NCERT Class 7 Science Chapter 7: Weather, Climate and Adaptations of Animals to Climate YouTube Lecture Handouts

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NCERT Class 7 Science Chapter 7: Weather, Climate & Adaptations of Animals to Climate

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Activities Are Planned Based on Predicted Weather & Place

Weather

  • Information on temperature (Max & Min), humidity (Max & Min), wind and rainfall for last 24 hours – day to day condition

  • These are known as elements of weather

  • Complex phenomena and varies over very small time

  • By Meteorological Department of Govt.

  • Rainfall is measured by rain gauge

  • Maximum and Minimum Thermometers (Chapter 4) – maximum temperature in afternoon while minimum in early morning

  • Sun plays a major role - Energy absorbed and reflected by the earth’s

  • surface, oceans and the atmosphere play important roles in determining the weather at any place

  • Sunrise and sunset timings change

Climate

  • Weather records preserved for several decades – around 25 years or more

  • If temperature is high, we say climate is hot

  • Find average over month; across months and average of such averages over many years

  • West India – Arid and semi-arid

  • NE India – Wet

Climate and Adaptations

  • Animals are adapted to survive in the conditions in which they live

  • Features to protect themselves from extreme cold or hot conditions

  • Refer Class 6 Chapter 9

  • Polar Regions are Canada, Greenland, Iceland, Norway, Sweden, Finland, and Alaska in U.S.A. and Siberian region of Russia.

  • Extreme climate

  • Cold

  • Snow

  • 6 months day and 6 months night

  • Adapt to severe weather conditions

Polar Bears

  • White fur – not visible in white snow background, maintain warmth (thick layer of fat) – well insulated; move slowly and rest often to avoid being overheated; in summers they head for swimming (wide and large paws to swim and walk easily in snow)

  • For underwater swimming it can close nostrils and remain there for hours

  • Strong sense of smell - helps to locate and catch prey

  • 2 thick layers of fur – to keep itself warm

Penguins

  • White merges with background

  • Thick skin and lot of fat – protect from cold

  • Good swimmers

  • Streamlined bodies

  • Webbed feet – swimming

  • Fishes, musk oxen, reindeers, foxes, seals, whales, and birds are seen in polar areas. Fishes can remain in cold for long but birds have to move to warm areas (migratory birds) – Siberian crane to Bharatpur (Rajasthan) and Sultanpur (Haryana)

  • Birds can travel upto 15000 km to save themselves – fly high helpful with wind flow; cold conditions allow heat to dispersed by flight muscles – sense of direction and use magnetic field of earth to find direction. Besides birds, fishes and insects which allow migrate.

  • Tropical rainforests are found in India (Assam and Western Ghats), Malaysia, Indonesia, Brazil, Republic of Congo, Kenya, Uganda, and Nigeria.

  • Hot climate

  • Near equator

  • Even for coldest month temperature is more than

  • Days and nights are equal in length

  • Variety of animals - monkeys, apes, gorillas, tigers, elephants, leopards, lizards, snakes, birds and insects

  • Competition for food

  • Sensitive hearing, sharp eyesight, thick skin and a skin color which helps them to camouflage

  • Loud voice, sharp patterns, diet of fruits

  • 6% area – with half animal life and 2/3rd plant life

  • Red-eyed frog - sticky pads on its feet to help it climb trees on which it lives.

  • Monkeys – long grasping tails to live on trees; hands and feet can hold branches

  • Toucan – long, large beak (reach branches which are hard to support its weight)

  • Big cats like lion and tiger have thick skin and sensitive hearing

  • Lion tailed macaque (Beard ape) – rainforest of Western Ghats - silver-white mane, which surrounds the head from the cheeks down to its chin, good climber, feed fruits, eat seeds, search for insects under bark of trees

  • Elephant – trunk – nose for smell, pick food; tusks are modified teeth – tear the bark, large ears for soft sounds- keeps it cool in hot humid weather

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