Cuscuta is an example of
1. predation.
2. endoparasitism.
3. ectoparasitism.
4. brood parasitism.

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:

A sedentary sea anemone gets attached to the sheel lining of hermit crab. The association is
1. ectoparasitism
2. symbiosis.
3. commensalism.
4. amensalism.

Just as a person moving from Delhi to Shimla to escape the heat for the duration of hot summer, thousands of
Migratory birds from Siberia and other extremely cold northern regions move to:
1. Western Ghat
2. Meghalaya
3. Corbett national park
4. Keoladeo national park

The following graph depicts changes in two populations (A and B) of herbivores in a grassy field. A possible reason for these changes is that

1. both plant populations in this habitat decreased.
2. population B competed more successfully for food than population A.
3. population A produced more offspring than population B.
4. population A consumed the members of population B.

Gause’s principle of competitive exclusion states that:

When does the growth rate of a population following the logistic model equal zero? The logistic model is given
As dN/dt=rN(1─N/K)
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 death rate is greater than birth rate.

Which of the following is correct for r-selected species?
1. Large number of progeny with large size.
2. Small number of progeny with small size.
3. Small number of progeny with large size.
4. Large number of progeny with small size.

The principle of competitive exclusion was stated by:

If ‘+’ sign is assigned to beneficial interaction, ‘─’ sign to detrimental and ‘0’ sign to neutral interaction, then the
Population interaction represented by ‘+’ ‘─’ refers to
1. amensalism.
2. commensalism.
3. parasitism.
4. mutualism.