CBSE Class 12 Biology Biodiversity and Conservation Assignment Set B

POINTS TO REMEMBER

Biodiversity : Term used to describe diversity at all levels of biological organisation. Term coined by socio-biologist Edward Wilson and was also used by Walter G Rosen for the diversity of life forms. Biodiversity refers to totality of genes in species and ecosytems of a region.

Three inter-related levels of Biodiversity : Genetic diversity, Species diversity, Ecological diversity.

¶ Genetic diversity : Diversity in the number and types of genes, as well as chromosomes present in different species and the variations in the genes and their alleles in the same species. It helps in speciation.

¶ Species diversity : Varieties in the number and richness of the species of a region.

¶ Ecological diversity : Variety in the types of ecosystems. IUCN : International Union for Conservation of Nature and Natural Resources. It is situated in Morges, Switzerland.

India has : More than 50,000 genetically different varieties of rice; 1000 varieties of mango;

¶ India has 1,42,000 known species of plants and animals (Around 45,000 species of plants and rest of animals);

¶ India has 8.1% of share of global biodiversity.

¶ India is one of 12 Mega diversity countries of the world. Latitudinal Gradients

¶ In general, species diversity decreases as we move away from the equator towards the poles.

¶ With very few exceptions, tropics (latitudinal range of 23.5¢X N to 23.5¢XS) harbour more species than temperate or polar areas.

¶ Colombia located near the equator has nearly 1,4000 species of birds while New York at 41°X N has 105 species and Greenland at 71°X N only 56 species.

q India has more than 1,200 species of birds.

q A forest in a tropical region like Equador has up to 10 times as many species of vascular plants as a forest of equal area in a temperate region like the Midwest of the USA.

q The largely tropical Amazonian rain forest in South America has the greatest biodiversity on earth.

Species-Area relationships

¶ German naturalist and geographer Alexander von Humboldt observed that within a region species richness increased with increasing explored area, but only up to a limit.

¶ The relation between species richness and area for a wide variety of taxa (angiosperm plants, birds, bats, freshwater fishes) turns out to be a rectangular hyperbola. 

¶ On a logarithmic scale, the relationship is a straight line decribed by the equation

log S = log C + Z log A

Where S = Species richness, A = Area; Z = slope of the line (regression coefficient) C = Y - intercept.

q Value of Z lies in the range of 0.1 to 0.2, regardless of the taxonomic group or the region.

q The species-area relationships among very large areas like the entire continents has much steeper slope of the line (Z values in the range of 0.6 to 1.2).

Causes of Biodiversity Losses

1. Habitat loss and fragmentation : This is most important cause of plants and animals extinction. For example : Tropical rain forest being destroyed fast. The Amazonian rain forest is called the lungs of the planet. It is being cut for cultivating soyabeans.

2. Over exploitation : Many species extinctions are due to over exploitation by humans. eg :- extinction of steller's cow, passenger pigeon is last 500 years.

3. Alien Species Invasions : When alien species are introduced some of them turn invasive and cause decline or extinction of indigenous species. eg. :- Carrot grass (Parthenium), Lantana and water hyacinth (Eichornia) posed threat to native species.

4. Co-extinctions : When a species becomes extinct, the plant and animal species associated with it in an obligating way also become extinct. eg.:- When a host fish species becomes extinct, its assemblage of parasites also becomes extinct.

Reasons for Conservation of Biodiversity

1. Narrowly utilitarian : Humans derive countless direct economic benefit from nature food (cereals, pulses, fruits), firewood, fibre, construction material, industrial products (tannins, lubricants, dyes, resins, perfumes) and products of medicinal importance.

2. Broadly utilitarian : Biodiversity plays a major role in many ecosystem services that nature provides.

3. Ethical : every species has an intrinsic value, even if it may not be of any current economic value to us. We have a moral duty to care for their well-being and pass on our biological legacy in good order to future generations.

