SELINA Solutions for Class 10 Biology Chapter 15 - Population - The Increasing Numbers and Rising Problems

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Chapter 15 - Population - The Increasing Numbers and Rising Problems Exercise Ex. 1

Question A.1

What was directly responsible for the rapid rise of world population in the twentieth century?

(a) Increased food production

(b) Better transport facilities

(c) Better education and job prospects

(d) Use of antibiotics and prophylactic vaccinations

Solution A.1

(d) Use of antibiotics and prophylactic vaccinations

Question A.2
Birth rate is the number of live births

(a) Per 1000 people per year

(b) Per 100 people per decade

(c) Per 1000 people per decade

(d) Per 100 people per year
Solution A.2
(a) Per 1000 people per year
Question B.1
Give the technical term for statistical study of human population of a region.
Solution B.1
Demography
Question B.2
Name two surgical techniques (one for the human male and another for the human female) that can be used to prevent pregnancy.
Solution B.2
(i) Tubectomy (For Female)

(ii) Vasectomy (For Male)
Question C.1

Mention whether of the following statements are true (T) or false (F).

(a) Vasectomy is the surgical method of sterilisation in human males.

(b) Tubectomy is the placing of a diaphragm on the cervix.

(c) Cow was the first domesticated animal.

(d) Rapidly growing industries favoured population rise.

(e) Present human population growth is following arithmetic progression.

(f) Birth rate (natality) is the number of live births per hundred people of population per decade.

(g) Tubectomy is a popular surgical method of contraception in human males.

Solution C.1

(a) True.

(b) False. In tubectomy, fallopian tubes are cut or ligated i.e. tied with nylon thread to close the passage of the egg.

(c) False. Dog was the first domesticated animal.

(d) True.

(e) False. Present human population growth is following geometrical progression.

(f) False. Birth rate (natality) is the number of live births per 1000 people of population per year.

(g) False. Vasectomy is a popular surgical method of contraception in human males.

Question C.2

Give two advantages of a small family.

Solution C.2

Two advantages of small family are:

(a) Parents can give more attention to their children.

(b) Small family helps every country in controlling the growth of population.

Question C.3

List three major landmarks in human history which contributed to the sudden rise in population of the world.

Solution C.3

(i) Tool making revolution.

(ii) Agricultural revolution.

(iii) Scientific industrial revolution.

Question C.4

What is meant by family welfare centres? What is the symbol of family welfare in our country?

Solution C.4

Family welfare centres are those places where any help or advice about family planning is available free of cost. These places could be any hospitals, dispensaries, etc. The inverted red triangle is the symbol of family welfare in India.

Selina Solutions Icse Class 10 Biology Chapter - Population The Increasing Numbers And Rising Problems

Question C.5

Sterilisation in men means preventing the flow of sperms into the seminal vesicles by cutting or ligaturing the vas deferens. Can there be a corresponding operation made in women? If yes, where?

Solution C.5

Yes, there could be a corresponding operation made in women. The name of the surgical procedure in females is 'tubectomy'. In tubectomy, 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.

Selina Solutions Icse Class 10 Biology Chapter - Population The Increasing Numbers And Rising Problems

Question C.6

What is the present rate of growth of population of the world and of our own country?

Solution C.6

The rate of growth of population of the world is 1.092% (this rate results in about 145 net additions to the worldwide population every minute or 2.4 every second {2011 estimates}) and for India is 1.344%.

Question C.7

What are the age restrictions for marriage by law for boys and girls in India?

Solution C.7

By law the minimum age is 21 years for boys and 18 years for girls.

Question C.8
Mention two reasons for the rapid increase of population in India.
Solution C.8

(a) Illiteracy:

Most of the rural population which forms the bulk of our society is still illiterate, ignorant and superstitious.

They also do not know the functioning of the human reproductive system.

(b) Traditional Beliefs:

Among the people from lower strata of the society, children are regarded as a gift of God and a sign of prosperity.

