Quick summary
This chapter looks at how humans and the environment affect each other. It covers the growth of human population and its stages, rural and urban settlements, indigenous communities and their traditional knowledge, the link between environment and health, and the right to live in a clean environment with value education.
Key points
- Humans first lived as hunters and gatherers. Three big changes increased population: the agricultural revolution (10,000–12,000 years ago), the industrial revolution (about 275 years ago) and the medical/technological revolution.
- World population: about 170 million in 1 C.E.; doubled to 2 billion between 1850 and 1950; 5 billion in 1987; 6 billion in 1999. Growth from about 1650 onwards is exponential.
- Birth rate (natality) and death rate (mortality) are counted per 1000 people per year.
- Demographic transition: pre-industrial phase (high birth and death rates, slow growth) → transitional phase (death rate falls, birth rate stays high, rapid growth) → industrial phase (both fall) → post-industrial phase (stable or falling population).
- Population pyramids show age groups: a broad base means rapid growth; an urn shape means a shrinking young population.
- Rapid urbanisation brings slums, poor sanitation, pollution, traffic and pressure on water and land.
- Indigenous knowledge is the traditional knowledge of local communities about farming, plants, weather and conservation.
- Examples: the Warlis of Maharashtra care for forests; the Bishnois protect the Khejri tree and blackbuck; Devrais (sacred groves) of Maharashtra are forest patches protected in the name of local deities and act as gene banks.
- WHO defines health as complete physical, mental and social well-being, not merely the absence of disease.
- Polluted air, water and soil harm health: about 80% of diseases are water-borne; Delhi's smog (October 2016, PM2.5 far above safe limits) forced emergency steps.
- Every organism has a right to a clean, peaceful environment. Value education teaches compassion for life and sharing of natural resources.
Important terms
- Carrying capacity – largest population an environment can support for a long time.
- Demographic transition – shift from high to low birth and death rates as a country develops.
- Indigenous knowledge – traditional local knowledge held by a community.
- Sacred grove (Devrai) – forest patch protected by local people for religious reasons.
Key facts
| Year | World population |
|---|---|
| 1 C.E. | about 170 million |
| 1950 | about 2 billion |
| 1987 | 5 billion |
| 1999 | 6 billion |
5 important questions
Q1. Define birth rate and death rate.
Birth rate is the number of live births per 1000 people in a year; death rate is the number of deaths per 1000 people in a year.
Q2. What are sacred groves?
Forest patches protected by local communities in the name of deities, where cutting, hunting and grazing are forbidden; they conserve biodiversity.
Q3. Explain the stages of demographic transition.
Pre-industrial: high birth and death rates. Transitional: death rate drops, birth rate high, population rises fast. Industrial: birth rate also drops. Post-industrial: low rates, stable population.
Q4. How does environment affect health?
Polluted air causes breathing diseases, contaminated water spreads cholera and typhoid, chemicals in soil enter food, and radiation and e-waste cause serious illness.
Q5. Explain the role of indigenous communities in conservation.
They use resources carefully, protect sacred groves and species (Bishnois, Warlis), preserve wild crop varieties and pass on knowledge of plants and weather.
Exam tip
Draw the demographic transition curve and one population pyramid; diagrams earn marks in EVS answers.