I. Choose the correct answer:
1. The surrounding in which organisms live and interact is called Environment.
2. The process of clearing the forests by human is called as Deforestation.
3. The process by which eco system species become extinct is Loss of biodiversity.
4. The excessive use of artificial fertilizer greatly reduces the quality of soil.
II. Match the following:
1. Global warming -CO2
2. Deforestation -Coastal flooding
3. Automobile -air pollution
4. Water pollution -pesticides
5. Urbanisation -unauthorized encroachments
III.ANSWER IN BRIEF:
1. What are the major environmental issues?
- Environmental pollution
- Global warming
2. What is global warming?
Global warming is defined as an increase in the atmospheric temperature near the earth surface due to rise in carbon dioxide levels and green house effects.
3. What is Deforestation?
Deforestation simply means cutting down a tree.
It has seriously affected the quality of environment by increasing the temperature, decreasing rainfall, top soil erosion, flash flood.
4. Name some of green house effect?
Carbon-di-oxide, Methane, Nitrous oxide and Chloro-fluoro-carbon.
5. What is pollution?
Substances released into an environment that cause harm to living organism and built up structures are called pollution.
6. What is urbanization?
It refers to increasing inhabitants of people with non agricultural occupation with a higher population density than the surrounding regions.
7. What are the main threats to biodiversity?
Uncontrolled commercial exploitation of natural resources like forest, coastal areas, wet lands.
8. What are the sources of land pollution?
Land pollution is the contamination of land by solid wastes.
IV. ANSWER THE FOLLOWING:
1. What are the effects of the global warming?
Heat waves and fluctuating weather causes diseases and warming up of Antarctic and Arctic ocean.
Sea level rise coastal flooding due to glaciers melting coral reefs bleaching due to the change in the ecosystem frequent drought fire and heavy snowfall.
2. What is the main objectives of the biosphere reserves?
The main objectives of the reserves is to conserve the genetic diversity of species and to restore degraded ecosystems to their natural and original conditions.
To protect the biosphere, biosphere reserves have been set up in the Nilgiris and Gulf of Mannar.
3. Mention the areas of water pollution in Tamil Nadu and what steps have been taken by the government to stop it?
- The indiscriminate discharge from textile bleaching and dyeing units in and around Tiruppur, Erode and Karur areas have caused polluting the river system of Noyyil and Amaravathi
- Effluents from tanneries for land quality deterioration in the river palar basin of Vellore district
- Most towns located along the banks of major rivers causes sewage pollution.
- The Kaveri river receives sewage from eleven towns, Palar from six towns, Vaigai from five towns and Tamirabarani from three towns.