Therefore, they make no effort to avoid pregnancy.
Question C.9

Explain briefly the relationship between poverty and population and how one affects the other.

Solution C.9

Poverty and population have been closely linked ever since the world faced changes due to the major revolutions. Poverty has its own effects on the population and vice versa. Poverty prevails because of illiteracy and traditional beliefs in the economically weaker strata. Since illiteracy and traditional beliefs prevail the people from this stratum, they regard children as gift of God and a sign of prosperity. They consider children to be helping hands in increasing the family income, hence they keep producing more children forgetting that their current situation would do no good for the children and they would add more to this already overburdened poverty strata. Hence, the population keeps on rising and so does poverty. As the population increases the quality of life goes down.

Question C.10

What was the approximate Indian population according to the 1991 census? What was it in 2011?

Solution C.10

According to census, the Indian population in 1981 was 846 million and it was 1210 million in 2011.

Question D.1

Define the following terms:

(a) Population

(b) Population density

(c) Demography

(d) Resources

(e) Growth rate of population

Solution D.1

(a) Population: The number of inhabitants living at a place together is called population.

 

(b) Population density: It is the number of individuals per square kilometre (km2) at any given time.

 

(c) Demography: It is the statistical study of human population specifically with reference to size and density, distribution and other vital statistics.

 

(d) Resources: Resource is any substance (natural or artificial), energy or organism which is used by humans for their welfare.

 

(e) Growth rate of population: It is the difference between the birth rate and the death rate. As long as the birth rate exceeds the death rate, the population grows. If the birth rate is lower than the death rate, the population declines.

Question D.2

Distinguish between the following pairs:

(a) Exhaustible and Inexhaustible resources

(b) Conventional and Non-conventional sources of energy

(c) Natality and Mortality

(d) Tubectomy and Vasectomy

(e) Deforestation and Afforestation

Solution D.2

(a) Differences between exhaustible and inexhaustible resources:

Exhaustible resources

Inexhaustible resources

1. Resources which cannot be renewed readily by natural means and available in finite quantities in nature which can be easily consumed are called exhaustible resources.

1. Resources which are abundantly available in nature and can be used for unlimited time and cannot be exhausted by humans are called inexhaustible resources.

2. Examples: Coal, petroleum.

2. Examples: Wind, sun

 

(b) Differences between conventional and non-conventional sources of energy:

Conventional sources of energy

Non-conventional sources of energy

1. Conventional sources of energy are the natural energy resources which are present in a limited quantity and are being used for a long time.

1. Non-conventional sources of energy are the energy sources which cannot be exhausted easily and are continuously replenished by natural processes.

2. Examples: Coal, petroleum.

2. Examples: Solar energy, wind energy.

 

(c) Differences between natality and mortality:

Natality

Mortality

The total number of live births per 1000 people of population per year is called birth rate or natality.

The total number of deaths per 1000 people of population per year is called death rate or mortality.

 

(d) Differences between tubectomy and vasectomy:

Tubectomy

Vasectomy

1. It is the process which involves cutting or ligating of fallopian tubes by nylon thread to close the passage of egg.

1. It is the process in which vas deferens from each testes is ligated and a small piece between the two ligatures is removed.

2. It is contraceptive practice in females.

2. It is contraceptive practice in males.

 

(e) Differences between deforestation and afforestation:

Deforestation

Afforestation

1. It is the destruction of trees and forests for human habitation and use.

1. It is the planting of trees in a previously barren environment.

2. It has a detrimental effect on the environment.

2. It has a beneficial effect on the environment.

 

Question D.3

What do you mean by the 3 Rs in the context of sustainable development?

Solution D.3

The 3 Rs in the context of sustainable development are Reduce, Reuse and Recycle.

1. Reduce: Reduce the amount of Earth's resources which we use. Use of less paper and plastic carry bags.

2. Reuse: Reuse means not to throw old goods away, but to use the same goods again so that the demand for new goods is reduced. Plastic jars can be reused for storing salt, food grains etc.