 

Important Questions for NCERT Class 12 Biology Biodiversity and Conservation

 

Question. In species area relationship, on a logarithmic scale.
The relationship is -
(a) Rectangular hyperbola
(b) Rectangular parabola
(c) Straight line
(d) Sigmoid

Answer : C

Question. More species in community, tends to more stability than communities with less species'. It was supported by-
(a) David Tilman
(b) Paul Ehrlich
(c) Humboldt
(d) Tansley

Answer : A

Question. "Rivet popper hypothesis" was proposed by -
(a) Tilman
(b) Hombolat
(c) Paul Ehrlich
(d) Mayer

Answer : C

Question. Alien species invasion is one of the cause of Biodiversity loss. Introduction of Nile perch in victoria lake lead to extinction of more than 200 species of -
(a) Cichlid fish
(b) Gambusia
(c) Salmon fish
(d) Cat fish

Answer : A

Question. The recent illegal introduction of which African fish becomes severe cause of threatening of indigenous cat fishes -
(a) Gambusia
(b) Labeo
(c) Clarias gariepinus
(d) Dog fish

Answer : C

Question. Find out the following w.r.t. economic importance of biodiversity -
(a) Production of oxygen
(b) Pollination
(c) Medicinal utility
(d) All

Answer : C

Question. Match the following-
(a) Ants (i) 20,000 species
(b) Beetles (ii) >28,000 species
(c) Fishes (iii) >3,00,000 species
(d) Orchids (iv) >20,000 species
(a) a (iv), b (ii), c (iii), d (i)
(b) a (ii), b (iii), c (iv), d (i)
(c) a (iv), b (iii), c (ii), d (i)
(d) a (iii), b (ii), c (i), d (iv)

Answer : C

Question. In biosphere, diversity (heterogeneity) exist at -
(a) Species level
(b) Genetic level
(c) Ecosystem level
(d) All the above

Answer : D

Question. Find out the odd one with respect to 'Biodiversity hot spots' -
(a) Western Ghats & Srilanka
(b) Indo - Burma
(c) Himalaya
(d) Gangatic plains

Answer : D

Ques. Which of the following regions of the globe exhibits highest species diversity?
(a) Western Ghats of India
(b) Madagascar
(c) Himalayas
(d) Amazon forests 

Answer: D

Ques. According to Robert May, the global species diversity is about
(a) 1.5 million
(b) 20 million
(c) 50 million
(d) 7 million.

Answer: D

Ques. Which of the following is the most important for animals and plants being driven to extinction?
(a) Alien species invasion
(b) Habitat loss and fragmentation
(c) Drought and floods
(d) Economic exploitation 

Answer: B

Ques. Decline in the population of indian native fishes due to introduction of Clarias gariepinus in river Yamuna can be categoriesd as
(a) co-extinction
(b) habitat fragmentation
(c) over-exploitation
(d) alien species invasion.

Answer: D

Ques. Alexander von Humboldt described for the first time
(a) laws of limiting factor
(b) species area relationships
(c) population growth equation
(d) ecological biodiversity. 

Answer: B

Ques. Which of the following is correctly matched?
(a) Aerenchyma – Opuntia
(b) Age pyramid – Biome
(c) Parthenium – Threat to hysterophorus biodiversity
(d) Stratification – Population 

Answer: C

Ques. Red list contains data or information on
(a) all economically important plants
(b) plants whose products are in international trade
(c) threatened species
(d) marine vertebrates only. 

Answer: C

Ques. Which is the national aquatic animal of India?
(a) Blue whale
(b) Sea-horse
(c) Gangetic shark
(d) River dolphin

Answer: D

Ques. Which of the following is the most important cause of animals and plants being driven to extinction?
(a) Habitat loss and fragmentation
(b) Co-extinctions
(c) Over-exploitation
(d) Alien species invasion 

Answer: A

Ques. A species facing extremely high risk of extinction in the immediate future is called
(a) vulnerable
(b) endemic
(c) critically endangered
(d) extinct. 

Answer: C

Ques. The organization which publishes the Red list of species is
(a) ICFRE
(b) IUCN
(c) UNEP
(d) WWF.

Answer: B

Ques. Which of the following represent maximum number of species among global biodiversity?
(a) Fungi
(b) Mosses and Ferns
(c) Algae
(d) Lichens

Answer: A

Ques. Which of the following has maximum genetic diversity in India?
(a) Mango
(b) Wheat
(c) Groundnut
(d) Rice

Answer: D

Ques. Which organization publishes the ‘Red Data Book’?
(a) IUCN
(b) UNEP
(c) WWF
(d) GEF

Answer: A

Ques. Which one of the following have the highest number of species in nature?
(a) Fungi
(b) Insects
(c) Birds
(d) Angiosperms

Answer: B

Ques. Biodiversity of a geographical region represents
(a) endangered species found in the region
(b) the diversity in the organisms living in the region
(c) genetic diversity in the dominant species of the region
(d) species endemic to the region. 

