Worksheets Class 12 Biology Biodiversity and Conservation

Students should refer to Worksheets Class 12 Biology Biodiversity and Conservation Chapter 15 provided below with important questions and answers. These important questions with solutions for Chapter 15 Biodiversity and Conservation have been prepared by expert teachers for Class 12 Biology based on the expected pattern of questions in the class 12 exams. We have provided Worksheets for Class 12 Biology for all chapters on our website. You should carefully learn all the important examinations questions provided below as they will help you to get better marks in your class tests and exams.

Biodiversity and Conservation Worksheets Class 12 Biology

Question. Term “biodiversity” was popularised by-
(a) Edward Wilson
(b) Humboldt
(c) Tilman
(d) Paul Ehrlich

Question. According to IUCN (2004), how many plant and animal species have been described so far –
(a) <1.5 billion
(b) >1.5 million
(c) 7.1 million
(d) 7.1 billion

Question. When large habitats are broken up in to small fragments due to human activities, which of the following get badly affected –
(a) Mammals and birds requiring large territories
(b) Animals with migratory habitats
(c) Animals with large bodysize
(d) Both (a) and (b)

Question. Which method is thought to be best for estimation of mirobial biodiversity –
(a) Bio statistical method
(b) Bio chemical or molecular method
(c) Paleobotanical method
(d) Culture method

Question. What is the contribution of India in global species diversity –
(a) 2.4 %
(b) 12 %
(c) 8.1 %
(d) 7.1 %

Question. Which of the following is not the reason of great biodiversity in tropics ?
(a) Undisturbed climate for millions of years
(b) Less seasonal variations
(c) More nutritive soil
(d) More solar energy

Question. Find out the wrong match –
(a) Bioshpere reserves – 14
(b) National parks – 85
(c) Wild life sanctuaries – 448
(d) Indian Biodiversity hot spot – 3

Question. ‘Sacred groves is also one of the important mean of Biodiversity conservation. In respect of this find out the odd one –
(a) Khasi and Jaintia – Meghalaya
(b) Aravalli hills – Rajasthan
(c) Sarguja, Chanda and Bastar – Mizoram
(d) Western Ghat – Maharashtra

Question. When we conserve and protect the whole ecosystem, its biodiversity at all levels is called –
(a) In situ conservation
(b) Ex -situ conservation
(c) On site conservation
(d) Both (a) and (c)

Question. Which statement is incorrect –
(a) There is increase in biodiversity from pole to equator
(b) There is increase in biodiversity from low altitude to high altitude
(c) There is directly proportional relationship between area & biodiversity
(d) Tropics has less seasonal, relatively more constant and predictable environment.

Question. In equation log S = log C + Z log A, what is Z –
(a) Species richness
(b) Area
(c) Regression coefficient
(d) Y-intercept

Question. For frugivorous birds and mammals in tropical forest of different continents, the slope(Z) is found to be :-
(a) 0.1 – 0.2
(b) 0.6 – 1.2
(c) 1.15
(d) 11.5

Question. Select the wrong match for extinction of species as per the IUCN red list 2004 –
(a) Vertibrates – 338
(b) Invertebrates – 359
(c) Plants – 87
(d) Prokaryotes – 2001

Question. According to ecologists warn that if the present trends continue. Nearly half of the species on earth might be wiped out within how many years –
(a) 100
(b) 1000
(c) 50
(d) 500

Question. In general, the loss of biodiversity in a region may not lead to –
(a) Decline in plant production
(b) Lowered resistance to environmental perturbations
(c) Constant pest and disease cycles
(d) Increased variability in certain ecosystem processes such as plant productivity

Question. Find out the right one –
(a) India has 7.1% species diversity
(b) India is one of the 22 mega diversity countries of world
(c) According to Robert May’s global estimate only 22% of the total species have been recorded so for
(d) According to Robert May’s estimation, more than 3,00,000 plant species yet to be discovered in India

Read the following passage and answer the questions from 46 to 50 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. Refer to the given figure representing different zones of a biosphere reserve and select the correct option regarding it.   

(a) A-Limited human activity is allowed such as for research and education.
(b) B-An active co-operation occurs between reserve management and local people for activities like cropping, settlements, etc.
(c) C-No human activity is allowed.
(d) None of these
Answer : D

Question. Biosphere reserves differ from national parks and wildlife sanctuaries because in the former
(a) human beings are not allowed to enter
(b) people are an integral part of the system
(c) plants are paid greater attention than the animals
(d) living organisms are brought from all over the world and preserved for posterity.
Answer : B

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.
Answer : A

Question. Refer to the given diagrammatic representation of a biosphere reserve.   

