BIODIVERSITY
Biodiversity is the abbreviated word for Biological diversity. This was first put forward by Norse and Mc manus. The term biodiversity was coined by W.C Rosen.
Definitions : Biologists most often define biodiversity in terms of species richness and species diversity . In 1992 United Nations earth summit in Rio de Janerio defined Biological diversity as the variability among living organisms from all sources including inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part. This definition includes diversity within species, between species. This definition was adopted by United Nations convention on biological diversity. The second most commonly used definition of biodiversity is sponsored by Global biodiversity strategy “the totality of genes, species and ecosystems of a region”
Concepts of biodiversity:
i). Biodiversity is the variety of life on earth.
ii). It is generally described at three levels – Genetic diversity, species diversity and ecosystem diversity
iii) All life forms that make biodiversity, including humans are ultimately connected to all other life forms and to their physical environment.
iv). No one living element of any ecosystem can survive independently on others.
v). Connections among living and non living elements keep the environment functioning and healthy.
vi). Human impact on the environment directly or indirectly effect the functioning of other living things and by extension ourselves.
Scope of biodiversity:
i).The science of biodiversity has the potential to unify all fragmented disciplines of biology and bring together the activities of all scientists.
ii). Biodiversity is the back bone for agriculture, aquaculture, animal husbandry, forestry and a host of other applied branches of biology. Thus helping in the adequate supply of food grains and main needs for the population.
iii). Alarming changes due to intense globalization can be nullified by the deep understanding of biodiversity in all aspects.
iv). Biodiversity will offer in the coming years new sources food, medicine and other requirements.
v). Biodiversity is the resource on which all human existence depends. Biodiversity is the pillar of human development.
vi). Sustainable development can be achieved through economic, environmental, social and cultural facets of biodiversity.
Q. Write about Earth Summit.
Earth summit:
The 20th anniversary of Stockholm declaration took place in Rio de Janerio in Brazil in 1992. The UN conference on environment and development popularly known as earth summit. The assembled leaders signed the convention on climate change and the convention on biological diversity. They also endorsed the Rio declaration and the forest principles and adapted azanda 21 to plan for achieving sustainable development in the 21st century.
Earth summit 2002 (Rio +10): The world summit on sustainable development was held in Johannesberg of South Africa in 2002. Its main aim is to examine the progress made on the outcomes of the 1992 Earth summit in Rio and also reinvigorate the world’s people towards the true sustainable development.
Earth summit 2012 (Rio +20): The UN general assembly in December 2009 agreed to hold a new earth summit in 2012. This summit held in Brazil and will focus on the green chemistry emerging issues, sustainable development, governance and review of previous commitments.
Q. Write an essay on the levels and types of Biodiversity.
LEVELS AND TYPES OF BIODIVERSITY
Biodiversity or biological diversity is the sum total of all life on earth. It includes the vast array of life forms, then individual genetic makeup, their life processes and their interrelation ship in communities and ecosystems.
Biodiversity is commonly studied at three different levels. i). Genetic diversity, ii). Species diversity and iii). Ecossystem diversity. These three levels of Biodiversity form an intricate web.
i). Genetic diversity:
Genetic diversity refers to the variation of genes with in species. This covers genetic variation between distinct populations of the same species. It also covers genetic variation with in a population. Genetic diversity can be measured using a variety of DNA based techniques like Restriction fragment like polymorphism (RFLP), Polymerase chain reaction (PCR), Serial analysis gene expression (SAGE). Individuals belonging to a species share contain characteristics, but genetic variations determine the particular characteristics of individuals with in a species. The genetic makeup of an individual species is not static but it changes as a result of both external and internal factors. The main forces that determine current levels of genetic diversity within species are mutations, migration, selection and genetic drift.
ii). Species diversity:
Species diversity is related to number and relative abundance of species in a given area in a community. Species diversity is the highest in the equatorial region and gradually declines towards the Polar Regions. Species diversity is essential for the proper functioning of communities in an ecosystem. The species diversity of a region is measured on the basis of species richness (number of species in a defined area), species abundance (relative number in each species) and phylogenitic diversity (relationship between different groups of species). Greatest species richness is commonly found in relatively stable environments having high rates of productivity.
