Case Study Questions Class 12 Biology Chapter 15 Biodiversity and Conservation
CBSE Class 12 Case Study Questions Biology Biodiversity and Conservation. Term 2 Important Case Study Questions for Class 12 Board Exam Students. Here we have arranged some Important Case Base Questions for students who are searching for Paragraph Based Questions Biodiversity and Conservation.
At Case Study Questions there will given a Paragraph. In where some Important Questions will made on that respective Case Based Study. There will various types of marks will given 1 marks, 2 marks, 3 marks, 4 marks.
CBSE Case Study Questions Class 12 Biology Biodiversity and Conservation
Case study 1
In our biosphere immense diversity (or heterogeneity) exists not only at the species level but at all levels of biological organisation ranging from macromolecules within cells to biomes. Biodiversity is the term popularised by the sociobiologist Edward Wilson to describe the combined diversity at all the levels of biological organisation. The most important of them are– (i) Genetic diversity: A single species might show high diversity at the genetic level over its distributional range. The genetic variation shown by the medicinal plant Rauwolfia vomitoria growing in different Himalayan ranges might be in terms of the potency and concentration of the active chemical (reserpine) that the plant produces. India has more than 50,000 genetically different strains of rice, and 1,000 varieties of mango. (ii) Species diversity: The diversity at the species level, for example, the Western Ghats have a greater amphibian species diversity than the Eastern Ghats. (iii) Ecological diversity: At the ecosystem level, India, for instance, with its deserts, rain forests, mangroves, coral reefs, wetlands, estuaries, and alpine meadows has a greater ecosystem diversity than a Scandinavian country like Norway.
It has taken millions of years of evolution, to accumulate this rich diversity in nature, but we could lose all that wealth in less than two centuries if the present rates of species losses continue. Biodiversity and its conservation are now vital environmental issues of international concern as more and more people around the world begin to realise the critical importance of biodiversity for our survival and well- being on this planet.
Que. 1) ……………………………………………………………………………….. was the one who popularized ‘Biodiversity’ term.
(a) Edward Wilson
(b) Jack Wilson
(c) Albert William
(d) John William
Que. 2) The ………………………………………………………………….. medicinal plant shows genetic variation.
(a) Hypera postia
(b) Nicrophorus aloinis
(c) Oecanthus allardi
(d) Rauwolfia vomitoria
Que. 3) How many levels are there in the diversity?
(a) Six
(b) Nine
(c) Three
(d) One
Que. 4) Which species shows more species diversity in Western Ghats?
Que. 5) Give examples of ecological diversity in India.
Answer Key
Que. 1)(a) Edward Wilson.
Que. 2) (d) Rauwolfia vomitoria.
Que. 3) (c) Three.
Que. 4) Answer: Species of amphibians show more species diversity in Western Ghats.
Que. 5) Answer: In India, rain forests, coral reefs, deserts, estuaries and wetlands all show ecological diversity.
Case study 2
Let us look at some interesting aspects about earth’s biodiversity based on the currently available species inventories. More than 70 per cent of all the species recorded are animals, while plants (including algae, fungi, bryophytes, gymnosperms and angiosperms) comprise no more than 22 per cent of the total. Among animals, insects are the most species-rich taxonomic group, making up more than 70 per cent of the total. That means, out of every 10 animals on this planet, 7 are insects. Again, how do we explain this enormous diversification of insects? The number of fungi species in the world is more than the combined total of the species of fishes, amphibians, reptiles and mammals. Biodiversity is depicted showing species number of major taxa. It should be noted that these estimates do not give any figures for prokaryotes. Biologists are not sure about how many prokaryotic species there might be. The problem is that conventional taxonomic methods are not suitable for identifying microbial species and many species are simply not culturable under laboratory conditions. If we accept biochemical or molecular criteria for delineating species for this group, then their diversity alone might run into millions.
Que. 1) More than 70% ………………………………………………………………………………… species are recorded in the biodiversity.
(a) Plants
(b) Animals
(c) Tigers
(d) None of these
Que. 2) 22% of total is occupied by ……………………………………………………………………………………….. in the biodiversity.
(a) Plants
(b) Reptile
(c) Birds
(d) Fishes
Que. 3) In the given estimation, ………………………………………………………………………………… do not have any figures.
(a) Insects
(b) Gymnosperms
(c) Prokaryotes
(d) Worms
Que. 4) Which is the most species rich taxonomic group in the animals?
Que. 5) Why biologist are not sure about prokaryotic species when it comes to estimate?
Answer Key
Que. 1)(b) Animals.
Que. 2) (a) Plants.
Que. 3) (c) Prokaryotes.
Que. 4) Answer: Insects species are the most species rich group in the animals.
Que. 5) Answer: The issue which biologists are facing is conventional taxonomic methods. These are not suitable for the identification of microbial species. They might think that if they will consider these species then their diversity alone run into millions. Even the species are not culturable in the laboratories. Hence, the biologist are not sure about prokaryotic species when it comes to estimate.
Case study 3
During his pioneering and extensive explorations in the wilderness of South American jungles, the great 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. In fact, 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 described 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 Ecologists have discovered that the value of Z lies in the range of 0.1 to 0.2, regardless of the taxonomic group or the region (whether it is the plants in Britain, birds in California or molluscs in New York state, the slopes of the regression line are amazingly similar). But, if you analyse the species-area relationships among very large areas like the entire continents, you will find that the slope of the line to be much steeper (Z values in the range of 0.6 to 1.2). For example, for frugivorous (fruit-eating) birds and mammals in the tropical forests of different continents.