Answer: B

Ques. Study the four statements (i–iv) given below and select the two correct ones out of them.
(i) A lion eating a deer and a sparrow feeding on grains are ecologically similar in being consumers.
(ii) Predator star fish Pisaster helps in maintaining species diversity of some invertebrates.
(iii) Predators ultimately lead to the extinction of prey species.
(iv) Production of chemicals such as nicotine, strychnine by the plants are metabolic disorders.
The two correct statements are
(a) (ii) and (iii) (b) (iii) and (iv)
(c) (i) and (iv) (d) (i) and (ii).

Answer: D

 

Very Short Answer Type Questions

Question. Write the level of biodiversity represented by mangrove. Give another example falling in the same level.
Answer : Mangroves represent ecological diversity. The same level of biodiversity is also shown by rain forests, coral reefs wetlands, estuaries and alpine meadows, etc. 

Question. State ‘two’ observations made by German naturalist, Alexander von Humboldt during his extensive explorations in South American jungles.
Answer : Within a region, species richness increases with increasing explored area but only up to a limit, this relation for a wide variety of taxa turns out to be a rectangular hyperbola.

Question. Suggest two practices giving one example of each, that help protect rare or threatened species. 
Answer : (i) In situ conservation, biodiversity hotspot / biosphere reserve / national parks / sanctuaries / Ramsar sites / sacred groves (Any one)
(ii) Ex situ conservation, zoological parks / botanical garden / wild life safari parks / cryopreservation techniques / Tissue culture / seed bank / pollen banks. (Any one) 

Question. Why are sacred groves highly protected ?
Answer : Sacred groves are highly protected because of religious and cultural traditions, refugees for large number of rare and threatened plants, ecologically unique and biodiversity rich regions. 

Question. State how does ex situ conservation help in protecting biodiversity.
                                                    OR
List any four techniques where the principle of ex situ conservation of biodiversity has been employed.
Answer : Cryopreservation, in vitro fertilization, micropropagation / tissue culture, sperm bank / seed bank / gene bank. 

Question. Plants that inhabit a rain-forest are not found in a wetland. Explain.
Answer : Plants that inhabit rain forest are well adapted to that particular habitat. The climate of the rainforest is wet and humid and in this climate, large trees and shrubs are predominantly present.
The climate of wetlands, on the other hand, is cool and wet.

Question. Why Western Ghats in India have been declared as biological hotspots ?
Answer : Due to greater species diversity/presence of endemic species. 

Question. How the species-area relationship is represented on a log scale ?
Answer : The species-area relationship is represented in linear form on a log scale.

Question. Why are mango trees unable to grow in temperate climate?
Answer : Because temperature affects the basal metabolism/ physiological function of the plant not adapted to low temperature of temperate climate. Mango trees are not able to grow in temperate below 30 degrees thus cannot grow in temperate climate. 

Question. Name one of the ex-situ conservation method for endangered species
Answer : Cryopreservation is one of the ex-situ conservation methods for endangered species.

Question. Write the function of ‘‘Sacred groves’’. 
Answer : Sacred groves are a method for In situ conservation of biodiversity and conserving rare threatened species. 

Short Answer Type Questions

Question. Why are conventional methods not suitable for the assessment of biodiversity of bacteria?
Answer : Many bacteria are not culturable under normal condition in the laboratory. This becomes a problem in studying their morphological, biochemical and other characterisations which are useful for their assessment. Thus conventional methods are not suitable.

Question. Is it true that there is more solar energy available in the tropics? Explain briefly.
Answer : As one moves from the equator to the polar regions, the length of the day decreases and the length of the night increases. The length of day and night are same at the equator.Therefore, it is true that there is more solar energy available in the tropics.

Question. What does the term genetic diversity refer to? What is the significance of large genetic diversity in a population?
Answer : Genetic diversity is the measure of variety in genetic information contained in the organisms.
Significance of large genetic diversity are as follows:
(i) Larger genetic diversity provides adaptability at the time of environmental changes and helps the species in surviving.
(ii) Larger genetic diversity is also useful in the evolution of species.

