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You are here: Home / Geography / 7th standard geography NCERT Summary

7th standard geography NCERT Summary

April 30, 2020 by BureaucratONE Leave a Comment Last Updated April 30, 2020

Table of Contents hide
1 ENVIRONMENT
1.1 Component of Environment
2 INSIDE OUR EARTH
2.1 Crust
2.2 Mantle
2.3 Core
2.4 Rocks and Minerals
3 OUR CHANGING EARTH
4 AIR
4.1 Composition of the atmosphere
4.2 Structure of Atmosphere
4.3 Weather and Climate
4.4 Temperature
4.5 Air pressure
4.6 Wind
4.7 Moisture
4.8 WATER
4.9 DISTRIBUTION OF WATER BODIES
4.9.1 Salinity
4.9.2 Ocean circulation
4.9.3 Ocean Currents
5 NATURAL VEGETATION AND WILD LIFE
5.1 3 types of natural vegetation
5.2 FORESTS
5.3 GRASSLAND
6 HUMAN ENVIRONMENT --SETTLEMENT, TRANSPORT AND COMMUNICATION
7 Human-Environment Interactions - The tropical and the subtropical Region
7.1 AMAZON BASIN
7.2 GANGA-BRAHMAPUTRA BASIN
8 Life in Temperate Grassland
8.1 The Prairies
8.2 THE VELDS
9 LIFE IN THE DESERTS

ENVIRONMENT

Component of Environment

  • Natural
    • Air - atmosphere
    • Water - hydrosphere
    • Land - Lithosphere
    • Living Things - Biosphere
  • Human-made
    • Parks, building, roads, monuments
  • Human
    • Individual, family, community, religion, educational, economic, political situation
  • Environment
    • Biotic and abiotic
  • Environment - French word Environer/Environner meaning neighbourhood
  • Ecosystem - It is the system formed by the interaction of all living organisms with each other and with the physical and chemical factors of the environment in which they live, all linked by transfer of energy and material
  • 5 June - World Environment Day 

INSIDE OUR EARTH

Crust

  • Continental crust - 35km - SIAL = Silica and Aluminium
  • Oceanic crust - 5km - SIMA = Silica and Magnesium
  • 1% of earth's volume

Mantle

  • 2900km
  • 84% earth's volume

Core

  • 3500km
  •  NIFE - Nickel and Ferrous
  • 15% earth's volume

Rocks and Minerals

  • Igneous
    • Ignis(latin) - fire
    • Molten magma cools and solidifies to become igneous
    • Two types
      1. Intrusive - inside earth
        • Cools down slowly so large grains
        • granite
      2. Extrusive - outside earth
        • Cools fast so fine grain
        • Basalt- Deccan plateau
  • Sedimentary
    • Sedimentum(latin) - settle down
    • Sediments compressed and hardened to form sedimentary rocks
    • Sandstone - sand
  • Metamorphic
    • Metamorphose(greek) - change form
    • Igneous and sedimentary change into metamorphic
    • Clay into slate
    • Limestone into marble
  • Minerals
    • Naturally occurring substances which have certain physical properties and definite chemical composition
    • Coal, petroleum, gold uranium

OUR CHANGING EARTH

  • Lithosphere is broken into a number of plates known as the Lithospheric plates
  • Earth movements
    • Endogenic forces
      • Sudden forces - Earthquake, Volcano, Landslides
      • Diastrophic forces - Building mountains
    • Exogenic forces
      • Erosional and depositional
        • River, Wind, Sea-waves, Glaciers
  • Volcano
  • Earthquake
    • The place in the crust where the movement starts is focus 
    • The place on the surface above the focus is epicentre
    • Earthquake waves
      • P waves - longitudinal waves
      • S waves - transverse wave
      • L waves - surface waves
    • Seismograph is used to measure earthquake
    • Richter scale is used to measure the intensity
  • Major Land forms
    1. Waterfall
      • Highest - Angel waterfall in Venezuela
      • Others - Niagara between USA and Canada / Victoria between Zambia and Zimbabwe Africa
    2. Meanders
      • Forms ox-bow lake
    3. Flood plains
      • River overflows its bank deposits sediments and forms a fertile flood plains
    4. Levees
      • Raised bank of river
    5. Distributaries
      • River slows down as it approaches sea and break up into distributaries
    6. Delta
      • Each distributaries forms its own mouth and collection of sediments from all the mouth is delta
    7. Coastal landforms
      • Sea caves - cavities
      • Sea arches - caves become big
      • Stacks - arches roof falls
      • Sea cliff - steep rocky coast
    8. Glacial landforms
      • Glacial deposits - all glacial deposits
    9. Work of wind
      • Mushroom rocks
      • Sand dunes
      • Loess - very fine and light grains of sand carried over long distance and deposited over large area like in china

