In This Post we are providing Chapter- 15 BIODIVERSITY AND CONSERVATION NCERT MOST IMPORTANT QUESTIONS for Class 12 BIOLOGY which will be beneficial for students. These solutions are updated according to 2021-22 syllabus. These MCQS can be really helpful in the preparation of Board exams and will provide you with a brief knowledge of the chapter
NCERT MOST IMPORTANT QUESTIONS ON BIODIVERSITY AND CONSERVATION
1. Hot spots are the regions of exceptionally high biodiversity . But they have become regions of accidental habitat loss too. Name the three hot spots of our country. Why are they called ‘Hot spot’?
Ans. Western Ghats and Sri lanka; Indo-Burma; Himalaya called ¡¥biodiversity hot spots¡¦ as they show
(i) High level of species richness
(ii) High degree of
2. Study the diagram of the earth given below . Give the name of the pattern of biodiversity therein. Suggest any two reasons for this type of occurance.
Ans. Latitudinal gradients
(i) More solar energy available in tropics, more productivity.
(ii) Tropical environments are less seasonal, so more predictable.
3. What is so special about tropics that might account for their greater biological diversity?
Ans.a) Speciation is a function of time, unlike temperate regions subjected to frequent glaciations in the past, tropical latitude have remained relatively undisturbed for million of years and thus had long evolutionary time for species diversification
b) Tropical environment are less seasonal, more const ant and predictable
c) More solar energy awailable in the tropics contributing to high productivity leading to greater diversity .
4.What do you mean by biodiversity? What are the different types of Biodiversity?
Ans. Biodiversity can be defined as the totality of genes species & ecosystem of a given region.
Three important components of Biodiversity are:-
i) Genetic Biodiversity:- It refers to the diversity of genes within a species, Greater the genetic diversity amongorganisms of a species. More sustenance it has against environmental perteburations whereas geneticallyuniform populations are highly prone to diseases or harsh environment
ii) Species Biodiversity:- It refers to variety of species within a region. It has two important measures :-
a) Species richness:- i.e. number of species per unit area.
b) Species evenness:- i.e. abundance with which each species is represented in an area.
iii) Ecosystem Biodiversity:- It refers to variation of habitats, community types & abiotic environment present in an area. It is further of three types:-
a) αα – diversity- It refers to number of species in a given community.
b) ββ– diversity – biodiversity which appears in range of communities due to replacement ofspecies with change in community is called ββ– diversity.
c) γγ– diversity – It refers to diversity of habitats over the total geographical area.
5.What do you mean by latitudinal gradient? What could be the possible reasons for diversity between tropic & temperate region?
Ans. Latitudinal gradient in diversity means that species diversity usually decreases as we move away fromequator towards the poles, Tropic area of latitudinal range 23.50c harbor more species than temperate orpolar area. Three hypothesis have been proposed to explain this difference:-
i) Speciation is a function of time, which temperate regions were subjected to frequent glaciations in the past,the tropics have remain unchanged & hence evolved more species diversity.
ii) As compared to temperate region, tropical environment are less seasonal, relatively more constant &predictable; such constant environment have promotes niche specialization & greater species diversity.
iii) There is more solar radiation avail able in tropical region this contributes directly to greater productivity &indirectly to greater species diversity.
6.Why is it necessary to conserve biodiversity?
Ans.The reasons for conserving biodiversity can be grouped into three categories.
i) Narrow utilitarian reasons:- Human beings derive a number of economic benefits like food, fibre,firewood, industrial product & medicinal products.
ii) Broad utilitarian reasons:- Biodiversity plays a major role in providing ecosystem services like :-
a) production of oxygen
b) Pollination of flowers, without which seeds or fruits are not produced.
c) Aesthetic pleasures like bird watching, watching spring flowers, walking through thick forest, workingup to bulbul’s song etc.
iii) Ethical reasons :- Every species has an intrinsic value even if it is not of any economic value to us-wehave a moral duty to care for their well-being & pass on the biological legacy in a proper from to ourfuture generation.
7.What is the relation between species richness & area? What is the significance of slope of regression?
Ans.Alexander Von Humboldt has observed that within a region, species richness increased withincrease explored area but only upto a limit thus the relationship between species richness & area for anumber of taxa is found to be a rectangular hyperbola. On a log scale, the relation ship becomes linear & is described layequation
Log S = log C + Z log A
The values of slope of regression are identical regardless of the taxonomic group or the region. When such analysis is made among very large areas, the slope ofregression would be much steeper.
8.What are the different approaches for biodiversity conservation in India?
Ans.There are two major approaches for conservation of biodiversity:-
i) In-situconservation :- It is the process of protecting the endangered species of plant or animal in thenatural habitat lay either protecting or cleaning up the habitat or by defending species from predators Itincludes:-
a) Biosphere Reserves:- There are 425 biosphere reserve in the world of which 14 are in India. Hotspotshave been identified for maximum protection to endemic or endangered species.
b) National park or wildlife Sanctuaries:- India has about 90 national parks & 448 wildlife sanctuaries.
c) Sacred forests:- These are undisturbed forests without any human intervention & are surrounded by highly degraded landscapes.
ii) Ex- situ Conservation:- It is the process of protecting the endangered species of plants or animals by removing it from threatened habitat & placing them under care of humans. It includes :-
a) Botanical garden, zoological park and arboreta are conventional methods of ex-situ conservation
b) Cryopreservation to the storage of materials at ultra low temperature either by rapid cooling or by gradual cooling & simultaneous dehydration at low temperature.
9.Give an account of Biodiversity in India?
Ans.India is one of the 10th mega biodiversity countries of the world because of the presence of variety ofclimatic conditions prevailing on different ecological habitat ranging from tropical, subtropical,temperate, So far as biodiversity of India is concerned, it comprises about 47,000 plants & 81,000 animalspecies. India occupies 2-4% of total land area of would but in terms of biodiversity, India contributeabout 10-35% of global diversity.
A large number of species is native of India. About 5000 species of flowering plants belonging to 141genera& 47 families had a birth in India. There are 62% of amphibian species& 50% of lizards endemicto our country with large number in Western Ghats. India is an origin place of 166 species of crop plants& 320 species of wild relatives of cultivated crop. India is rich in marine biodiversity lying along coastlineof 7500 km. There are two hotspots located in India out of 25 in would – These are Western Ghats&Eastern Himalayas.
10.What is the significance of Biodiversity to Human beings?
Ans.Biodiversity provide numerous direct or indirect services to human beings. These are-
i) Source of food & improved varieties:- Biodiversity directly or indirectly adds as the source of food,cloth& shelter.
ii) Fats & Oils:- A variety of plants are used to extract different kinds of oils.
iii) Fibres:- A variety of plants eg. cotton, hemp, jute are chief sources of fibres.
iv) Resins:- Resins are sticky exudation of plants.
v) Gums, Timber, Paper, Tannins, Dyes:- Plants species provide variety of useful products eg. gums,raisins, dyes, similarly animal species provide leather, fur, honey, silk, pearl etc.
vi) Drugs & Medicines:- Hiving organism also contain number of therapeutically useful substances.
vii) Stability of Ecosystem:- The food web, food chain energy flow in various tropic level & biochemicalcycles occurs in natural ways without any hindrance if there is proper availability of diversified species
viii) Aesthetic, Scientific & Recreational values :- Indian people grow many plants because they regardthem as sacred.
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