1.(a) Define the following (any five)
(i) Land degradation
(ii) Atmosphere
(iii) Wetlands
(iv) Nuclear energy
(v) Ozone hole
(vi) Tundra ecosystem
Answer -
(i) Land degradation
| Land degradation means the deterioration of land quality. It is caused by the loss of soil fertility, structure, and nutrients. This process is mainly caused by excessive cultivation, deforestation, grazing, and pollution. Water and wind erosion, chemical use, and urbanization also promote land degradation. It affects crop production, environment, and fauna. Soil conservation, tree planting, and water management are necessary to prevent it. |
 |
(ii) Atmosphere
The atmosphere is the layer of air surrounding the Earth, filled with gases essential for life such as oxygen, nitrogen, and carbon dioxide. The atmosphere protects the Earth from the sun's harmful rays and controls the weather.
Troposphere: It is the lowest layer of the atmosphere, in which weather changes and clouds form.
Stratosphere: The ozone in the stratosphere protects life on Earth from harmful ultraviolet (UV) radiation and is therefore often called 'good' ozone.
Mesosphere: It is the middle layer of the atmosphere, where the temperature is very low.
Thermosphere: It is the upper layer, which has very high temperatures and ionized particles. |
|
Click Here For Full Notes
(iii) Wetlands
| Wetland means an area where there is mostly moisture or marshy land. Wetlands are transitional land between terrestrial and aquatic ecosystems. In these, the water level is usually at or near the ground surface or the land is covered with shallow water. Wetlands are an important part of the natural ecosystem. Wetlands can be of many types: swamps, lakes and ponds, water-in-soil wetlands They are very important for climate change, flood control, water recharge and environmental balance. |
|
(iv) Nuclear energy
Nuclear energy is a type of energy that is present in the atomic nucleus (the centre of the atom). It can be obtained from two main processes:
|
1. Nuclear Fission: In this, the nucleus of a heavy element, such as
uranium-235, is broken into smaller nuclei by hitting it with a neutron. A large amount of energy is released in this process. It is used in controlled nuclear reactors to produce electricity.
2. Nuclear Fusion: In this, two nuclei of lighter elements, such as hydrogen, combine to form a heavier nucleus. This process produces a lot of energy but requires very high temperatures (about 1 billion degrees Celsius).
The heat released from both these processes is used to make steam and then run electric turbines to generate electricity.
|
|
(v) Ozone hole
|
An ozone hole is an area where the ozone layer is thinned or damaged. This layer protects life on Earth by absorbing the sun's harmful ultraviolet (UV) rays. Ozone holes are mainly found over Antarctica in the Southern Hemisphere. Human activities, especially the use of chlorofluorocarbons (CFCs), damage the ozone layer. The problem came to light in the 1980s, following which awareness and international efforts grew. Ozone holes cause problems like skin cancer, eye diseases and environmental imbalances.
|
|
Click Here For Full Notes
(vi) Tundra ecosystem
| The tundra ecosystem is found in cold regions, such as the Arctic and alpine tundra, where there are long winters, low precipitation, and permafrost. The flora includes mosses, lichens, grasses, and dwarf trees, while the fauna includes arctic foxes, lemmings, and snowy owls. Climate change and human activities, such as oil-gas exploration, are harming it. Melting permafrost is causing the expansion of coniferous trees. |
|
(b) State whether True or False
(i) In an ecosystem, energy flows from consumers to producers.
(ii) Mangrove forests can be found in the state of Madhya Pradesh.
(iii) Biomedical waste is an example of hazardous waste.
(iv) Rubber, resins, tree oils etc are examples of Non timber Forest Products (NTFP)
(v) Removal of top layer of soil by the action of wind or water is called as land degradation.
Answer-
| (i) In an ecosystem, energy flows from consumers to producers. |
False |
| (ii) Mangrove forests can be found in the state of Madhya Pradesh. |
False |
| (iii) Biomedical waste is an example of hazardous waste. |
True |
| (iv) Rubber, resins, tree oils etc are examples of Non timber Forest Products (NTFP). |
True |
| (v) Removal of top layer of soil by the action of wind or water is called as land degradation. |
False |
Click Here For Full Notes
