NIOS Class 12 Environmental Science Chapter 6 Natural Ecosystem

NIOS Class 12 Environmental Science Chapter 6 Natural Ecosystem Solutions to each chapter is provided in the list so that you can easily browse throughout different chapters NIOS Class 12 Environmental Science Chapter 6 Natural Ecosystem Notes and select need one. NIOS Class 12 Environmental Science Chapter 6 Natural Ecosystem Question Answers Download PDF. NIOS Study Material of Class 12 Environmental Science Paper Code 333.

NIOS Class 12 Environmental Science Chapter 6 Natural Ecosystem

Also, you can read the NIOS book online in these sections Solutions by Expert Teachers as per National Institute of Open Schooling (NIOS) Book guidelines. These solutions are part of NIOS All Subject Solutions. Here we have given NIOS Class 12 Environmental Science Chapter 6 Natural Ecosystem Solutions, NIOS Senior Secondary Course Environmental Science Solutions for All Chapter, You can practice these here.

Natural Ecosystem

Chapter: 6

Module 2: Ecological Concepts and Issues

Textual Question Answer

INTEXT QUESTIONS 6.1

1. What is a natural ecosystem?

Ans: It is an assemblage of plants and animals functions as a unit and is capable of maintaining its identity.

2. Which are the main categories of natural ecosystems?

Ans: Terrestrial and Aquatic.

3. Give examples of terrestrial ecosystems.

Ans: Forest, grasslands, deserts and tundra

4. Give examples of fresh water ecosystems.

Ans: Rivers, lakes and ponds.

INTEXT QUESTIONS 6.2

1. What are deciduous trees? 

Ans: The leaves of these trees shed in autumn and new foliage grows in spring.

2. Explain two common characteristics of the desert.

Ans: Hot and low ration areas, suffering from water shortage.

3. How are the animals and plants of deserts adapted to heat and drought?

Ans: Animals– are fast runners, nocturnal habit conserve water by excreting concentrated urine.

Plants – are mostly shrubs, leaves absent or reduced in size leaves and stems are succulent, root system well developed.

4. Where are Prairies and Steppes are found? 

Ans: North America and Eurasia.

INTEXT QUESTIONS 6.3

1. What is plankton?

Ans: Microscopic floating organisms such as diatoms, protozoan and larval forms are called plankton.

2. What is aquatic ecosystem? 

Ans: Refers to plant and animal communities occurring in water bodies. Flora and Fauna of marine ecosystem.

3. Name two plants and two animals which found in marine ecosystem.

Ans: Vascular plants are completely absent. Diatoms, algae, dinoflagellates and jelly fishes are free floating forms. Large crustaceans mollusks, turtles and mammals like seals, porpoises, dolphins and whales are free floating animals. Bottom dwellers are generally sessile (fixed) organisms like sponges, corals, crabs and starfish.

INTEXT QUESTIONS 6.4

1. Name the various zones of the Himalayas.

Ans: The Eastern Himalayas, the Central Himalayas, the Western Himalayas and the North- West Himalayas.

2. Where are deserts found in India? 

Ans: From Punjab, Haryana, Rajasthan to Gujarat state.

3. Give two differences between Western and eastern ghats? 

Ans: 

Aspect	Eastern Ghats	Western Ghats
Location	Extends in a north-south-west direction in the Indian Peninsula	Extends from Tapti River to Kanyakumari along the western coast of India
Rainfall	Varies from 60 cm to 160 cm	Varies from 100 cm to 500 cm
Vegetation	Ranges from evergreen trees to dry savannas	Known for rich biodiversity, with over 3500 species of flowering plants recorded
Elevation	Lower elevation compared to Western Ghats	Higher elevation, a UNESCO World Heritage Site
Rivers	Includes rivers like Godavari and Mahanadi	Supports many rivers like Krishna, Kaveri, and Tungabhadra
Biodiversity	Less diverse compared to the Western Ghats	A hotspot for biodiversity with numerous species of plants, animals, and birds

4. Give two plants and two animals which found in grassland.

Ans: Plants – Sedges and sunflower.