There are three perspectives of diversity at community level. They are alpha diversity, beta diversity and gamma diversity.
(a). Alpha diversity: It is the species diversity within a community or habitat. It is also defined as the variety of organisms occurring in a particular habitat. It is often called as local diversity. It is measured as the number of species within a given area. Alpha diversity comprises two components i.e, species richness and species evenness.
(b). Beta diversity: It indicates diversity between communities. It is also called differentiation diversity or turn over diversity. Species frequently change when habitat or community changes. There are differences in species composition of communities along environmental gradients.
(c). Gamma diversity: It refers to the diversity of habitat over the total land scape or geographical area. The higher diversity at community level provides stability and productivity. Gamma diversity includes both alpha and beta diversities.
[γ = α + β + Q; where Q= total number of communities; α, β are the average values of alpha and beta diversities respectively.]
iii). Ecosystem diversity: Ecosystem diversity is the highest level of biodiversity. It refers to the variation of different ecosystems such as rain forests, coral reefs. Ecosystem diversity arises due to the variation in energy flow, food chain and water cycle of different ecosystems. The enormous range of terrestrial and aquatic environments on the earth has been classified into a number of ecosystems and the examples tropical rain forests, grass lands, wet lands, coral reefs and mangroves.
All the above components of biodiversity do not work singly, but they work jointly to give rise to the manifestation of biodiversity.
Q. Describe the values of Biodiversity.
VALUES OF BIODIVERSITY
Humans derive many direct and indirect benefits from the living world. Biodiversity or biological resources is the source of food, medicines, pharmaceutical drugs, fibres, rubber and timber understanding the value of biodiversity is required for future conservation plans.
Value of Biodiversity:
The value of biodiversity is categorized basing on the benefit it provides to human society. They include (i) Cultural, social and ethical values and (ii) Aesthetic value
(i) Cultural, social and ethical values:
The cultural value of biodiversity for present and future generations is an important reason for conserving it today. Human cultures all over the globe co-evolved with their environment. So the conservation of biodiversity is essential for cultural density of a human community. Plants and animals are considered to be the symbols of national pride and cultural heritage peacock, tiger and lotus have become national icons of our country. The people should understand and appreciation of the inherent value of each and every life form that constitutes the ethical value of biodiversity.
(ii) Aesthetic value:
Nature has an aesthetic value that can be experienced by human beings when they are in natural surroundings. Nature inspires painters, architects and musicians to create works, reflecting and celebrating its beauty.
(iii) Food Security:
Biodiversity is essential requirement for the maintenance of global food supply. The main sources of human food include animals, fish and plant products. Only the conservation of biodiversity can ensure global food security for the rapidly increasing human population as well as for the animal population. To get the best balanced diet to maintain good health diversified food supply is essential.
(iv) Drugs and Medicines:
Natural flora and fauna are the major sources of pharmaceuticals (medicines) for curing ailments. The Indian system of ayurvedic medicine is dependent on plant biodiversity.
(v) Source of Genes:
Natural populations of different biological species harbour all the genes of a species irrespective of the economic value of the genes. Biodiversity protects the gene pool of a species and acts as a store house of many useful genes. The derivable genes such as resistance to pests, diseases and nematodes stress resisting gene are present in the gene pool of different biological species.
(vi). Ecosystem Services:
Ecosystem services are essential for the survival of the human beings on this planet earth. The world cannot afford to replace these services. Therefore, we must work to protect our ecosystems.
Source of these services provided by ecosystems are as follows:
(i) Air purification-Natural communities maintain proper gaseous concentrations in the atmosphere and prevent rapid climate changes of mainly by air purification.
(ii) Watershed Services-Forests regulate water flows down stream areas.
(iii) Soil formation and protection-Soil formation is promoted by biological weathering of the soil by soil organisms and the soil erosion is prohibited by grass lands and forests, which enables the soil protection.
