Biodiversity and Conservation Class 12 Biology Important Questions
Please refer to Biodiversity and Conservation Class 12 Biology Important Questions with answers below. These solved questions for Chapter 15 Biodiversity and Conservation in NCERT Book for Class 12 Biology have been prepared based on the latest syllabus and examination guidelines issued by CBSE, NCERT, and KVS. Students should learn these solved problems properly as these will help them to get better marks in your class tests and examinations. You will also be able to understand how to write answers properly. Revise these questions and answers regularly. We have provided Notes for Class 12 Biology Important Questions for all chapters in your textbooks.
Important Questions Class 12 Biology Chapter 15 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. Equation for relationship (A) between species richness and area is
(a) log S = log C + Z log A
(b) log C = log S + Z log A
(c) Z log A = log S + log C
(d) log S = log C + log A.
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. Which of the following is similar to biosphere reserve in terms of conservation?
(a) Gene banks
(b) Offsite collection
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
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 : Buffer zone surrounds the core area and limited human activities like resource use strategies, research and education are allowed here.
Reason : There is no biotic interference except in buffer zone.
Question. Assertion : Dodo, Passenger pigeon, Steller’s sea cow have become extinct due to over exploitation.
Reason : Excessive exploitation of a species, whether animal or plants reduces size of its population so that it becomes vulnerable to extinction.
Question. Assertion : Many endemic species are seen to flourish in sacred forests.
Reason : Sacred forests are undisturbed forest patches and biodiversity rich areas.
Very Short Answer Type Questions
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. 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.
Question. Name the three zones of biosphere reserves.
Answer : Biosphere reserves have three zones:
Core or natural zone: Undisturbed and legally protected area where no human activity is allowed.
Buffer zone: Limited human activity like research, education and resource utilisation strategies are allowed.
Transition zone: Outermost region where human activity like recreation, cropping, forestry, etc., are allowed.
Short Answer Type Questions
Question. What is IUCN red list? Give any two uses of this list.
Answer : IUCN red list is a catalogue of taxa facing risk of extinction. The two uses of this list are:
(i) It provides awareness to the degree of threat to biodiversity.
(ii) It is useful in identification and documentation of species which are at high risk of extinction.
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.
Question. Mention the kind of biodiversity more than a thousand varieties of mangoes in India represent. How is it possible?
Answer : “More than a thousand varieties of mango in India” exhibit genetic diversity. Genetic diversity represents the diversity in number and types of genes as well as chromosomes present in different species and variations in the genes and their alleles in the same species.
The reason for this genetic diversity is the occurrence of variations in environmental parameters and use of horticulture techniques like grafting, breeding, etc.
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. 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. (a) Explain the concept of endemism.
(b) Name four regions in an around our country that are considered hotspots.
Answer : (a) Endemism is the ecological state of a species being unique to a defined geographical location such as an island, nation, country or other defined zone. E.g., The Tasmanian Devil is the largest carnivorous marsupial in the world and found only on the Australian island state of Tasmania.
(b) Western Ghats and Sri Lanka, Indo-Burma and Himalayas are hotspots in India. Others include mountains of southwest China, Caribbean Island hotspot, etc.
Question. List any four techniques where the principle of ex situ conservation of biodiversity has been employed.
Answer : Four techniques where principles for ex situ biodiversity conservation has been employed are:
(i) Orchards – Plants with recalcitrant seeds are grown in orchards where all possible strains and varieties are maintained, e.g., litchi.
(ii) Cryopreservation – Cells, embryos, tissues are preserved at – 196°C.
(iii) Seed banks – Storing viable seeds at low temperature, and germinating them to obtain fresh seeds.
(iv) Tissue culture – Production of large number of plants through callus culture, pollen grain culture, embryoids, etc.
Question. Many plant and animal species are on the verge of their extinction because of loss of forest land by indiscriminate use by the humans. As a biology student what method would you suggest along with its advantages that can protect such threatened species from getting extinct?
Answer : Conservation of biodiversity is 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 generations. There are two types of conservation strategies – in situ (on site) and ex situ (offsite).
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.
Long Answer Type Questions
Question. Explain the narrowly utilitarian, broadly utilitarian and ethical arguments in favour of conservation of biodiversity.
Answer : I. 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.