Biodiversity and Conservation VBQs Class 12 Biology

VBQs for Class 12

VBQs Biodiversity and Conservation Class 12 Biology with solutions has been provided below for standard students. We have provided chapter wise VBQ for Class 12 Biology with solutions. The following Biodiversity and Conservation Class 12 Biology value based questions with answers will come in your exams. Students should understand the concepts and learn the solved cased based VBQs provided below. This will help you to get better marks in class 12 examinations.

Biodiversity and Conservation VBQs Class 12 Biology

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 the ecological diversity. The same level of biodiversity is also shown by rain forests, coral reefs wetlands, estuaries and alpine meadows, etc. 

Question. Name the type of biodiversity represented by the following :
(i) 50,000 different strains of rice in India.
(ii) Estuaries and alpine meadows in India.
Answer :
(i) Genetic diversity.
(ii) Ecological diversity.

Question. Why is tropical environment able to support greater species diversity ?
Answer :
Tropical environments, unlike temperate ones, are less seasonal, relatively more constant and predictable. Such constant environments promote niche specialization and lead to a greater species diversity. 

Question. The Amazon rain forest is referred to as ‘the lungs of the planet’. Mention any one human activity that causes loss of biodiversity in this region.
Answer :
The Amazon rain forest is so huge that it is called the lungs of the planet. Cutting down of forest for cultivation of soya beans and its conversion to grasslands for raising beef cattle caused loss of biodiversity in this region. 

Question. What does the term genetic diversity refer to ?
What is the significance of large genetic diversity in a population ? 
Answer :
The genetic diversity refers to the variation of genes within a species. The genetic diversity helps the population to adapt into its environment and to respond to natural selection. It also helps in speciation or evolution of new species. 

Question. An exotic variety of prickly pear introduced in Australia turned out to be invasive. How was it brought under control ?
Answer :
It was controlled by introducing a cactus – feeding predator (a moth) from its natural habitat. 

Question. Name the unlabelled areas ‘a’ & ‘b’ of the pie chart representing biodiversity of vertebrates showing the proportionate number of species of major taxa.

Biodiversity and Conservation VBQs Class 12 Biology

Answer : (i) Fishes 
(ii) Amphibians. 

Short Answer Type Questions

Question. Mention the kind of biodiversity of more than a thousand varieties of mangoes in India represent. How is it possible ?
Answer :
Genetic diversity/single species show high diversity at genetic level. 
Single species show high diversity at genetic level over its distributional range/different varieties grow in different geographical areas/climatic conditions/breeding/mutations. 
Detailed Answer :
More than a thousand varieties of mangoes in India represent the genetic diversity because
(i) a single species show high diversity at genetic level over its distributional range.
(ii) different varieties
grow in different geographical regions and climatic condition. This is also possible because of breeding and mutations.

Question. What is meant by ‘alien species’ invasion ? Name one plant and one animal alien species that are a threat to our Indian native species.
Answer :
‘Alien species’ invasion means introducing those that are, firstly, outside their natural distribution area, and, secondly, threatens biological diversity.
Plants : Lantana camara
Animals : Equus caballus (horse) or, Canis familiaris (dog). 

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 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.

Biodiversity and Conservation VBQs Class 12 Biology


The above graph shows Species-Area relationship.
Write the equation of the curve ‘a’ and explain.
Answer :
(i) S = CAZ
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. List any two causes of biodiversity loss and explain any one of them. 
Answer :
Causes of biodiversity losses :
(i) Habitat loss and fragmentation.
(ii) Over-exploitation.
(iii) Alien species invasions.
(iv) Co-extinctions. (Any two)
Co-extinctions : When a species becomes extinct, the plant and animal species associated with it in an obligatory way also become extinct.
For example, when a host fish species becomes extinct, its unique assemblage of parasites also meets the same fate. Another example is the case of a co-evolved plant pollinator mutualism where extinction of one invariably leads to the extinction of the other. 

Question. In the biosphere, immense biological diversity exists at all levels of biological organisation.
Explain any two levels of biodiversity.
Answer : (i) Genetic diversity :
A single species might show high diversity at the genetic level over its distributional range. The genetic variation is shown by the medicinal plant Rauwolfia vomitoria. 
(ii) Species diversity : It is the product of both species richness and evenness i.e. species richness is weighed by species evenness.
E.g., amphibian species are found more in the western ghats as compared to the eastern ghats. 

Question. Giving two reasons explain why there is more species biodiversity in tropical latitudes than in temperate ones.
Answer :
(i) Tropical environments, unlike temperate ones, are less seasonal, relatively more constant and predictable. Such constant environments promote niche specialization and lead to a greater species diversity. 
(ii) There is more solar energy available in the tropics, which contributes to higher productivity; this in turn might contribute indirectly to greater diversity. 

Question. Evaluate the effect of loss of biodiversity in a region. Mention any four such effects.
Answer :
(i) Decline in plant production/Decline in number of animal species
(ii) Lowered resistance to environmental perturbations such as drought
(iii) Increased variability in certain ecosystem processes such as plant productivity / water use / pest & disease cycles
(iv) Species may become endangered / increased rate of species extinction. 

Question. Explain, giving three reasons, why tropics show greatest levels of species diversity.
Answer :
(i) Tropical latitude have remained relatively undisturbed, have a long evolutionary time for species diversification. 
(ii) Less seasonal variations, constant and predictable environmental condition, promote niche specialization for greater species diversity. 
(iii) More availability of solar energy, contributes to higher productivity. 
Detailed Answer :
(i) Speciation is generally a function of time.
Unlike temperate 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) 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. 
(iii) There is more solar energy available in the tropics, which contributes to higher productivity; this in turn might contribute indirectly to greater diversity.

Question. Since the origin of life on the earth, there were five episodes of mass extinction of species.
(i) How is the ‘Sixth Extinction’, presently in progress, different from the previous episodes ?
(ii) Who is mainly responsible for the ‘Sixth Extinction’ ?
(iii) List any four points that can help to overcome this disaster. 
Answer :
(i) The rates are faster / accelerated / current species extinction rate are estimated to be 100-1000 times faster than in the pre-human times.
(ii) Human activities.
(iii) (a) Preventing habitat loss and fragmentation
(b) Checking over exploitation
(c) Preventing alien species invasion
(d) Preventing co-extinction
(e) Conservation / Preservation of species. 

Question. Taking one example each of habitat loss & fragmentation, explain how are the two responsible for biodiversity loss.
Answer :
Habitat loss and fragmentation are two main causes of extinction of plants and animals and therefore loss of biodiversity. One of the important examples of habitat loss is the reduction in area of tropical rain forests. The Amazonian forests commonly called as lungs of planet are cleared for cultivation. This has resulted in extinction of a number of species and thus loss of biodiversity.
Fragmentation of habitat disrupts the interaction amongst species and annihilation of species resulting in the decreased biodiversity. 

Question. Explain the level of biodiversity at genetic, specific and ecological levels with the help of one example for each of the three.
Answer :
Genetic level : A single species might show high diversity at genetic level, e.g., Rauwolfia vomitoria/ rice/Mango (any other suitable example)
Specific level : Diversity at species level, e.g. Amphibian species (Any other suitable example)
Ecological level : Diversity at ecosystem level, e.g., Deserts/rain forest/mangroves/ coral reef/
wet lands/estuaries/ alpine meadows/ (Any other suitable example) 

Long Answer Type Questions

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) Hot spots 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.