AIR

Composition of the atmosphere

  • Nitrogen - 78%
  • Oxygen - 21%
  • Argon - 0.93%
  • Carbon dioxide - 0.03%

Structure of Atmosphere

  1. Troposphere
    • 13km
    • All weather activities
  2. Stratosphere
    • 13-50km
    • Free from clouds and weather so aeroplane
    • Ozone
  3. Mesosphere
    • 50-80Km
    • Meteorites burns up here
  4. Thermosphere
    • Temperature rises rapidly with height
    • Ionosphere part of it - radio waves reflect here
    • 80-400Km
  5. Exosphere
    • Thin layer
    • Light gas like helium and hydrogen

Weather and Climate

  • Average Weather condition of a place for a longer period of time represents the climate

Temperature

  • Insolation - Isolation is the incoming solar energy intercepted by the earth
  • IS unit - Celsius invented by Anders Celsius
  • Thermometer is used to measure it

Air pressure

  • Pressure exerted by the pressure by the weight of air on the earth's surface
  • With height pressure decreases
  • High temperature - warm air rises - low-pressure areas - high rainfall
  • Low temperature - cold air sinks - high-pressure areas - low rainfall 
  • Barometer is used to measure pressure

Wind

  • High to low pressure
  • Wind Vane is used to show direction
  • Three types
    1. Permanent winds
      • Trade winds
      • Westerlies
      • Easterlies 
    2. Seasonal Winds
      • Monsoon
    3. Local Winds
      • Hot and dry local winds in northern planes - Loo
900N 
Polar 
aster es 
600N 
350 
BOON 
23.50N - 
Sib-Polar Low 
Prevaili g Westerli 
Sub - Tropical High Pressure (Horse Latitudes) 
Cancer 
ort he t Tra 
u the a 
Win 
Wind 
Tropic o Capricorn 
23.50 
350S 
Sub - Tropical High (Horse LatituMæ) 
Prevaili 
Westerlfe 
Sub-Polar Low Pressure 
Polar 
aster es 
Bio Pmsure 
ocrs 
Major Pressure Belts and Wind System

Moisture

  • 3 type of rainfall
    • Convectional rainfall - warm air goes up
    • Relief or orographic rainfall - moist air hits mountain
    • Cyclonic rainfall - cold air and warm air meets

WATER

  • World - Major seas, lakes and rivers
AFRICA 
OCEAN 
OCEAN

DISTRIBUTION OF WATER BODIES

  • 3/4th of earth is water
  • Ocean - 97.3%
  • Ice caps - 2%
  • Other sources - 0.7%
  • March 22 - World Water Day 

Salinity

  • Amount of salt in grams present in 1000 grams of water
  • 35 parts per 1000 - average ocean salinity
  • Dead sea in Israel - 340 grams per litre

Ocean circulation

  1. Waves
    • Tsunami - 15m high
    • Highest 150m
    • Speed - 700km/hr
    • Tsunami is a Japanese word meaning harbour waves
  2. Tides
    1. Spring Tide(high tides) - During full moon and new moon day - earth-sun-moon same line
      • Helps in arrive at harbour more easily
      • Helps fisherman also
    2. Neap Tide(low tide) - When moon and sun at right angle

Ocean Currents

Eq Cum* 
westwg,d 
Eq Cuw't 
00 
SOUTHERN 
1800
Ocean Currents

NATURAL VEGETATION AND WILD LIFE

3 types of natural vegetation

  • Forests - high rainfall region
  • Grasslands - moderate rainfall region
  • Shrubs - dry region