Select the incorrect statement regarding X, Y and Z.
(i) X is devoted to strict protection of wildlife and no human activity is allowed in this zone.
(ii) In Y, only limited human activity (compatible with conservation) is allowed.
(iii) In X, commercial exploitation of natural resources is allowed.
(iv) Tourism is allowed in Y zone only.
(v) Zone Y helps to maintain the lifestyle of the tribal people living in the area.
(a) (iii), (iv) and (v) only
(b) (ii), (iii) and (v) only
(c) (i), (iii) and (iv) only
(d) (ii), (iii) and (iv) only
Answer : A

Question. Which of the following is similar to biosphere reserve in terms of conservation?
(a) Gene banks
(b) Offsite collection
(c) Orchards
(d) Hotspots
Answer : D

Question. Biosphere reserves differ from national parks and wildlife sanctuaries because in the former
(a) human beings are not allowed to enter
(b) people are an integral part of the system
(c) plants are paid greater attention than the animals
(d) living organisms are brought from all over the world and preserved for posterity.
Answer : B

Assertion & Reasoning Based MCQs

For question numbers 51-58, 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.
(iv) Tourism is allowed in Y zone only. 
(v) Zone Y helps to maintain the lifestyle of the tribal people living in the area.
(a) (iii), (iv) and (v) only
(b) (ii), (iii) and (v) only
(c) (i), (iii) and (iv) only
(d) (ii), (iii) and (iv) only

Question. Assertion : Species diversity decreases as we ascend towards high mountains.
Reason : Due to drop in temperature, no seasonal variability occurs in high mountains.
Answer : A

Question. Assertion : Alpha diversity refers to species diversity present in a given community or habitat.
Reason : Alpha diversity is expressed by species richness and species evenness in a community or habitat.
Answer : B

Question. Assertion : Many endemic species are seen to flourish in sacred forests.
Reason : Sacred forests are undisturbed forest patches and biodiversity rich areas.
Answer : A

Question. Assertion : The rate of extinction of organisms have increased in recent years.
Reason : Human activities like deforestation, industrialisation, etc., have destroyed the natural habitat of plants and animals.
Answer : A

Very Short Answer Type Questions

Question. Who proposed Rivet popper hypothesis?
Answer : The Rivet popper hypothesis was proposed by Stanford ecologist Paul Ehrlich.

Question. About 200 species of cichlid fish became extinct when a particular fish was introduced in lake Victoria of Africa. Name the invasive fish
Answer : Nile perch

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. Sometimes introduction of an exotic species upsets native species of the ecosystem.
Substantiate the statement with two examples from India.
Answer : Exotic species often become invasive and drive away the local species. Water hyacinth was introduced in Indian waters due to its aesthetic value. However, it has clogged water bodies resulting in death of several aquatic plants and animals. Eupatorium odoratum has reduced the population of Tectona grandis in North-East.

Question. India has more than 50,000 strains of rice. Mention the level of biodiversity it represents.
Answer : When species show high diversity at the genetic level over its distributional range then the biodiversity is at genetic diversity level. The 50,000 strains of rice differ at genetic level.

Short Answer Type Questions

Question. Differentiate between in situ and ex situ napproaches of conserving biodiversity.
Answer : Differences between in situ and ex situ conservation are: 

Question. Name and describe any three causes of biodiversity losses.
Answer : 29. 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. 

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. The following graph shows the species-area relationship. Answer the following question as directed.
(a) Name the naturalist who studied the kind of relationship shown in the graph. Write the observation made by him.
(b) Write the situation as discovered by the ecologists when the value of ‘Z’ (slope of the line) lies between
(i) 0.1 and 0.2 (ii) 0.6 and 1.2 What does ‘Z’ stand for?
(c) When would the slope of the line ‘b’ become steeper? 

Answer :  (a) Alexander von Humboldt studied species-area relationship. He observed that within a region, the species richness increased with increasing area but upto a certain limit.
(b) (i) Ecologists have discovered that the value of Z lies in the range of 0.1–0.2 regardless of taxonomic group or region, i.e., whether it is plants in Britain, birds in California or molluscs in New York, the slopes of the regression line are similar.
(ii) When the species-area relationship is considered for a very large area like a whole continent, regression coefficient Z or slope of the line become steeper with Z values in the range of 0.6 –1.2.
(c) Slope of line b, would become steeper when the value of Z ranges from 0.6 to 1.2 as for mammals of tropical forests of different continents, the slope is found to be 1.15.

Question. Where would you expect more species biodiversity– in tropics or in polar regions? Give reasons in support of your answer.
Answer : Tropics have more species biodiversity than the polar regions because of favourable environmental conditions as compared to polar regions where harsh conditions are prevalent. The reasons behind the maximum biological diversity of tropical regions are:
(i) Prolonged evolutionary time : Speciation is generally a function of time, unlike polar regions subjected to frequent glaciations in the past, tropical latitudes have remained relatively undisturbed for millions of years and thus, had a long evolutionary time for species diversification.
(ii) High productivity : There is more solar energy available in the tropics, which contributes to higher productivity; this in turn might contribute indirectly to greater diversity.