Question. List the features that make a stable biological community. 
Answer : Features of a stable biological community are as follows:
(i) Communities should have greater biodiversity for greater stability.
(ii) It should be able to prevent invasion by alien species.
(iii) It should be able to restore itself in a short period of time.
(iv) Variations should be minimal in the community.

Question. Biodiversity must be conserved as it plays an important role in many ecosystem services that nature provides. Explain any two services of the ecosystem. 
Answer : The two ecosystem services are:
(i) Forest ecosystem purify air, mitigate droughts and floods.
(ii) The cycling nutrients generate fertile soil and maintains biodiversity.

Question. How is the presently occurring species extinction different from the earlier mass extinctions?
Answer : Species extinction occurring at present is due to anthropogenic or man-made causes whereas the earlier extinction was due to natural causes. Present extinction is occurring at 100 – 1000 times fast rate.

Question. In an experiment, the slope of regression (Z) is 0.2 and in another experiment the value obtained is 1.2. Explain the two situations in respect of species area relationships. 
Answer : 0.2 is obtained in studies regardless of the taxonomic group and the region 1.2 is obtained if species area relationship is analysed among very large areas like the entire continents.

Question. Discuss one example, based on your day-to-day observations, showing how loss of one species may lead to extinction of another. 
Answer : In case a species becomes extinct, the plant and animal species associated within an obligatory way also become extinct. For example,
(i) When a fish species which is a host for a number of parasites becomes extinct, the parasite species which are uniquely dependent on the host fish will also become extinct.
(ii) The insects may be polyphagous (feed on more than one plant species) or monophagous
(feed on only one particular plant species) in nature. The monophagous insect species are valuable and may become extinct if the plant species upon which it feeds becomes extinct.

Question. What is the ecological importance of biodiversity?
Answer : The ecological importance of biodiversity:
(i) Biodiversity is required for maintaining and sustainable use of goods and services from ecosystem.
(ii) Various insects help in pollination.
(iii) Various micro-organisms help in the decomposition of organic matter thereby increasing the soil fertility and cleaning the environment.
(iv) Various drugs and medicines are extracted from plants.

Question. Narrowly utilitarian arguments are put forth in support of biodiversity conservation. Explain the other two arguments that are put forth in support of the same cause. 
Answer :  Broadly utilitarian arguments
- Biodiversity plays a major role in maintaining and sustaining supply of goods and services from various species as well as ecological systems.
- The different ecological services provided are:
(a) Amazon forest is estimated to contribute 20 per cent of the total oxygen in the atmosphere on earth by photosynthesis.
(b) Ecosystem provides pollinators like bees, bumble bees, birds and bats which pollinate plants to form fruits and seeds.
Ethical reasons
OU There are thousands of plants, animals and microbes on this earth which are not useless. Every one has some intrinsic value even if it is not of any economic value to us.
OU It is, therefore, our moral duty to ensure well-being of all the living creatures for the utilisation of future generations

Question. Why are certain regions on the Earth called hot-spots? Name any two hot-spots in India.
Answer : Certain regions have been declared as “hot spots” for maximum protection of these regions which have high levels of species richness and high degree of endemism. Western Ghats and Sri Lanka and Himalayas are two example of hot-spots.

Question. Justify with the help of an example where a deliberate attempt by humans has led to the extinction of a particular species.
Answer : When Nile perch, a large predator fish, was introduced in Lake Victoria, it started feeding on the native fish, Cichlid fish. As a result, Cichlid fish became extinct and Nile perch, not finding any food for itself, died too.

Question.‘In situ‘ conservation can help endangered / threatened species. Justify the statement.
Answer : Threatened organisms are conserved in their natural habitat / ecosystem, and such regions are legally protected As hotspots / biosphere reserves / national parks / sanctuaries / sacred groves / Ramsar sites

Question.State any two criteria for determining biodiversity hotspots. Name any two hotspots designated in India.
Answer : Criteria for determining biodiversity hot spots are :
• High levels of species richness 
• High degree of endemism. 
Hotspots in India - Western Ghats, Himalaya (Indo-Burma/Sundaland to be accepted

Question.Co-extinction and introduction of alien species too are responsible for the loss of biodiversity. Explain, how.
Answer : Co-extinction : When a species becomes extinct, the plant and animal species associated with it in an obligatory way, also becomes extinct.
Introduction of alien species : When alien species are introduced, some of them turn invasive (because of not having their predator there), and hence cause decline / extinction of indigenous species. 