(iv) Nutrient storage and cycling-Ecosystems perform the vital function of nutrients. Biological diversity is essential in this process.
(v) Potential pest and disease control-Source microbes and plants can act as potential pest and disease control. Which are named as biopesticides.
(vi) Pollution control-Ecosystems and ecological processes play an important in break down and absorption of many pollutants, created by humans and their activities.
(vii) Pollination-Many flowering plants rely on animals for their pollination (Ornithophily pollinating agent is birds) Chaeropteriphily pollinating agents are bats, Malacophily pollinating agents are Molluscans etc.
Q. Describe the various threats to Biodiversity.
THREATS TO BIODIVERSITY
Loss of biodiversity is a serious threat to civilization, second only to thermonuclear war in its severity all other environmental problems like pollution, global warming and ozone depletion can be overcome, but not the erosion of biodiversity or extinction of species.
The prominent threats to biodiversity which can be loss of biodiversity as follows:
1. Destruction of Habitats:- Destruction of natural habitats is the largest single cause of biodiversity loss. Tropical forests, which harbor at least 50% of the world’s biodiversity are declining at a rapid rate with current rate of deforestation 50-90% of earth’s forest inhabiting species is projected to be lost by the mid 21st century. An assessment of world life habited in tropical Asia in 1986 reported that India has already lost about 80% of its natural habitat.
2. Habitat fragmentation:- Habitat fragmentation is another serious problem that often goes unrecognized. Roads, fields, canals, power lines etc. Divide the habitat into small fragments. Fragmentation reduces biodiversity because, many species, such as bears and large cats, require large territories to subsist fragmentation divides the large populations into very small populations. These small populations are vulnerable to catastrophic events. Thus it cause loss to biodiversity.
3. Over exploitation of resources:- The overuse are over harvesting of plants, animals or natural resources threatens earth’s biodiversity. Over exploitation, such as logging, hunting or fishing reduce species number to the level of extinction. The African elephants, whose numbers have drastically declined are ruthlessly killed for their tusks.
4. Introduction of Exotic species:- The introduction of (non native species) exotic species into new areas often creates a problem and for the life of native species and causes the loss of biodiversity. The native species fast to compete with the alien species that grows abundantly. The exotic species may be pests and pathogens which causes elimination of native species. Similarly weedy invaders spread at the expense of the diverse range of indigenous undergrowth species.
5. Pollution:- The environmental pollution causes the loss of biodiversity. The excessive use of pesticides in crop fields have resulted in the decline of the populations of fish eating birds and falcons. Lead poisoning is one of the major cause of mortality of many aquatic birds like ducks, swans and cranes.
6. Poaching:- Specific threats to certain animals are related to large economic benefits. Animals are very seriously affected by this poaching only for the economically important parts.
7. Global environmental changes:- The air pollution causes global warming which effects the distribution of organisms on the earth. It is estimated that the green house effect is expected to threaten 400 species of birds, 660 species of fresh water fish and tens of thousands species of invertebrates and plants.
8. Predator and pest control:- Application of predator and pest control has led to the killing of natural predators of insect pests and spread of other dangerous pests. Thus loss to biodiversity occurs.
It may be concluded that biodiversity is being destroyed mainly by human activities at alarming rates almost in all parts of the earth. If the present rate of loss of biodiversity continues, it is not surprising that many valuable species will become extinct even before they are described and named.
The main effects of loss of biodiversity are (i). Loss of valuable genes. (ii). Loss of cultural diversity. (iii). Loss of ecosystems etc;.
Q. Describe the various modes of conservation of biodiversity.
CONSERVATION OF BIODIVERSITY
The conservation of biological diversity has become a global concern due to rapid destruction of ecosystems and wild life. The most effective mechanism for conserving biodiversity is to prevent further degradation of habitats by human beings. The conservation of biodiversity is essential for the sustainable development. There are two types of conservation strategies – (i). in situ (on site) and (ii). ex situ (off site).
