Assertion (A): | Ecologically similar species can coexist in a community if one or more significant differences in their niches arise through time. |
Reason (R): | Two species cannot coexist permanently in a community if their niches are identical. |
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. |
Assertion (A): | The adaptations of both predators and prey tend to be refined through natural selection. |
Reason (R): | Predation provides energy to prolong life and promote the reproduction of the organism that does the killing, the predator, to the detriment of the organism being consumed, the prey. |
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. |
Assertion (A): | Apex predators help in maintaining species diversity in a community. |
Reason (R): | Apex predators are often keystone species. |
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. |
Assertion (A): | Milkweeds are particularly favoured as their food by most herbivores. |
Reason (R): | Milkweeds produce cardiac glycosides that are very good for the heart of herbivores. |
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. |
Assertion (A): | The newly acquired predators and parasites are often more damaging than the older ones. |
Reason (R): | The older ones are familiar and the species getting affected have adjusted. |
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. |
Assertion (A): | In every species, there are trade-offs between survival and reproductive traits. |
Reason (R): | Life history traits are products of natural selection. |
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. |
Assertion (A): | The human population is no longer growing exponentially but is still increasing rapidly. |
Reason (R): | Most countries of the world have undergone a demographic transition. |
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. |
‘Realized niche’ of an organism can be best described as:
1. | the area a species can occupy in the face of exploitive competition |
2. | the habitat of a species within a community resulting from clumping |
3. | the habitat that exists in nature as opposed to the ideal |
4. | the life pattern that the organism actually assumes |
The competitive exclusion principle can be best expressed as:
1. | the more abundant species will exclude the less abundant species through competition |
2. | competition for the same resources excludes species having different lifestyles |
3. | no two species can occupy the same niche indefinitely when resources are limited |
4. | larger organisms exclude smaller ones through competition as in the case of large trees controlling underbrush |
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A parasitism that does not involve feeding on the body of the host is:
1. | ectoparasitism | 2. | endoparasitism |
3. | parasitoids | 4. | brood parasitism |
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