Selina Concise Solutions for ICSE Class 10 Biology Chapter 11 Population The Increasing Numbers and Rising Problems

Review Questions

A. Multiple Choice Type:

Question 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
Answer: (d) Use of antibiotics and prophylactic vaccinations
In simple words: Medical advances like antibiotics and vaccines helped people live longer and reduced deaths from diseases, causing population to grow quickly.

📝 Teacher's Note: Emphasize how medical breakthroughs in the 20th century dramatically reduced infant mortality and death from infectious diseases. Use examples like polio vaccine and penicillin to make it concrete.

🎯 Exam Tip: Focus on "medical advances" as the key factor - antibiotics saved lives from infections while vaccines prevented deadly diseases.

Question 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
Answer: (a) Per 1000 people per year
In simple words: Birth rate counts how many babies are born for every 1000 people in the population each year.

📝 Teacher's Note: Stress the standard units: per 1000 people per year. Compare with death rate which uses the same units for consistency in demographic calculations.

🎯 Exam Tip: Remember the formula: "per 1000 people per year" - this is the standard demographic measurement unit.

B. Very Short Answer Type:

Question 1. Give the technical term for the statistical study of human population of a region
Answer: Demography
In simple words: Demography is the science that studies population numbers, growth, and patterns.

📝 Teacher's Note: Connect this to real-world examples like census data and population surveys. Explain how demographers help governments plan for schools, hospitals, and resources.

🎯 Exam Tip: The one-word answer is "Demography" - remember it comes from Greek words meaning "people writing" or population study.

Question 2. Name two surgical techniques (one for the human male and another for the human female) that can be used to prevent pregnancy.
Answer:
(i) Tubectomy (For Female)
(ii) Vasectomy (For Male)
In simple words: These are permanent surgical methods to prevent pregnancy by blocking the tubes that carry eggs or sperm.

📝 Teacher's Note: Explain that these are permanent methods and require careful consideration. Discuss the anatomy involved - fallopian tubes in females and vas deferens in males.

🎯 Exam Tip: Remember: Tubectomy = Tubes (fallopian) for females, Vasectomy = Vas deferens for males.

C. Short Answer Type:

Question 1. Write true (T) or false (F) for the following:
(a) Vasectomy is the surgical method of sterilization in human males
(b) Tubectomy is the placing of a diaphragm on the cervix
Answer:
(a) True
(b) False
In simple words: Vasectomy is indeed for males, but tubectomy is surgery on fallopian tubes, not placing a diaphragm.

📝 Teacher's Note: Clarify the difference between surgical permanent methods (tubectomy/vasectomy) and barrier temporary methods (diaphragm). Draw diagrams to show where each procedure occurs.

🎯 Exam Tip: Don't confuse tubectomy (permanent surgery) with diaphragm (temporary barrier device) - they are completely different methods.

Question 2. What is the total world population at present?
Answer: It is approximately 7 billion.
In simple words: The world currently has about 7 billion people living on it.

📝 Teacher's Note: Update this figure if using current data (now over 8 billion). Show how this number has grown rapidly in recent decades using a population growth timeline.

🎯 Exam Tip: Use the figure given in your textbook - population numbers change rapidly, so stick to the data provided in your study material.

Question 3. Define the following terms:
(a) Birth rate
(b) Death rate
(c) Rate of growth of population
(d) Population density
(e) Exhaustible resource
Answer:
(a) Birth Rate: It is the number of live births per 1000 people of population per year.
(b) Death Rate: It is the number of deaths per 1000 of population per year.
(c) Rate of growth 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.
(d) Population density: It is the number of individuals per square kilometre (Km²) at any given time.
(e) Exhaustible resource: Exhaustible resources are the once which are perished by the prolonged us and they can never be renewed or replaced.
In simple words: These terms help measure how populations change and how crowded places are, plus what resources we might run out of.

📝 Teacher's Note: Use examples for each term - birth/death rates from your country, population density of your city vs rural areas, and exhaustible resources like fossil fuels vs renewable ones like solar energy.