(i). In situ (on site) conseravation :
This is the conservation of biological diversity in their natural habitats through protection of total ecosystem. The in situ approach includes protection of a group of typical ecosystem through a net work of protected areas. The areas which provide protection to biological diversity include protected areas, biosphere reserves, sacred forests and sacred lakes.
1. Protected areas:- They are ecological bio-geographical areas where biological diversity along with natural and cultural resources is protected, maintained and managed through legal or other effective measures. The main examples for protected areas are cold desert (Ladak), hot desert (Thar), Saline swampy areas (Sundarbans). The protected areas provide benefits such as maintaining genetic diversity and viable populations. These protected areas prevent man made introduction of alien species and make it possible for the species to shift in response to environmental changes.
2. National parks:- These are the areas maintained by government and reserved for the welfare of wild life. Cultivation, grazing, foresting and habitat manipulation are not allowed in a national park. There are 92 national parks in India. The first national park in India was the Jim Crbett national park near nainital in 1936.
3. Sanctuaries:- A sanctuary is an area of land, which is reserved for the conservation of animals only. Operations such as collection of forest harvests, harvesting of timber, private owner ship of land, tilling of land etc,. are allowed, provided they donot effect the animals adversely. At present, India gas 492 wild life sanctuaries. (Eg: Nagarjuna sagar sanctuary of Guntur of A.P.)
4. Biosphere reserves:- The man and biosphere (MAB) programme of UNESCO formulated the concept of biosphere reserves in 1975. This programme meant for the conservation of ecosystems and the genetic resources contained therein. People are an integral component of an ecosystem. Biosphere reserves serves as a laboratory for sustainable development. At present there are 13 biosphere reserves in India. (Eg: Sundarbans of west Bengal; Nandadevi of Uttaranchal; Simplipal of Orissa etc.). Each biosphere reserve consists of three zones – Core, buffer and Transition zones.
Core or natural zone: It consists of an undisturbed and legally protected ecosystem. No human activity is allowed in this region.
Buffer zone: It surrounds the core area and is managed to accommodate a greater variety of resource use strategies and research and educational activities.
Transition zone: It is the outer most part of the biosphere reserve, which serves as an area of active cooperation between reserve management and local people without disturbing the ecology.
Biosphere reserve helps in restoration of degraded ecosystems and habitats. They ensure the conservation of lands scapes, ecosystems and species. They ensure culturally, socially and ecologically sustainable development. There is a regular monitoring of development and conservation progress in biosphere reserves. The biosphere reserves provide support for education and research in various ecological aspects.
5. Sacred forests and sacred lakes :- Sacred forests are forest patches around places of worship which are held in high esteem by tribal communities. They are found in several parts of India (Eg: Karnataka, Kerala etc;). Similarly, aquatic life form degradation will be inhibited in sacred lake regions.
(ii). Ex situ (off site) conseravation :
It is conservation of selected rare plants or animals in places outside their natural homes (habitats). For ex situ conservation of biodiversity, germ plasm banks or gene banks are established. There include Botanical gardens, zoos, genetic resource centers, pollen grains, seeds, seedlings, tissue culture banks. Seed gene banks are the easiest way to store germplasm of wild and cultivated plants at low temperatures in cold rooms. Storage of germplasm at ultra low temperature (at a temperature of -196 0C in liquid Nitrogen) is called Cryopreservation. There are more than 1500 Botanical gardens and arboreta. Similarly there are more than 800 zoos around the world.
There are certain draw backs to Ex situ conservation. Ex situ conservation is a supplement to in situ conservation because it cannot recreate the habitat as a whole. Natural evolution and adaptation processes are either temporarily halted or altered, when the species is introduced in an unnatural habitat. Ex situ conservation techniques are often costly.
Significance of Conservation of Biodiversity:-
The main significance of conservation of biodiversity is to provide breeders and genetic engineers with a ready source of genetic material. The plants and animals conserved in botanical gardens, zoos and aquaria can be used to restore degraded land, reintroduce species into wild and restock depleted populations.
