NCERT Solutions for Class 11th: Ch 16 Biodiversity and Conservation

NCERT Solutions for Class 11th: Ch 16 Biodiversity and Conservation

Exercises

Page No. 118

1. Multiple choice questions.

(i) Conservation of biodiversity is important for :
(a) Animals
(b) Animals and plants
(c) Plants
(d) All organisms
► (d) All organisms

(ii) Threatened species are those which :
(a) threaten others
(b) Lion and tiger
(c) are abundant in number
(d) are suffering from the danger of extinction
► (d) are suffering from the danger of extinction

(iii) National parks and sanctuaries are established for the purpose of :
(a) Recreation
(b) Hunting
(c) Pets
(d) Conservation
► (d) Conservation

(iv) Biodiversity is richer in :
(a) Tropical Regions
(b) Polar Regions
(c) Temperate Regions
(d) Oceans
► (a) Tropical Regions

(v) In which one of the following countries, the ‘Earth Summit’ was held?
(a) the UK
(b) Mexico 
(c) Brazil
(d) China
► (c) Brazil

2. Answer the following questions in about 30 words.

(i) What is biodiversity?

Answer

Biodiversity refers to the varieties of plants, animals and micro-organisms, the genes they contain and the ecosystems they form.

(ii) What are the different levels of biodiversity?

Answer

There are three different levels of biodiversity:
• Genetic diversity: It refers to the variation of genes within species.
• Species diversity: It refers to the variety of species.
• Ecosystem diversity: It refers to the number of ecosystems in a certain area.

(iii) What do you understand by ‘hotspots’?

Answer

The areas rich in species diversity are called hotspots of diversity.

(iv) Discuss briefly the importance of animals to human kind.

Answer

Animals capture and store energy, produce and decompose organic materials, help to cycle water and nutrients throughout the ecosystem, fix atmospheric gases and help regulate the climate.

(v) What do you understand by ‘exotic species’?

Answer

Species which are not the natural inhabitants of the local habitat but are introduced into the system are called exotic species.

3. Answer the following questions in about 150 words.

(i) What are the roles played by biodiversity in the shaping of nature?

Answer

Biodiversity has contributed in many ways to the development of human culture and, in turn, human communities have played a major role in shaping the diversity of nature at the genetic, species and ecological levels. Biodiversity plays the following roles:

• Ecological Role of Biodiversity: Species capture and store energy, produce and decompose organic materials, help to cycle water and nutrients throughout the ecosystem, fix atmospheric gases and help regulate the climate. These functions are important for ecosystem function and human survival.

• Economic Role of Biodiversity: Biodiversity is seen as a reservoir of resources to be drawn upon for the manufacture of food, pharmaceutical, and cosmetic products.

• Scientific Role of Biodiversity: Biodiversity also helps in understanding how life functions and the role of each species in sustaining ecosystems of which we are also a species.

(ii) What are the major factors that are responsible for the loss of biodiversity? What steps are needed to prevent them?

Answer

The major factors that are responsible for the loss of biodiversity are:

• Growth in human population has increased the rate of consumption of natural resources which accelerated the loss of species and habitation in different parts of the world.
• Overexploitation of resources and deforestation.
• Destruction of natural habitats.
• Natural calamities such as earthquakes, floods, volcanic eruptions, forest fires, droughts, etc.
• Pesticides and other pollutants such as hydrocarbons and toxic heavy metals.

The steps which are needed to prevent them are:
• Efforts should be made to preserve the species that are endangered.
• Prevention of extinction requires proper planning and management.
• Varieties of food crops, forage plants, timber trees, livestock, animals and their wild relatives should be preserved.
• Each country should identify habitats of wild relatives and ensure their protection.
• Habitats where species feed, breed, rest and nurse their young should be safeguarded and protected.
• International trade in wild plants and animals be regulated.

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