Question. Giving two reasons explain why there is more species biodiversity in tropical latitudesthan 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. Why are sacred groves highly protected?
Answer : Sacred groves are forest patches around places of worship, held in high esteem by tribal communities. They are most undisturbed forest patches which are often surrounded by highly degraded landscapes. Not a single branch is allowed to be cut from these forests and as a result, many endemic species which are rare or have become extinct elsewhere can be seen to flourish here. E.g., Jaintia and Khasi hills in Meghalaya. 

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. 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. “Stability of a community depends on its species richness.” Write how did David Tilman show this experimentally.
Answer :  Communities with more species tend to be more stable than those with less species as it is able to resist occasional disturbance. This has been confirmed experimentally by David Tilman. He raised plots with different diversities in Minesota grassland and subjected them various stresses. He found that plots with more species showed less year to year variation in total biomass. He also showed that in his experiments, increased diversity contributed to higher productivity.

Question.

The above graph show species-area relationship.
Write the equation of the curve ‘a’ and explain.
Answer : The equation of curve ‘a’ is S = CAz where, S = Species richness C = Y – intercept A = Area Z = Slope of the line (regression coefficient). The graph on species- area relationship shows that within a region, species richness increases with increasing explorable area, but only upto a certain limit. The relation between species richness and area for a wide variety of taxa turns out to be rectangular hyperbola.

Question. What is alpha diversity in an ecosystem?
Answer : Alpha diversity is diversity present in organisms sharing the same community present in an area of more or less uniform habitat. Alpha diversity determines the stability of the community, as more diversity indicates better adjustment and interrelationships amongst the members of the community.

Long Answer Type Questions

Question. (a) Explain the species-area relationship using the graphical representation given below. 

(b) Explain giving reasons why there is greater biodiversity in tropical regions of the Earth.
Answer : (a) Alexander von Humboldt studied species-area relationship. He observed that within a region, the species richness increased with increasing area but upto a certain limit. Ecologists have discovered that the value of Z lies in the range of 0.1–0.2 regardless of taxonomic group or region, i.e., whether it is plants in Britain, birds in California or molluscs in New York, the slopes of the regression line are similar. When the species-area relationship is considered for a very large area like a whole continent, regression coefficient Z or slope of the line become steeper with Z values in the range of 0.6 –1.2. Slope of line would become steeper when the value of Z ranges from 0.6 to 1.2 as for mammals of tropical forests of different continents, the slope is found to be 1.15. The equation of curve is S = CAz where, S = Species richness C = Y – intercept A = Area Z = Slope of the line (regression coefficient). The graph on species- area relationship shows that within a region, species richness increases with increasing explorable area, but only upto a certain limit. The relation between species richness and area for a wide variety of taxa turns out to be rectangular hyperbola.
(b) Tropics have more species biodiversity than the polar regions because of favourable environmental conditions as compared to polar regions where harsh conditions are prevalent. The reasons behind the maximum biological diversity of tropical regions are:
(i) Prolonged evolutionary time : Speciation is generally a function of time, unlike polar regions subjected to frequent glaciations in the past, tropical latitudes have remained relatively undisturbed for millions of years and thus, had a long evolutionary time for species diversification.
(ii) High productivity : There is more solar energy available in the tropics, which contributes to higher productivity; this in turn might contribute indirectly to greater diversity.
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. Explain the narrowly utilitarian, broadly utilitarian and ethical arguments in favour of conservation of biodiversity.
Answer :   There are a number of reasons to conserve biodiversity which can be grouped as:
(a) Narrowly Utilitarian : Human derive a major part of their requirement from organisms. Their direct benefits are countless, like (i) Food : Pulses, fruits, vegetables, milk, egg, meat comes from plants and animals
(ii) Fats and oils are obtained from plants and animals.
(iii) Firewood as a source of energy for cooking and heating.
(iv) Fibres, e.g., cotton, flax, silk, wool.
(v) Industrial products like tannins, lubricant,dyes, resins, and perfumes.
(vi) Drugs: Nearly 25% of drugs being used by us are directly coming from plants.
(b) Broadly Utilitarian : Biodiversity is fundamental to ecosystem services of nature. For example
(i) Oxygen: Through their photosynthetic activity plants are replenishing oxygen of the atmosphere. Amazon rain forest is estimated to contribute 20% of it.
(ii) Pollination: Bees, bumble bees, butterflies, moths, beetles, birds and bats are engaged in pollination of plants which is essential for formation of fruits and seeds.
(iii) Climate regulation: Forest and oceanic systems regulate global climate.
(iv) Aquifers: Plant cover is essential for retention of rain water, its percolation and storage in aquifers and reservoirs.
(v) Flood and erosion control: Plant cover protects the soil from wind and water erosion. Run off of rain water is reduced so that flood water is rarely formed.
(vi) Nutrient cycling : It is essential for continued availability of nutrients to plants without which there would be no photosynthetic activity. Ethical Human beings share the biosphere with over a million species of plants, animals and microbes. They have evolved just as we have evolved. Every living species has an intrinsic value though it may not have any direct economic value. It is therefore, our moral and ethical duty not to destroy them. Instead we should take care of their well being so as to pass the rich biological legacy to future generations.