Biodiversity is the abbreviated word for Biological diversity. This was first put forward by Norse and Mc manus. The term biodiversity was coined by W.C Rosen.
Definitions : Biologists most often define biodiversity in terms of species richness and species diversity . In 1992 United Nations earth summit in Rio de Janerio defined Biological diversity as the variability among living organisms from all sources including inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part. This definition includes diversity within species, between species. This definition was adopted by United Nations convention on biological diversity. The second most commonly used definition of biodiversity is sponsored by Global biodiversity strategy “the totality of genes, species and ecosystems of a region”
Concepts of biodiversity:
i). Biodiversity is the variety of life on earth.
ii). It is generally described at three levels – Genetic diversity, species diversity and ecosystem diversity
iii) All life forms that make biodiversity, including humans are ultimately connected to all other life forms and to their physical environment.
iv). No one living element of any ecosystem can survive independently on others.
v). Connections among living and non living elements keep the environment functioning and healthy.
vi). Human impact on the environment directly or indirectly effect the functioning of other living things and by extension ourselves.
Scope of biodiversity:
i).The science of biodiversity has the potential to unify all fragmented disciplines of biology and bring together the activities of all scientists.
ii). Biodiversity is the back bone for agriculture, aquaculture, animal husbandry, forestry and a host of other applied branches of biology. Thus helping in the adequate supply of food grains and main needs for the population.
iii). Alarming changes due to intense globalization can be nullified by the deep understanding of biodiversity in all aspects.
iv). Biodiversity will offer in the coming years new sources food, medicine and other requirements.
v). Biodiversity is the resource on which all human existence depends. Biodiversity is the pillar of human development.
vi). Sustainable development can be achieved through economic, environmental, social and cultural facets of biodiversity.
Q. Write about Earth Summit.
Earth summit:
The 20th anniversary of Stockholm declaration took place in Rio de Janerio in Brazil in 1992. The UN conference on environment and development popularly known as earth summit. The assembled leaders signed the convention on climate change and the convention on biological diversity. They also endorsed the Rio declaration and the forest principles and adapted azanda 21 to plan for achieving sustainable development in the 21st century.
Earth summit 2002 (Rio +10): The world summit on sustainable development was held in Johannesberg of South Africa in 2002. Its main aim is to examine the progress made on the outcomes of the 1992 Earth summit in Rio and also reinvigorate the world’s people towards the true sustainable development.
Earth summit 2012 (Rio +20): The UN general assembly in December 2009 agreed to hold a new earth summit in 2012. This summit held in Brazil and will focus on the green chemistry emerging issues, sustainable development, governance and review of previous commitments.
Q. Write an essay on the levels and types of Biodiversity.
LEVELS AND TYPES OF BIODIVERSITY
Biodiversity or biological diversity is the sum total of all life on earth. It includes the vast array of life forms, then individual genetic makeup, their life processes and their interrelation ship in communities and ecosystems.
Biodiversity is commonly studied at three different levels. i). Genetic diversity, ii). Species diversity and iii). Ecossystem diversity. These three levels of Biodiversity form an intricate web.
i). Genetic diversity:
Genetic diversity refers to the variation of genes with in species. This covers genetic variation between distinct populations of the same species. It also covers genetic variation with in a population. Genetic diversity can be measured using a variety of DNA based techniques like Restriction fragment like polymorphism (RFLP), Polymerase chain reaction (PCR), Serial analysis gene expression (SAGE). Individuals belonging to a species share contain characteristics, but genetic variations determine the particular characteristics of individuals with in a species. The genetic makeup of an individual species is not static but it changes as a result of both external and internal factors. The main forces that determine current levels of genetic diversity within species are mutations, migration, selection and genetic drift.
ii). Species diversity:
Species diversity is related to number and relative abundance of species in a given area in a community. Species diversity is the highest in the equatorial region and gradually declines towards the Polar Regions. Species diversity is essential for the proper functioning of communities in an ecosystem. The species diversity of a region is measured on the basis of species richness (number of species in a defined area), species abundance (relative number in each species) and phylogenitic diversity (relationship between different groups of species). Greatest species richness is commonly found in relatively stable environments having high rates of productivity.