Question.Analyse the effects of ‘Alien species invasion’ on the biodiversity of a given area. Provide two examples. 
Answer : Introduction of alien species causes decline or extinction of indigenous species due to tough competition for utilization of resources 
Examples : Introduction of Nile perch in Lake Victoria led to extinction of more than 200 species of Cichlid fish. Introduction of African catfish
(Clarias gariepinus) for aquaculture poses threat to indigenous catfish. Threat posed to native species by invasive exotic weeds like carrot grass (Parthenium) / Lantana and water hyacinth (Eichhornia) /Extinction of Abingdon tortoise by introduction of goat.   

Question.List six advantages of “ex situ” approach to conservation of biodiversity.
Answer : An endangered / threatened species can be conserved / genetic strains of commercially important plants can be preserved for a long
time (seed banks) / biodiversity loss is reduced / gametes of threatened species can be preserved in a viable and fertile condition for long periods (using cryopreservation) / eggs can be fertilized in vitro / plants can be propagated using tissue culture / economically beneficial / conserve large number of species / aesthetic value.

Question.Explain the importance of biodiversity hotspots and sacred groves.
Answer : Importance of biodiversity hot-spots and sacred groves.
Hotspots—region with high level of species richness, high degree of endemism.
Sacred groves—tracts of forest containing tree/ wild life were venerated and given total protection, to protect last refuses for a large number of rare, and threatened plants 

Question.Explain the ‘ex situ conservation’ of Biodiversity. How is the in situ conservation different from it ?
Answer : Ex situ conservation : Threatened animals and plants are taken out from their natural habitat and placed in special settings where they can be protected and given special care , by keeping the gametes of threatened species preserved in viable and fertile condition for long time. Zoological parks / botanical gardens / wildlife safari parks / cryopreservation / eggs can be fertilised in vitro / tissue culture method / seed banks. (Any correct example explained) 
In situ conservation : Organisms are given protection
in their natural habitat in which biodiversity is
protected at all levels. 

Question.Differentiate between in situ and ex situ approaches for conserving biodiversity. Give an example for each. 
Answer : In situ Conservation – Threatened /endangered plants and animals are provided with urgent measures to save from extinction within their natural habitat and they are protected and allowed to grow naturally.
Example- Wildlife sanctuaries/ national parks / biosphere reserves/ sacred groves. (Any one example)
Ex situ Conservation – Threatened animals and plants are taken out of their natural habitat and placed in a setting where they can be protected and given care.
Example : In botanical gardens/ zoological gardens/ seed/pollen/gene banks. 

Question.Narrowly utilitarian arguments are put forth in support of biodiversity conservation.
Explain the other two arguments that are put forth in support of the same cause.
Answer : Broadly utilitarian arguments : Biodiversity plays an important role in maintaining sustaining supply of goods & ecological services. 
The different ecosystem services provided are : purifies air, cycling of nutrients, habitat for wildlife, pollinating crops, aesthetic pleasure. 
Ethical reasons : It is our philosophical/spiritual & moral duty to ensure well being of all living beings for utilization of future generations. 

Long Answer type Questions

Question. There are many animals that have become extinct in the wild but continue to be maintained in Zoological parks.
(i) What type of biodiversity conservation is observed in this case?
(ii) Explain any two other ways which help in this type of conservation. 
Answer : (i) Ex-situ conservation
(ii) (a) In-vitro fertilisation: Gametes of threatened species can be fertilised for their propagation.
(b) Cryopreservation techniques: Gametes of threatened species can be preserved in viable and fertile condition for long periods

Question. Co-extinction and introduction of alien species too are responsible for the loss of biodiversity.
Explain how. 
Answer :
Alien (exotic) species invasions
- Some alien (exotic) species when introduced unintentionally or deliberately, become invasive and cause harmful impact, resulting in extinction of the indigenous species.Nile perch, a large predator fish when introduced in Lake Victoria (East Africa) caused the extinction of an ecologically unique assemblage of more than 200 species of Cichlid fish in the lake.
- Invasive weed species like Parthenium (carrot grass), Lantana and Eichhornia (water hyacinth) caused environmental damage and posed threat to our native species.
- Introduction of African catfish (Clarias gariepinus) for aquaculture purposes is posing a threat to the indigenous cat fishes of Indian rivers.
Co-extinctions
- What species becomes extinct, the plant and animal species associated with it in an obligatory manner, also become extinct.
- For example, (a) if the host fish species becomes extinct, all those parasites exclusively dependent on it, will also become extinct; (b) in plant–pollinator mutualism also, extinction of one results in the extinction of the other.