🎯 Exam Tip: For growth rate, remember it's simply birth rate minus death rate. For density, it's people per area unit. For exhaustible resources, emphasize "non-renewable."

Question 4. Mention whether the following statements are true (T) or false (F) Give reason in support of your answer
(a) Cow was the first domesticated animal
(b) Rapidly growing industries favoured population rise
(c) Present human population growth is following arithmetic progression
(d) Birth rate (natality) is the number of live births per hundred people of population per decade
(e) Tubectomy is a popular surgical method of contraception in human males
Answer:
(a) False. Dog was the first domesticated animal.
(b) True. 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.
(c) False. Present human population growth is following geometrical progression.
(d) False. Birth Rate (natality) is the number of live births per 1000 people of population per year.
(e) False. Vasectomy is the surgical method of contraception in human males while tubectomy is the surgical method used in females.
In simple words: Dogs were first pets, industries helped population grow, population grows exponentially (not linearly), birth rate is per 1000 per year, and tubectomy is for women not men.

📝 Teacher's Note: Explain geometric vs arithmetic progression with examples - geometric grows much faster (like 2,4,8,16) while arithmetic grows steadily (like 2,4,6,8). This is crucial for understanding population explosion.

🎯 Exam Tip: Remember: Dogs first, industries helped growth, population grows exponentially, standard units are per 1000 per year, and match surgical methods to correct gender.

Question 5. What is the present rate of growth of population of the world and of our own country?
Answer: 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%.
In simple words: The world's population grows by about 1.1% each year, while India's grows slightly faster at 1.3% per year.

📝 Teacher's Note: Help students visualize these percentages - 1.344% means India adds about 13-14 people for every 1000 people each year. Use classroom analogies to make these numbers tangible.

🎯 Exam Tip: Remember India's growth rate is higher than the world average - this explains why India is set to become the world's most populous country.

Question 6. What are the age restrictions for marriage by law for boys and girls in india?
Answer: By law the minimum age is 21 years for boys and 18 years for girls.
In simple words: Indian law says boys must be at least 21 and girls at least 18 before they can legally marry.

📝 Teacher's Note: Note that these laws recently changed - the age for girls was raised to 21 in 2021. Discuss how legal marriage age relates to education completion and population control efforts.

🎯 Exam Tip: Check if your textbook reflects the updated law (girls now 21, same as boys) or uses the older figures (girls 18, boys 21).

Question 7. Give two advantage of a small family
Answer: 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.
In simple words: Smaller families mean better care for each child and help control overall population growth.

📝 Teacher's Note: Expand on quality vs quantity - fewer children means better education, healthcare, and opportunities for each child. Connect to national benefits like better resource distribution.

🎯 Exam Tip: Focus on both individual benefits (better child care) and societal benefits (population control) to show complete understanding.

Question 8. Mention two reasons for the rapid increase of population in india
Answer:
(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.
In simple words: Lack of education and old beliefs about children being blessings lead people to have more babies than they can support.

📝 Teacher's Note: Be sensitive when discussing these topics. Emphasize how education and awareness (not judgment) are key to addressing population challenges. Discuss how these factors interact with poverty.

🎯 Exam Tip: Link illiteracy to lack of family planning knowledge, and traditional beliefs to cultural attitudes toward large families.