There are three perspectives of diversity at community level. They are alpha diversity, beta diversity and gamma diversity.
(a). Alpha diversity: It is the species diversity within a community or habitat. It is also defined as the variety of organisms occurring in a particular habitat. It is often called as local diversity. It is measured as the number of species within a given area. Alpha diversity comprises two components i.e, species richness and species evenness.
(b). Beta diversity: It indicates diversity between communities. It is also called differentiation diversity or turn over diversity. Species frequently change when habitat or community changes. There are differences in species composition of communities along environmental gradients.
(c). Gamma diversity: It refers to the diversity of habitat over the total land scape or geographical area. The higher diversity at community level provides stability and productivity. Gamma diversity includes both alpha and beta diversities.
[γ = α + β + Q; where Q= total number of communities; α, β are the average values of alpha and beta diversities respectively.]
iii). Ecosystem diversity: Ecosystem diversity is the highest level of biodiversity. It refers to the variation of different ecosystems such as rain forests, coral reefs. Ecosystem diversity arises due to the variation in energy flow, food chain and water cycle of different ecosystems. The enormous range of terrestrial and aquatic environments on the earth has been classified into a number of ecosystems and the examples tropical rain forests, grass lands, wet lands, coral reefs and mangroves.
All the above components of biodiversity do not work singly, but they work jointly to give rise to the manifestation of biodiversity.
Q. Describe the values of Biodiversity.
VALUES OF BIODIVERSITY
Humans derive many direct and indirect benefits from the living world. Biodiversity or biological resources is the source of food, medicines, pharmaceutical drugs, fibres, rubber and timber understanding the value of biodiversity is required for future conservation plans.
Value of Biodiversity:
The value of biodiversity is categorized basing on the benefit it provides to human society. They include (i) Cultural, social and ethical values and (ii) Aesthetic value
(i) Cultural, social and ethical values:
The cultural value of biodiversity for present and future generations is an important reason for conserving it today. Human cultures all over the globe co-evolved with their environment. So the conservation of biodiversity is essential for cultural density of a human community. Plants and animals are considered to be the symbols of national pride and cultural heritage peacock, tiger and lotus have become national icons of our country. The people should understand and appreciation of the inherent value of each and every life form that constitutes the ethical value of biodiversity.
(ii) Aesthetic value:
Nature has an aesthetic value that can be experienced by human beings when they are in natural surroundings. Nature inspires painters, architects and musicians to create works, reflecting and celebrating its beauty.
(iii) Food Security:
Biodiversity is essential requirement for the maintenance of global food supply. The main sources of human food include animals, fish and plant products. Only the conservation of biodiversity can ensure global food security for the rapidly increasing human population as well as for the animal population. To get the best balanced diet to maintain good health diversified food supply is essential.
(iv) Drugs and Medicines:
Natural flora and fauna are the major sources of pharmaceuticals (medicines) for curing ailments. The Indian system of ayurvedic medicine is dependent on plant biodiversity.
(v) Source of Genes:
Natural populations of different biological species harbour all the genes of a species irrespective of the economic value of the genes. Biodiversity protects the gene pool of a species and acts as a store house of many useful genes. The derivable genes such as resistance to pests, diseases and nematodes stress resisting gene are present in the gene pool of different biological species.
(vi). Ecosystem Services:
Ecosystem services are essential for the survival of the human beings on this planet earth. The world cannot afford to replace these services. Therefore, we must work to protect our ecosystems.
Source of these services provided by ecosystems are as follows:
(i) Air purification-Natural communities maintain proper gaseous concentrations in the atmosphere and prevent rapid climate changes of mainly by air purification.
(ii) Watershed Services-Forests regulate water flows down stream areas.
(iii) Soil formation and protection-Soil formation is promoted by biological weathering of the soil by soil organisms and the soil erosion is prohibited by grass lands and forests, which enables the soil protection.
