The population of an insect species shows an explosive increase in numbers during rainy

season followed by its disappearence at the end of the season. What does this show?

1. S-shaped or sigmoid growth of this insect

2. The food plants mature and die at the end of the rainy season

3. Its population growth curve is of J-type

4. The population of its predators increases enormously

Geometric representation of age structure is a characteristic of:

1. Biotic community

2. Population

3. Landscape

4. Ecosystem

A high density of elephant population in an area can result in:

1. Mutualism

2. Intraspecific competition

3. Interspecific competition

4. Predation on one another

Praying mantis is a good example of:

1. mullerian mimicry

2. warning colouration

3. social insects

4. camouflage

The formula for exponential population growth is :-

1. dt/dN = rN

2. dN/rN = dt

3. rN/dN = dt

4. dN/dt = rN

Annual migration does not occur in the case of:

1. Salmon

2. Siberian crane

3. Salamander

4. Arctic tern

The population dynamics of a species is basically regulated by

1. Climate

2. Food supply

3. Competition between and within the species

4. All of the above

In a lake that undergoes thermal stratification, blooms of phytoplankton tend to occur

1. before thermal stratification 

2. after thermal stratification 

3. at the onset of thermal stratification 

4. at the mid-phase of thermal stratification 

Commensalism is an association of two species in which

1. one lives, attached to the other, without harming it

2. both organisms derive benefits from each other

3. one derives its nutrition from the other

4. none of the above

Some students, during a study, caught, marked and released 80 fishes in a pond. Later

100 fishes were caught at random. Among these 40 were found to be marked. What is

the approximate number of fishes in the pond?

1. 50                   

2. 100

3. 200                 

4.  4000