Assertion (A): | If introduced species evolved under great competition or predation in their native habitat, they are more likely to become invasive in the introduced habitat. |
Reason (R): | Then the new environment may host fewer able competitors, allowing the invader to proliferate quickly. |
In the light of the above statements, choose the most appropriate answer from the options given below :
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and reason are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | Both (A) and (R) are false. |
Assertion (A): | Island ecosystems are generally more prone to invasion by the introduced species. |
Reason (R): | Invasion is more likely in ecosystems that was similar to the one in which the potential invader evolved. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | Both (A) and (R) are false. |
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Assertion (A): | Animals like elephants and whales are highly prone to extinction due to over-exploitation. |
Reason (R): | Large-body-sized animals with low rates of reproduction makes them more susceptible to extinction. |
In the light of the above statements, choose the most appropriate answer from the options given below :
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | Both (A) and (R) are false. |
When the habitat gets fragmented, the edge effect:
1. | increases | 2. | decreases |
3. | remains the same | 4. | is irrelevant |
The best preservation areas are:
1. small in size but multiple in number
2. large ones are better than small-sized ones
3. the size is less important than the number
4. size and number are irrelevant
The dramatic increase in the population of Nile perch in Lake Victoria was due to:
1. | floods | 2. | eutrophication |
3. | drought | 4. | the introduction of new food |
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Migratory birds like Siberian cranes are facing threats of extinction mainly due to:
1. pesticides
2. fragmentation or loss of habitat
3. urbanization
4. bad weather
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The peregrine falcon in the United States got extinct due to:
1. | loss of habitat | 2. | pesticides |
3. | loss of food supply | 4. | predation |
The species that are vulnerable to extinction do not include the species that:
1. have high genetic variability
2. are hunted or harvested by people
3. have a declining population size
4. are local endemic species
The current extinction is called a ‘biodiversity crisis’ because:
1. the extinctions are not a natural phenomenon
2. the rates are high and is due to the human activities
3. the extinction is mainly affecting animals rather than plants
4. only keystone species are being lost
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