3. Recycle: Recycle means rather than throwing materials away, they can be recycled. Used and discarded plastic, glass, paper and metal are sent to the respective industries where they can be converted into other useful products such as lampshades, handbags etc.

Question D.4

Our resources cannot keep pace with the rising population. Give three examples in support of this statement.

Solution D.4

(i) Food: The first and most important need of the humans (or any living organism) is food. But with the production of food rising by arithmetic progression and population growing by geometric progression i.e. the number at each step is being multiplied. At the same time growing population is increasing the use of more and more agricultural land to build houses. Thus it is evident that food would be running short for the unchecked rising population.

(ii) Water: Availability of clean and germ-free water for drinking purposes would be more and more scarce with increase in population; the reason would be mainly, the pollution of rivers, ponds, lakes etc.

(iii) Land: Man is bringing more and 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.

Question D.5

How can the knowledge of processes of reproduction help people in limiting the size of their families? Give two concrete examples.

Solution D.5

(i) The orthodox view, to have at least one son especially in Indian society, should be modified with education. People should be educated that their greed for a son can lead to numerous children in the household which would worsen both their family's health and wealth. They should focus on proper upbringing of the child, be it a son or a daughter.

(ii) Married couples should be educated to delay the birth of their first child, to space the second with a sufficient interval for proper upbringing and to stop the third. They should also be educated to adopt family planning methods by which they can prevent pregnancy after two children. These include devices for both men and women, for example: Condoms, intrauterine devices (IUD) and oral pills.

Question D.6

What is the idea behind the phrase "population explosion"?

Solution D.6

For developing countries like India, population explosion is a curse and is damaging the development of the country and its society. The developing countries are already facing a lack in their resources, and with the rapidly increasing population, the resources available per person are reduced further, leading to increased poverty, malnutrition, and other large population-related problems. The literal meaning of population is "the whole number of people or inhabitants in a country or region", and the literal meaning of population explosion is "a pyramiding of numbers of a biological population". As the number of people in a pyramid increases, so do the problems related to the increased population. Some of the reasons for this population explosion are poverty, better medical facilities, and immigration from the neighboring countries. The population in India continues to increase at an alarming rate. The effects of this population increase are evident in the increasing poverty, unemployment, air and water pollution, and shortage of food, health resources and educational resources.

Question E.1

Given below are hypothetical figures in regard to population (in crores) of two countries A and B during the last three decades.

 

Country

1971

1981

1991

     A

6.4

9.6

10.6

     B

15.7

15.7

15.3

 

Fill in the blanks:

(a) Rate of growth of population of country .................. has declined between years ................ and ................

(b) The country ................... shows negative population growth between years ................... and ...................

(c) The country .................... shows zero population growth between years ................. and ....................

Solution E.1

(a) B; 1981; 1991.

(b) B; 1981; 1991.

(c) B; 1971; 1981.

Question E.2

Observe the diagrams (A) and (B) given below and answer the following questions.

Selina Solutions Icse Class 10 Biology Chapter - Population The Increasing Numbers And Rising Problems 

(a) Label the parts 1 to 5.

(b) What does figure A depict?

(c) What does figure B depict?

(d) Comment on P and Q.

(e) Mention one function each of part 2 and 4.

Solution E.2

(a) 1: Sperm duct/Vas deferens

2: Testis/Seminiferous tubule

3: Oviduct/Fallopian tube

4: Uterus

5: Ovary

 

(b) Vasectomy

 

(c) Tubectomy

 

(d) P is the cut part of vas deferens while Q is the cut part of the oviduct. A small piece of oviduct in females and vas deferens in males is cut and then the remaining portions are ligated as a part of the contraceptive process of tubectomy and vasectomy respectively.

 

(e) Part 2 (testes): They produce the sperm cells or sperms by the process of spermatogenesis.

Part 4 (uterus): It functions to nourish and house a fertilized egg until the fetus, or offspring, is ready to be delivered.