Animals – Rat and deer.

5. Name three gulf which are found in India.

Ans: Gulf of Mannar, gulf of Kutch and gulf of Khambhat.

INTEXT QUESTIONS 6.5

1. Name two threatened ecosystems.

Ans: Estuaries and islands.

2. Where are mangrove ecosystem found in India. 

Ans: East and west coast and islands of Andaman and Nicobar.

3. Why is estuary a more productive ecosystem than ocean or fresh water? 

Ans: Estuaries are very dynamic and productive ecosystems since the river flow, tidal range and sediment distribution is continuously changing in them. They are richer in nutrients than fresh waters or marine waters therefore; they are highly productive and support abundant fauna.

4. What are islands?

Ans: Island is land masses surrounded by sea water from all sides.

INTEXT QUESTIONS 6.6

1. Define ecotone.

Ans: Ecotone is a zone of function between two or more diverse ecosystems. e.g. the mangrove forest.

2. Give four examples of ecotone.

Ans: Mangrove, grasslands, estuary and river bank.

3. Define edge species.

Ans: The organisms which occur primarily or most abundantly in this zone are known as edge species.

4. Why there are more number of species of song birds in Mangrove forests?

Ans: There are more species of song birds in mangrove forests because they form an ecotone between land and sea, providing a mixed habitat of trees and wetlands. This rich and diverse environment supports a greater variety of bird species.

5. What is meant protection of natural ecosystem for an environmentalist.

Ans: Protection of natural ecosystems to an environmentalist means to protect animals and plants in their natural habitat in totality and not the protection of any one species.

TERMINAL EXERCISE

1. What do you understand by natural ecosystem ? Give examples.

Ans: A natural ecosystem is a collection of plants and animals which act as a unit and is capable of sustaining its identities, such as forest and grassland.

2. Give differences between the following:

(a) Alpine and arctic tundra.

Ans: Arctic tundra stretches as a continuous belt below polar cap ice whereas alpine tundra occurs at high mountains above the tree line. Arctic tundra extends as a continuous belt below the polar ice cap and above the tree line in the northern hemisphere. Simultaneously, the Alpine tundra is located in high mountains above the tree line the vegetation of the arctic tundra sedges, cotton grass, dwarf heath, birches, and willows. Animals of alpine tundra are musk ox, reindeer, arctic hare, caribous, and lemming.

(b) Savanna and prairie.

Ans: Tropical grasslands are commonly called Savannas. They occur in eastern Africa, South America, Australia, and India. Savannas form a complex ecosystem with scattered medium-size trees in grasslands. At the same time, Prairies are temperate grasslands that are found in North America.

(c) Tropical and temperate forests.

Ans: Tropical forests are present in the high rainfall regions on either side of the equator. They are present on the western coast of India, some parts of Africa, and South America. Whereas temperate forests are found in regions of moderate climatic conditions. They are present in northwest, central, and eastern Europe, north China, Korea, far eastern Russia, and Australia.

3. What do you understand by biodiversity? Explain its significance.

Ans: Biodiversity refers to the variety or diversity of living organisms. It has two aspects: species evenness and species richness. Biodiversity can be seen at various levels like in genes, species communities, and population.

Biodiversity is crucial for the sustenance of life. Each species has a structural and functional role within an ecosystem, and their removal may have a detrimental effect on the whole ecosystem due to interrelatedness. It provides various ecosystem services and acts as reservoirs of resources.

4. Give two desert adaptations of plants and animals.

Ans: Desert adaptations of plants include:

(i) Reduced or modified leaves or leaves may be completely absent.

(ii) Succulent leaves and stems that store water.

Desert adaptations of animals include:

(i) Some animals are nocturnal in nature or may live underground to escape the intense heat.

(ii) Animals and birds usually have long legs to keep the body away from the hot ground.

