Population - Pollution and Rising Numbers
ICSE Class 10 Biology • Chapter 11
1. Population Explosion
Population Density: Number of individuals of a species per unit area at a given time.
Reasons for sharp rise in Human Population:
- Better Healthcare: Reduction in Death Rate (Mortality).
- Food Security: Availability of food due to improved agriculture.
- Fewer Wars: Relative peace in the 20th century.
- Lack of Education: Traditional beliefs desiring more children.
2. Demography
Key Terms:
- Natality (Birth Rate): Number of live births per 1000 people per year.
- Mortality (Death Rate): Number of deaths per 1000 people per year.
- Growth Rate: (Natality - Mortality).
CONCEPT CHECK Define Population Density.
Ans: The number of individuals of a species present per unit area at a given time.
3. Consequences of Overpopulation
- Resource Depletion: Shortage of food, water, and land.
- Unemployment: Jobs cannot keep up with population growth.
- Poverty: Lower standard of living.
- Pollution: Increased waste, vehicles, and industrial activity leading to environmental
degradation.
4. Population Control
A. Surgical Methods (Sterilization)
Permanent method. Prevents gamete transport.
- Vasectomy (Males): Vas deferens is cut and tied. Sperm cannot reach urethra.
- Tubectomy (Females): Fallopian tubes are cut and tied. Egg cannot reach uterus.
[IMAGE PLACEHOLDER: TUBECTOMY AND VASECTOMY]
Diagram showing Vasectomy (Cut Vas Deferens) and Tubectomy (Cut Fallopian Tube).
Label cuts and ties clearly.
BOARD QUESTION Name the surgical method of sterilization in males.
Ans: Vasectomy (Cutting and tying of Vas Deferens).
B. Contraceptive Methods (Temporary)
- Barrier Methods: Condoms, Diaphragms (Prevent sperm meeting egg).
- Chemical Methods: Oral Pills (Hormonal, prevent ovulation).
- IUCD (Intra-Uterine Contraceptive Devices): Copper-T (Prevents implantation). Placed in
Uterus.
5. Symbols
Red Triangle: Specifically inverted red triangle is the symbol for Family Welfare in
India.
Exam Practice Questions
APPLICATION If Natality > Mortality, what happens to the population size?
ignoring Migration.
Ans: The population size increases.
Q1: What is the main aim of 'Family Welfare' programs?
Ans: To maintain a small family norm (Hum Do Hamare Do) to ensure better quality of
life, health, and education.
