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Tamilnadu Samacheer Kalvi 9th Social Science Geography Solutions Chapter 5 Biosphere

Biosphere Textual Exercise

I. Fill in the blanks.

1. An area where animals, plants and micro organisms live and interact with one another is known as ………
2. ……… are also called Heterotrophs.
3. ……. is a system of interlocking and independent food chains.
4. ………. is an extensive large ecosystem.
5. The vegetative type commonly found in desert biomes is called …..
6. ……. is an aquatic biome that is found where fresh water and salt water mix.
Answers:
1. Habitat
2. Consumers
3. Food web
4. A biome
5. Xerophytes
6. Estuary

II. Choose the correct answer.

Biosphere Provides A Stable Ecosystem Give Reason Question 1.
The coldest biome on Earth is ……….
(a) Tundra
(b) Taiga
(c) Desert
(d) Oceans
Answer:
(a) Tundra

Biosphere Provides A Stable Ecosystem Question 2.
This is the smallest unit of biosphere.
(a) Ecosystems
(b) Biome
(c) Environment
(d) None of the above
Answer:
(a) Ecosystems

Biosphere 9th Class Social Question 3.
Nutrients are recycled in the atmosphere with the help of certain micro organisms, referred to as
(a) Producers
(b) Decomposers
(c) Consumers
(d) None of the above
Answer:
(b) Decomposers

Biosphere Lesson Class 9 Question 4.
To which climatic conditions are Xerophytic plants specifically adapted to?
(a) Saline and sandy
(b) Limited moisture availability
(c) Cold temperature
(d) Humid
Answer:
(a) Saline and sandy

Biosphere Class 9 Question 5.
Why is the usage of rainforest biomes for large scale agriculture unsustainable?
(a) because it is too wet
(b) because the temperature is too warm
(c) because the soil is too thin
(d) because the soil is poor
Answer:
(b) because the temperature is too warm

Questions 6-8 are assertion type questions.
Directions:
(A) Both assertion (A) and reason (R) are true; R explains A
(B) Both assertion (A) and reason (R) are true; R does not explain A
(C) A is true; R is false
(D) Both A and R are false
Answer:
(C) A is true; R is false

Biosphere Solutions Question 6.
(A): Heterotrophs do not produce their own food.
(R): They depend on autotrophs for their nourishment.
Answer:
(C) A is true; R is false

Biosphere Provides A Stable Ecosystem. Question 7.
(A): Hotspots are the regions characterised by numerous endemic plants and animal species
living in a vulnerable environment.
(R): To manage and focus on conservation work more effectively, researchers identified hotspots.
Answer:
(A) Both assertion (A) and reason (R) are true; R explains A

9th Class Social Biosphere Lesson Question 8.
(A): The number of gorillas in Africa has plummeted by 60% in the past twenty years.
(R): Non intervention of human beings in the forest areas.
Answer:
(D) Both A and R are false

III. Answer the following in brief:

9th Class Social Biosphere Question 1.
What is Biosphere?
Answer:
Biosphere is a life supporting layer that exists on the earth’s surface. This layer on earth encompasses the Lithosphere, Hydrosphere and Atmosphere. It includes flora and fauna that thrive on or near the earth’s surface.

Samacheer Kalvi 9th Social Science Geography Chapter 1 Question 2.
What is an ecosystem?
Answer:
The place on earth where living organisms live and interact with one another and with their physical environment is called an ecosystem.

Question 3.
What does the term ‘biodiversity’ meant
Answer:
Biodiversity or biological diversity refers to a wide variety of living organisms (plants, animals and other micro organisms) which live in a habitat. It is highly influenced by topography, climate as well as human activities.

Question 4.
What is meant by loss of biodiversity?
Answer:
The extinction of species (flora and fauna) due to human and natural influences is called loss of biodiversity. The biodiversity loss has a great impact on mankind and also affects land, water, air etc. Habitat destruction due to deforestation, population explosion, pollution and global warming are the major cause for loss of biodiversity.

