Bihar Board Class 12 Biology Solutions Chapter 15 Biodiversity and Conservation Textbook Questions and Answers, Additional Important Questions, Notes.
BSEB Bihar Board Class 12 Biology Solutions Chapter 15 Biodiversity and Conservation
Bihar Board Class 12 Biology Biodiversity and Conservation Text Book Questions and Answers
Name the three important components of biodiversity.
The three important components of biodiversity are :
How do ecologists estimate the total number of species present in the world?
Biologists make a statistical comparison of the temperature- tropical species richness of an exhaustively studied group of insects and extrapolate this ratio to other group of animals and plants to come up with a gross estimate of the total number of species on earth.
Give three hypotheses for explaining why tropics show greatest levels of species richness.
Tropics show greatest levels of species richness because of the following reasons:
- Tropical latitudes have remained relatively undisturbed for million of years and thus had a long evolutionary time for species diversification.
- Tropical environments are less seasonal, relatively more constant and predictable. Such environments promote niche specialisation and thus, leads to a greater species diversity.
- There is more solar energy available in the tropics, which contributes to high productivity and this leads to greater diversity.
What is the significance of the slope of regression in a species-area relationship?
According to geographer Alexander von Humboldt, species richness increased with increasing explored area but only up to a limit. In fact, the relationship between species richness and area for a wide variety of taxa turns out to be a rectangular hyperbola.
log S = log C + Z log A
where S = species richness
A = area
Z = slope of the line
C = Y-intercept
Ecologists have discovered that the value of Z (regression coefficient) lies in the range of 0.1 to 0.2. However, if we analyse the species-area relationships among very Targe areas like the entire continents, we will find the slope of the line to be much steeper (Z values in the range of 0.6 to 1.2).
What are the major causes of species losses in a geographical region?
The major causes of species losses are :
(a) Habitat loss and fragmentation – This is the most important cause driving animals and plants to extinction. Once the tropical forests covered more than 14 per cent of the earth’s surface but now they cover no more than 6 per cent. They are being destroyed fast. Increase in population also threatens the survival of many species. Due to various human activities, large habitats are broken into. small fragments. Due to this, mammals and birds requiring large territories and certain animals with migratory habits are badly affected, leading to population declines.
(b) Over-exploitation – Population expansion has led to over-exploitation of resources. In the last 500 years, many species extinctions were due to over exploitations by humans. The harvesting of marine fish populations around the world presently, is endangering the continued existence of some commercially important species.
(c) Alien species invasions – The introduction of alien species unintentionally or deliberately for whatever purpose can decline or extinction of indigenous species. For example, the Nile perch introduced into Lake Victoria in east Africa led eventually to the .extinction of an ecologically unique assemblage of more than 200 species of cichlid fish in the lake. The recent illegal introduction of the African Catfish Clarias gariepinus for aquaculture purposes is posing a threat to the indigenous catfishes in our rivers.
(d) Co-extinctions – When a species becomes extinct in an environment, the plant and animal species associated with it in an obligatory way also become extinct. For example, when a hot fish species becomes .extinct, its unique assemblage of parasites also meets the same fate.
How is biodiversity important for ecosystem functioning?
According to Tilman, plots with more species showed less year to year variation in total biomass. In his experiments, he showed, ecosystem health but imperative for the very survival of the human race in this planet.
Earth’s rich biodiversity is vital for the very survival of mankind. Besides the direct benefits, there are many indirect benefits we receive through ecosystem services such as pollination, pest control, climate moderation and flood control.
Thus, loss of key species that play a major role in ecosystem functioning of a particular area can lead to the destruction of the entire ecosystem of that area.
In general, loss of biodiversity in a region may lead to
(a) decline in plant production.
(b) lowered resistance to environmental perturbations such as drought and
(c) inversed variability in certain ecosystem processes such as plant productivity, water, use, and pests and disease cycle.
What are sacred groves? What is their role in conservation?
Sacred groves are areas where tracts of forest are set aside, and all the trees and wildlife within are Venerated and given total protection.
The sacred groves help to conserve rare and threatened species of both plants and animals.
Among the ecosystem services are control of floods and soil erosion. How is this achieved by the biotic components of the ecosystem?
Control of floods and soil erosion can be prevented by conserving the ecosystem.
