These DAV Class 7 SST Notes and DAV Class 7 SST Chapter 6 Notes – Life on the Earth hold significant importance as study material for students.
Life on the Earth Class 7 DAV Notes
→ Biosphere is the living zone. It is divided into two plant kingdom and animal kingdom which live together in complete harmony. In this zone, living and non-living things are also dependent on each other for their existence.
→ Under the plant kingdom, we study different vegetation belts of the world. Vegetation includes forests, grasslands, bushes and shrubs. They vary from place to place because of the variation in climatic conditions.
→ Vegetation belts of the world are- tropical hardwood forests, grasslands, deserts and temperate softwood forests.
→ Tropical hardwood forests are found in tropical regions. These forests are divided into two groups- tropical evergreen forests and tropical deciduous forests. Tropical evergreen forests are found in the regions of heavy rainfall while tropical deciduous forests grew in the regions where there is moderate rainfaii.
→ Grasslands are found in the areas of scanty rainfall. They are of two types- tropical grasslands and temperate grasslands. Tropical grasslands receive about 100 cm rainfall while temperate grasslands receive about 25 to 75 cm rainfall.
→ Deserts are vast areas with scanty vegetation due to poor rainfall. There are two types of deserts- hot deserts and cold deserts. The Sahara desert in Africa is a hot desert and northern part of Siberia in Russia is a cold desert.
→ Temperate softwood forests are known as Taiga. These are also known as coniferous forests.
→ The animal kingdom includes birds, insects or animals. These animals vary from place to place because of the variation in the natural environment.
→ A large variety of animals is found in the equatorial region. The common animals found there are different types of monkeys, elephants, crocodiles etc.
→ Grasslands are the homes of animals like lion, cheetah, leopard, deer, rabbit, etc. in the polar region, the animals have thick fur on their body which protect them from extreme cold. For example, poiar bear, yak, etc.
→ Forests are fast depleting due to man’s selfish activites. As the result of the ecological balance is highly disturbed all over the world. The pollution level is also increasing day by day. Hence, we must stop the exploitation of nature on such scale. We should encourage afforestation.
→ Ecosystem : The relationship between plant kingdom, animal kingdom and human beings with their environment.
→ Homosapiens : The first human beings on the Earth’s surface.
→ Taiga : A type of vegetation found in the higher attitudes of Northern Hemisphere.
→ Flora : Plant kingdom.
→ Fauna : Animal kingdom.
→ Afforestation : The process of establishing a forest especially on land not previously forested or land cleared earlier due to deforestation.
→ Deciduous trees : Trees that shed their leaves in the same season every year.
→ Ecological balance : A term describing how ecosystems are organised in a state of stability where species co-exist with other species and their environment.
→ Habitat: The part of environment that offers the conditions favourable for plants or animals to exist.
→ National parks : Large areas of public land set aside for protection of their natural beauty, native plants, animals and habitats in which they live. Generally national parks make the core zone of a biosphere reserve in which wildlife is strictly protected and no human activity is permitted.
→ Wildlife sanctuary : A place that is set aside for the purpose of protecting wild animals, generally endangered species, where these live, breed and are closely monitored for their survival.
→ Biosphere reserve : An area of land or water that is protected by law in oraer to support the conservation of ecosystems as well as the sustainable co-exisience of man with nature.