Population — The Increasing Numbers and Rising Problems

ICSE Class 10 Biology — Chapter 12

12.1 Rising Population — A Global Threat

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. If not solved, it will lead to grave consequences in the future.

Today, we hear a lot about the population problem in 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.

12.2 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 reasons, he had learnt to live in groups and to use his intellect in many ways as in hunting large animals like the mammoths.

12.3 Rapid Rise in Population

Two major phases in the recent past significantly favored population rise:

1. (i) Industrial revolution: As discussed above, it brought comfortable living, jobs, and food.
2. (ii) New Discoveries in Medical Science: The twentieth century (1901-2000) witnessed remarkable discoveries in medical science, especially the antibiotics and prophylactic vaccinations against many diseases ("prophylactic" means guarding beforehand). This resulted in a sharp reduction in the number of deaths of all age groups, especially 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.

12.4 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. Two-thirds of the present world population belong to the developing nations where more than half the people live below the poverty line. India and China make one-third of the total world population.

In earlier years, the human population remained fairly constant. The sharp dip shortly after 1000 A.D. is due to severe epidemics, especially 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.

12.5 A Highly Simplified Model of Population Growth

A hypothetical model shows that starting with 20 individuals (10 couples) who have an average of 4 children, the population grows exponentially. By the fourth generation at the end of 60 years, the population multiplies ten times (from 60 total to 600 total). At this rate, food and other requirements of life simply cannot keep pace with the rising population.

12.6 Population in India

The trend of rise of population in India is as alarming as in the rest of the world. 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.

• Current Indian population is a little more than 1.32 billion and is growing rapidly (approx. 52 per minute, 74,480 per day).
• India has already numbered more than 1.21 billion and would overtake China in the near future to become TOP MOST in population.

12.7 Factors Responsible for Population Explosion in India

The major factors driving the rapid population growth in India are:

1. Illiteracy: Most of the rural population which forms the bulk of our society are still illiterate, ignorant, and superstitious. They do not know the functioning of the human reproductive system.
2. Traditional beliefs: Among the people from lower strata of society, children are regarded as a gift of God and a sign of prosperity. Therefore, they make no effort to avoid pregnancy.
3. Mortality rate: Due to high infant mortality rate in our country, people from the economically weaker section think it safer to produce more children so that at least some may survive.
4. Economic reasons: Children are considered to be helping hands to increase the family income.
5. Religious and social customs: India is a centre of various religious and social customs, and as such most people do not accept family planning norms.
6. Desire for a male child: Most Indian families still hold the view that a male child is essential for keeping up the name of the family. Further, a male child is usually a great help to the aged parents.
7. Lack of recreation: Poor standard of living and poverty provide no recreation other than sex.

12.8 Rising Population — Pressure on Natural Resources

In the context of rising human population, the six main resources under pressure are:

• 1. FOOD: One most important need of humans. We are bringing more land under cultivation and using better farming methods, but food production rises arithmetically while population grows geometrically.
• 2. WATER: Availability of clean and germ-free water for drinking purpose would be more and more scarce with the increase in population. The reason would be mainly the pollution of rivers, ponds, lakes, etc.
• 3. LAND: Man is bringing more land under cultivation and also using up land for building more residential colonies, factories, and industries. Usable land would thus become less and less available.
• 4. FORESTS: Forests provide timber, firewood, resins, medicines, and wood-pulp. They are the main contributors of life-sustaining oxygen (Natural air purifiers). They bring rain (adding moisture by transpiration) and prevent floods (holding soil particles).
  Deforestation (cutting down of forests) to get land for cultivation/housing leads to: Droughts, Flash floods, Soil erosion, Extinction of wild animals, and Global warming.
• 5. ENERGY: We need energy for cooking, running factories, transportation, etc. Major sources are coal and petroleum (fossil fuels). These reserves underground are fast depleting.
• 6. MINERALS: More population means more requirements, more industries, more means of transportation. Minerals like iron and copper are non-renewable resources. Once finished, they can never be replaced.