(a) Thick growth of forests can prevent floods and soil erosion.
(b) Cutting trees can lead to change in climatic conditions.
(c) Deforestation can lead to both flood and soil erosion.
The species diversity of plants (22 per cent) is much less than that of animals (72 per cent). What could be the explanations to how animals achieved greater diversification?
Population explosion has led to the destruction of forest area. Man in order to modernize himself has led to the destruction of forest area. Thus, this is the main reason that the species diversity of plants (22 per cent) is less than that of animals (72 per cent).
Can you think of a situation where we deliberately want to make a species extint? How would you justify it?
When a species starts to cause environmental damage and possess threat to other native species, it is deliberately needed to make that species extinct. For example, the illegal introduction of the African catfish Clarias gariepinus for aquaculture purposes in posing a threat to the indigenous catfishes in our rivers.
Bihar Board Class 12 Biology Biodiversity and Conservation Additional Important Questions and Answers
Very Short Answer Type Questions
Name the bird which has recently become extinct.
Dodo (Raphus cucullate) of Mauritius.
What does ZSI and IBWL stands for?
ZSI: Zoological Survey of India,
IBWL: Indian Board of Wild. Life.
Give two examples of Indian endangered species.
Great Indian bustard, Kashmir stag.
How much area is covered by forests in India?
75 million hectares (23% of total -land area).
Name the two most biodiversity-rich zones of India.
Western Ghats and northeast (Eastern Himalayas) region.
What is extinction?
Extinction is disappearance of a species from earth when its last surviving member dies.
What are polymorphs?
These are differently looking individuals of the same species.
Biodiversity is the vast array of species of living organisms occurring on the earth and the ecological complexes of which they are apart.
Animals are not essential in an ecosystem. Justify.
Because producer-decomposer food chains can keep an ecosystem self-sufficient and viable.
Why wild animals breed rarely in zoos?
Limited area in zoo reduces free movement of animals which lower reproductive capacity of wild animals.
Why we should protect the species which are not anyway useful to us?
Because no one knows when a wild species, may turn out to be beneficial to man.
What are the parameters of biodiversity?
- The turnover of the species across the space.
Mention one step to preserve biodiversity.
Protection and conservation of threatened and endangered species.
What are three forms of biodiversity?
a-diversity, (1-diversity and y-diversity.
How forests help in maintenance of climate?
Forests increase the atmospheric humidity by transpiration. The increased humidity influences rainfall and makes the environment cool.
What is background extinction?
This is the slow replacement of existing species with the better-adapted species due to changes in environmental conditions.
Name the types of forests found in India.
Tropical dry deciduous forests, tropical moist deciduous forests and tropical thorn forests.
Name some areas where sacred groves are found in India.
Sacred groves are found in Khasi and Jaintia Hills in Meghalaya, Aravalli Hills of Rajasthan, Western Ghat region of Karnataka and Maharashtra and the Sarguja, Chanda and Bastar areas of Madhya Pradesh.
What is the other name of in situ?
In situ means on-site conservation.
What is the other name of on-site?
On-site means off-site conservation.
Short Answer Type Questions
Define wildlife. Write its significance in the maintenance of the environment.
The wildlife refers to the naturally occurring species of animals and plants which are not domesticated or cultivated.
- Wildlife has links in food chains operating in nature. These food chains are extremely beneficial to us.
- Wildlife maintains a balance in nature. For example, snakes, control rodent population which destroy our crops.
- Wildlife also performs the role of biological control. These help in the recycling of matter in nature.
- Green plants purify air, they gives us oxygen also maintain atmospheric temperature;
- Plants add water vapour by transpiration and influence rainfall.
How is diversity at all levels generally conserved?
Diversity is recognised by gene pool, species and biotic community. The ecosystem changes due to the pollution, climate changes and exploitation etc. There is need to prevent further destruction or degradation of habitats. There are on-site (in situ) and off-site (ex-situ) strategies of conservation. Protected areas like biosphere reserves should be maintained.
What are threatened species? Name their 3 types in order of the danger of extinction they face.
Species likely to disappear sooner or later are threatened species. Their 3 types are :
- Endangered species: These species are facing danger of imminent extinction, due to abundance of predators, pathogen or pollutant, very few in number or reduction in habitat.
