Please refer to Biology For Biodiversity and Conservation Class 12 Biology Exam Questions provided below. These questions and answers for Class 12 Biology have been designed based on the past trend of questions and important topics in your class 12 Biology books. You should go through all Class 12 Biology Important Questions provided by our teachers which will help you to get more marks in upcoming exams.
Class 12 Biology Exam Questions Biodiversity and Conservation
Case Based MCQs
Case I : Read the following passage and answer the questions from given below.
Within a region, species richness increases with increasing explored area, but only upto a limit.
The given graph explains this relationship.
Question. The shape of curve for relationship between species richness and areas for a wide variety of taxa is
(a) straight line
(c) rectangular hyperbola
(d) bell shaped.
Question. What is the value of slope of line or regression coefficient Z for frugivorous birds?
Case II : Read the following passage and answer the questions from given below.
Biosphere reserves are multipurpose protected areas which are meant for preserving genetic diversity in representative ecosystems of various natural biomes and unique biological communities by protecting wild populations, traditional life style of tribals and domesticated plant/animal genetic resources. Each biosphere reserve has three zones-core, buffer and transition zone.
Question. MAB Programme means
(a) Man and biosphere programme
(b) Man and biodiversity conservation programme
(c) Manually aided biosphere conservation programme
(d) none of these.
Assertion & Reasoning Based MCQs
Two statements are given-one labelled Assertion and the other labelled Reason.
Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.
(a) Both assertion and reason are true and reason is the correct explanation of assertion.
(b) Both assertion and reason are true but reason is not the correct explanation of assertion.
(c) Assertion is true but reason is false.
(d) Assertion is false but reason is true.
Question. Assertion : Species diversity decreases as we ascend towards high mountains.
Reason : Due to drop in temperature, no seasonal variability occurs in high mountains.
Question. Assertion : Alpha diversity is said to be higher if the dissimilarity between communities is higher.
Reason : Alpha diversity is dependent upon species richness and evenness / equability.
Very Short Answer Type Questions
Question. Name any three sites of sacred groves.
Answer : (i) Khasi and Jaintia hills in Meghalaya.
(ii) Aravall Hills of Rajasthan
(iii) Sarguja, Chanda and Bastar areas of Madhya Pradesh
Question. Who proposed Rivet popper hypothesis?
Answer : The Rivet popper hypothesis was proposed by Stanford ecologist Paul Ehrlich.
Question. Mention one application of pollen bank. How are pollens stored in a bank?
Answer : Pollen banks are used to maintain stocks of biodiversity.
Pollens are stored in a bank at a very low temperature of –196°C in liquid nitrogen, i.e., by cryopreservation.
Short Answer Type Questions
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 a greater ecosystem diversity than Norway as India comes under the tropical region whereas, Norway lies in temperate region. Tropical regions accountfor greater biological diversity as they have deserts, rainforests, mangroves, coral reefs, wetlands, estuaries and alpine meadows than temperate regions. In tropical region, more solar energy is available that also promotes higher productivity and increased biological diversity.
(b) Differences between genetic and species biodiversity are as follows :
|Genetic biodiversity||Species biodiversity|
|(i)||It is related to the number of genes and their alleles found in organisms.||It is related to number and distribution of species found in an area.|
|(ii)||It is trait of the species.||It is trait of a community.|
|(iii)||It influences the adaptability and distribution of a species in diverse habitats.||It influences biotic interactions and stability of the community.|
|(iv)||Example : India has more than 50,000 genetically different strains of rice and 1,000 varieties of mango.||Example : Western ghats have a greater amphibian species diversity as compared to Eastern ghats.|
Question. What is beta diversity in an ecosystem?
What is the significance of large genetic diversity in a population ?
Answer : Beta diversity is diversity which develops due to change in habitat or community along environmental gradients like altitude, latitude, moisture gradient, etc. Higher beta diversity indicates the presence of unique habitats or unique communities in the region.