Que. 1) In the species-area relationship equation, species richness is shown by ……………………………………………………………………………….
(a) S
(b) Z
(c) A
(d) C
Que. 2) According to the ecologist, the value of Z ranges between ………………………………………………………………………………………….
(a) 0 to 10
(b) 0.1 to 10
(c) 0.1 to 0.2
(d) 0 to 6
Que. 3) In the above equation, Z is a …………………………………………………………………………………….
(a) Y intercept.
(b) Regression coefficient
(c) Slop of the line
(d) Both (b) and (c)
Que. 4) What does Alexander von Humboldt’s observed?
Que. 5) Write an equation which shows Species-area relationship.
Answer Key
Que. 1)(a) S.
Que. 2) (c) 0.1 to 0.2.
Que. 3) (d) Both (b) and (c).
Que. 4) Answer: The Alexander von Humboldt was a geographer and German naturalist. Alexander von Humboldt observed that species richness within an area increases with increasing explored area. But, this happens only up to a limit. This was his observation.
Que. 5)Answer: log S = log C + Z log A. This is equation of Species-area relationship.
Case study 4
The accelerated rates of species extinctions that the world is facing now are largely due to human activities. There are four major causes (‘The Evil Quartet’ is the sobriquet used to describe them). (i) Habitat loss and fragmentation: This is the most important cause driving animals and plants to extinction. The most dramatic examples of habitat loss come from tropical rain forests. Once covering more than 14 per cent of the earth’s land surface, these rain forests now cover no more than 6 per cent. They are being destroyed fast. By the time you finish reading this chapter, 1000 more hectares of rain forest would have been lost. The Amazon rain forest (it is so huge that it is called the ‘lungs of the planet’) harbouring probably millions of species is being cut and cleared for cultivating soya beans or for conversion to grasslands for raising beef cattle. Besides total loss, the degradation of many habitats by pollution also threatens the survival of many species. When large habitats are broken up into small fragments due to various human activities, mammals and birds requiring large territories and certain animals with migratory habits are badly affected, leading to population declines.
Que. 1) ………………………………………………………….……. Is the main reason behind plants and animals extinction.
(a) Crop yield
(b) Soil cultivation
(c) Species
(d) Habitat loss
Que. 2) Which of the following causes loss of biodiversity?
(a) Fragmentation
(b) Gametogenesis
(c) Fermentation
(d) Budding
Que. 3)……………………………………………………………….. used to covers more than 14% of earth’s land before biodiversity loss.
(a) Rain
(b) Forests
(c) Animals
(d) Soil
Que. 4) What was the other name of Amazon rain forest?
Que. 5) What is the main reason behind biodiversity loss?
Answer Key
Que. 1)(d) Habitat loss.
Que. 2) (a) Fragmentation.
Que. 3) (b) Forests.
Que. 4) Answer: Amazon rain forest was also known for ‘lungs of the planet’.
Que. 5) Answer: Biodiversity loss mainly causes due to human activities.
Case study 5
Humans have always depended on nature for food and shelter, but when ‘need’ turns to ‘greed’, it leads to over -exploitation of natural resources. Many species extinctions in the last 500 years (Steller’s sea cow, passenger pigeon) were due to overexploitation by humans. Presently many marine fish populations around the world are over harvested, endangering the continued existence of some commercially important species. Co-extinctions: When a species becomes extinct, the plant and animal species associated with it in an obligatory way also become extinct. When a host fish species becomes extinct, its unique assemblage of parasites also meets the same fate. Another example is the case of a coevolved plant-pollinator mutualism where extinction of one invariably leads to the extinction of the other.
The narrowly utilitarian arguments for conserving biodiversity are obvious; humans derive countless direct economic benefits from nature food (cereals, pulses, fruits), firewood, fibre, construction material, industrial products (tannins, lubricants, dyes, resins, perfumes ) and products of medicinal importance. More than 25 per cent of the drugs currently sold in the market worldwide are derived from plants and 25,000 species of plants contribute to the traditional medicines used by native peoples around the world.
Que. 1) When certain species undergoes extinction, then other related species of animals and plants undergo ………………………………………………………………………………….
(a) Decomposition.
(b) Reproduction
(c) Extinction
(d) Migration
Que. 2) In the biodiversity, species are ………………………………………………………………………………. due to co-extinctions.
(a) Decreased
(b) Increased
(c) Remain the same
(d) Constant
Que. 3) Over-exploitation is done by the …………………………………………………………………………………….
(a) Birds
(b) Insects
(c) Fishes
(d) Humans
Que. 4) What is narrowly utilitarian argument?
Que. 5) Give an example of co-extinction.
Answer Key
Que. 1)(c) Extinction.
Que. 2) (a) Decreased.
Que. 3) (d) Humans.
Que. 4) Answer: Main reason behind narrowly utilitarian argument is the conservation of biodiversity. This argument is about economic benefits that human gets from the plants and other animals. The cereals, pulses and fruits gives us food. Medicinal plants are also important for the diseases. The whole argument is about why to conserve biodiversity.
Que. 5) Answer: If a fish species will extinct then the parasite which lives in fish body will also extinct. This is an example of co-extinction.