Weather, Climate and Adaptations of Animals to Climate Class 7 Notes NCERT and MCQs

30-08-2023 19:01 PM IST Yadvendra Singh

The chapter defines weather and climate. It discusses adaptations in animals found in polar regions and tropical rainforests.

What is Weather?

Weather of a place refers to the day-to-day condition of the atmosphere at a place with respect to the temperature, humidity, rainfall, wind-speed, etc.

The temperature, humidity, and other factors are called the elements of the weather.

Weather is a complex phenomenon. It is not easy to predict. All the changes in the weather are driven (caused) by the sun.

Energy absorbed and reflected by the earth’s surface, oceans and the atmosphere play important roles in determining the weather at any place.

What is Climate?

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.

NOTE: Rainfall is measured by an instrument called Rain Gauge. 

The maximum and minimum temperatures are recorded using maximum and minimum thermometers.

The maximum temperature of the day occurs generally in the afternoon while the minimum temperature occurs in the early morning.

Adaptations of animals living in polar regions

Some well-known countries that belong to the polar regions are Canada, Greenland, Iceland, Norway, Sweden, Finland, Alaska in U.S.A. and Siberian region of Russia. 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. In order to explain adaptations of animals living in polar regions, the examples of polar bears and penguins are given below.

A. Polar bears: Polar bears have following adaptations.

• White fur: It is not easily visible in the snowy white background. It protects polar bears from their predators. It also helps them in catching their prey.
• Two thick layers of fur and a layer of fat under skin: They protect polar bears from extreme cold. They are so well-insulated that they have to move slowly and rest often to avoid getting overheated.  
• Swimming: Polar bear is a good swimmer. Its wide and large paws help it in swimming well. They also help it walk easily in the snow. While swimming under water, it can close its nostrils and can remain under water for long durations

B. Penguin:

• It is also white and merges well with the white background. It also has a thick skin and a lot of fat to protect it from cold.
• Penguins huddle together to keep themselves warm. Penguins are also good swimmers.
• Their bodies are streamlined and their feet have webs, making them good swimmers. 

C. Other animals living in polar regions: Many types of fishes, musk oxen, reindeers, foxes, seals, whales, and birds are also found in polar regions.

While fish can remain under cold water for long, birds must remain warm to survive. They migrate to warmer regions when winter sets in. They come back after the winter is over.

Migration

It is a means to escape the harsh, cold conditions. 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.

Migratory birds

India is one of the destinations of many of these migratory birds. Siberian crane comes from Siberia to places like Bharatpur in Rajasthan and Sultanpur in Haryana.

Generally, migratory birds fly high because the wind flow at heights is helpful and the cold conditions allow them to disperse the heat generated by their flight muscles.

How migratory 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.

Adaptations of animals living in tropical rainforests

Examples of some countries where the tropical rainforests are found are India, Malaysia, Indonesia, Brazil, Republic of Congo, Kenya, Uganda, and Nigeria.

The tropical region has generally a hot climate. These regions get plenty of rainfall. Tropical rainforests are found in Western Ghats and Assam in India, Southeast Asia, Central America and Central Africa. Because of the hospitable climatic conditions, huge populations of plants and animals are found in the tropical rainforests.

Names of animals living in tropical rainforests are Monkeys, apes, gorillas, tigers, elephants, leopards, lizards, snakes, birds and insects.

1. Red-eyed frog: It has developed sticky pads on its feet to help it climb trees on which it lives.
2. Monkeys: To help them live on the trees, monkeys have long tails for grasping branches. Their hands and feet are such that they can easily hold on to branches.
3. Toucan:  Bird Toucan possesses a long, large beak. This helps a toucan to reach the fruits on branches which are otherwise too weak to support its weight.
4. Lion-tailed macaque:

• The lion-tailed macaque (also called Beard ape) lives in the rainforests of Western Ghats.
• Its most outstanding feature is the silver-white mane, which surrounds the head from the cheeks down to its chin.
• It is a good climber and spends a major part of its life on the tree. It feeds mainly on fruits. This beard ape also searches for insects under the bark of the trees.
• Since it is able to get sufficient food on the trees, it rarely comes down on the ground.

5. Elephant:

• It uses its trunk as a nose because of which it has a strong sense of smell. It also uses trunk for picking up food.
• Its tusks are modified teeth. These can tear the bark of trees that elephant eats.
• Large ears of the elephant help it to hear even very soft sounds. They also help the elephant to keep cool in the hot and humid climate of the rainforest.

MCQs based on NCERT Class 7 Science Chapter 7: Weather, Climate and Adaptations of Animals to Climate

1. Migratory birds are known to travel to the same place year after year. Which of the following possibly help birds in traveling to same places year after year?

a. Bird’s built–in sense of direction

b. The sun and the stars

c. The magnetic field of the earth

d. All of the above

Ans. d

Explanation: How migratory 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.

2. Which of the following is/are elements of weather?

a. Humidity

b. Temperature

c. Rainfall

d. All of the above

Ans. d

Explanation: Temperature, Humidity, Rainfall, Wind-speed, etc. are the elements of weather. 

3. Rajasthan has a ___ type of climate.

a. Hot and humid

b. Hot and dry

c. Cold and humid

d. Cold and dry

Ans. b

Explanation: Rajasthan receives very little rainfall and has a typical desert type climate i.e. hot and dry.

4. A carnivore with stripes on its body moves very fast while catching its prey. It is likely to be found in

a. Polar regions

b. Deserts

c. Oceans

d. Tropical rainforests

Ans. d

Explanation: A carnivore with stripes on its body moves very fast while catching its prey. It is likely to be found in Tropical rainforests.

5. Which features adapt polar bears to live in extremely cold climate?

a. A white fur, fat below skin, keen sense of smell.

b. Thin skin, large eyes, a white fur.

c. A long tail, strong claws, white large paws.

d. White body, paws for swimming, gills for respiration.

Ans. a

Explanation: Polar bears are able to adapt to living in such a cold temperature due to the presence of white fur, fat beneath the skin, and a keen sense of smell.

6. Which option best describes a tropical region?

a. hot and humid

b. moderate temperature, heavy rainfall

c. cold and humid

d. hot and dry

Ans. a

Explanation: The tropical region has generally a hot climate because of its location around the equator. Even in the coldest month the temperature is generally higher than about 15°C.