Q. No.Between which of the following, the relationship is not an example of commensalism?
1.
Orchid and the tree on which it grows
2.
Cattle Egret and grazing cattle
3.
Sea Anemone and Clownfish
4.
Female wasp and fig species
Carnivorous animals - lions and leopards, occupy the same niche but lions predate mostly larger animals and leopards take smaller ones. This mechanism of competition is referred to as:
1. Character displacement
2. Altruism
3. Resource partitioning
4. Competitive exclusion
The formula for exponential population growth is:
1. dt/dN= rN
2. dN/rN= dt
3. rN/dN= dt
4. dN/dt= rN
Geometric representation of age structure is a characteristic of:
1. Biotic community
2. Population
3. Landscape
4. Ecosystem
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 |
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 |
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