- Vulnerable species: Their abundant population is present but threatened to deplete in number due to some factors like DDT in bird population.
- Rare species: These are naturally present in small populations,.they have risks from predators/pathogen or environmental factors.
What kind of threats to the biodiversity may lead to its loss?
Some important factors that lead to extinction of species and consequent loss of biodiversity are :
- habitat loss and fragmentation,
- introduction of non-native species,
- soil, water and atmospheric pollution and
- intensive agriculture and
Habitat loss is the primary reason because if habitat is destroyed, then species would be destroyed (e.g. burning of forest, cutting of trees etc.) Pollution may eliminate some species. Eutrophication in lakes reduces biodiversity. Introduction of exotic species hinder the development of natural species, e.g. exotic fish Nile perch, water hyacinth and Lantana Camara.
What do you understand by conservation of wildlife? What are its main objectives?
Wise use and preservation of natural resources is called ‘conservation of wild life. Its main objectives are :
- To ensure utilization of species and ecosystems: All the endangered species of plants and animals should be preserved. National Parks and Sanctuaries should be set up for wildlife. Wildlife should be protected in zoological gardens.
- Preservation of species diversity: If a particular species migrates from one area to another, arrangements should be made to set up that species in the other area.
- Maintenance of life-supporting systems: Unique ecosystem should be protected. National protection programmes should be linked with international programmes.
Give two main cases of extinction of species by human intervention.
Two main causes of extinction of a species are :
- By destroying their natural habitat. Many wild areas are being converted to human settlements, harbour, dams, reservoirs, croplands, mining sites etc. Environmental pollution and deforestation also results in the destruction of habitat, e.g., Habitat of largest flying bird (California Condor) of today has been affected by human cleanliness. Minor disturbances in the routes of migratory animals also affect them, i. e., some dams are blocking spawning.
- Indiscriminate killing of the organism. Due to some properties of particular organisms, 6.g., Rhinoceros is hunted for its horn, snakes are killed because of their venom and skin; Tigers, Lions, Leopards are killed on a large scale because of their skin and demand of some . plants because of its medicinal ornamental property.
Broadly classify the extinction process.
Extinction of species: The extinction of species is a natural process. Species have disappeared and new ones have evolved to take their place over. There are three types of extinction processes :
- Natural extinction: When there is change in environment conditions, certain species disappear and others, (which are more adapted to changed conditions) take their place. This loss of species that occurred in the geological past at a very slow rate is known as natural (background extinction).
- Mass extinction: There have been several periods in the earth’s geological history when large number of species became extinct due to catastrophes.
- Anthropogenic extinction: More number of species is disappearing, from the face of the earth due to human activities. Man-made mass extinction represents a very severe depletion of biodiversity.
World Conservation Monitoring Centre has recorded that 533 animal (mostly vertebrates) and 384 plant species (mostly flowering plants) have become extinct since the year 1600. The current rate of extinction is 1000 to 10000 times higher than the background rate of extinction.
Describe the role of wildlife in modern agriculture.
Many new improved varieties of crops and useful animals have been derived from their wild relatives by genetic modifications. The wild forms serve as a reserve gene pool which may be tapped for improving disease resistance, pest resistance, cold tolerance and drought tolerance etc.
Why there is legal lapse as far as. wildlife conservation is concerned?
The existing laws are adequate to protect our wildlife. The failure of enforcement of these laws of protection of wildlife is one of the reasons for the depletion and extinction of wildlife.
Write a note on extinction.
Extinction is the disappearance of a species from earth when its last surviving member dies. It is of three types :
- Natural extinction is the slow replacement of existing species with better-adapted species.
- Mass extinction is extinction of large number of species due to catastrophe, for e.g, extinction of dinosaurs.
- Anthropogenic extinction is extinction of species due to human activities.
What are the main causes of extinction of species?
Main causes of extinction of species are as follows :
- Hunting for commercial purposes and as a sport.
- Destruction of habitats due to deforestation, establishment of new human settlements, polluted water bodies, roads, dams building etc.
- Exotic species produce ecological imbalance due to removal of biological control.
- Pollution-environmental pollution has degraded many important habitats, resulting in decrease in life.
- Deforestation reduces the area of free movement of wild animals and reduces their reproductive capacity.
