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Biodiversity is the variation of taxonomic Life forms within a given Ecosystem , Biome or for the entire Earth . Biodiversity is often used as a measure of the health of Biological System s. EVOLUTION AND MEANING OF THE TERM ''Biodiversity'' is a Clearing-House Mechanism, retrieved April 26, 2006 . The word ''biodiversity'' was deemed more effective in terms of communication than ''biological diversity'' Since 1986 the terms and the concept have achieved widespread use among biologists, environmentalists, political leaders, and concerned citizens worldwide. It is generally used to equate to a concern for the natural environment and nature conservation. This use has coincided with the expansion of concern over Extinction observed in the last decades of the 20th century. The term "natural heritage" pre-dates "biodiversity", though it is a less scientific term and more easily comprehended in some ways by the wider audience interested in conservation. "Natural Heritage" was used when Jimmy Carter set up the Georgia Heritage Trust while he was governor of Georgia; Carter's trust dealt with both natural and Cultural Heritage . It would appear that Carter picked the term up from Lyndon Johnson , who used it in a 1966 Message to Congress. "Natural Heritage" was picked up by the Science Division of The Nature Conservancy when, under Jenkins, it launched in 1974 the network of State Natural Heritage Programs. When this network was extended outside the USA , the term "Conservation Data Center" was suggested by Guillermo Mann and came to be preferred. DEFINITIONS The most straightforward definition is "variation of life at all levels of biological organization".Kevin J. Gaston & John I. Spicer. 2004. "Biodiversity: an introduction", Blackwell Publishing. 2nd Ed., ISBN 1-4051-1857-1(pbk.) A second definition holds that biodiversity is a measure of the relative diversity among organisms present in different ecosystems. "Diversity" in this definition includes diversity within a species and among species, and comparative diversity among ecosystems. A third definition that is often used by ecologists is the "totality of genes, species, and ecosystems of a region". An advantage of this definition is that it seems to describe most circumstances and present a unified view of the traditional three levels at which biodiversity has been identified:
This third definition, which conforms to the traditional Five Organization Layers in biology, provides additional justification for multilevel approaches. The 1992 . If the gene is the fundamental unit of Natural Selection , according to E. O. Wilson, the real biodiversity is genetic diversity. For Geneticist s, ''biodiversity'' is the diversity of genes and Organism s. They study processes such as mutations, gene exchanges, and genome dynamics that occur at the DNA level and generate evolution. For Ecologist s, biodiversity is also the diversity of durable interactions among species. It not only applies to species, but also to their immediate environment ( Biotope ) and their larger Ecoregion . In each Ecosystem , living organisms are part of a whole, interacting with not only other organisms, but also with the air, water, and soil that surround them. MEASUREMENT OF BIODIVERSITY Biodiversity is a broad concept, so a variety of objective measures have been created in order to Empirical ly measure biodiversity. Each measure of biodiversity relates to a particular use of the data. For practical Conservationist s, this measure should quantify a value that is broadly shared among locally affected people. For others, a more economically defensible definition should allow the ensuring of continued possibilities for both adaptation and future use by people, assuring environmental Sustainability . As a consequence, biologists argue that this measure is likely to be associated with the variety of genes. Since it cannot always be said which genes are more likely to prove beneficial, the best choice for Conservation is to assure the persistence of as many genes as possible. For ecologists, this latter approach is sometimes considered too restrictive, as it prohibits Ecological Succession . Biodiversity is usually plotted as taxonomic richness of a geographic area, with some reference to a temporal scale. Whittaker Whittaker, R.H., ''Evolution and measurement of species diversity'', Taxon, 21, 213-251 (1972) described three common metrics used to measure species-level biodiversity, encompassing attention to Species Richness or Species Evenness :
There are three other indices which are used by ecologists:
DISTRIBUTION OF BIODIVERSITY Biodiversity is not distributed evenly on Earth. It is consistently richer in the Tropics and in other localized regions such as the California Floristic Province . As one approaches polar regions one generally finds fewer species. Flora and fauna diversity depends on Climate , altitude, Soil s and the presence of other species. In the year 2006 large numbers of the Earth's species are formally classified as Rare or Endangered or Threatened Species ; moreover, most scientists estimate that there are millions more species actually endangered which have not yet been formally recognized. About 40 percent of the 40,177 species assessed using the IUCN Red List criteria, are now listed as Threatened Species with extinction - a total of 16,119 species. {Link without Title} A , leading to threats to their many endemic species. As a result of the pressures of the rapidly growing