👉NCERT-GEOGRAPHY-CLASS-7-NOTES 👀
Tropical region
- As we know, the Earth’s axis is tilted at an angle of 23.5°. Due to this axial inclination, the apparent position of the Sun shifts between the Northern Hemisphere and the Southern Hemisphere throughout the year.
- The maximum northward position of the Sun is marked by the "Tropic of Cancer (23.5° N)", while the maximum southward position is marked by the Tropic of Capricorn (23.5° S).
- The region lying between these two latitudes receives direct rays of the Sun at least once a year. Therefore, this area is known as the Tropical Zone or the Torrid Zone of the Earth.
Equatorial region
Generally, the term equatorial region is often used synonymously with the tropical region, but geographically, they are not exactly the same.
- More specifically, the equatorial region refers to the area surrounding the Equator.
- It is commonly considered to extend from 10° North latitude to 10° South latitude. Some geographers define it more narrowly, from 8° North to 8° South.
- This region represents the broad, relatively bulged part of the Earth around the Equator.
- Due to the Earth’s shape and position, it receives the most direct and vertical rays of the Sun throughout the year.
- As a result, the equatorial region experiences=
- high temperatures,
- intense heating,
- heavy convectional rainfall, and
- dense vegetation, especially tropical rainforests.
- A place where a water stream or river merges with the larger river / Sea, known as the river mouth
- Every river has its horizontally expanded catchment area, that is, the geographical area covered by the main river and its tributaries, known as river basins.
- Because a water stream or a river always flows in a low-lying area rather than its surroundings, that's why that low-lying area with a gentle slope is known as a basin.
👉NCERT-GEOGRAPHY-CLASS-6-NOTES👀
The climate of the tropical region
- The tropical region, as we have studied, receives vertical sun rays throughout the year.
- Because of these vertical sun rays, the tropical region, throughout the year, receives more heat from the process of insulation, which is catalysed by the Earth's surface being almost flat around the equator.
- This combined effect results in a hot and humid/wet climate.
- Due to vertical sun rays, no transformation of season.
- The highest level of rainfall almost every day.
- The relative humidity on average is between 75% to 88%.
Canopy
- Due to plenty of rainfall, a thick forest cover grew in the tropical region which forms a dense tree roof created by leaves and branches, which is known as a canopy.
Shade-tolerant vegetation
- Due to the presence of canopy and ground, throughout the year, it remains dark and damp.
- So in the forest area, the vegetation grew on the ground, known as shade-tolerant vegetation.
Slash and burn agriculture.
- In slash-and-burn agriculture, the vegetation and trees on a particular piece of land are first cut down and cleared.
- After drying, the vegetation is burned, and the ashes left behind increase the fertility of the soil. Farmers then cultivate crops on that land for a short period of time.
- When the fertility of the soil decreases after continuous cultivation, the cultivators leave that piece of land and move to another area, where the same process is repeated.
- The previously used land is left fallow so that natural vegetation can regenerate over time.
- This method of farming is also known as "shifting cultivation" and is practised in some tropical forest regions of the world.
Manioc?
- Manioc is the staple food of tropical regions of people.
- Also known as "cassava".
- Manioc grows beneath the ground like a potato.
- The large apartment-like houses in the tropical region have a steeply slanting roof, known as maloca.
- The subtropical region extends approximately from 20° North to 30° North latitude in the Northern Hemisphere and from 20° South to 30° South latitude in the Southern Hemisphere.
- The equatorial influence is strongest near the Equator up to around 10°.
- Tropical climatic influence dominates roughly up to 20°.
- Beyond 20° latitude, subtropical climatic characteristics such as:
- high-pressure belts,
- dry conditions,
- desert formation,
- Mediterranean-type climate,
- begin to develop prominently.
Monsoon climate
- Monsoon climate refers to a type of climate that is strongly influenced by seasonal monsoon winds.
- It is mainly found in tropical and subtropical regions and is characterized by a distinct seasonal reversal of winds, resulting in a wet season and a dry season.
- This climate receives a high amount of rainfall during the monsoon season and generally experiences high temperatures throughout the year.
- In most monsoon climatic regions, the monthly mean temperature remains above 18°C.
The Indian state of the Ganga-Brahmaputra river basin
- In total, we have 17 states of the Ganga - Brahmaputra river basin.
- In the state's classification, 11 States of the Ganga river basin and six states of the Brahmaputra river basin.
- The geographical area covered by the Ganga river basin is about 8,60,000 square kilometres, which is about 26.5% of the country's total geographical area.
- Uttar Pradesh,
- Madhya Pradesh,
- Rajasthan,
- Bihar,
- West Bengal,
- Uttarakhand,
- Jharkhand,
- Haryana,
- Chhattisgarh,
- Himachal Pradesh and
- Delhi is in the state of the Ganga river basin.
- On the other hand, the basin area of the Brahmaputra River in India is about 200000 square kilometres.
- The present States include
- Arunachal Pradesh,
- Assam,
- Meghalaya,
- Sikkim,
- Nagaland and
- West Bengal.
How the environment plays a dominant role in the distribution of the population
- As we know, the environment has three components: it is
- natural environment,
- human environment and
- human itself.
- So, if we have our surrounding environment where we have a mountain with a steep slope and an in-hospital train, a general distribution pattern of population will not be smooth, as hard efforts need to be made to achieve something.
- Where in respect of planes, the availability of water, and flat terrain are the prime characteristics, which provide good opportunities for agricultural activities that produce raw materials for every kind of manufacturing and economic activity.
- That's why taking into cognisance, the comparative availability of our environment determines a good distribution of the population in the plains area.
What is the density of the population?
- The number of people living in an area unit of 1 square kilometre is known as the density of the population.
Paddy
- It is the staple crop for the Ganga Brahmaputra river basin.
Cash crops
- The crops that are cultivated to be directly sold into the market are known as cash crops.
- That means the crop has commercial value rather than domestic use.
- This is the common vegetation cover of the Brahmaputra plains.
Susu?
- A kind of dolphin we found in the rivers Ganga & Brahmaputra.
- The dolphin is locally known as "Susu".
- The prime characteristic of this dolphin is that it is used to living in clean and healthy water.
- This dolphin is essentially blind, which is why also known as a "blind dolphin".
- Along with the Ganga and Brahmaputra rivers, this dolphin is also found in the Indus River in the area of Pakistan.
- Presently is on the list of endangered species.
- In 2009 is dolphin was declared India's national aquatic animal.
Complexities of this river basin area
- A great amount of sewage water, which is untreated water, gets discharged into rivers, causing great harm to the river ecosystem and ecology.
- Unknown scientific and unidirectional economic development is causing great harm to our environment.
- We need to interconnect economic development and nature-friendly scientific proceedings to achieve this.
Swachh Bharat Mission?
- The mission launched in the year 2014 to target the elimination of
- open defecation and
- Improvement of solid waste management.
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