Question 9. Some great author has said that a population explosion is far more dangerous than an atomic explosion. Justify his statement?
Answer: Population growth is not the only threat humanity is facing, but it will be a major contributor to the crises that await us and the planet in the coming century. Overpopulating the planet puts us all at risk of extreme environmental and social consequences that we are beginning to witness today. The extreme growth in human population is mortally taxing the Earth and its resources. Each individual person has a unique impact on the planet's environment. Some people may be relatively less damaging than others, but no living individual is without an ecological footprint. In other words, each person needs basic resources and almost all people aspire to utilize significantly more resources than are required by their basic needs. As a result, the Earth is attempting to impose its own checks on human population. We can witness these "checks" in the form of widespread disease and the emergence of new disease strains, food and water shortages, poor harvests and violent and destructive weather caused by climate change. While it should be obvious that the Earth is a finite sphere and cannot endure infinite growth by any single species, we should also remember that Earth's current web-of-life is the result of billions of years of complex evolution. It is irreplaceable. When we look forward to the next 40 years, the most significant population increases will take place in the areas of our world where natural resources and the infrastructure of modernity are already the scarcest. 95% of the human population growth is occurring in countries already struggling with poverty, illiteracy and civil unrest. It will further stress, the already strained ecological systems and worsen poverty in much of the developing world, thus aggravating threats to international security. Thus, the statement made by an author 'some great author has said that a population explosion is far more dangerous than an atomic explosion' is true.
In simple words: While an atomic explosion destroys quickly, population explosion slowly destroys our planet's resources, environment, and ability to support life.

📝 Teacher's Note: Break this complex answer into key points: resource depletion, environmental damage, poverty cycles, and long-term consequences. Use current examples like climate change and water scarcity.

🎯 Exam Tip: Structure your answer around: immediate vs long-term effects, local vs global impact, and reversible vs irreversible damage. Show that population explosion has broader, lasting consequences.

Question 10. Explain briefly the relationship between poverty and population and how one affects the other.
Answer: 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.
In simple words: Poor people often have more children hoping for help with income, but more children actually make them poorer, creating a vicious cycle.

📝 Teacher's Note: Draw the poverty-population cycle on the board: poverty leads to more children, more children increase expenses and reduce per-capita resources, leading to deeper poverty. Emphasize how education breaks this cycle.

🎯 Exam Tip: Show the two-way relationship clearly: poverty causes high birth rates, and high birth rates worsen poverty. Mention the cycle aspect for full marks.

Question 11. List three major landmarks in human history which contributed to the sudden rise in population of the world.
Answer:
(i) Tool making revolution.
(ii) Agricultural revolution.
(iii) Scientific industrial revolution.
In simple words: Making tools, learning to farm, and developing science and industry all helped humans survive better and live longer.

📝 Teacher's Note: Explain how each revolution improved survival rates: tools for hunting/protection, agriculture for stable food supply, and industrial/scientific advances for medicine and living conditions.

🎯 Exam Tip: Remember the chronological order and how each revolution built upon the previous one to support larger populations.

Question 12. What was the approximate Indian population according to the 1981 census? What was it in 1991?
Answer: According to census, the Indian population in 1981 was 685 million and it was 846 million in 1991.
In simple words: India's population grew from about 685 million to 846 million people in just 10 years.

📝 Teacher's Note: Calculate the percentage increase (about 23.5% in 10 years) to show how rapid this growth was. Compare with current population figures to show continued growth.

🎯 Exam Tip: Remember both figures: 685 million (1981) and 846 million (1991). The large increase shows India's high population growth rate.

Question 13. Sterilization 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?
Answer: 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.
In simple words: Yes, women can have tubectomy where the fallopian tubes are cut or tied to prevent eggs from reaching the uterus.

📝 Teacher's Note: Compare the anatomy: vas deferens carry sperm in men, fallopian tubes carry eggs in women. Both procedures block gamete transport but at different locations in male vs female reproductive systems.

🎯 Exam Tip: Emphasize the parallel: vasectomy blocks sperm flow, tubectomy blocks egg flow. Both are permanent surgical contraceptive methods.

Question 14. What is meant by family welfare centres? What is the symbols of family welfare in our country?
Answer: 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.
In simple words: Family welfare centres are free clinics or hospitals where people can get advice and help with family planning. India uses an upside-down red triangle as the official symbol for these services.

📝 Teacher's Note: Show students the actual red triangle symbol and explain that they might see it on government hospitals and health centers. Emphasize that these services are completely free and confidential.

🎯 Exam Tip: Remember the key points: free of cost, any hospitals/dispensaries, and inverted red triangle symbol. These are the exact keywords examiners look for.

