CBSE – 7th Standard Science

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Chapter 7 – Weather, Climate and Adaptations of Animals to Climate

Chapter 7

Weather, Climate and Adaptations of Animals to Climate

  • The day to-day condition of the atmosphere at a place with respect to the humidity, rainfall, temperature, wind speed, etc., is called the weather at that place.

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  • The temperature, humidity, and other factors are called the elements of the weather.
  • The weather is such a complex phenomenon that it can vary over very short periods of time, it is not easy to predict.
  • Rainfall is measured by an instrument called the rain gauge.
  • It is basically a measuring cylinder with a funnel on top to collect rainwater.

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  • There are special thermometers for maximum and minimum thermometers.
  • The maximum temperature of the day occurs generally in the afternoon while the minimum temperature occurs generally in the early morning.
  • Sun is the primary source of energy that causes changes in the weather.
  • Energy absorbed and reflected by the earth’s surface, oceans and the atmosphere play important roles in determining the weather at any place.

 

  • Meteorologists record the weather every day.
  •  The records of the weather have been preserved for the past several decades.

 

  • The average weather pattern taken over a long time, say 25 years, is called the climate of the place like hot and dry, rainy or cool.

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  • Climate has a profound effect on all living organisms. Animals are adapted to survive in the conditions in which they live.
  • Animals living in very cold and hot climate must possess special features to protect themselves against the extreme cold or heat.
  • The Polar Regions present an extreme climate, in winters the temperature can be as low as –37°C.
  •  Animals living there have adapted to these severe conditions.
  • Polar bears have white fur so they are not easily visible in snow, it protects them from their predators also helps them in catching their prey.
  • To protect them from extreme cold, they have two thick layers of fur and also a layer of fat under their skin.
  • Penguin bodies are streamlined and their feet have webs, making them good swimmers.
  • Other animals living in the Polar Regions are many types of fishes, musk oxen, reindeers, foxes, seals, whales, and birds, fish can remain under cold water for long, and birds must remain warm to survive.
  • Birds migrate to warmer regions when winter sets in. They come back after the winter is over.
  • The tropical region has generally a hot climate because of its location around the equator. These regions get plenty of rainfall.
  • An important feature of this region is the tropical rainforests.

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  • The major types of animals living in the rainforests are monkeys, apes, gorillas, tigers, elephants, leopards, lizards, snakes, birds and insects.
  • The climatic conditions in rainforests are highly suitable for supporting an enormous number and a variety of animals.
  • Since the numbers are large, there is intense competition for food and shelter.

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  • Many animals are adapted to living on the trees. Red-eyed frog has developed sticky pads on its feet to help it climb trees on which it lives.
  • To help them live on the trees, monkeys have long tails for grasping branches.

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  • Their hands and feet are such that they can easily hold on to the branches.
  • As there is competition for food, some animals are adapted to get food the bird
  • Toucan which possesses a long, large beak.
  •  This helps a toucan to reach the fruits on branches which are otherwise too weak to support its weight.
  • Many tropical animals have sensitive hearing, sharp eyesight, thick skin and a skin colour which helps them to camouflage by blending with the surroundings. This is to protect them from predators.
  • Elephant uses trunk as a nose because of which it has a strong sense of smell. The trunk is also used by it for picking up food.
  • The Beard ape lives in the rainforests silver-white mane surrounds the head from the cheeks down to its chin ,it is a good climber , it feeds mainly on fruits, seeds, young leaves, stems, buds and also searches for insects under the bark of the trees. They get sufficient food on the trees, it rarely comes down on the ground
  • The day-to-day condition of the atmosphere at a place with respect to the temperature, humidity, rainfall, wind-speed, etc., is called the weather at that place.
  • The maximum temperature of the day occurs generally in the afternoon while the minimum temperature occurs in the early morning.
  • The times of sunrise and sunset also change during the year.
  • All the changes in the weather are driven by the sun.
  • The average weather pattern taken over a long time, say 25 years, is called the climate of the place.
  • The tropical and the polar regions are the two regions of the earth, which have severe climatic conditions.
  • Animals are adapted to the conditions in which they live.
  • The polar regions are very cold throughout the year. The sun does not set for six months in a year and in the other six months it does not rise.
  • Animals in the polar region are adapted to the extremely cold climate by having some special characteristics such as white fur, strong sense of smell, a layer of fat under the skin, wide and large paws for swimming and walking, etc.
  • Migration is another means to escape the harsh, cold conditions.

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  • Because of the hospitable climatic conditions huge populations of plants and animals are found in the tropical rainforests.
  • Animals in the tropical rainforests are adapted such that they eat different kinds of food to overcome the competition for food and shelter.
  • Some adaptations of animals living in the tropical rainforests include living on the trees, development of strong tails, long and large beaks, bright colours, sharp patterns, loud voice, diet of fruits, sensitive hearing, sharp eyesight, thick skin, ability to camouflage in order to protect themselves from predators, etc.

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  • The weather reports are prepared by the Meteorological Department of the Government.
  • This department collects data on temperature, wind, etc., and makes the weather prediction.
  • Rainfall is measured by an instrument called the rain gauge. It is basically a measuring cylinder with a funnel on top to collect rainwater.

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  • All changes in the weather are caused by the sun.
  • The sun is a huge sphere of hot gases at a very high temperature.
  • The distance of the sun from us is very large.
  • Even then the energy sent out by the sun is so huge that it is the source of all heat and light on the earth.
  • So, the sun is the primary source of energy that causes changes in the weather.
  •  Energy absorbed and reflected by the earth’s surface, oceans and the atmosphere play important roles in determining the weather at any place.
  • If you live near the sea, you would have realised that the weather at your place is different from that of a place in a desert, or near a mountain.

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  • Some migratory birds travel as much as 15000 km to escape the extreme climatic conditions at home.
  • Generally they fly high where the wind flow is helpful and the cold conditions allow them to disperse the heat generated by their flight muscles.
  • But how these birds travel to the same place year after year is still a mystery.
  • It seems that these birds have a built–in sense of direction and know in which direction to travel.
  • Some birds probably use landmarks to guide them.
  •  Many birds may be guided by the sun during the day and stars at night.
  • There is some evidence that birds may use the magnetic field of the earth to find direction. And it is not only birds that migrate; mammals, many types of fish and insects are also known to migrate seasonally in search of more hospitable climates.

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