List some special Wild Life Projects in India*
- Gir Lion Sanctuary Project: It has started since 1972 by Gujarat and Central Government to save Asiatic Lion.
- Project Tiger: This programme has started on 1,1973 by Central Government.
- Project Hangul: This project was launched by IUCN, WWF and Government of Jammu and Kashmir in 1970 for Kashmir Stag or hangul.
- Himalayan Musk Deer Project .’ This is a joint effort of Gujarat and Central Government to save Musk deer. It was started in 1972.
- Crocodile Breeding Project: It was started in 1975 by Central Government and UNDP to save gharial and mugger.
What do you mean by conservation of biodiversity? What are its objectives?
Conservation may be defined as a technique of deriving, maximum advantage from the biosphere without in any may be degrading it. Conservation of biodiversity has three main objectives :
- To maintain essential ecological processes and life-supporting systems like air, water and soil.
- To preserve the diversity of species and the range of genetic material of world’s organisms.
- To ensure a continuous use of species, and ecosystems which will .support the rural communities and urban industries.
What is species richness? How is it related to species diversity?
Species richness is the nuclear of species per unit area. With the increase in area, species richness also increases because of availability of natural resources. Number of individuals of different species will give an idea about evenness or equitability of species.
Species diversity is the product of species richness and species evenness.
What are the factors responsible for loss of biodiversity?
Various factors responsible for loss of biodiversity are natural, mass extinction and anthropogenic or due human activities. Human activities have accelerated extinction of species by hunting, destroying habitats, fragmentation, introduction of new species in ecosystem, environmental pollution, construction of buildings, highways, industries, over-exploitation of rare species and due to ignorance.
How can biodiversity be conserved?
For conservation, main steps include, protection of wildlife in natural and artificial habitats, preference should be given to threatened species during conservation programmes emphasis on preserving ecosystem rather than a single species, protection of critical habitats like breeding habitats, feeding habitat etc., stopping animal trade of rare species, making international agreements to protect the migratory animals, setting up of National parks and Sanctuaries to protect animals. Combining national efforts with international effort and active public participation for various in their natural habitat. Biodiversity in not homogeneously distributed over time and space. It differs from place to place.
How do you define biodiversity? Explain its significance in the present context.
Biodiversity is the totality of genes, species and ecosystem of a region. Depending upon the environmental conditions and species tolerance, biodiversity differs from place to place. Significance: Human race depends on biodiversity for food source, breeding improved varieties, drugs and medicines, for aesthetic and cultural values and for maintaining the ecological balance.
Human beings are destroying biologically rich and unique habitats for their own interests.
Due to increasing population, consumption of resources and pollution human beings are destroying the delicate balance of biosphere, this is affecting biological diversity and causing extinction of species. Biodiversity loss is one of world’s most concerned crisis. It is essential to conserve biodiversity.
What is species diversity?
Species are distinct units of diversity, each one is playing a unique role in the ecosystem. Species diversity is the variety of species within a region. It can be measured in terms of species richness, which is the number of species per unit area. So greater the species richness, greater is the species diversity. The number of species increases with the area of the site.
Name the three divisions of diversity.
Biodiversity may be divided into three types: genetic diversity, species diversity and community or ecological diversity. Genetic diversity is related to the variations of genes within a species. The variations may be present in same genes, in entire genes or in chromosomal structures. Species diversity is the variety of species within a region. It depends on species richness and species evenness.
Species richness is the number of species per unit area. Community dr ecological or ecosystem diversity is the different types of habitats or ecosystems. It contains diverse number of niches, trophic levels and various ecological processes which support energy flow, food webs and nutrient recycling.
Write a short note on Ex-situ conservation.
Ex-situ conservation: This approach of conservation of endangered species includes the protection of a group of typical ecosystem by a network of protected areas. Artificial conditions for individuals of a species are maintained under human supervision. Cultivation of rare plants and rearing of threatened animals is done in botanical and zoological gardens and are preserved in seed banks (plants) or genemic banks (animals).
Long Answer Type Questions
(a) How is biodiversity distributed along major environmental gradients?
(b) What are the main strategies for conservation of the wildlife?