Question 15. List the advantages of having small families.
Answer: Below are some of the advantages of having a small family:
(i) Financial condition of family is deeply related to the size of the family. A living cost of a large family is surely much higher than a small family. A large family has more expenses on cloth, toys, education and food whereas expenses in small family are very low.
(ii) Parents can easily fulfill the needs of one or two children. They can provide them best education and look after them very well whereas when there are many children to look after parents just cannot fulfill even the basic needs of the children properly. Therefore, as a result, children suffer, the parents suffer and the nation suffers.
(iii) A child in a small family receives more support from their parents than in a large family. In large family, parents have many children to look after, so they cannot give their best support to everyone whereas in small family parents can give more support to children as they have only one or two children to look after.
(iv) Family size also affects the health, especially that of the mother and the child. Frequent pregnancies can cause illness to both the mother and the children. It can disrupt the health of the women. It puts mother and baby's health at risk. So having a small family definitely leads to healthy and happy family.
In simple words: Small families have several benefits: lower expenses, better education and care for children, more parental attention, and healthier mothers and babies. It's like having a small garden that you can tend to perfectly versus a huge one where plants don't get enough care.

📝 Teacher's Note: Use real-life examples students can relate to - compare pocket money distribution between families with different numbers of children. This makes the concept more tangible.

🎯 Exam Tip: Structure your answer with clear points: (i) Financial, (ii) Education/Care, (iii) Parental Support, (iv) Health. Use these exact categories for full marks.

D. Long Answer Type:

Question 1. Our resources cannot keep pace with the rising population. Give three examples in support of this statement.
Answer: (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.
In simple words: Population grows much faster than our ability to produce food, clean water, and usable land. It's like having a pizza that stays the same size but more and more people wanting to eat it - eventually there won't be enough slices for everyone.

📝 Teacher's Note: Explain arithmetic vs geometric progression with simple numbers: 2,4,6,8 vs 2,4,8,16. Students often confuse these mathematical concepts but understanding them is crucial here.

🎯 Exam Tip: Always mention all three resources - Food, Water, and Land. For food, specifically mention arithmetic vs geometric progression for extra marks.

Question 2. How can the knowledge of processes of reproduction help people in limiting the size of their families? Give two concrete examples
Answer: (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.
In simple words: Education about reproduction helps people make smart choices about family size. They learn that having many children just to get a son is harmful, and they can use family planning methods to control when and how many children they have.

📝 Teacher's Note: Handle this topic sensitively, focusing on scientific facts rather than cultural judgments. Emphasize the health and economic benefits of family planning.

🎯 Exam Tip: Mention specific family planning methods (condoms, IUD, oral pills) and address both social factors (son preference) and practical solutions (spacing, limiting children).

Question 3. What is the idea behind the phrase "population explosion"?
Answer: 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.
In simple words: Population explosion means people are increasing so fast it's like a bomb going off - sudden and dramatic. It creates a pyramid effect where more people means bigger problems with resources, jobs, and pollution.

📝 Teacher's Note: Draw a pyramid diagram to show how population growth creates cascading problems. Students understand visual representations better than abstract concepts.

🎯 Exam Tip: Define the term, explain the pyramid concept, mention causes (poverty, medical facilities, immigration) and effects (poverty, unemployment, pollution, resource shortage).

E. Structured / Application /Skills Type:

Question 1. Given below are hypothetical figures in regard to population (in crores) of two countries A and B during the last three decades.

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 …………………..

Answer:
(a) B; 1981; 1991.
(b) B; 1981; 1991.
(c) B; 1971; 1981.
In simple words: Country A's population kept growing, but Country B's population stayed the same from 1971-1981 (zero growth) and then actually decreased from 1981-1991 (negative growth).

📝 Teacher's Note: Teach students to calculate growth rates by comparing consecutive years. Show them that same numbers = zero growth, decreasing numbers = negative growth.

🎯 Exam Tip: Always compare consecutive time periods, not the first and last years. Look for patterns: increasing, staying same, or decreasing numbers.