12.9 Population Growth and Urbanisation Causing Serious Pressure on Resources

12.9.1 Changing Face of the Earth

Urbanisation: The process where villages turn into towns, towns into cities, and cities into megacities or the metropols. Some of the major changes occurring are:

• More and more residential buildings, markets, schools, hospitals, etc.
• More streets and roads, more highways, railway lines, and airports.
• More industrial installations, godowns, and reservoirs.

All such developmental activities are encroaching upon the open land, agricultural land, and forests. There is a loss of natural vegetation which is degrading the environment.

12.9.2 Rising Living Standards of Growing Population

Living standards of the people are rising very fast, leading to the usage of:

• More and more household equipment — furniture, crockery, electric gadgets.
• More clothes (shirts, suits, sarees, shoes).
• Means of personal conveyance (cycles, motor cycles, cars, taxis).

12.9.3 Need to Check Exploitative Use of Resources

The increasing numbers and rising standards of modern living are causing very rapid depletion of natural resources. Therefore, it is absolutely necessary that every citizen becomes conscious and contributes to the sustainable use of natural resources.

Non-Conventional Sources of Energy	Conventional Sources of Energy
Solar energy, nuclear energy, tidal energy, wind energy. Solar cookers and solar batteries harness solar energy. Biogas is produced from organic wastes. These are renewable and should be further popularised.	Coal and petroleum. They have been in use since long. They are non-renewable; once finished, they cannot be formed again during a lifetime.

12.10 Rate of Population Growth Must be Reduced

12.11 Need for Adopting Control Measures

As the population density increases in a country beyond its means, it brings many problems, for example:

• Per capita income comes down.
• Natural resources like land, minerals, wood, fuel, etc., decrease.
• General health goes down.

Therefore, there is pressing need for adopting population control measures.

12.12 Population Education and Population Control

It is necessary that the people should be educated about the need to limit the population. Steps include:

1. The message about the population problem should reach as many people as possible, including those in remote areas.
2. People should be made aware of the advantages of having small families. China is almost reaching the norm of 1 child per family, whereas India has to strive hard even to reach the 2 children per family norm.
3. The orthodox view, to have at least one son specially in Indian society, should be modified by education.
4. Marriageable age should be higher. [The age restriction of at least 18 years for girls and 21 years for boys under the law must be followed strictly].
5. Married couples should be educated to delay the birth of their first child, to space the second with a sufficient interval, and to stop the third.
6. People should be advised to adopt family planning methods (contraception).

12.13 Methods of Contraception

The common methods of contraception to prevent pregnancy are as follows:

1. Hormonal Methods (Pills): Various hormonal preparations come in the form of tablets or pills (commonly called contraceptive pills). These hormones prevent the release of the egg from the ovary.
2. Barrier Methods:
   • (a) Condom (e.g. Nirodh): It is used by men. Made of latex (rubber sheath). It prevents the sperms from being deposited in the vagina.
   • (b) Diaphragms: Round latex caps with coil spring. Fitted deep in the vagina on the mouth of the uterus (cervix). They prevent the entry of sperms into the uterus.
   • (c) Sperm-killing (spermicidal) agents: Chemicals placed in the vagina near the cervix, which kill the sperms if they are there.
3. Intra-Uterine Devices (IUDs): The two devices commonly used in India are Lippe's Loop and Copper-T. These are fitted inside the uterus. These do not stop fertilisation but prevent implantation of the blastocyst (embryo).
4. Surgical Methods:
   • (a) Tubectomy (for female): In this, the abdomen is opened and the fallopian tubes (oviducts) are cut or ligated i.e. tied with nylon thread to close the passage of the egg.
   • (b) Vasectomy (in male): In this surgery, a small cut is made in the scrotum, vas deferens (sperm duct) from each testis is ligated and a small piece between the two ligatures is removed. This surgery is easier, quicker and safer. (No harmful effect on manliness or libido).

5. Induced Abortion or Medical Termination of Pregnancy (MTP)

If the woman has somehow become pregnant and there is definite evidence of any serious genetic disease in the embryo based on a special test, then the foetus can be removed. This method should not be considered a contraceptive method, but as a last step. This operation (forced abortion) should be performed only by a trained doctor at a hospital. Abortion is legally permitted (only within 5 months of pregnancy) and can be requested at any government hospital at no cost.