Genetic diversity enables a population to adapt to its environment and the changes occurring in the environment.
Genetic diversity within a species is the basis of speciation or formation of new species.
Question. Giving two reasons explain why there is more species biodiversity in tropical latitudes than in temperate ones.
Answer : The two reasons for more species biodiversity in tropical latitudes than in temperate ones are:
(i) Temperate region was subjected to frequent glaciations in the past, while tropical latitudes have remained relatively undisturbed for millions of years and thus, had a long evolutionary time for species diversification.
(ii) Tropical environments, unlike temperate ones, are less seasonal, relatively more constant and predictable. Such constant environments promote niche specialisation and lead to a greater species diversity.
Question. Justify with the help of an example where a deliberate attempt by humans has led to the extinction of a particular species.
Answer : Extinction of species due to human activities is known as anthropogenic extinction. Various human activities have led to extinction of particular species. The most common example is Nile perch, a large predator fish introduced in Lake Victoria for commercial purpose turned out to be a problematic species. It started feeding on the native fish cichlid fish, which results in extinction of ecologically unique assemblage of over 200 native species of small cichlid fish.
Question. Study the given figure and answer the following questions.
(a) Identify the figure and the types of diversity labelled as A, B and C in it.
(b) Give a brief description of diversity labelled as A and C.
(c) Which of the diversities labelled as A, B and C will face maximum competition, adjustments and interrelationships amongst the members of the same community?
Answer : (a) The given figure is of ecological diversity. Here, A is alpha diversity, B is beta diversity and C is gamma diversity.
(b) Alpha diversity (A) is a species diversity in a given community or habitat. Alpha diversity is dependent upon species richness and evenness/equitability. Gamma diversity (C) is a diversity present in ranges of communities as represented by diversity of habitats/ecosystems over a total landscape or geographical area.
(c) Alpha diversity (A) will face maximum competition, adjustments and interrelationships amongst the members of the same community.
Question. Since the origin of life on Earth, there were five episodes of mass extinction of species.
(a) How is the ‘Sixth Extinction’, presently in progress, different from the previous episodes?
(b) Who is mainly responsible for the ‘Sixth Extinction’?
(c) List any four points that can help to overcome this disaster.
Answer : (a) Sixth extinction, i.e., the current species extinction is 100 – 1000 times faster than extinctions in pre-human times.
(b) Human activities like settlements, hunting, overexploitation and habitat destruction are mainly responsible for ‘Sixth extinction’.
(c) This disaster can be overcome by the following ways:
(i) Planting large number of trees on road sides and where space is available.
(ii) Avoid introduction of invasive alien species.
(iii) Conserving biodiversity by maintaining national parks, zoos, etc.
(iv) Deforestation and fragmentation of forested areas should be stopped.
Question. Name and describe any three causes of biodiversity losses.
Answer : The three major causes of biodiversity loss are :
(i) Habitat loss and fragmentation – Over-population, urbanisation and industrialisation require additional land every year. It can come through destruction or fragmentation of natural habitats through filling wetlands, ploughing grasslands, cutting down trees, burning a forest and clearing some area of vegetation. Loss of habitat results in annihilation of species of endemic plants, microorganisms and forcing out of animals which in alien lands die out after some time.
Migrating animals would go astray and get killed.
(ii) Over-exploitation – Excessive exploitation of a species, whether a plant or an animal, reduces size of its population so, that it becomes vulnerable to extinction. Due to overexploitation by humans, Dodo, three subspecies of tiger and Steller’s sea cow have become extinct in the last 500 years.
(iii) Alien species invasions – Non-native or alien species are often introduced by man for their economic and other uses.
They often become invasive and drive away the local species.
For example, water hyacinth (Eichhornia crassipes) was introduced in Indian waters due to its aesthetic value but turned out to be a problematic species. It clogged water bodies including wetlands at many places resulting in death of several aquatic plants and animals.
