Q. No.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
Interpretations
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
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
| 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 |
What type of human population is represented by the following age pyramid?
1. Stable population
2. Declining population
3. Expanding population
4. Vanishing population
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. |
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
In which of the following interactions both partners are adversely affected?
| 1. | Competition | 2. | Predation |
| 3. | Parasitism | 4. | Mutualism |
An association of individuals of different species living in the same habitat and having functional interactions is known as:
| 1. | Ecological niche | 2. | Biotic community |
| 3. | Ecosystem | 4. | Population |
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