Question 5.
Mention the various terrestrial biomes.
Answer:
The major terrestrial biomes of the world are:
A. Tropical Forest Biomes
B. Tropical Savanna Biomes
C. Desert Biomes
D. Temperate Grassland Biomes
E. Tundra Biomes

IV. Distinguish between the following:

Question 1.
Producers and Decomposers.
Answer:

S.No. Producers Decomposers
(i) They are self nourishing components of the ecosystem. They are organisms that are incapable of preparing its own food.
(ii) Producers are called Autotrophs. e.g. Plants, Algae, Bacteria, etc. Decomposers are organisms that are incapable of preparing its own food. They are called Saprotrophs. e.g. Fungus, Mushrooms.

Question 2.
Terrestrial biomes and Aquatic biomes
Answer:

S.No. Terrestrial biomes Aquatic biomes
(i) It is a group of living organisms that live and interact with one another on land. It is a group of living organisms that live and interact with one another for nutrients and shelter.
(ii) They are determined by temperature and rainfall. These are influenced by a series of abiotic factors.
(iii) Terrestrial biomes are Tropical forest biomes, Tropical Savanna biomes, Desert biomes, Temperate Grassland biomes and Tundra biomes. Aquatic biomes are Fresh water biomes and Marine biomes.

Question 3.
Tropical vegetation and Desert vegetation
Answer:

S.No. Tropical vegetation Desert vegetation
(i) Half of the World’s Tropical forests are found in Central and South America. Deserts are found in the Western Margin of the continents.
(ii) This biome extends between 10°N and 10°S of the equator. This extends between 20°N and 30°S latitudes.
(iii) This weather condition favours thick vegetative cover. They possess special type of vegetation called xerophytes.
(iv) People in this region sustain their livelihood through food gathering. People in this region sustain their life through food gathering and hunting.
(v) High annual rainfall and relatively constant temperature is likely Annual rainfall is less than 25 c.m in these regions.

Question 4.
Savannas and Tundra
Answer:

S.No. Savannas Tundras
(i) Tropical grasslands are generally found between tropical forests. These vast lowlands are found where the ground remains frozen.
(ii) Generally hot climate and dry. They also experience moderate to low rainfall. Generally long severe winter and short cool summer.
(iii) Found in the Sahel, South of Sahara in East Africa and in Australia. Found in Greenland Arctic and Antarctic regions and Northern parts of Asia, Canada and Europe.
(iv) Chief occupation is herding. Hunting and fishing are their main occupations.

V. Give reasons for the following:

Question 1.
Producers are also called autotrophs.
Answer:
Producers are self nourishing components of the ecosystem. Hence they are called Autotrophs. They are found both on land and water, e.g. Plants, Algae, Bacteria etc.

Question 2.
Biosphere provides a stable ecosystem.
Answer:

  1. Biosphere extends from the deep ocean trenches to lush rain forests.
  2. People play an important role in maintaining the flow of energy in the biosphere.
  3. There are places on earth that are both biologically rich and deeply threatened.
  4. Hence Biosphere provides a stable ecosystem.

VI. Answer the following in a paragraph:

Question 1.
Explain the various components of ecosystem.
Answer:
An ecosystem is a community, where all living organisms live and interact with one another and also with their non-living environment such as land, soil, air, water etc. Ecosystems range in size from the smallest units (e.g. bark of a tree) that can sustain life to the global ecosystem or ecosphere. (e.g. Cropland, Pond ecosystem, Forest ecosystem, Desert ecosystem etc.). Biosphere harbours all ecosystems on the earth and sustains life forms including mankind.
Components of ecosystem:
An ecosystem consists of three basic components, namely
(A) Abiotic components
(B) Biotic components and
(C) Energy component

A) Abiotic Components: Abiotic components include the non-living, inorganic, physical and chemical factors in the environment, e.g. Land, Air,Water, Calcium, Iron etc.

B) Biotic Components: Biotic components include plants, animals and micro organisms. Biotic components can be classified into three categories:

  • Producers are self nourishing components of the ecosystem. Hence they are called Autotrophs. They are found both on land and water, e.g. Plants, Algae, Bacteria etc.
  • Consumers are those that depend on producers, directly or indirectly. Hence they are called Heterotrophs.

