ICSE Class 10 Biology Chapter 12 Population

Population - The Increasing Numbers and Rising Problems

Syllabus: Population: Problems posed by the increase in population in India; need for adopting control measures - Population control.

Scope of Syllabus: Main reasons for the sharp rise in human population in India and in the world. The terms demography, population density, birth rate, death rate and growth rate of population should be explained. With population growth, increased consumption and urbanisation there is a need to keep a check on demands of urban areas over rural areas of exploitative use of resources rather than sustainable use. Methods of population control to be taught.

Human population throughout the world and in India, in particular, has been rising at an alarming rate. This is by far the most serious problem the world is facing today, and if not solved, will lead to grave consequences in future. What all this problem of rising world population embodies and what steps may help to solve it, are the topics covered here.

Rising Population - A Global Threat

Today, we hear a lot about population problem in the developing countries including India. All the media of mass communication - radio, television, stage, press, etc. - are trying their best to educate people about the grave dangers of rising population. It is becoming a serious threat, not for any one country in particular, but for the world as a whole.

World Population Through The Ages

It is estimated that the total world population about 50,000 years ago would have been around one million (1,000,000). At that time, man lived a very primitive life. He knew nothing about farming, but he had begun to use tools which he made from stones, sticks and bones. He was a wanderer and took shelter in caves. He used to kill animals and eat them raw or roast them on fire. He used to catch fish from waters. He collected eggs from birds' nests or gathered fruits, roots and leaves from wild plants. Meanwhile, due to safety reason, he had learnt to live in groups and to use his intellect in many ways as in hunting large animals like the mammoths. He had improved his tools which were still mainly of stones (stone age). This tool-making revolution thus helped man to improve his life.

About 10,000 years ago, the total world population had reached approximately 5.3 million. At that time, the human way of life was undergoing a remarkable change - a kind of revolution.

He started living in settled communities in primitive huts.

He had started domesticating animals - dog being the first.

He learnt to sow crops and store food. This was the beginning of agriculture.

His primitive stone tools and weapons were now gradually replaced by those of bronze and iron. He had thus stepped into the metal age.

As a result of all the above progress, the human population began to grow faster.

Rapid Rise In Population

Industrial Revolution

A major phase of the growth of human population started with the scientific and industrial revolution, which began around the seventeenth century. Rapidly growing industries made human life more and more comfortable, with greater opportunities of jobs and with more production of food. All this favoured population rise. However, there was one drawback. As the community groups were increasing, there were widespread outbreaks of infectious diseases due to close contact of the people. Nutritional diseases also appeared due to unbalanced diets.

New Discoveries In Medical Science

The twentieth century (1901-2000) witnessed remarkable discoveries in medical science, specially the antibiotics and the prophylactic vaccinations against many diseases ("prophylactic" means guarding beforehand). This resulted in a sharp reduction in the number of deaths of all age groups, specially the infants and the old. More children per family began to reach the reproductive age and as they reproduced, the rate of growth of population began to rise very rapidly.

The two big question marks (?). Figure 12.3 depicts a diagrammatic curve of the growth of human population where three main revolutions in human culture have been indicated: (1) Tool making revolution (2) Agricultural revolution (3) Scientific industrial revolution.

World Population - Some important dates and figures

World population crossed the 5.0 billion mark on July 11, 1987.

World population in 1995 was nearly 5.6 billion.

Number of babies born every day is more than 1,00,000.

October 12, 1999, The World Population crossed the 6,000,000,000 (six billion) figure. The six billionth member of the world population was born in Sarajevo (Yugoslavia).

According to one estimate the total world population will reach 10 billion around the year 2050.

With the present trend of population growth, India is overtaking China to becoming World's "TOP MOST" in population by the year 2025 or so.

July 11 is observed as World Population Day

Each cultural revolution was followed by a rapid rise in population till it became somewhat stabilised or rose very slowly (flattened curve) for a long period (shown by wavy gaps). The next revolution provided further improved means of livelihood and the human population again moved upward rapidly, and so on.

The modern period is marked by the end of the solid curve; we do not know exactly whether the population would continue to rise rapidly or slowly, or would soon tend to stabilise, and hence the two big question marks.

Progress Check

1. Name the three great cultural revolutions that favoured a steep rise in population.

2. Mention two areas of medical sciences which have indirectly contributed to high growth in human population.

3. Is the present day human population growth following a J-shaped curve or S-shaped curve?

Population Explosion - A Serious Global Concern

According to demographers, about one-third of the total number of all the people who have ever lived on earth are alive today, is termed as population explosion that began in the middle of the nineteenth century. Two-thirds of the present world population belong to the developing nations where more than half the people live below poverty line. India and China make one-third of the total world population. Figure 12.4 represents the profile of human population growth in the world from the earliest times, particularly during the last 12,000 years. In earlier years, the human population remained fairly constant. The sharp dip shortly after 1000 A.D. is due to severe epidemics, specially the Black Death (Plague, caused by a bacterium spread by the ratflea bite). Later, the scientific and industrial age gave a fresh momentum to the population rise. Today, the rate of growth of population has reached a point such that the population more than doubles in about 35 years. The total world population reached 7 billion on 31 October 2011. According to the present rate of population grown, it is likely to reach 50 billion by the end of this century (more than seven times the present number)

Six main reasons for sharp rise in World Human Population in the recent past.

1. Better health care, for all age groups. There are more health care centres, hospitals, and practising doctors available for help.

2. Fewer deaths due to better medical aid. This is for two reasons: there are regular vaccination programmes, many diseases have been controlled or even wiped out and secondly, more patients get cured and live longer.

3. Food shortages minimised and green revolution. More food is produced and stored. There are very few starvation deaths.

4. Improved nutrition (due to consciousness) especially for growing children. They keep healthy, suffer less from diseases and live longer.

5. Large scale immunisation against fatal diseases.

6. Fewer infant deaths. In older times, an average family used to get 4-6 children out of which, 1 or more would not survive due to certain diseases. 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 of all the above factors, even if a couple produced only 2-3 children, the total population rises sharply.

More and more children are reaching the reproductive age and they contribute to population growth.

Teacher's Note

The concepts of population growth and its historical patterns help us understand why modern cities are becoming overcrowded and why resources are becoming scarce - issues we see reported in news about housing shortages and traffic congestion daily.

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