Chapter 4, Problem 27A

(a)

Summary Introduction

Introduction :

Fertility rate: It is the number of live births per 1000 women of reproductive ages (15 years to 49 years) per year.

Technological advances and medicine have improved the chances of human survival. However, different countries have different population growth patterns. Developing countries have a higher fertility rate in comparison to developed countries, which results in a higher population growth rate.

Answer to Problem 27A

Correct answer :

The correct answer is option (C) 3.2 billion.

Explanation of Solution

Explanation/justification for the correct answer :

The projected population of developing countries that have a high fertility rate by 2050 is 10.5 billion and the projected population of developing countries that have a low fertility rate by 2050 is 7.3 billion.

The difference between the projected populations of above mentioned developing countries is:

10.5 billion-7.3 billion= 3.2 billion.

Explanation for incorrect answer :

Option (A) 1.5 billion is the difference between projected population of developing countries with high fertility rate and developing countries with average fertility rate by 2050.

Option (B) 1.7 billion is the difference between projected population of developing countries with average fertility rate and developing countries with low fertility rate by 2050.

Option (D) 9 billion is the projected population of developing countries that have average fertility rate by 2050.

(b)

Summary Introduction

Introduction :

Dispersion Pattern: It is one of the characteristic of population, which is defined as pattern of spacing of a population within an area. It describes spacing of individuals in a population with respect to one another.

Primary factors in the dispersion pattern for all organisms are the availability of resources (food, water).

There are three main types of dispersion: Uniform, Clumped groups and Random.

Answer to Problem 27A

Correct answer :

The correct answer is option (A) clumped.

Explanation of Solution

Explanation/justification for the correct answer :

Clumped dispersion: Individuals are clumped in groups.

Reasons for clumped dispersion: Safety from predators, thermoregulation, clumped distribution of resources, tendency of progeny to remain near parents.

So herding animals shows clumped dispersion pattern.

Explanation for incorrect answer :

Option (B) Random: In this dispersion pattern position of each individual is independent of the other individuals. But in herding animals, individuals remain in groups. It is a rare dispersion pattern and primarily because of random distribution of resources.

Option (C) Uniform: individuals maintain a minimum distance from other individuals (also called, evenly spaced). Maintenance of minimum distance among individuals, to avoid competition e.g., to avoid fights over food, or interference while foraging

Option (D) Unpredictable: It is not a type of dispersion pattern.