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) Mutualism

(2) Amensalism

(3) Commensalism

(4) Parasitism

The principle of competitive exclusion was stated by 

(1) C Darwin

(2) GF Gause

(3) MacArthur

(4) Verhuisd and Pearl

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 nears the carrying capacity of the habitat

(2) when N/K equals zero

(3) when death rate is greater than birth rate

(4) when N/K is exactly one

Gause's principle of competitive exclusion states that

An association of individuals of different species living in the same habitat and having functional interactions is.

1. ecological niche

2. biotic community

3. ecosystem

4. population

In which of the following interactions both partners are adversely affected?

(1) Competition

(2) Predation

(3) Parasitism

(4) Mutualism

Most animals are tree dwellers in a 

1. coniferous forest

2. thorn woodland

3. temperate deciduous forest

4. tropical rainforest

The following graph depicts changes in two populations (A and B) of herbivores in 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

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

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. 10         

2. 15           

3. 05           

4. zero