C) Energy Components: All organisms in the biosphere use energy to work and convert one form of energy into another. The Sun is the ultimate source of energy for the biosphere as a whole. The solar energy gets transformed into other forms of energy through the various components in the ecosystem. The producers, consumers and the decomposers contribute a lot to the energy flow in an ecosystem.

Question 2.
Write a paragraph on the functions of an ecosystem.
Answer:
Functions of an ecosystem: The living organisms form an interacting set of flora and fauna which are organized into trophic levels, food chains and food webs. The functioning of an ecosystem depends on the pattern of the energy flow, as it helps in the distribution and circulation of the organic and inorganic matter within an ecosystem. Energy flow generally takes place in a hierarchical order in an ecosystem through various levels. These levels are called trophic levels. The chain of transformation of energy from one group of organisms to another, through various trophic levels is called a food chain. A system of interlocking and interdependent food chains is called a food web.

Question 3.
Explain about the aquatic biomes on Earth.
Answer:
Aquatic biome is a group of living organisms that live and interact with one another and its aquatic environment for nutrients and shelter. Like terrestrial biomes, aquatic biomes are influenced by a series of abiotic factors. It is broadly classified as fresh water biomes and marine biomes.

A. Fresh water Biomes: It comprises lakes, ponds, rivers, streams, wetlands etc. It is influenced by various abiotic components such as the volume of water, water flow, composition of oxygen, temperature, etc. Humans rely on freshwater biomes for drinking water, crop irrigation, sanitation and industry. Water lily, lotus, duck weeds etc. are the common plants found here. Trout, salmon, turtles, crocodiles etc. are the animals found here.

B. Marine Biomes: They are the largest aquatic biomes on earth. They are continuous bodies of salt water and provide a wide range of habitats for marine plants and animals. Coral reefs are a second kind of marine biomes within the ocean. Estuaries, coastal areas where salt water and fresh water mix, form a third unique marine biome. As water provides maximum mobility to marine organisms, nutrients are circulated more quickly and efficiently here than the terrestrial biomes. Apart from animals, plants such as kelp, algae, phytoplankton etc. also grow in water. Aquatic biomes are not only important for plants and animals, but also for humans. Humans use aquatic biomes for water, food and leisure activities. Some of the threats and issues to aquatic biomes are overfishing, pollution and rise in sea level.

VII. Find out the dates for the following:

1. World Wild Life Day – …………
2. International Day of Forest – ………..
3. World Water Day – ………..
4. Earth Day – ………….
5. World Environment Day – June 5th
6. World Oceans Day – …………
Answers:
1. March 3rd
2. March 21st
3. March 22nd
4. April 22nd
6. June 8th

VIII. Map Study

Locate the following on the world outline map.

  1. Priairies
  2. Downs
  3. Tundra Biomes
  4. Equatorial Biomes

You can identify and locate the above mentioned grasslands with the help of an atlas.
Hint: Temperate grasslands are called differently in different parts of the world.
Prairies – North America
Downs – Australia and New Zealand
Tundra – Greenland, Arctic and Antarctic regions and Northern parts of Asia, Canada and Europe
Equatorial Biomes – Near the equator in Central and South America, parts of Africa and Asia

IX. Picture Study

Narrate the given food web of Arctic Tundra in your own words.

  1. The flow of energy from the sun through an eco system can be illustrated in a food chain.
  2. Within a food Chain there are produces. e.g., grasses, lichens, Arctic wild flower, etc.
  3. Life in any biome includes producers (plants) and consumers (energy obtained from producers)
  4. These consumers may be further classified as herbivores (plant eater) carnivores(meat eaters) (or) anniores (feed on combination of both animals and plants).