FORESTS

  • Tropical evergreen forests or Tropical rainforest
    • Equatorial climate - hot and wet
    • Thick canopy
    • No dry season for shedding - so evergreen
    • Hard Wood
      • Rosewood
      • Ebony
      • Mahogany
  • Tropical deciduous forests or monsoon forest
    • Places
      • India, NA, Central America
    • Trees shed during dry season
    • Hard Wood
      • Sal
      • Teak
      • Neem
      • Shisham
    • Animals
      • Tiger
      • Lion
      • Elephant
  • Temperate Evergreen Forests
    • Mid Latitudes
      • Eastern margin of continents
      • S.E USA
      • South China
      • South East Brazil
    • Hard and soft wood
      • Oak
      • Pine
      • Eucalyptus
  • Temperate Deciduous Forests E
    • N.E part
      • USA
      • CHINA
      • NEW ZEALAND
      • CHILE
    • Trees
      • Oak
      • Ash
      • Beech
    • Animal
      • Deer
      • Foxes
      • Wolves
    • Birds
      • Pheasants
      • Monals
  • Mediterranean Vegetation
    • Hot dry summer and mild rainy winters
    • Thich barks and wax coated leaves protect from transpiration
    • Mediterranean region is Orchards of the world
    • West and South west margins of continents
      •  Around Mediterranean sea
      • California
      • S.W Africa
      • S.W South Africa
      • South Australia
    • Trees
      • Citrus fruits like oranges, figs, olives and grapes
    • Not much wild life
  • Coniferous Forests or taiga
    • Higher latitudes - 50*-70* of northern hemisphere
    • Taiga means pure in Russian
    • Higher altitude like Himalayas
    • Soft Wood evergreen trees - used for paper, match boxes, packing boxes
      • Chir
      • Pine
      • Cedar
    • Animals
      • Siler fox
      • mink
      • Polar bear

GRASSLAND

  1. Tropical Grassland
    • Either side of equator
      • Savannah grassland of Africa
      • Brazil - Campos
      • Venezuela - Llanos 
    • Tall grasses - 3 to 4 m
    •  Animals
      • Elephant
      • Zebras
      • Giraffes
      • Deer
      • Leopards
  2. Temperate grasslands
    • Mid Latitudes and interior part of continents
      • Argentina - Pampas
      • North America - Prairie
      • South America - Veld
      • Central Asia - Steppe
      • Australia - Down  
    • Short but nutritious grass
    • Animals
      • Wild buffaloes
      • Bison
      • Antelopes
  3. Thorny bushes
    • Found in dry desert with scanty rainfall and scorching heat
    • Western margin of continents
  4. Tundra
    • Polar region
    • Only mosses, lichens and very small shrubs during very short summer
    • Thick fur and thick skin
      • Seal
      • Walrus
      • Musk-oxen
      • Arctic owl
      • Polar Bear
      • Snow foxes

HUMAN ENVIRONMENT --SETTLEMENT, TRANSPORT AND COMMUNICATION

  • Transhumance - It is a seasonal movement of people who rear animals in search of new pastures

Human-Environment Interactions - The tropical and the subtropical Region

AMAZON BASIN

  • Amazon River - Named after fierce tribe called Amazons
  • Sunlight doesn't hit the ground in Amazon
  • Shade tolerant vegetation in Amazon forest - Orchids and Bromeliads(water is stored in its leaves which is used by frogs to lay eggs)
  • Birds - usually makes loud noise
    • Toucans
    • Humming bird
  • Animals
    • Monkeys
    • Sloth
    • Ant-eating tapirs
  • Reptiles
    • Anaconda
    • Crocodile
    • Snakes
    • Python

GANGA-BRAHMAPUTRA BASIN

  • Ganga's tributaries - Ghaghra, son, Chambal, Gandak, Kosi
  • Brahmaputra's other names - Bengali Jamuna, Tibetan Tsangpo, Chinese (Pinyin) Yarlung Zangbo Jiang
  • Vegetation
    • Plains - tropical deciduous, teak, sal, peepal and bamboo
    • Delta- Mangrove
    • Uttarakhand, Sikkim and Arunachal - Coniferous
  • Wildlife
    • Tigers
    • Deer
    • Monkeys
    • One horned rhinoceros
    • Delta
      • Bengal tiger
      • Crocodiles
      • Alligator
    • Aquatic
      • Blind dolphin or Susu

