chapter 10 geography class 7D

 

 

I. Tick the Correct Option

1. The discovery of Antarctica can be traced back to theories of a vast southern continent called
   a) Terra Australis
2. The Antarctic Treaty was signed in
   a) 1959
3. The Larsen B Ice Shelf breakup in 2002 was attributed to ______.
   a) Global warming
4. The highest peak in Antarctica is ______.
   a) Mount Vinson
5. The Indian research station established in 1989 in Antarctica is called ______.
   c) Maitri

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II. Fill in the Blanks

1. Antarctica is the fifth largest continent in terms of area.
2. The Antarctic Treaty prohibits military activities in Antarctica.
3. The Aurora Australis phenomenon is caused by solar winds colliding with the Earth's magnetic field.
4. The Larsen C Ice Shelf experienced a major iceberg breakaway in 2017.
5. The temperature in Antarctica can reach as low as -89°C in winter.

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III. True and False

1. The Larsen B Ice Shelf breakup was caused by volcanic activity.
   False (It was caused by global warming.)
2. Antarctica is the largest continent in terms of area.
   False (It is the fifth largest.)
3. The Antarctic Treaty supports scientific research in Antarctica.
   True
4. The temperature in Antarctica can reach -89°C.
   True
5. Humans have inhabited Antarctica since ancient times.
   False (There is no archaeological evidence of human presence before the early 20th century.)

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IV. Short Answer Questions

1. What was the significance of the Larsen B Ice Shelf breakup in 2002?
   The breakup of the Larsen B Ice Shelf in 2002 was attributed to global warming. It highlighted the impact of rising temperatures on Antarctica's ice shelves, leading to accelerated glacier flow and contributing to rising sea levels.
2. Name two physical features of Antarctica.
• Vinson Massif (highest peak, 5,139 meters).
• Transantarctic Mountains (divides East and West Antarctica).
3. What is the purpose of the Indian expeditions to Antarctica?
   The primary objective is to study the region's geology and molecular biodiversity. Indian scientists have discovered around 120 new microbes and contributed significantly to Antarctic research.
4. What is Aurora Australis?
   Aurora Australis is a natural light display caused by solar winds interacting with the Earth's magnetic field. It illuminates the night sky in Antarctica, often visible on clear nights.
5. How does global warming affect Antarctica?
   Global warming leads to rising temperatures, causing the breakup of ice shelves (e.g., Larsen B in 2002 and Larsen C in 2017). This accelerates glacier flow, contributes to rising sea levels, and threatens the continent's ecosystem.

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V. Long Answer Questions

1. Describe the discovery and exploration of Antarctica, including significant expeditions and the race to the South Pole.
• Early theories of a southern continent (Terra Australis) date back to the 2nd century AD.
• James Cook crossed the Antarctic Circle in 1773 but did not sight Antarctica.
• In 1820, the Russian expedition led by Fabian Gottlieb von Bellingshausen and Mikhail Lazarev first sighted Antarctica.
• Roald Amundsen (Norway) and Robert Falcon Scott (UK) raced to the South Pole. Amundsen's team reached it on December 14, 1911, while Scott's team perished on their return journey.
2. Discuss the climate and environment of Antarctica, including its extreme conditions and natural phenomena.
• Climate: Antarctica is the coldest, driest, and windiest continent. Temperatures can drop to -89°C (Vostok Station).
• Precipitation: It is a desert, with annual precipitation as low as 200 mm along the coast.
• Daylight: Experiences 6 months of continuous daylight (summer) and 6 months of darkness (winter).
• Natural Phenomena:
• Aurora Australis: Caused by solar winds interacting with Earth's magnetic field.
• Ozone Layer Depletion: Caused by CFCs, leading to a hole in the ozone layer above Antarctica.
3. Explain the flora, fauna, and mineral resources found in Antarctica.
• Flora: Limited to mosses, lichens, and small flowering plants due to harsh conditions.
• Fauna: Includes penguins (Emperor penguins), whales, seals, and migratory birds.
• Mineral Resources: Believed to contain coal, iron ore, copper, uranium, gold, and diamonds, but mining is prohibited under the Antarctic Treaty.
4. Provide an overview of the Indian expeditions to Antarctica and their contributions to scientific research.
• First Expedition: 1981, under the National Centre for Antarctic and Ocean Research.
• Research Stations:
• Dakshin Gangotri (1983, first station).
• Maitri (1989, second station).
• Bharati (2015, third station).
• Contributions:
• Discovery of 120 new microbes (20 credited to Indian researchers).
• Over 300 published scientific papers (as of 2007).
• Studies in geology, geography, medicine, and molecular biodiversity.
5. Discuss the future challenges and concerns related to Antarctica, including the exploitation of its resources and environmental impacts.
• Antarctic Treaty: Ensures peace, prohibits military activities, and bans mining.
• Environmental Concerns:
• Global Warming: Causes ice shelf breakups (e.g., Larsen B and C), accelerating glacier melt and rising sea levels.
• Ozone Depletion: Threatens ecosystems due to UV radiation.
• Future Pressures:
• Resource Exploitation: As global energy/mineral reserves deplete, there may be pressure to exploit Antarctica's resources.
• Tourism: Increasing tourism could threaten the fragile environment.

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VI. Assertion-Reason Questions

1. Assertion (A): The Antarctic Treaty prohibits military activities in Antarctica.
   Reason (R): The treaty aims to maintain Antarctica as a peaceful continent dedicated to scientific research.
   Answer: a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
2. Assertion (A): The temperature in Antarctica can reach as low as -89°C.
   Reason (R): The extreme cold temperatures in Antarctica are a result of its location and weather conditions.
   Answer: a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).

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VII. Case Study: India’s Antarctic Exploration

1. When did the Indian Expedition to Antarctica begin?
   a) 1981
2. Which research station was established in 1983 as part of the Indian Expedition?
   c) Dakshin Gangotri (Note: The document mentions "Dakshin Gangster," but the correct name is Dakshin Gangotri.)
3. How many research stations does India have in Antarctica?
   c) Three (Dakshin Gangotri, Maitri, Bharati)
4. What is the focus of the Indian Expeditions in Antarctica?
   a) Geology and molecular biodiversity

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VIII. Picture Identification and Explanation

(Note: Since no image is provided, I’ll assume the picture is of Aurora Australis based on the context.)

• Identification: Aurora Australis (Southern Lights).
• Explanation: This phenomenon occurs when solar winds (charged particles from the Sun) collide with the Earth's magnetic field. These interactions excite atoms in the atmosphere, releasing energy as colorful light displays, typically green, pink, or purple. It is most visible in polar regions like Antarctica during clear nights.