(iv) Nutrient storage and cycling-Ecosystems perform the vital function of nutrients. Biological diversity is essential in this process.
(v) Potential pest and disease control-Source microbes and plants can act as potential pest and disease control. Which are named as biopesticides.
(vi) Pollution control-Ecosystems and ecological processes play an important in break down and absorption of many pollutants, created by humans and their activities.
(vii) Pollination-Many flowering plants rely on animals for their pollination (Ornithophily pollinating agent is birds) Chaeropteriphily pollinating agents are bats, Malacophily pollinating agents are Molluscans etc.
Q. Describe the various threats to Biodiversity.
THREATS TO BIODIVERSITY
Loss of biodiversity is a serious threat to civilization, second only to thermonuclear war in its severity all other environmental problems like pollution, global warming and ozone depletion can be overcome, but not the erosion of biodiversity or extinction of species.
The prominent threats to biodiversity which can be loss of biodiversity as follows:
1. Destruction of Habitats:- Destruction of natural habitats is the largest single cause of biodiversity loss. Tropical forests, which harbor at least 50% of the world’s biodiversity are declining at a rapid rate with current rate of deforestation 50-90% of earth’s forest inhabiting species is projected to be lost by the mid 21st century. An assessment of world life habited in tropical Asia in 1986 reported that India has already lost about 80% of its natural habitat.
2. Habitat fragmentation:- Habitat fragmentation is another serious problem that often goes unrecognized. Roads, fields, canals, power lines etc. Divide the habitat into small fragments. Fragmentation reduces biodiversity because, many species, such as bears and large cats, require large territories to subsist fragmentation divides the large populations into very small populations. These small populations are vulnerable to catastrophic events. Thus it cause loss to biodiversity.
3. Over exploitation of resources:- The overuse are over harvesting of plants, animals or natural resources threatens earth’s biodiversity. Over exploitation, such as logging, hunting or fishing reduce species number to the level of extinction. The African elephants, whose numbers have drastically declined are ruthlessly killed for their tusks.
4. Introduction of Exotic species:- The introduction of (non native species) exotic species into new areas often creates a problem and for the life of native species and causes the loss of biodiversity. The native species fast to compete with the alien species that grows abundantly. The exotic species may be pests and pathogens which causes elimination of native species. Similarly weedy invaders spread at the expense of the diverse range of indigenous undergrowth species.
5. Pollution:- The environmental pollution causes the loss of biodiversity. The excessive use of pesticides in crop fields have resulted in the decline of the populations of fish eating birds and falcons. Lead poisoning is one of the major cause of mortality of many aquatic birds like ducks, swans and cranes.
6. Poaching:- Specific threats to certain animals are related to large economic benefits. Animals are very seriously affected by this poaching only for the economically important parts.
7. Global environmental changes:- The air pollution causes global warming which effects the distribution of organisms on the earth. It is estimated that the green house effect is expected to threaten 400 species of birds, 660 species of fresh water fish and tens of thousands species of invertebrates and plants.
8. Predator and pest control:- Application of predator and pest control has led to the killing of natural predators of insect pests and spread of other dangerous pests. Thus loss to biodiversity occurs.
It may be concluded that biodiversity is being destroyed mainly by human activities at alarming rates almost in all parts of the earth. If the present rate of loss of biodiversity continues, it is not surprising that many valuable species will become extinct even before they are described and named.
The main effects of loss of biodiversity are (i). Loss of valuable genes. (ii). Loss of cultural diversity. (iii). Loss of ecosystems etc;.
Q. Describe the various modes of conservation of biodiversity.
CONSERVATION OF BIODIVERSITY
The conservation of biological diversity has become a global concern due to rapid destruction of ecosystems and wild life. The most effective mechanism for conserving biodiversity is to prevent further degradation of habitats by human beings. The conservation of biodiversity is essential for the sustainable development. There are two types of conservation strategies – (i). in situ (on site) and (ii). ex situ (off site).