Life in Temperate Grassland

  • Grassland 1/4 th land surface
  • Two types
    • Temperate
    • Tropical

The Prairies

  • North America
    • Prairie means meadow in Latin
    • Mostly treeless
    • Tall grass upto 2m
    • Drained by Mississippi in USA and Saskatchewan in Canada
    • Rock Mountain in west and Great Lakes in East
    • Prairies were home land of Red Indians and other tribes like Apache, Crow, Cree and Pawnee
  • Climate
    • Heart of continent so continental climate
    • Summers are warm(20) and winters very cold(-20*)
    • Chinook is hot wind that blows in this region due to absence of north-south barrier
    • Rainfall is moderate
  • Flora 
    • Willows
    • Alders
    • Poplars
  • Fauna
    •  Bison or American Buffalo
    • Rabbits
    • Coyotes
    • Gophers
    • Prairies dog
  • Economy
    • Cattle rearing - large cattle farms are called as RANCHES
    • Dairy farms
  • Important Cities
    • USA
      • Minneapolis
      • Indianapolis
      • Kansas
      • Denver
    • Canada
      • Edmonton
      • Saskatoon
      • Calgary
      • Winnipeg

THE VELDS

  • Name given by Dutch settlers before south Africa was colonised
    • Velds are rolling plateaus with varying heights - 600m and 1100m
    • Tributaries of Orange and Limpopo drain the region
  • Climate
    • Mild climate due to Indian Ocean
    • Winters are cold and dry - 5*-10*
    • Summer is short and warm - 20*
    • Flora
      • Red Grass
      • Acacia
      • Maroola
    • Animals
      • Lions
      • Leopards
      • Cheetah
      • Kudu
    • People
      • Wool industry and sheep rearing - Merino Sheep
      • Soil is not fertile
      • Iron and Steel Industry 
      • Gold and Diamond mining
      • Johannesburg is known as Gold capital of World
      • Kimberley is famous for its diamond mines

LIFE IN THE DESERTS

  1. The hot Desert -SAHARA
    • Biggest in the world - Bigger than India
    • Touches 11 countries - Algeria, Chad, Egypt, Libya, Mali, Mauritania, Morocco, Niger, Sudan, Tunisia and Western Sahara
    • Extreme hot days and cold nights
    • Al Azizia, Libya recorded 57.7*C in 1922
    • Flora and Fauna
      •  Cactus
      • Date
      • Palms
      • Acacia
    • Fauna
      • Camels
      • Hyenas
      • Jackals
      • Foxes
      • Scorpions
      • Snakes and lizards
    • People
      • Oasis and Nile valley supports them
      • Egypt's cotton
      • Bedouins and Tuaregs are the tribes
      • Oil in Algeria, Libya and Egypt
  2. The Cold Desert - LADAKH
    • La-mountain pass and Dak- country
    • Ladakh a.k.a KHAPA-CHAN means snow land
    • Drass - Coldest inhabited places on earth is in Ladakh
    • Karakoram Range in North
    • Zanskar mountain In South
    • Indus
    • Gangri Glacier
    • Kargil - 8000km in the karakoram
      • Air is so thin Sun can be felt intensely
    • Flora
      • Willows
      • Poplars
      • Apples
      • Walnuts
      • Apricots
    • Birds
      • Robins
      • Redstarts
      • Tibetan snowcock
      • Raven
      • Hhoopoe
    • Animals
      • Wild goats
      • Wild sheep
      • Yak
      • Special kind of dogs
      • Chiru or Tibetan Antelope - its wool is known as SHAHTOOSH
    • People
      • Buddhist or Muslims
      • Famous monasteries
        • Hemis
        • Thiksey
        • Shey
        • Lamayuru
      • Leh capital of Ladakh is connected to Kashmir with National highway 1A passing through Zoji La Pass
      • Leh highway passes through 4 passes
        • Rohtang La
        • Baralacha La
        • Lungalacha la
        • Tanglang La 

Filed Under: Geography, GS1, NCERT, UPSC

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