Biodiversity and Its Conservation
Test 5

Correct answer Carries: 4.

Wrong Answer Carries: -1.

According to Robert May's estimate cited in NCERT, the total global species diversity is approximately:

1.5 million
3 million
7 million
50 million
3

Robert May estimated the total global species diversity to be about 7 million species, although only about 1.5–1.8 million species have been identified and described.

According to NCERT, approximately what percentage of the world's described species is found in India?

2.4%
5%
8.1%
12%
3

India occupies only about 2.4% of the world's land area but accounts for about 8.1% of the world's described species.

Approximately what percentage of all described species are plants, according to NCERT?

10%
22%
50%
72%
2

Plants account for about 22% of all described species, whereas animals constitute more than 70%.

Which of the following is a consequence of biodiversity loss?

Decline in plant productivity
Reduced resistance to environmental disturbances
Increased variability in ecosystem processes
All of the above
4

Biodiversity loss reduces productivity, lowers resistance to environmental disturbances, and increases variability in ecosystem processes.

Which of the following does NOT contribute to the present high rate of species extinction?

Habitat loss and fragmentation
Overexploitation
Increase in speciation rate
Alien species invasions
3

Habitat loss and fragmentation, overexploitation, alien species invasions, and co-extinctions are the major causes of biodiversity loss described in NCERT.

Which of the following statements about species extinction is correct?

The current extinction rate is lower than the natural background rate.
Human activities have greatly accelerated species extinction.
Species become extinct only because of natural disasters.
All extinct species can be revived using modern technology.
2

Human activities have accelerated extinction rates to about 100–1000 times the natural background rate.

Which of the following is an example of co-extinction?

Extinction of a host fish leading to extinction of its parasites
Formation of a new species
Migration of birds during winter
Growth of algae in ponds
1

When a species becomes extinct, the plant or animal species associated with it in an obligatory way may also become extinct. This is known as co-extinction.

Which factor is primarily responsible for the high species richness observed in tropical regions?

Frequent climatic fluctuations
Long evolutionary time and a relatively stable climate
Greater seasonal variation
Low availability of solar energy
2

NCERT attributes the high biodiversity of tropical regions to their long evolutionary history, relatively undisturbed and stable environment, and greater availability of solar energy.

Which of the following is an example of in situ conservation?

Seed banks
Botanical gardens
National parks
Cryopreservation
3

National parks, wildlife sanctuaries, and biosphere reserves are examples of in situ conservation.

Which of the following statements about ecosystem stability is incorrect?

Greater biodiversity generally increases ecosystem stability.
Ecosystems with fewer species are usually more stable than species-rich ecosystems.
Species-rich communities are generally more productive.
Species-rich communities are generally more resistant to environmental disturbances.
2

NCERT states that species-rich communities are generally more productive, more stable, and better able to resist environmental disturbances than species-poor communities.

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