rate

D

Delayed reproduction

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6

2010 · Life Sciences · Ecology · Ecosystems, Populations and Biogeography

Life Sciences (XL) 2010

A population growing exponentially can be described by the differential equation \( dN/dt = rN \), where \( dN/dt \) represents the rate at which the whole population grows, \( N \) is the size of the population, \( r \) is the intrinsic rate of increase, and \( t \) is time. According to this equation, the per capita rate of growth is

A

Highest at large \(N \)

B

Constant

C

Lowest at large \(N \)

D

Highest at small \(N \)

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7

2010 · Life Sciences · Ecology · Ecosystems, Populations and Biogeography

Life Sciences (XL) 2010

The amount of chemical energy available to consumers in an ecosystem is best represented by

A

Gross primary production

B

Net primary production

C

Respiration

D

Photosynthesis

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8

2010 · Life Sciences · Ecology · Ecosystems, Populations and Biogeography

Life Sciences (XL) 2010

Regarding the relationships between two organisms in an ecosystem, match the following

Group I (Relationship)	Group II (Definition)
P. Commensalism	1. Both organisms are benefited
Q. Mutualism	2. One impeding the success of the other
R. Parasitism	3. One organism benefits but the other is unaffected
S. Amensalism	4. One beneficial, other is harmed

A

P-1, Q-2, R-3, S-4

B

P-2, Q-3, R-4, S-1

C

P-3, Q-1, R-4, S-2

D

P-1, Q-4, R-3, S-2

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9

2010 · Life Sciences · Ecology · Ecosystems, Populations and Biogeography

Life Sciences (XL) 2010

In the field of community ecology, the term “competitive exclusion” refers to two species that cannot co-exist

A

in a community if the niches are identical.

B

in two different communities if the niches are identical.

C

if the ecosystem is imbalanced.

D

in the event of a volcanic eruption.

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10

2011 · Life Sciences · Ecology · Ecosystems, Populations and Biogeography

Life Sciences (XL) 2011

Which of the following statements are INCORRECT on ecological point of view?
P. Primary succession involving xerosee is initiated in a wet habitat
Q. Halones commonly found in electronic equipment are one of the active force destroying the protective ozone layer in the stratosphere
R. Sympatric speciation occurs when the new species evolves in geographic isolation from the parent species
S. α-Diversity is the diversity of species within a habitat or community

A

P, Q

B

P, R

C

Q, R

D

Q, S

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11

2012 · Life Sciences · Ecology · Ecosystems, Populations and Biogeography

Life Sciences (XL) 2012

Which of the following best represents the flow of energy through an ecosystem?

A

Producers → Primary consumers → Secondary consumers

B

Sun → Producers → Secondary consumers → Primary consumers

C

Sun → Producers → Primary consumers → Secondary consumers

D

Secondary consumers → Primary consumers → Producers → Sun

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12

2012 · Life Sciences · Ecology · Ecosystems, Populations and Biogeography

Life Sciences (XL) 2012

Trees in the equatorial region of earth supply oxygen into the atmosphere that sustains species living in distant polar regions. This relationship is called as

A

mutualism

B

symbiosis

C

commensalism

D

parasitism

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13

2013 · Life Sciences · Ecology · Ecosystems, Populations and Biogeography

Life Sciences (XL) 2013

Considering environment and ecosystem, identify the INCORRECT statement

A

In detrital food chain, it is very difficult to measure the energy flow although the use of radioactive tracers give some idea about the energy flow

B

The change in species composition, community structure and function over time is ecological succession

C

The slower rise of environmental temperature may be attributed to the increase in pollution in environment which reflects enough solar energy back to other spacer to slow down global warming

D

Photoperiodism has no relation with the environment and ecosystem, rather it is a biological event taking place in every plant

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14

2013 · Life Sciences · Ecology · Ecosystems, Populations and Biogeography

Life Sciences (XL) 2013

The term “ecological succession” refers to:

A

A process wherein new species populate a region that was devoid of flora and fauna

B

A transition phase wherein one particular set of species is replaced by another set of species

C

Changes in the community due to a disturbance in the habitat

D

All the above

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15

2013 · Life Sciences · Ecology · Ecosystems, Populations and Biogeography

Life Sciences (XL) 2013

The relative number of individuals in each age group is an important demographic factor for the study of future growth trends, and this is normally depicted in the form of an age-structure pyramid. Based on your understanding on population dynamics, match the following distribution properties of age structure (Group 1) with the individual forecast given (Group 2):
Group 1
I. Uniform age distribution in the pyramid
II. Distribution skewed towards younger age groups
III. Distribution skewed towards older age groups
IV. Reduction in the number of males in the middle age group
Group 2
i. Emigration in the recent past and the possible increase in the older age groups in the near future.
ii. Likely to be a stable population
iii. Possible unemployment in the near future
iv. Increased government expenditure on medical needs and social security related issues in the near future

A

I – iii; II – ii; III – i; IV – iv

B

I – ii; II – iii; III – iv; IV – i

C

I – ii; II – i; III – ii; IV – iv

D

I – i; II – iii; III – ii; IV – iv

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16

2014 · Life Sciences · Ecology · Ecosystems, Populations and Biogeography

Life Sciences (XL) 2014

In any given year, the probability of an earthquake greater than Magnitude 6 occurring in the Garhwal Himalayas is 0.04. The average time between successive occurrences of such earthquakes is ____ years.

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17

2014 · Life Sciences · Ecology · Ecosystems, Populations and Biogeography

Life Sciences (XL) 2014

The population of a new city is 5 million and is growing at 20% annually. How many years would it take to double at this growth rate?

A

3-4 years

B

4-5 years

C

5-6 years

D

6-7 years

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18

2014 · Life Sciences · Ecology · Ecosystems, Populations and Biogeography

Life Sciences (XL) 2014

Plant which grows attached to another plant species but is not a parasitic is known as

A

Endophyte

B

Halophyte

C

Epiphyte

D

Lithophyte

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19

2015 · Life Sciences · Ecology · Ecosystems, Populations and Biogeography

Life Sciences (XL) 2015

Identify the CORRECT statements with respect to functioning of ecosystem.
P. A food chain is a series of organisms, each one feeding on the organism succeeding it
Q. Food web presents a complete picture of the feeding relationships in any given ecosystem
R. In ecosystem, energy flows in unidirectional way, whereas nutrients flow in cyclic fashion
S. In biogeochemical cycles, nutrients do not alternate between organisms and environment

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20

2017 · Life Sciences · Ecology · Ecosystems, Populations and Biogeography

Life Sciences (XL) 2017

The phenomenon where an organism lives at the expense of another organism by harming it but not killing, is called

A

Commensalism

B

Predation

C

Symbiosis

D

Parasitism

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