Q. No.A biologist studied the population of rats in a barn. He found that the average natality was 250, average mortality 240, immigration 20 and emigration 30. The net increase in population is:
1. 15
2. 05
3. zero
4. 10
According to Darwin, organic evolution is due to:
| 1. | Interspecific competition. |
| 2. | Competition within closely related species. |
| 3. | Reduced feeding efficiency in one species due to the presence of interfering species. |
| 4. | Intraspecific competition. |
The conditions:
| I. | Burrowing in soil to escape high temperature |
| II. | Losing heat rapidly from the body during high temperature |
| III. | Bask in the sun when the temperature is low |
| IV. | Insulating body due to the thick fatty dermis |
| 1. | (I) and (III) | 2. | (II) and (IV) |
| 3. | (I) and (II) | 4. | (III) and (IV) |
What type of human population is represented by the following age pyramid?
1. Stable population
2. Declining population
3. Expanding population
4. Vanishing population
| 1. | Human foetus developing inside the uterus draws nourishment from the mother |
| 2. | Head louse living on the human scalp as well as laying eggs on human hair |
| 3. | The cuckoo (koel) lays its eggs in a crow's nest |
| 4. | The female Anopheles bites and sucks blood from humans |
Study the four statements (a–d) given below and select the two correct ones out of them:
| a: | A lion eating a deer and a sparrow feeding on grain are ecologically similar in being consumers |
| b: | Predator starfish Pisaster helps in maintaining species diversity of some invertebrates |
| c: | Predators ultimately lead to the extinction of prey species |
| d: | Production of chemicals such as nicotine and strychnine by plants is metabolic disorder |
The two correct statements are:
1. a and d
2. a and b
3. b and c
4. c and d
The figure given below is a diagrammatic representation of the response of organisms to abiotic factors. What do (a), (b) and (c) represent, respectively?
|
(a) |
(b) |
(c) |
|
|
1. |
Regulator |
Conformer |
Partial regulator |
|
2. |
Conformer |
Regulator |
Partial regulator |
|
3. |
Regulator |
Partial regulator |
Conformer |
|
4. |
Partial regulator |
Regulator |
Conformer |
A country with a high rate of population growth took measures to reduce it. The figure below shows age-sex pyramids of populations. A and B are twenty years apart. Select the correct interpretation about them:
Interpretations
| 1. | 'A' is more recent and shows a slight reduction in the growth rate |
| 2. | 'B' is an earlier pyramid and shows stabilised growth rate |
| 3. | 'B' is more recent showing that the population is very young |
| 4. | 'A' is the earlier pyramid and no change has occurred in the growth rate |
Geometric representation of age structure is a characteristic of:
1. Biotic community
2. Population
3. Landscape
4. Ecosystem
The formula for exponential population growth is:
1. dt/dN= rN
2. dN/rN= dt
3. rN/dN= dt
4. dN/dt= rN
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