Biosphere Provides A Stable Ecosystem Give Reason Samacheer Kalvi 9th Social Science Geography Solutions Chapter 5

Biosphere Additional Questions

I. Fill in the blanks.

1. ……… are self nourishing components of the ecosystem.
2. All living things, large or small are grouped into ………
3. The ……. is the ultimate source of energy for the biosphere as a whole.
4. Decomposers live on dead and decaying plants and animals and are called ………
5. The extinction of species (flora and fauna) due to human and natural influences is called ………
6. The branch of science that deals with ecosystem is called ………
7. The temperate grasslands are called …… in North America.
8. ……….. is a fertile fresh water source found in deserts and semi-arid regions.
Answers:
1. Producers
2. species
3. sun
4. Saprotrophs
5. Lass of biodiversity
6. Ecology
7. Prairies
8. An Oasis

II. Choose the correct answer.

Question 1.
……….. the fourth sphere of the Earth.
(a) Lithosphere
(b) Hydrosphere
(c) Biosphere
(d) Atmosphere
Answer:
(c) Biosphere

Question 2.
………. are found both on land and water.
(a) Autotrophs
(b) Heterotrophs
(c) Saprotrophs
(d) None of the above
Answer:
(a) Autotrophs

Question 3.
Consumers are those that depend on directly (or) indirectly are called ………..
(a) Saprotrophs
(b) Heterotrophs
(c) Autotrophs
(d) None of the above
Answer:
(b) Heterotrophs

Question 4.
A group of living organisms that live and interact with One another on land is ………
(a) Tropical Savanna Biomes
(b) Tropical Forest Biomes
(c) Desert Biomes
(d) Terrestrial Biomes
Answer:
(d) Terrestrial Biomes

Question 5.
The chain of transformation of energy from one group of organisms to another through various trophic levels is called as ……….
(a) Food chain
(b) Food web
(c) Trophic level
(d) None of the above
Answer:
(a) Food chain

Questions 6-8 are Assertion (A) Reason (R) type.
(A) Both Assertion (A) and Reason (R) are true. (R) explains (A).
(B) Both Assertion (A) and Reason (R) are true. (R) does not explain (A).
(C) (A) is true; (R) is false.
(D) Both (A) and (R) are false.

Question 6.
Assertion (A): In Biodiversity each species, no matter how big of small has an important role to play in the ecosystem.
Reason (R): It maintains the ecological balance.
Answer:
(A) Both Assertion (A) and Reason (R) are true. (R) explains (A).

Question 7.
Assertion (A): As the soil is sandy and saline deserts remain agriculturally unproductive. Reason (R): Tribal people who live in deserts practice food gathering and hunting.
Answer:
(B) Both Assertion (A) and Reason (R) are true. (R) does not explain (A).

Question 8.
Assertion (A): Aquatic animals use 10% energy to obtain oxygen.
Reason (R): Terrestrial animals use only 2-4% of energy to obtain oxygen.
Answer:
(D) Both (A) and (R) are false.

III. Answer the following in brief.

Question 1.
What does an ecosystem consists of?
Answer:
An ecosystem consists of three basic components, namely
(A) Abiotic components
(B) Biotic components and
(C) Energy component.

Question 2.
Define Abiotic Components.
Answer:
Abiotic components include the non-living, in-organic, physical and chemical factors in the environment, e.g., Land, Air, Water, Calcium, Iron, etc.

Question 3.
What are energy components?
Answer:
All organisms in the biosphere use energy to work and convert one form of energy into another. The Sun is the ultimate source of energy for the biosphere as a whole. The solar energy gets transformed into other forms of energy through the various components in the ecosystem. The producers, consumers and the decomposers contribute a lot to the energy flow in an ecosystem.

Question 4.
State the unique weather condition that favours thick vegetative cover in the Tropical Forest Biomes.
Answer:
The climate in these biomes shows little seasonal variation with high annual rainfall and relatively constant, high temperature. This unique weather condition favours thick vegetative cover.

Question 5.
How do the people live Desert Biomes?
Answer:
People who live here practice food gathering and hunting. They move their temporary settlements frequently in search of pastures. Transportation becomes very difficult here and is carried on by camels. Reptiles like snakes, lizards, scorpions etc., are most commonly found here.

Question 6.
Mention the Temperate Grasslands in different parts of the world.
Answer:
Temperate grasslands are called differently in different parts of the world.
Prairies – North America
Steppes – Eurasia
Pampas – Argentina and Uruguay
Veld – South Africa
Downs – Australia and Newzealand.