(a) Gradients of biodiversity: The biodiversity varies with change in latitude or altitude. The biodiversity increases from the poles
to the equator. In the temperate region, the climate is severe with short growing period for plants. In topical rain forest the conditions are favourable for growth throughout the year. Speciation occurs during favourable conditions. Mean number of vascular species per 0.1 ha sample area in tropical rain forests varies from 118-236. This is only in the range of 21-48 species in the temperate zones. Such correlation between diversity and latitude exists for a wide variety of taxonomic groups, like ants, birds, butterflies, and moths.
There is a decrease in species, diversity from lower to higher altitudes on a mountain. A. 1000m increase in altitude results in a temperature drop of about 6.5°C. Drop-in temperature and greater seasonal variability at higher altitudes are a major factor to reduce biodiversity. The latitudinal and altitudinal gradients of species diversity are two master gradients. More complex and diverse flora and fauna will be in complex and heterogenous physical environment.
(b) Strategies for conservation of wildlife:
- Wildlife protection in natural as well as artificial habitats.
- Endangered, vulnerable and rare species should be given preference over others in the conservation programmes.
- To provide proper habitat to the wild animals, air, water and land should be properly managed.
- Wild varieties of plants and animals should be preserved for various breeding programmes.
- The feeding areas, breeding grounds, resting sites etc. of wild animals should be kept intact for animals safe growth and reproduction.
- Instead of a single species, whole ecosystem should be safeguarded.
- Areas should be protected for migratory animals.
- National parks and Sanctuaries should be set up to take care of wild animals.
- Hunting should be prohibited; especially during breeding season.
- People should be educated and children should be inspired about the need and modes of conservation of wildlife.
- International trade on wild plants, animals and their products should be regulated by law.
Write short notes on the following :
(a) Wild life sanctuary
(b) Biosphere reserves
(c) Genetic diversity
(d) India’s effort in biodiversity conservation.
(a) Wild Life Sanctuary – In a sanctuary, protection is given only to the fauna and operations such as harvesting of timber, collection of minor forest products and private ownership rights are permitted so long as they do not interfere with the well-being of animals. There are presently 368 Sanctuaries in India covering over 1,07,310,13 square kilometres, amounting to 3.2 per cent of India’s total geographical area.
(b) Biosphere reserves: Biosphere reserves are a special category of protected areas of land and/or coastal environments wherein people are an integral component of the system. The concept of biosphere reserve was launched in 1975 as a part of the UNESCO’s MAB (man and biosphere programme. There are 13 biosphere reserves in India which are notified as National Parks. Each biosphere reserve has a core, buffer and a transition zone.
(c) Genetic diversity: It is the genetic variations found amongst members of the same population and geographically separated population of the species. On the basis of genetic differences, all the individuals of the same species become different from one another. Environment plays major role in imparting diversity of living organisms. For e.g. there are various races of human beings like Mongoloid, Negrito etc. The differences can be in alleles, in entire genes or in chromosomal structures.
(d) India’s effort in biodiversity conservation: India has contributed a lot to the global biodiversity. India is a homeland of 167 cultivated species and 320 wild relatives of crop plants. It is the centre of diversity of animal species (zebu, Mithun, chicken, water buffalo, camel); crop plants (rice, sugarcane, banana, tea, millet); fruit plants and vegetables (mango, jackfruit, cucurbits), edible diascoreas, alocasia, colocasia, spices and condiments (cardamom, black pepper, ginger, turmeric); bamboos, brassicas, and tree cotton.
The in situ conservation of biodiversity is being carried out through Biosphere reserves, National parks, Wild Life Sanctuaries and other protected areas by the Ministry of Environment and Forests. The joint forest management systems involve forest departments and local communities.
National Bureau of Plant, Animal and Fish Genetic Resources has a number of programmes to collect and conserve the germplasm of plants and animals in seed gene banks, and field gene banks for in vitro conservation.
The landraces and diverse food and medicinal plants are also being conserved.
One Word Type Questions
What do you mean by heterogeneity?
Where are the largest Amazonian main forests found?
More than 70 per cent of all the species recorded on earth are :
22 per cent of the total species on earth comprise of :
Name one country located near the equator which has nearly 1,400 species of birds.
The graph between species-area relationships is :
Who found that plots with more species showed less year to year variation in total biomass?
More than 25 per cent of the drugs currently sold in the market worldwide are derived from :
In which year was the historic Convention of Biological Diversity held?
Where was the World Summit on Sustainable Development held in 2002?