ICSE Class 7 Biology Chapter 08 Increasing Population Its Impact on The Environment

Unit 8: Rising Population

Increasing Population - Its Impact on the Environment

Syllabus

1. Reasons for sharp rise in world population.

2. Trends of population growth in India

3. Factors responsible for population explosion in India

4. Impact of increasing population on the environment.

5. Impact of increasing population on our resources.

Introduction

Population means a set of humans in a given area, like a village, town, state or a country or even all humans inhabiting the planet earth.

In 1000 A.D., the world population was probably about 300 million (3000 Lakh). At that time, the motto of human beings might have been "Go Forth And Multiply". That is what the human population has successfully been doing for hundreds of years - expanding, utilizing, civilizing, industrializing, and now "destroying the very land upon which we live".

In early 19th century, the world population rose to 1000 million (1 billion), and hit the 6.5 billion mark in 2006. On an average, each year the world population increases by about 80 million. Towards the end of 2011 the total crossed seven billion, having more than doubled since 1965. According to recent projections by the United Nations, it is projected to rise to 9.3 billion in 2050. It is estimated that by 2100, India (1.7 billion) is forecast to overtake China (1.4 billion). Together these two countries may then account for over a third of the global population.

Fig. 8.1 Increase in population over the year

Population Explosion - Why?

If a population is to grow, the birth rate must be higher than the death rate. Suppose a population of 1000 people produces 100 babies each year but only 50 people die each year. This means 50 new individuals are added to the population each year and the population will double in 20 years (if the new individuals start reproducing at 16 years of age).

The abrupt rise of world population has been termed as "Population Explosion".

Reasons for population explosion in recent times

1. Fewer infant mortality: One of the reasons affecting the size of population is infant mortality, i.e., the death rate for children less than one year old. Population in the developing world is growing, not because of an increase in the number of babies born per family, but because more babies are surviving to reach reproductive age. Infant mortality is falling and more people are living longer. That is, life expectancy is increasing.

Life expectancy is the average age to which a new born baby is expected to live.

Today, most new born babies survive due to better health care. Maternity homes provide safety for both the child as well as the mother. As a result, more and more children are reaching the reproductive age and contribute to population growth.

An increase in the number of people over the age of 60 does not change the rate of population growth much, because these people have passed child-bearing age. On the other hand, if death rate among children falls and the extra children survive to reproduce, the population will continue to grow. This is one major reason for the rapid increase in the population world over.

2. Better health care: Agricultural development and economic expansion led to the improvement in nutrition, housing and sanitation, and to clean water supplies. There are more health care centres, hospitals available for help. These improvements reduced the incidence of infectious diseases in the population. Not only this, better-fed children could also resist these infectious diseases.

Traditionally, it is assumed that the population growth is limited by famine, disease or war. Undoubtedly, these factors are affecting local population in some parts of the world, but they are unlikely to have a limiting effect on the rate of overall population growth.

3. Fewer deaths: Due to discovery of modern drugs and improved medical techniques, particularly immunization, many diseases have been controlled or even wiped out. Diseases like diphtheria, tuberculosis and polio are now quite rare. Small pox has been wiped out by the World Health Organisation Vaccination Programme.

Pulse Polio programme is another such campaign to totally eradicate this deadly disease.

4. Food scarcity minimized, and improved nutrition: Better and scientific practices in agriculture, more food is produced and safely stored. Thus there are only few starvation deaths. People and specially the children, by and large, are getting healthier food with the result that they suffer less from diseases and live longer.

Teacher's Note

Better healthcare and nutrition are why people in your family likely live longer than their grandparents did - fewer childhood illnesses and more access to doctors mean populations naturally grow.

Trends of Population Growth in India

The trend in the rise of population in India is alarming. Except for a slight fall in 1911-21, the population of India has been steadily increasing for the last 100 years. Since 1951, the growth rate has been very high. The table given below shows this trend during the last hundred years:

A few years ago, it was estimated that India's population in 2001 would be around 760 million but now, we find that it has already crossed 1000 million (one billion).

The population in 2010 was about 1050 million and is growing approximately at the rate of -

52 per minute

3,020 per hour

72,480 per day

2.74 crore per year

Teacher's Note

India's population growth means more people need food, water, and schools in your community - something you can observe when comparing your town's size to old photographs.

Factors Responsible for Population Growth in India

Some factors responsible for growth of population in India are:

Illiteracy: Most of the rural population is still illiterate, ignorant and superstitious. So they think a child is a gift of the God.

Mortality rate: Due to high infant mortality rate in our country, people from economically weaker section think it safer to produce more children so that at least some may survive.

Economic reasons: People from low income group think more children will help in enhancing the income of the family.

Religious and social customs: People in India believe in various religious and social customs, and as such many do not accept family planning norms.

Desire for a male child: Many families still believe that (i) a male child is essential for keeping up the name of the family, (ii) will be a great help to the aged parents. These two reasons often contribute to getting several children before getting one son or sometimes not even that.

Lack of recreation: Poor standard of living and poverty provide no recreation other than sex.

Teacher's Note

Understanding why families in different regions have different numbers of children helps explain population differences you see between rural and urban areas in India.

Problems Due to Population Explosion

Increase in population in a country beyond its means, may cause many problems, for example:

Per capita income of the people comes down.

Natural resources like land, minerals, wood, fuel, etc. decrease.

General health of the people goes down.

Overall, the quality of life of the people goes down.

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