The most important cause of loss of biodiversity today is:
1. habitat loss and fragmentation
2. over-exploitation
3. alien species invasions
4. co-extinctions
The Earth Summit was held in Rio de Janeiro in:
1. 1987
2. 1990
3. 1992
4. 2002
When a threatened plant needs urgent measures to save it from extinction, the desirable approach is
1. in-situ conservation
2. ex-situ conservation
3. cryopreservation
4. biopreservation
Loss of biodiversity may lead to all except:
1. decline in plant production
2. increased resistance to environmental perturbance
3. increased variability in water use
4. increased variability in pest and disease cycle
Which of the following is not a reason that accounts for greater biodiversity of tropics?
1. availability of more solar energy
2. more niche specialization
3. more time for species diversification
4. large seasonal variations in environmental factors
The greatest biodiversity on the earth is found in
1. African grasslands
2. Amazonian rain forest in South America
3. Western Ghats in India
4. Nile delta in Egypt
Biodiversity loss is now one of the world's most pressing crises. The primary reason for this is:
1. we cannot do anything about it
2. we are not responsible for this loss
3. we still do not know its entire extent
4. it is affecting only the developing countries
The main difference between "Sixth Extinction" and the previous five extinctions is that the sixth extinction:
1. is mainly occurring on islands
2. is mainly affecting plants
3. is occurring at a faster rate
4. does not involve human activities
Which of the following does not contribute to the species diversity of the tropics?
1. Predictability
2. Predation
3. High productivity
4. Spatial homogeneity