5. Describe the various types of forest found in India (in brief).

Ans: The main kinds of forests in India include –

(i) Tropical rainforest: The tropical evergreen forests and tropical semi-evergreen forests are present in regions that receive abundant rainfall and sunshine all over the year. They are found within plains of West Bengal, rainy slopes of the Western Ghats and Orissa, and north-eastern India.

(ii) Tropical deciduous forest: They shed their leaves for about 6-8 weeks in summer. They are also known as the monsoon forests due to their grandeur and form natural cover all over India. They are majorly found in Kerala.

(iii) Temperate broadleaf forests: Trees canopy is dense, the herbaceous layer is least developed, and grasses are usually absent. They exhibit peak leaf fall during summer. They mainly occur in the western Himalayas.

(iv) Coniferous forests: They possess an evergreen canopy of long needle-like leaves that always remains green. They comprise economically valuable gymnosperms trees and are found in the Himalayas.

(v) Alpine and Tundra forests: Vegetation growing at altitudes above 3600 m is usually called alpine vegetation, and with the increment of the altitude, the plants show stunted growth.

6. Explain various zones of Himalayas.

Ans: The Himalayas are classified into various zones. These include;

(i) The Assam Himalayas or the Eastern Himalayas: Eastern Himalaya has a diverse ecosystem. It has many primitive and endemic species. Eastern Himalayas are called the center of origin of cultivated plants.

(ii) The Nepal Himalayas or the Central Himalayas.

(iii) The Western Himalayas: Cold deserts of Ladakh sustain drought and cold resistant varieties of plants and animals. For example-Yak.

(iv) The Punjab Himalayas or the North-West Himalayas.

7. Write short note on grassland and deserts found in India.

Ans: In India, grasslands are present as grazing grounds and extensive low pastures of dry regions of the western part of the country and also in Alpine Himalayas. The dominant plant community is perennial grasses. In some regions, grasslands also sustain a variety of other herbaceous plants like legumes and sedges. The Thar desert in Rajasthan is an expansion of the Sahara deserts. They stretch from Punjab, Haryana, Rajasthan to Gujarat state. Indian deserts are classified into 4 main types: hills, plains with hills, marshes, and plains with dunes. The distinct Rann of Kutch-Bhuj in Gujarat is a separate zone within Thar deserts due to its distinct climatic conditions. Indian deserts support many endangered species of birds and mammals.

8. Explain how deforestation has resulted in ecological imbalance.

Ans: Deforestation or clearing of forests can affect the ecological balance detrimentally and result in catastrophic events like desertification or climate change. Deforestation or clearing forest lands for other purposes like main agriculture and recreational activities, mining, or urbanization. Deforestation poses an undeniable threat to ecosystems. The forest is an interrelated system that consists of a web of interdependencies, and their destruction will ultimately result in ecological Imbalance, This can result in climate change, soil erosion, and desertification.

9. What is an ecotone? Explain its significance for the edge species.

Ans: Ecotone is a zone of junction between two adjoining communities e.g. estuaries, mangroves and grassland.

The richness of species and the population density of some particular species is more in this zone than in either community. This is called the edge effect. The organisms which occur endemically or primarily or most abundantly in this zone are called edge species. It has conditions intermediate to the 2 communities and represents a zone of tension. Hence, edge species are specifically adapted to this zone. Ecotone is sensitive zones, and disturbances can detrimentally affect edge species.

10. Give two methods of protecting natural ecosystems.

Ans: The two methods of protection of natural ecosystems include:

(i) The areas should be declared as reserve zones. This can be done via marking transitional zones around the protected area. The IUCN protected area management classification includes Natural reserves, Wilderness Area, Protected landscape, and protected habitat.

(ii) Zones of megadiversity and hot spots of biodiversity should be protected. Mega diversity zones have the largest number of species. India is one of the megadiversity countries. Hot spots are the most endangered reservoirs of flora and fauna existing on the earth. They also include a large number of endemic species. 25 hot spots have been classified for the safeguarding of biodiversity. The 2 hot spots of India are Western ghats and Eastern Himalayas.