Biodiversity is a term applied to describe the complexity of life. It is generally measured at three levels: the variety of species; the genetic diversity found within members of the same species (what makes you different from your neighbour); and the diversity of the ecosystems within which species live. These three levels are intimately connected. Genetic diversity is essential to the prosperity of the species, giving it the resources to adapt. And the number of species within an ecosystem is closely tied to the health and size of the ecosystem itself.
However it is defined, biodiversity is the stuff of life. However far we may be removed from "wild" biodiversity in our daily lives, it remains the source of our food and most of our medicines. In addition, 15 percent of our energy is derived from burning plant materials. Even in the United States, wild species contribute around 4.5 percent of GDP. Due to agricultural modernisation, changes in diets and population density, humankind increasingly depends on a reduced amount of agricultural biological diversity for its food supplies.
A dozen species of animals provide 90% of the animal protein consumed globally and just four crop species provide half of plant-based calories in the human diet. FAO estimates that about three-quarters of the genetic diversity found in agricultural crops have been lost over the last century. Of 6, 300 animal breeds, 1,350 are endangered or already extinct. This rapidly diminishing gene pool is cause for concern.
Nobody knows how many species there are in the world -- or how fast they are disappearing. Fewer than 2 million have been catalogued and estimates of the total vary wildly, ranging from 7 million to as many as 80 million. The currently accepted working estimate is 13.6 million.
At least 40 per cent of the world's economy and 80 per cent of the needs of the poor are derived from biological resources. In addition, the richer the diversity of life, the greater the opportunity for medical discoveries, economic development, and adaptive responses to such new challenges as climate change.
Biodiversity is an immense resource, built up over 3.5 billion years of evolution. It embraces not only the number of species on Earth, but the range of habitats and genetic diversity within species as well. It is of enormous importance to humans. Of the 270,000 known plants, some 3,000 are exploited for food, and between 25,000 and 50,000 more are used in traditional medicine. Wild plants are potential sources of new medicines and of material for genetic engineering. Biodiversity is a major attraction for tourism, and not least a lasting source of human aesthetic pleasure.
Around 1.75 million species have been scientifically described. More than half of these are insects, while vertebrates -- including fish, birds, mammals, reptiles and amphibians -- make up only 2.5 percent. But the real number is certainly far higher. Most recent estimates fall in the 7 to 20 million ranges, though a widely acceptable working estimate, used by the United Nations Environment Programme's Global Biodiversity Assessment of 1995, is 13.6 million.
Most ecologists believe that we are currently undergoing a mass extinction driven by human activities. Since 1600, 484 animal and 654 plant species are known to have become extinct through human actions. But these are only the tip of a vast iceberg. Since most species are as yet undescribed, the majority of current extinctions are going unrecorded -- species are dying out before we even learn of their existence. Projections of future losses vary widely, from 2 to 25 percent of all species over the next 25 years. But even the low end of this range is 1,000 times the background rate of extinction.
The total extinction of a species is drastic and at present irreversible. But local extinctions are serious, and far more common. Data on species are far from complete, but countries and taxonomic groups with more complete information have a higher share of species threatened, so it is quite likely that as more data become available, the percentage judged to be under threat will rise. The prospects for the coming decades look gloomy. Forests are the home of between 50 and 90 percent of all land species in the world. If tropical deforestation continues at present rate for the next 30 years, it is estimated that 5 to 11 percent of forest species will eventually be lost.
Wildlife habitat is becoming increasingly fragmented by human activities -- making way for cities, farms and roads. Fragmentation lowers the size of individual populations, reducing their genetic variability, and making them more vulnerable to extinction. Human barriers also make it difficult for animals and plants to migrate in response to environmental change.
At the same time, global warming will be shifting present temperature zones generally polewards and uphill. Species will have a greater need to migrate but will encounter human barriers blocking their way. Some species which prefer cold temperatures will see their natural habitats disappear completely. Meanwhile genetic engineering -- unless it is rigorously controlled -- may introduce new genes which could spread to wildlife with unforeseeable consequences. There is no doubt that genes from existing commercial crops can pass to wild relatives, and even with rigorous control measures, it is unlikely that accidental transfers could be prevented indefinitely. The extent to which this is likely to have negative impacts on the environment and biological diversity is still not known.
The Global Biodiversity Assessment found that the major threat to biodiversity was habitat loss, fragmentation and degradation, due to the need for land for farms, dwellings, industry, services, transport and leisure. Of those species that are threatened, habitat loss affects 44 percent of the bird species, 55 percent of the fishes, 68 percent of the reptiles, and 75 percent of the mammals. Other direct pressures are overexploitation of species for commercial gain, for subsistence or for sport. The introduction of alien species, pollution and climate change are all major threats. Population is a major indirect cause underlying most of these threats.
Population density is closely linked with most forms of habitat loss. A sample of 50 non-desert countries in Asia and Africa where wildlife habitat loss has been estimated showed that the percentage loss tends to be highest where population density is highest. The top 20 percent of countries, ranked in terms of habitat loss, had lost an average of 85 percent of their original wildlife habitat. Their average population density was 189 people per square kilometer. The 20 percent with lowest population density had lost an average of only 41 percent of their wildlife habitat -- and their average population density was only 29 people per square kilometer.
