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 twenty years apart. Select the correct interpretation about them.

Interpretations

1. 'A' is more recent and shows slight reduction in the growth rate

2. 'B' is earlier pyramid and shows stabilized growth rate

3. 'B' is more recent showing that population is very young

4. 'A' is the earlier pyramid and no change has occured in the growth rate  

Consider the following four statements (i-iv) about certain desert animals such as

kangaroo rat.

(i) they have dark colour and high rate of reproduction and excrete solid urine.

(ii) they do not drink water, breathe at a slow rate to conserve water and have their

body

covered with thick hairs.

(iii) they feed on dry seeds and do not require drinking water

(iv) they excrete very concentrated urine and do not use water to regulate body

temperature.

Which two of the above statements for such animals are true?

1. iii and iv

2. ii and iii

3. iii and i

4. i and ii

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