human population, human activity in many of these areas is increasing dramatically. Most of these hotspots are located in the Tropics and most of them are forests. For example, Brazil 's Atlantic Forest contains roughly 20,000 plant species, 1350 vertebrates, and millions of insects, about half of which occur nowhere else in the world. The island of Madagascar including the unique Madagascar Dry Deciduous Forests and lowland rainforests possess a very high ratio of species Endemism and biodiversity, since the island separated from mainland Africa 65 million years ago, most of the species and ecosystems have evolved independently producing unique species different than other parts of Africa. Many regions of high biodiversity (as well as high Endemism ) arise from very specialized Habitat s which require unusual adaptation mechanisms. For example the peat Bog s of Northern Europe and the alvar regions such as the Stora Alvaret on Oland , Sweden host a large diversity of plants and animals, many of which are not found elsewhere. BIODIVERSITY AND EVOLUTION ]] Biodiversity found on Earth today is the result of 4 billion years of Evolution . The Origin Of Life is not well known to science, though limited evidence suggests that life may already have been well-established only a few 100 million years after the Formation Of The Earth . Until approximately 600 million years ago, all life consisted of Bacteria and similar single-celled organisms. The history of biodiversity during the Phanerozoic (the last 540 million years), starts with rapid growth during the Cambrian Explosion —a period during which nearly every Phylum of Multicellular Organism s first appeared. Over the next 400 million years or so, global diversity showed little overall trend, but was marked by periodic, massive losses of diversity classified as Mass Extinction events. The apparent biodiversity shown in the Fossil Record suggests that the last few million years include the period of greatest biodiversity in the Earth's History . However, not all scientists support this view, since there is considerable uncertainty as to how strongly the fossil record is biased by the greater availability and preservation of recent Geologic sections. Some (e.g. Alroy et al. 2001) argue that corrected for sampling artifacts, modern biodiversity is not much different from biodiversity 300 million years ago.J. Alroy, C.R. ''et al''.2001. Effect of sampling standardization on estimates of Phanerozonic marine diversification. Proceedings of the National Academy of Science, USA 98: 6261-6266 Estimates of the present global macroscopic species diversity vary from 2 million to 100 million species, with a best estimate of somewhere near 10 million. Most biologists agree however that the period since the emergence of humans is part of a new mass extinction, the Holocene Extinction Event , caused primarily by the impact humans are having on the environment. At present, the number of species estimated to have gone extinct as a result of human action is still far smaller than are observed during the major mass extinctions of the Geological Past . However, it has been argued that the present rate of extinction is sufficient to create a major mass extinction in less than 100 years. Others dispute this and suggest that the present rate of extinctions could be sustained for many thousands of years before the loss of biodiversity matches the more than 20% losses seen in past global extinction events. New species are regularly discovered (on average about three new species of Bird s each year) and many, though discovered, are not yet classified (an estimate states that about 40% of freshwater fish from South America are not yet classified). Most of the terrestrial diversity is found in Tropical Forest s. BENEFITS OF BIODIVERSITY There are a multitude of benefits of biodiversity in the sense of one diverse group aiding another such as: Resistance to Catastrophe Monoculture , the lack of biodiversity, was a contributing factor to several agricultural disasters in history, including the Irish Potato Famine , the European wine industry collapse in the late 1800s, and the US Southern Corn Leaf Blight epidemic of 1970. http://cropdisease.cropsci.uiuc.edu/corn/southerncornleafblight.html See also: Agricultural Biodiversity Higher biodiversity also controls the spread of certain diseases as e.g. virusses will need adapt itself with every new species. Food and drink Biodiversity provides food for humans. About 80 percent of our food supply comes from just 20 kinds of plants. Although many kinds of animals are utilized as food, again most consumption is focused on a few species. There is vast untapped potential for increasing the range of food products suitable for human consumption, provided that the high present extinction rate can be stopped. Medicines A significant proportion of drugs are derived, directly or indirectly, from biological sources; in most cases these medicines can not presently be synthesized in a laboratory setting. Moreover, only a small proportion of the total diversity of plants has been thoroughly investigated for potential sources of new drugs. Many Medicine s and Antibiotic s are also derived from Microorganism s. Industrial materials A wide range of industrial materials are derived directly from biological resources. These include building materials, fibers, dyes, resins, gums, adhesives, rubber and oil. There is enormous potential for further research into sustainably utilizing materials from a wider diversity of