The threat of extinction will be highest for:
1. | a very small population in an unstable environment |
2. | a moderate-sized population of r strategists |
3. | a large population with lots of genetic variabilities |
4. | a moderate sized population in a stable environment |
The growth rate of a natural population equals zero:
1. | when N/K is exactly one |
2. | when N nears the carrying capacity of the habitat |
3. | when N/K equals zero |
4. | when mortality is greater than natality |
The growth of a population is unlikely to be limited by:
1. | predation | 2. | harsh weather |
3. | disease | 4. | an abundance of natural resources |
Identify the correct statements about symbiotic relationships:
I: | in a parasitic relationship, one organism is harmed and the other is benefited. |
II: | coevolution is a feature of many symbiotic relationships. |
III: | a relationship that appears to be commensalism may in fact be mutualistic or parasitic. |
IV: | the most efficient type of parasite is one that kills its host. |
1. | I, II and III only | 2. | I, III and IV only |
3. | II, III and IV only | 4. | I, II, III and IV |
Temperature is significant for living organisms as it primarily affects:
1. | Body size | 2. | Fertility |
3. | Enzyme kinetics | 4. | Muscular contraction |
Assertion(A): | A population that fits the logistic growth model increases more rapidly at intermediate size rather than at relatively small and large sizes. |
Reason (R): | The population growth rate decreases dramatically as the population size approaches the carrying capacity. |
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): | India’s population is set to overtake China’s population by 2025. |
Reason(R): | The birth rate in china is decreasing while it is increasing in India. |
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): | Age-structure pyramids for the population of a country not only predict a population’s growth trends but can also illuminate social conditions. |
Reason (R): | These pyramids show the distribution of various age groups in a population, typically that of a country or region of the world. |
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): | 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. |