(i). In situ (on site) conseravation :
This is the conservation of biological diversity in their natural habitats through protection of total ecosystem. The in situ approach includes protection of a group of typical ecosystem through a net work of protected areas. The areas which provide protection to biological diversity include protected areas, biosphere reserves, sacred forests and sacred lakes.
1. Protected areas:- They are ecological bio-geographical areas where biological diversity along with natural and cultural resources is protected, maintained and managed through legal or other effective measures. The main examples for protected areas are cold desert (Ladak), hot desert (Thar), Saline swampy areas (Sundarbans). The protected areas provide benefits such as maintaining genetic diversity and viable populations. These protected areas prevent man made introduction of alien species and make it possible for the species to shift in response to environmental changes.
2. National parks:- These are the areas maintained by government and reserved for the welfare of wild life. Cultivation, grazing, foresting and habitat manipulation are not allowed in a national park. There are 92 national parks in India. The first national park in India was the Jim Crbett national park near nainital in 1936.
3. Sanctuaries:- A sanctuary is an area of land, which is reserved for the conservation of animals only. Operations such as collection of forest harvests, harvesting of timber, private owner ship of land, tilling of land etc,. are allowed, provided they donot effect the animals adversely. At present, India gas 492 wild life sanctuaries. (Eg: Nagarjuna sagar sanctuary of Guntur of A.P.)
4. Biosphere reserves:- The man and biosphere (MAB) programme of UNESCO formulated the concept of biosphere reserves in 1975. This programme meant for the conservation of ecosystems and the genetic resources contained therein. People are an integral component of an ecosystem. Biosphere reserves serves as a laboratory for sustainable development. At present there are 13 biosphere reserves in India. (Eg: Sundarbans of west Bengal; Nandadevi of Uttaranchal; Simplipal of Orissa etc.). Each biosphere reserve consists of three zones – Core, buffer and Transition zones.
Core or natural zone: It consists of an undisturbed and legally protected ecosystem. No human activity is allowed in this region.
Buffer zone: It surrounds the core area and is managed to accommodate a greater variety of resource use strategies and research and educational activities.
Transition zone: It is the outer most part of the biosphere reserve, which serves as an area of active cooperation between reserve management and local people without disturbing the ecology.
Biosphere reserve helps in restoration of degraded ecosystems and habitats. They ensure the conservation of lands scapes, ecosystems and species. They ensure culturally, socially and ecologically sustainable development. There is a regular monitoring of development and conservation progress in biosphere reserves. The biosphere reserves provide support for education and research in various ecological aspects.
5. Sacred forests and sacred lakes :- Sacred forests are forest patches around places of worship which are held in high esteem by tribal communities. They are found in several parts of India (Eg: Karnataka, Kerala etc;). Similarly, aquatic life form degradation will be inhibited in sacred lake regions.
(ii). Ex situ (off site) conseravation :
It is conservation of selected rare plants or animals in places outside their natural homes (habitats). For ex situ conservation of biodiversity, germ plasm banks or gene banks are established. There include Botanical gardens, zoos, genetic resource centers, pollen grains, seeds, seedlings, tissue culture banks. Seed gene banks are the easiest way to store germplasm of wild and cultivated plants at low temperatures in cold rooms. Storage of germplasm at ultra low temperature (at a temperature of -196 0C in liquid Nitrogen) is called Cryopreservation. There are more than 1500 Botanical gardens and arboreta. Similarly there are more than 800 zoos around the world.
There are certain draw backs to Ex situ conservation. Ex situ conservation is a supplement to in situ conservation because it cannot recreate the habitat as a whole. Natural evolution and adaptation processes are either temporarily halted or altered, when the species is introduced in an unnatural habitat. Ex situ conservation techniques are often costly.
Significance of Conservation of Biodiversity:-
The main significance of conservation of biodiversity is to provide breeders and genetic engineers with a ready source of genetic material. The plants and animals conserved in botanical gardens, zoos and aquaria can be used to restore degraded land, reintroduce species into wild and restock depleted populations.
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