Navodaya Vidyalaya Samiti – Bhopal Region.
Salient features :-
1.
Biodiversity refers to the totality of genes, species and ecosystems of a region and it differs from place to place. At present, biological diversity is being lost which would possibly check the evolutionary capability of biota to cope up with environmental changes.
2.
Biological diversity includes three hierarchical levels-genetic diversity, species diversity and community and ecosystem diversity. These levels of biodiversity are inter-related.
3.
Biodiversity varies with change in latitude or altitude. As one moves from polar to equator, the biological diversity increases. Favourable environment conditions favour speciation and make it possible for a larger number of species to occur and grow.
4.
Biodiversity is the source of food, medicines, pharmaceutical drugs, fibres, rubber and timber. But, there is continuous loss of biodiversity due to habitat loss, fragmentation, introduction of non-native species, over-exploitation, soil, water and atmospheric pollution.
5.
The IUCN Red list is a catalogue of taxa that are facing the risk of extinction. Red list aims to impart information about the urgency and scale of conservation problems to the public and policy makers. There are 15500 species which are listed as threatened on the
2004 IUCN Red List.
6.
There is a need to conserve landscapes, ecosystems, species, and genetic resources.
Conservation strategies include in situ (on-site) and ex-situ (off-site) approaches.
Protected area network includes parks, wildlife sanctuaries and biosphere reserves etc.
Twenty five hot spots of terrestrial biodiversity have been identified, of which two are in india.
SOME IMPORTANT DEFINITIONS AND TERMS
1.Alien species – New species entering a geographical region.
2.Biodiversity – Refers to the totality of genes, species, and ecosystems of a region.
3.Biosphere reserve – A reserve area for multiple use of land.
4.Buffer zone – A region where limited human activity is allowed.
5.Core zone – A zone where no human activity is allowed.
6.Cryopreservation – Preservation in liquid N2 AT – 196 degree C.
7.Endangered species – Species in danger of extinction and are not likely to survive if the factors threatening their extinction continue.
8.
Ex situ conservation – Protective maintenance of threatened species in zoological parks and botanical gardens.
9.Exoyic species – Alien species that are introduced into a habitat by humans.
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Navodaya Vidyalaya Samiti – Bhopal Region.
10.Extinct – Species is extinct when there is no reasonable doubt that the last individual has died.
11.Genetic diversity – Refers to the variation of genes within species.
12.
In situ conservation – Endangered species are protected in their natural habitat.
13.IUCN – Internal union for the Conservation of Nature and Natural Resources.
14.National Park – Protected area reserved for wild life.
15.Speciation – Evolution of new species.
16.Taxol – Anticancerous drug.
17.Vulnerable species - Species that are likely to move into endangered category in near future if the.
18. WWF - World Wildlife Fund.
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Very short answer type question (1 marks)
1.
What is species diversity?
ANS:- Species diversity refers to the variety of species within in a given region.
2.
Name the three important components of biodiversity?
ANS:- Genetic diversity, species diversity and ecological/ecosystem diversity are the three important components of biodiversity.
3.
Name the most species-rich taxonomic group of animal. What percentage of animals, does the group constitute?
ANS:- - Insects are the most species- rich taxonomic group of animals.
This group constitutes about 70% of the total animals.
4.
What is the contribution (percentage)of India to global species diversity?
ANS:- India contributes 8.1% the global species diversity.
5.
What is the value of Z, slope of regression, for frugivorous birds found to be?
ANS:- The value of Z for frugrivorous birds is found to be 1.15.
6.
What do steeper slopes of regression mean/represent?
ANS:- Steeper slopes of regression represent species- are relationship of larger areas like the entire continent; is shows high species-richness.
7.
How much of tropical rain forests has decreased?
ANS:- The tropical rainforests were once covering 14% of the earth’s land area; now they cover only 6% of the earth’s; land area.
8.
About 200 species of cichlid fish became extinct when a particular fish was introduced in
Lake Victoria of Africa. Name the invasive fish.
ANS:- Nile Perch
9.
Name two animals that have become extinct by over-exploitation by humans.
ANS:- Steller’s sea cow and passenger pegion.
10.
What are endemic species?
11.
Name any two biodiversity hotspot in India?
ANS:- Western ghats and Sri lanka, Himalayas and Indo-barma region.
ANS:- Endemic species are those species, which are confined to particular region and are not found anywhere else in the world.
Short type answer questions(2 marks)
1.
What does the term genetic diversity refer to? What is the significance of large genetic diversity in a population?
ANS:- The term genetic diversity refers to the diversity of genes within of species.
Genetic diversity is important for the following reasons:
(i) Greater the genetic diversity among organisms of species, more sustenance, it has against environmental perturbations
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Navodaya Vidyalaya Samiti – Bhopal Region.
(ii) Genetically uniform populations are highly prone to diseases & harsh environment.
2.
Write the scientific name of the plant that yields reserpine. How is genetic variation expressed in the plant?
ANS:-Rauwolfia vomotoria is the plant that yields reserpine
-the genetic variation is shown in term of the potency & concentration of the active chemical reserpine.
3.
What is the significance of the slope of regression in a species-area relationship?