Observe the global biodiversity distribution of major plant taxa in the above diagram and answer the questions that follow.
(a) Which group of plant are most endangered?
(b) Why are mosses/ferns so few? Give reason.
(c) How do fungi that are heterotrophs sustain themselves as a large population?
(d) Which group of plant is most advanced and which one is most primitive?
Answer : (a) As per the given pie chart lichens are least in number, also lichens are pollution sensitive so with increasing globalisation we can assume that in near feature lichens will be subject to extinction and hence may be considered as most endangered among the given taxas.
(b) Mosses and ferns grow in shady and humid places or wet places and need water for fertilisation. Hence, they are few in numbers.
(c) Fungi can live as saprotrophs or parasites. As saprotrophs, they depend on only organic matter and hence survive in any environment. They produce a number of thick walled spores, which can withstand the unfavourable conditions and germinate when conditions become favourable. This helps fungi in sustaining a large population.
(d) Angiosperms are the most advanced whereas fungi are the most primitive.
Long Answer Type Questions
Question. (a) Why should we conserve biodiversity? How can we do it?
(b) Explain the importance of biodiversity hotspots and sacred groves.
Answer : (a) Conservation of biodiversity is the protection, uplift and scientific management of biodiversity so as to maintain it at its optimum level and derive sustainable benefits for the present as well as future strategies. The maintenance of a high level of biodiversity is important for the stability of ecosystem. The main reasons to conserve the biological diversity can be grouped in three categories :
– Narrowly utilitarian (useful products for humans like food, fibres, drugs and medicines etc.)
– Broadly utilitarian (ecosystem services like provision of pollination, climate regulation, flood and erosion control, ecological balance through nutrient cycling, microbial waste treatment, biological pest control, aesthetic and cultural values).
– Ethical (every living species has an intrinsic value though it may not have any direct economic value, and also, every species has the right to live).
The two types of conservation strategies are in situ (on site) and ex situ (off site).
In situ conservation is conservation and protection of the whole ecosystem and its biodiversity at all levels in their natural habitat in order to protect the threatened species.
It involves hotspots and protected areas. Hotspots are areas of high endemism and high level of species richness.
Protected areas are ecological/biogeographical areas where biological diversity along with natural and cultural resources is protected, maintained and managed through legal or other effective measures. Protected areas include national parks, sanctuaries and biosphere reserves.
Ex situ conservation is conservation of threatened plants and animals in places outside their natural homes under full protection and supervision. It includes offsite collections and gene banks.
(b) ‘Biodiversity hotspots’ are the regions which are characterised by very high levels of species richness and high degree of endemism. India has three hotspots – Indo-Burma (North-East India), Himalayas, and Western Ghats. Importance of hotspots are as follows:
– Maintaining genetic diversity of all present species and varieties.
– Maintaining viable populations of native species, subspecies and varieties.
– Maintaining resilience in species/habitats/ecosystems to adapt to environmental changes.
– Maintaining the various types of communities/ ecosystems/habitats both in number and distribution.
– Checking human aided introduction of alien/exotic species.
Sacred forests or sacred groves are forest patches around places of worship which are held in high esteem by tribal communities. They are the most undisturbed forest patches (island of pristine forests) which are often surrounded by highly degraded landscapes. They are found in several parts of India, e.g., Karnataka, Maharashtra, Rajasthan (Aravalli), Chandigarh (Sarguja, Chanada and Bastar), Kerala, Meghalaya. Temples built by tribals are found surrounded by deodar forests in Kumaon region. In Meghalaya scared groves are found in Jaintia and Khasi hills. Not a single branch is allowed to be cut from these forests. As a result, many endemic species which are rare or have become extinct elsewhere can be seen to flourish here. Bishnois of Rajasthan protect Prosopis cineraria and Black Buck religiously. Some water bodies are also held sacred in certain places, e.g., Khecheopalri in Sikkim. Their aquatic flora and fauna are naturally preserved.