Governments are gradually moving to give wider areas protected status, but progress is slow. Globally, in 1997, only 6.4 percent of the land area was protected. To protect the full range of species, large areas are needed, but 88 percent of protected areas in 1997 were smaller than 100,000 hectares -- a square with sides of about 32 kilometers.
Biodiversity is integral part of our life as different aspects of our activities. For our survival, we must be aware about biodiversity and take measures to check its the mass extinction. It is high time for sustainable use and conservation of biodiversity otherwise our own extinction will also come soon.
However it is defined, biodiversity is the stuff of life. However far we may be removed from "wild" biodiversity in our daily lives, it remains the source of our food and most of our medicines. In addition, 15 percent of our energy is derived from burning plant materials. Even in the United States, wild species contribute around 4.5 percent of GDP. Due to agricultural modernisation, changes in diets and population density, humankind increasingly depends on a reduced amount of agricultural biological diversity for its food supplies.
A dozen species of animals provide 90% of the animal protein consumed globally and just four crop species provide half of plant-based calories in the human diet. FAO estimates that about three-quarters of the genetic diversity found in agricultural crops have been lost over the last century. Of 6, 300 animal breeds, 1,350 are endangered or already extinct. This rapidly diminishing gene pool is cause for concern.
Nobody knows how many species there are in the world -- or how fast they are disappearing. Fewer than 2 million have been catalogued and estimates of the total vary wildly, ranging from 7 million to as many as 80 million. The currently accepted working estimate is 13.6 million.
At least 40 per cent of the world's economy and 80 per cent of the needs of the poor are derived from biological resources. In addition, the richer the diversity of life, the greater the opportunity for medical discoveries, economic development, and adaptive responses to such new challenges as climate change.
Biodiversity is an immense resource, built up over 3.5 billion years of evolution. It embraces not only the number of species on Earth, but the range of habitats and genetic diversity within species as well. It is of enormous importance to humans. Of the 270,000 known plants, some 3,000 are exploited for food, and between 25,000 and 50,000 more are used in traditional medicine. Wild plants are potential sources of new medicines and of material for genetic engineering. Biodiversity is a major attraction for tourism, and not least a lasting source of human aesthetic pleasure.
Around 1.75 million species have been scientifically described. More than half of these are insects, while vertebrates -- including fish, birds, mammals, reptiles and amphibians -- make up only 2.5 percent. But the real number is certainly far higher. Most recent estimates fall in the 7 to 20 million ranges, though a widely acceptable working estimate, used by the United Nations Environment Programme's Global Biodiversity Assessment of 1995, is 13.6 million.
The total extinction of a species is drastic and at present irreversible. But local extinctions are serious, and far more common. Data on species are far from complete, but countries and taxonomic groups with more complete information have a higher share of species threatened, so it is quite likely that as more data become available, the percentage judged to be under threat will rise. The prospects for the coming decades look gloomy. Forests are the home of between 50 and 90 percent of all land species in the world. If tropical deforestation continues at present rate for the next 30 years, it is estimated that 5 to 11 percent of forest species will eventually be lost.
Wildlife habitat is becoming increasingly fragmented by human activities -- making way for cities, farms and roads. Fragmentation lowers the size of individual populations, reducing their genetic variability, and making them more vulnerable to extinction. Human barriers also make it difficult for animals and plants to migrate in response to environmental change.
At the same time, global warming will be shifting present temperature zones generally polewards and uphill. Species will have a greater need to migrate but will encounter human barriers blocking their way. Some species which prefer cold temperatures will see their natural habitats disappear completely. Meanwhile genetic engineering -- unless it is rigorously controlled -- may introduce new genes which could spread to wildlife with unforeseeable consequences. There is no doubt that genes from existing commercial crops can pass to wild relatives, and even with rigorous control measures, it is unlikely that accidental transfers could be prevented indefinitely. The extent to which this is likely to have negative impacts on the environment and biological diversity is still not known.
The Global Biodiversity Assessment found that the major threat to biodiversity was habitat loss, fragmentation and degradation, due to the need for land for farms, dwellings, industry, services, transport and leisure. Of those species that are threatened, habitat loss affects 44 percent of the bird species, 55 percent of the fishes, 68 percent of the reptiles, and 75 percent of the mammals. Other direct pressures are overexploitation of species for commercial gain, for subsistence or for sport. The introduction of alien species, pollution and climate change are all major threats. Population is a major indirect cause underlying most of these threats.
Population density is closely linked with most forms of habitat loss. A sample of 50 non-desert countries in Asia and Africa where wildlife habitat loss has been estimated showed that the percentage loss tends to be highest where population density is highest. The top 20 percent of countries, ranked in terms of habitat loss, had lost an average of 85 percent of their original wildlife habitat. Their average population density was 189 people per square kilometer. The 20 percent with lowest population density had lost an average of only 41 percent of their wildlife habitat -- and their average population density was only 29 people per square kilometer.
Governments are gradually moving to give wider areas protected status, but progress is slow. Globally, in 1997, only 6.4 percent of the land area was protected. To protect the full range of species, large areas are needed, but 88 percent of protected areas in 1997 were smaller than 100,000 hectares -- a square with sides of about 32 kilometers.
Biodiversity is integral part of our life as different aspects of our activities. For our survival, we must be aware about biodiversity and take measures to check its the mass extinction. It is high time for sustainable use and conservation of biodiversity otherwise our own extinction will also come soon.
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