ANS:- ecologists have found that the value of Z, slope of regression, lies in the range of 0.1-0.2 regardless of the taxonomic group of the region.
-this value is in the range of 0.6-1.2, when the species –area relationship is calculated for very large areas like entire continents.
4.
Describe co-extinction?
ANS:- co-extinction is phenomenon in which when a species become extinct, the plant and animal species associated with it in an obligatory manner also become extinct. e.g.(i) when a host fish become extinct, its unique assemblage of parasites also faces extinction.
(ii) the plant pollinator mutualism is a case of co- evolution and extinction of one will invariably cause the extinction of other.
5.
What are biodiversity hotspot? How many such have been identified in the world and how many are present in India?
ANS:-biodiversity hot spots are those region with very high levels of species richness and high degrees of endemism.
-there are 34 hot spots in the world and three of them are found in India.
Short answer type question (3 marks)
1.
Describe with example, the latitudinal gradients of biodiversity?
ANS:- Latitudinal gradient of biodiversity is as following: i.
Species diversity decreases from equator towards pole ii.
The tropics (between 23.5˚ north to 23.5 ̊ South)harbour more species than temperatures region Columbia has about 1400 birds, new York has about 56 species and India has 1200 species. iii.
The number of species of vascular plants in the tropics about ten times more than that in temperate forests.
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Navodaya Vidyalaya Samiti – Bhopal Region. e.g. the Amazonian rain forests in south America harbours about 40000 species of plants and 125000 species of invertebrates
2.
When and where was the World Summit on Sustainable Development held? How many countries participated in that and what was the commitment made?
ANS:- the world summit on sustainable development was held in 2002 at Johannesburg south Africa
-190 countries participated in summit
-they pledge their commitment to achieve by 2010 a significant reduction in the current rate of biodiversity losses at global, regional and local levels.
3.
(i)What are biosphere reserves? How many of them are present in India?
(ii)Name two animals that have become extinct due to over-exploitation by man?
ANS:- Biosphere reserve are the ecologically unique and biodiversity – rich region that are legally protected. There are 14 biosphere reserves in India.
(ii) Steller sea cow, passenger pigeon.
4.
Enumerate the hypotheses proposed for justifying why tropics show the greatest levels of species richness as compared to temperate region?
ANS:- There are three hypothesis, which are as follows :-
(i) Speciation is a function of time; the temperate region were subjected to frequent glaciations in the past while the tropics have remained undisturbed and hence had longer time to evolve more species diversity.
(ii) The tropical environment are less seasonal and relatively more constant and more predictable than temperate regions; speciation have been promoted by such constant environments and hence there is greater species diversity.
(iii) There is more solar radiation available in the tropical region; this contributes directly to more productivity and indirectly to greater species diversity.
5.
Explain with three examples, how invasion or introduction of alien species into an ecosystem will lead to loss of biodiversity in that area?
(i) when Nile perch was introduced into lake Victoria in Africa, about 200 species of cichlid fish in the lake become extinct.
(ii)introductions of African catfish clarius gariepinus for aquaculture pour poses is posing a threat to indigenous catfishes.
(iv) Introductions of lantana and parthenium has caused considerable damaged to our indegenousplants and to the ecosystem.
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Long answer type question (5 marks)
1.
Explain with reasons, why we should conserve biodiversity?
ANS:-
(i) Narrowly utilitarian arguments:-
these are the obvious reasons that human beings derive a no. of direct economic benefits from the biodiversity, like food, fiber, construction materials etc.
(ii) Broadly utilitarian arguments:-
according to these, biodiversity plays a major role in many ecosystem service than nature provides. e.g. Providing oxygen to the atmosphere, pollination of plants for fruits & seed formation aesthetic pleasure etc.
(iii) Ethical arguments:-
this relates to what we owe to millions of plants, & microbe species with whom we share the earth; we have moral duty to care for their well being & pass on the biological legacy in goods form future generation.
2.
Describe in detail, the in situ approach of conservation of biodiversity?
ANS:-
(i)
(ii)
(iii)
-in situ conservation is the process of protecting the whole ecosystem & its biodiversity at all levels.
-The endangered species of plants & animals are protected in their natural habitats either they by protecting or cleaning up the habitat itself or by defending the species from their predators.
-It helps in recovering the population in the surroundings where they have developed their distinctive features.
Hotspots- eminent conservations have identified diversity “biodiversity hotspots” which are the region with high levels of species richness & high degree of endemism to provide more protection.
Biosphere reservebiosphere reserves are the ecologically unique & biodiversity rich regions that are legally protected; India has 14 biosphere reserves.
National parks & wildlife sanctuarythis are protected areas; India has
90national parks & 448 wildlife sanctuaries.
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3.
Describe in detail, the different methods of ex situ conservation of biodiversity?
ANS:-
(i) Zoological parks: this are the places where many animals have become extinct in the wild, continue to be maintained.
(ii) Botanical gardens: - many endangered species of plants & other plants are grown for conservation as well as reference purpose; India has 35 botanical gardens.
(iii) Cryopreservation:- cryopreservation is the storage of materials at ultra violet temperature either by very rapid cooling or by gradual cooling and simultaneous dehydration at low temperature.
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