Question. (a) “India has greater ecosystem diversity than Norway.” Do you agree with the statement?
Give reasons in support of your Answer :
(b) Write the difference between genetic biodiversity and species biodiversity that exists at all the levels of biological organisation. 
Answer : (a) Yes, India has greater ecosystem diversity than Norway because of following reasons. 

India (Tropical Region)	Norway (Temperate Region)
This region is less seasonal and the seasons are more constant.	This region is more seasonal and the seasons and less constant
Species diversity increases as we move towards equator.	Species diversity decreases as we move away from equator.
The climate in this region promotes niche specialisation resulting in greater biodiversity.	The climate in this region do not promote niche specialistion resulting in lower biodiversity.

(b) Genetic diversity refers to the variation within a species over its distributional range.
Species diversity refers to the variation at a species level.

Question. The given graph alongside shows species–area relationship. Write the equation of the curve ‘a’ and explain.

Answer : The equation of the curve ‘a’ is S = CAZ.
(i) Within a region, species richness increases with increasing explored area but only up to a limit.
(ii) Relationship between species richness and area for a wide variety of taxa turns out to be rectangular hyperbola.

Question. Explain, giving three reasons, why tropics show greatest levels of species diversity.
Answer : (i) Tropical latitude have remained relatively undisturbed and had a long evolutionary time for species diversification.
(ii) Tropical environments have less seasonal variations, more constant and predictable environmental conditions. This promotes niche specialisation for greater species diversity.
(iii) There is more availability of solar energy which contributes to higher productivity.

Question. The graph shows species-area relationship:

(a) If b denotes the relationship on log scale-
(i) Describe a and b.
(ii) How is slope represented? Give the normal range of slope.
(iii) What kind of slope will be observed for frugivorous birds and mammals in a tropical forest?
(b) Species diversity of plants (22%) is much less than that of animals (72%). Analyze the reasons for greater diversity of animals as compared to plants.
Answer : (a) (i) a is S = CA²
b is log S = log C + Z log A
(ii) Slope is Z (regression coefficient). Its normal value ranges from 0.6 to 1.2.
(iii) In frugivorous birds and mammals, value of Z=1.15
(b) Reasons for greater diversity of animals are:
(i) Animals are mobile and can avoid predator or unfavourable event.
(ii) Well developed nervous system to receive stimuli against external factors and respond to them.

Question. (a) According to ecologists, tropical regions in the world account for greater biological diversity. Justify. 
(b) Why are habitat loss and alien species invasion considered as the causes of biodiversity loss? Explain with the help of an example of each.
Answer : (a) Tropical regions have fewer seasonal variations and have more or less constant environment.
This promotes niche specialisation and thus,
high species richness.
(b) Habitat loss : Habitat of various organisms are altered or destroyed by uncontrolled and unsustainable human activities such as deforestation, slash and burn agricultural, mining and urbanisation. This results in the breaking up of the habitat into small pieces, which affects the movement of migratory animals and also, decreases the genetic exchange between populations leading to a declination of species. e.g., Tropical rain forests (loss from 14%
to 6%). Thousands of hectares of rain forests are being lost within hrs. Similarly, the Amazon rain forest is being cut for cultivating soya beans or for the conversion of grasslands for cattle.
Due to fragmentation, animals requiring large territories and migratory animals are badly affected. Alien species invasions : Accidental or intentional introduction of non-native species into a habitat has led to the declination or extinction of indigenous species. Alien species cause the decline or extinction of indigenous species. e.g., The Nile Perch introduced in Lake Victoria (East Africa) caused extinction of more than 200 species of native fish, cichlid fish in the lake. 

