About three-fourths of the earth’s surface is covered with water. But most of the water on earth is in the oceans. Ocean water is saline and hence is not fit for human consumption. Just 2.7% of the total water on the earth is available as freshwater. But 70% of the total freshwater on the earth is available as frozen ice in glaciers and icebergs. This leaves less than 1% of the total water on earth for human consumption. This is available as groundwater, as surface water and as water vapour.
Hence, freshwater is a precious resource for us. The total volume of water on the earth remains constant. Water keeps on getting cycled through oceans, the air, the land and back to ocean; through a process called water cycle.
Human beings use water for a variety of purposes; like drinking, bathing and washing. Water is also used in production of various things for our use. Moreover, water is used in agriculture, industries and in electricity generation.
Increasing population has resulted in exploitation of water on an even larger scale. This has resulted in shortage of water at many places. Shortage of drinking water is a major problem in many parts of the world. Almost all the continents are facing the problem of water scarcity.
Biosphere: Natural vegetation exists only in the biosphere. The narrow zone of contact between the lithosphere, hydrosphere and atmosphere; in which life exists is called biosphere.
Ecosystem: The living beings are inter-related and interdependent on each other for survival. This life supporting system is called ecosystem.
Importance of Natural Vegetation: Vegetation provides shelter to animals and provides us with timber and many other forest produce. Plants also produce oxygen when they make food and oxygen is the gas we breathe. Plants protect soil from degradation. Plants help in recharging the groundwater.
Wildlife: Animals, birds, insects as well as the aquatic life forms comprise the wildlife. We get meat and leather from animals. Honey bees provide us with honey. Insects are the major pollinators and thus help not only the plants but also the human beings. Some animals play the role of scavengers and clean the dead remains of animals. All animals play important role in maintaining the balance in the ecosystem.
Evergreen Forests: Trees of evergreen forests do not shed their leaves at a particular time in a year. Evergreen forests are found in tropical regions which get plenty of sunshine and rainfall.
Deciduous Forests: Trees of deciduous forests shed their leaves at a particular time in a year. Deciduous forests are found in subtropical regions which get moderate sunshine and rainfall.
Deforestation, soil erosion, construction activities, forest fires, tsunami and landslides are some of the factors which are causing extinction of forest and wildlife resources. Poaching is another concern which is leading to extinction of valuable wildlife.
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