Question 7.
What is an oasis?
Answer:
An oasis is a fertile fresh water source found in deserts and semi-arid regions. Oases are fed by springs. Crops like date palms, figs, citrus fruits, maize etc. are cultivated near these oases.

Question 8.
What is a Biosphere Reserve?
Answer:
A Biosphere Reserve is a special ecosystem or specialized environment with flora and fauna that require protection and nurturing. There are 18 Bioshpere Reserves in India.

IV. Distinguish the following.

Question 1.
Producers Consumers
Answer:

Producers Consumers
Producers are self nourishing components of the ecosystem. Hence they are called Autotrophs. They are found both on land and water, e.g. Plants, Algae, Bacteria etc. Consumers are those that depend on producers, directly or indirectly. Hence they are called Heterotrophs.

 

Question 2.
Abiotic components Biotic components
Answer:

Abiotic components Biotic Components
Abiotic components include the non-living, inorganic, physical and chemical factors in the environment, e g. Land, Air, Water, Calcium, Iron etc. Biotic components include plants, animals and micro organisms. Biotic components can be classified into three categories.

Question 3.
Mention any 3 points between Aquatic ecosystem and Terrestrial ecosystem.
Answer:

S.No. Aquatic Ecosystem Terrestrial Ecosystem
(i) Aquatic ecosystem exists on water covering 71% of the earth surface. Terrestrial ecosystem exists on land covering 29% of the earth surface.
(ii) Aquatic animals use 20% of energy to obtain oxygen. Terrestrial animals use only 1-2% of energy to obtain oxygen.
(iii) In this ecosystem there is abundant of water with limited oxygen supply. In this ecosystem there is less availability of water, greater availability of gases and temperature fluctuation.

V. Give reasons for the following.

Question 1.
Stable biosphere has to be conserved.
Answer:
A healthy eco system provides clean water, pure water, enriched soil, food, raw materials, medicines etc. Hence stable biosphere has to be conserved.

Question 2.
The Primary cause of today’s loss of biodiversity.
Answer:
The primary cause of today’s loss of biodiversity is habitat alteration caused by human activities. The ever increasing population results in over exploitation of biological resources. This has an adverse impact, on flora and fauna on earth. There are places on earth that are both biologically rich and deeply threatened.

Question 3.
The Net Primary productivity is low in Tundra.
Answer:
This biome experiences long severe winter and short cool summer. Due to the prevailing of low temperature and short growing seasons, the net primary productivity is very low in tundra.

VI. Answer in a paragraph.

Question 1.
Write down the differences between the Aquatic Ecosystem and Terrestrial Ecosystem.
Answer:

S.No. Aquatic Ecosystem Terrestrial Ecosystem
(i) Aquatic ecosystem exists on water covering 71 % of the earth surface. Terrestrial ecosystem exists on land covering 29% of the earth surface.
(ii) Aquatic animals use 20% of energy to obtain oxygen. Terrestrial animals use only 1-2% of energy to obtain oxygen.
(iii) In this ecosystem there is abundant of Water with limited oxygen supply. In this ecosystem there is less availability of water, greater availability of gases and temperature fluctuation.
(iv) The small drifting photosynthetic organisms of the ocean called photo phytoplankton are regarded as the major primary producer. The primary producer is the plant that produce food through photosynthetic process.
(v) Aquatic environment is more stable with smaller fluctuation in temperature and other variable. Terrestrial environment is quite unstable as the land surface is affected by great risks from external impacts.

Question 2.
Desert Biomes.
Answer:
Deserts are usually found on the western margins of the continents between 20° and 30° N and S latitudes. The annual rainfall is less than 25 cm in these regions. Due to the lack of rainfall and arid conditions, these regions do not possess any vegetation but have special vegetation type called Xerophytes. As the soil is sandy and saline, deserts remain agriculturally unproductive. Drought resistant thorny scrubs and bushes, palms are found here.

Tribal people who live here practice food gathering and hunting. They move their temporary settlements frequently in search of pastures. Transportation becomes very difficult here and is carried on by camels. Reptiles like snakes, lizards, scorpions etc., are most commonly found here.

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