Question. Explain any three ways other than zoological parks, botanical gardens and wildlife safaris, by which threatened species of plants and animals are being conserved ‘ex situ’.
Answer : The three ways by which threatened spices of plants and animals are being conserved ex-situ besides zoological parks, botanical gardens and wildlife safaries are :
(i) Seed bank : Seeds can show variable periods of dormancy. Therefore, many seed plants can be preserved in the form of their seeds in small packets for longer periods. Places, where seeds are stored, are called seed bank, gene bank or germplasm banks.
(ii) Cryopreservation : Germplasm refers to any living plant organ or its part from which a complete new plant can be generated. This utilises the technique of cryopreservation in liquid nitrogen at a temperature of -196˚C. Plants are propagated by using tissue culture methods called micropropagation.
(iii) Animal translocation : It involves the release of animals in a new locality. It takes place when :
(a) A species is endemic or restricted to a particular region.
(b) A species on which an animal is dependent becomes rare.
(c) Due to habit destruction and unfavourable conditions.
(d) Increase in population in an area. 

Question. Explain any two most important levels of biological organisation showing biodiversity with the help of an example each.
Answer : (i) Genetic diversity : High diversity at the genetic level over its distributional range.
Example : Rauwolfia vomitoria growing in different Himalayan ranges might be in terms of the potency and concentration of the active chemical that the plant produce./ India has more than 50,000 genetically different strains of rice and 1,000 varieties of mango.
(ii) Species diversity : Diversity at the species level.
Example : The Western Ghats have a greater amphibian species diversity than Eastern Ghats. 
(iii) Ecological diversity : At the ecosystem level.
Example : India for instance with its deserts / rain forests / mangroves / coral reefs / wetlands/ estuaries / alpine meadows have a greater ecosystem diversity than a Scandinavian country like Norway. 
(Any two examples of ecological diversity)
(Any two levels of diversity) 

Question. (i) Indiscriminate human activities such as alien species invasion, fragmentation and habitat loss have accelerated the loss of biodiversity. Justify by taking one example for each.
(ii) State the importance of (a) IUCN Red data list and (b) Hotspots in conservation of biodiversity. 
Answer : (i) Alien species invasion : When alien species are introduced unintentionally or deliberately for whatever purpose, some of them turn invasive and decline / extinction of indigenous species.
Examples :
(a) The introduction of African catfish / Clarias gariepinus (for aquaculture purpose) poses a threat to indigenous catfishes in our rivers.
(b) The Nile perch introduced into lake Victoria in East Africa led to the extinction of more than 200 species of Cichlid fish in the lake.
(c) Carrot grass / Parthenium, Lantana, Water hyacinth / Eichhornia poses a threat to indigenous species. Fragmentation :
(a) When large habitats are broken into small fragments due to various human activities.
(b) Mammals / birds requiring large territories and certain animals with migratory habits are badly affected.
Habitat Loss : The Amazon rain forest is being cut and cleared for cultivating soyabeans / conversion to grasslands for raising cattle.
(ii) (a) Provides information regarding extinction of species.
(b) Regions with very high levels of species richness, high degree of endemism / species confined to that region and not found anywhere else are identified which need to be conserved in all priority basis.

Question. (a) “India has greater ecosystem diversity than Norway.” Do you agree with the statement
? Give reasons in support of your answer.
(b) Write the difference between genetic biodiversity and species biodiversity that exists at all levels of biological organization.
Answer : (a) Yes 
India / tropical region : (i) are less seasonal / more constant / more predictable.
(ii) promote niche specialisation leading to greater bio-diversity.
(iii) Species diversity increases as we move towards equator.
(iv) More number of species exist. Norway / temperate region :
(i) more seasonal / less constant / less predictable.
(ii) do not promote niche specialisation leading to low bio-diversity.
(iii) Species diversity decreases as we move away from equator.
(iv) Less number of species exist. 
(b) (i) Genetic diversity : Diversity / variation within a species over its distributional range/ (same explanation with the help of a correct examples)
(ii) Species diversity : Diversity / variation at a species level (same explained with the help of a correct example). 

Question. (i) Taking one example each of habitat loss and fragmentation, explain how are two responsible for biodiversity loss.
(ii) Explain two different ways of biodiversity conservation.
Answer : (i) Habitat loss : Amazon rain forest destroyed for soya beans cultivation for growing grass land, for grazing cattle/colonisation of Pacific islands
extinction of 2000 species of native birds. Fragmentation : By human activity—migratory birds and animals are affected.
(ii) Ex situ- Threatened organism are taken out from the natural habitat and placed in special setting with care and protection. e.g.,
Zoological park / botanical garden / wild safari.
In situ- Threatened organisms are conserved in their natural habitat e.g., National park / Biosphere reserves.

Please refer to the link below for CBSE Class 12 Biology Biodiversity and Conservation Assignment Set B