Class 7 Social Science Natural Vegetation and Wild Life Exam Notes

Class 7 Social Science Natural Vegetation and Wild Life Exam Notes. Please refer to the examination notes which you can use for preparing and revising for exams. These notes will help you to revise the concepts quickly and get good marks.

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Class 7 Social Science – Natural Vegetation and Wild Life (Exam Notes)

Natural vegetation

Natural vegetation of an area means the plants that grow naturally in that area, and not because of any human activity. There is a close relationship between the height of the land and the character of the vegetation. With a change in height, the climate changes, and that changes the natural vegetation. The growth of vegetation depends on temperature and moisture. It also depends on factors like slope and the thickness of the soil. The type and thickness of natural vegetation varies from place to place because of the variation in these factors.

Natural vegetation is generally classified into three broad categories:

1. Forests: They grow where temperature and rainfall are plentiful enough to support a tree cover. Depending on these factors, dense and open forests grow.
2. Grasslands: They grow in regions of moderate rain.
3. Shrubs: Thorny shrubs and scrubs grow in the dry regions.

The changes in the type of natural vegetation occur mainly because of changes in the climatic conditions.

Forests

Tropical evergreen forests

1. These forests are also called tropical rainforests.
2. These thick forests occur in the regions near the equator and close to the tropics.
3. These regions are hot and receive heavy rainfall throughout the year.
4. As there is no particular dry season, the trees do not shed their leaves all at once. This is the reason they are called evergreen.
5. The thick canopies of the closely spaced trees do not allow sunlight to penetrate inside the forest, even in the daytime.
6. Hardwood trees like rosewood, ebony and mahogany are common here.

Tropical deciduous forests

1. Tropical deciduous forests are the monsoon forests found in a large part of India, northern Australia and Central America.
2. These regions experience seasonal changes.
3. The trees shed their leaves in the dry season to conserve water.
4. The hardwood trees found in these forests are sal, teak, neem and shisham. Hardwood trees are extremely useful for making furniture, transport and construction materials.
5. Tigers, lions, elephants, langurs and monkeys are the common animals of these regions.

Temperate evergreen forests

1. The temperate evergreen forests are located in the mid-latitudinal coastal regions.
2. They are commonly found along the eastern margins of the continents, for example in south-east USA, south China and south-east Brazil.
3. They comprise both hardwood and softwood trees like oak, pine and eucalyptus.

Temperate deciduous forests

1. As we go towards higher latitudes, there are more temperate deciduous forests.
2. These are found in the north-eastern part of the USA, China, New Zealand and Chile, and also in the coastal regions of Western Europe.
3. They shed their leaves in the dry season.
4. The common trees are oak, ash, beech and so on.
5. Deer, foxes and wolves are the animals commonly found.
6. Birds like pheasants and monals are also found here.

Mediterranean vegetation

1. Most of the east and north-east margins of the continents are covered by temperate evergreen and deciduous trees. The west and south-west margins of the continents are different. They have Mediterranean vegetation. It is mostly found in the areas around the Mediterranean Sea in Europe, Africa and Asia, hence the name.
2. This kind of vegetation is also found outside the actual Mediterranean region: in California in the USA, south-west Africa, south-western South America and south-west Australia.
3. These regions are marked by hot, dry summers and mild, rainy winters.
4. Citrus fruits such as oranges, figs, olives and grapes are commonly cultivated here, because people have removed the natural vegetation in order to cultivate what they want.
5. There is not much wildlife here.

Coniferous forests

1. In the higher latitudes (50° – 70°) of the Northern Hemisphere, the spectacular coniferous forests are found.
2. These are also called taiga.
3. These forests are also seen at higher altitudes.
4. They are tall, softwood evergreen trees.
5. These woods are very useful for making pulp, which is used for manufacturing paper and newsprint.
6. Matchboxes and packing boxes are also made from softwood.
7. Chir, pine and cedar are the important varieties of trees in these forests.
8. Silver fox, mink and polar bear are the common animals found here.

Grasslands

Tropical grasslands

1. These grow on either side of the equator and extend up to the tropics.
2. This vegetation grows in areas of moderate to low rainfall.
3. The grass can grow very tall, about 3 to 4 metres in height.
4. The savannah grasslands of Africa are of this type.
5. Elephants, zebras, giraffes, deer and leopards are common in tropical grasslands.

Temperate grasslands

1. These are found in the mid-latitudinal zones and in the interior parts of the continents.
2. Usually the grass here is short and nutritious.
3. Wild buffaloes, bison and antelopes are common in the temperate regions.

Desert vegetation

1. This is found in the dry, desert-like regions.
2. Tropical deserts are located on the western margins of the continents.
3. The vegetation cover is scarce here because of scanty rain and scorching heat.
4. Due to the scarcity of water, only those plants that can adapt to the hot and dry climate (for example, xerophytic plants) are found here.
5. In the hot deserts, thorny bushes and scrubs are common. Cactus and acacia are the main species.
6. Near the oases, date palms are found.
7. The camel is the most important among the animals found in the deserts. Desert wildlife consists of gazelles, antelopes, wild asses, desert foxes, hares, rodents, hyenas, snakes and lizards. The yak is found in the cold Tibetan desert.

Important deserts of the world are the Sahara (northern Africa), the Kalahari (southern Africa), the Atacama (Chile, South America), the Sonoran (North America), the Great Australian Desert, the Arabian Desert and the Indian Thar Desert. Cool deserts are found in Asia and South America. They include the Gobi Desert and the Tibetan Plateau in Asia and the Patagonian Plateau in South America.

Tundra vegetation

1. The growth of natural vegetation is very limited here.
2. Only mosses, lichens and very small shrubs are found here.
3. They grow during the very short summer.
4. This is called the tundra type of vegetation.
5. This vegetation is found in the polar areas of Europe, Asia and North America.
6. The animals have thick fur and thick skin to protect themselves from the cold climatic conditions.
7. Seals, walruses, musk oxen, the Arctic owl, the polar bear and snow foxes are some of the animals found here.