organisms. Intellectual value Through the field of bionics, a lot of technological advancement has been done which may not have been the case without a rich biodiversity. ''(See also: Bionics )'' Better crop-varieties For certain economical crops (e.g. foodcrops, ...), wild varieties of the domesticated species can be reintroduced to form a better variety than the previous (domesticated) species. The economic impact is gigantic, for even crops as common as the potato (which was bred through only one variety, brought back from the Inca), a lot more can come from these species. Wild varieties of the potato will all suffer enormously through the effects of climate change. A report by the Consultative Group on International Agricultural Research (CGIAR) describes the huge economic loss. Rice, which has been improved for thousands of years by man, can through the same process regain some of its nutritional value that has been lost since (a project is already being carried out to do just this). Other ecological services Biodiversity provides many Ecosystem Services that are often not readily visible. It plays a part in regulating the chemistry of our Atmosphere and Water Supply . Biodiversity is directly involved in recycling Nutrient s and providing fertile soils. Experiments with controlled environments have shown that humans cannot easily build ecosystems to support human needs; for example Insect Pollination cannot be mimicked by man-made construction, and that activity alone represents tens of billions of dollars in Ecosystem Services per annum to mankind. Leisure, cultural and aesthetic value Many people derive value from biodiversity through leisure activities such as enjoying a walk in the countryside, birdwatching or natural history programs on television. Biodiversity has inspired musicians, painters, sculptors, writers and other artists. Many cultural groups view themselves as an integral part of the natural world and show respect for other living organisms. THREATS TO BIODIVERSITY During the last century, erosion of biodiversity has been increasingly observed. Some studies show that about one of eight known plant species is threatened with ecological practices, because only a small number of species come into being each year. Almost all scientists acknowledge that the rate of species loss is greater now than at any time in human history, with extinctions occurring at rates hundreds of times higher than Background Extinction rates. Destruction of habitats Most of the species extinctions from 1000 AD to 2000 AD are due to human activities, in particular destruction of plant and animal , Deforestation , Pollution ( Air Pollution , Water Pollution , Soil Contamination ) and Global Warming or climate change, driven by human activity. These factors, while all stemming from overpopulation, produce a cumulative impact upon biodiversity. Some characterize loss of biodiversity not as ecosystem degradation but by conversion to trivial standardized ecosystems (e.g., Monoculture following Deforestation ). In some countries lack of property rights or access regulation to biotic resources necessarily leads to biodiversity loss (degradation costs having to be supported by the community). Exotic species See Also: Introduced species The rich diversity of unique species across many parts of the world exist only because they are separated by barriers, particularly large rivers, seas, oceans, mountains and deserts from other species of other land masses, particularly the highly fecund, ultra-competitive, generalist "super-species". These are barriers that could never be crossed by natural processes, except for many millions of years in the future through Continental Drift . However humans have invented ships and airplanes, and now have the power to bring into contact species that never have met in their evolutionary history, and on a time scale of days, unlike the centuries that historically have accompanied major animal migrations. The widespread introduction of Exotic Species by humans is a potent threat to biodiversity. When exotic species are introduced to ecosystems and establish self-sustaining populations, the endemic species in that ecosystem, that have not evolved to cope with the exotic species, may not survive. The exotic organisms may be either Predator s, Parasite s, or simply aggressive species that deprive indigenous species of nutrients, water and light. These exotic or Invasive Species often have features due to their evolutionary background and environment that makes them competitive, and similarly makes Endemic species defenceless and/or uncompetitive against these exotic species. As a consequence of the above, if humans continue to combine species from different ecoregions, there is the potential that the world's ecosystems will end up dominated by relatively a few, aggressive, Cosmopolitan "super-species".''' ;Other 'Decline in amphibian populations' See Also: Decline in amphibian populations Declines in amphibian populations have been observed since 1980s. These might critically threaten global biodiversity. BIODIVERSITY MANAGEMENT: CONSERVATION, PRESERVATION AND PROTECTION The Conservation Of Biological Diversity has become a global concern. Although not everybody agrees on extent and significance of current extinction, most consider biodiversity essential. There are basically two main types of conservation options, In-situ Conservation and Ex-situ Conservation . In-situ is usually seen as the ideal conservation strategy. However, its implementation is sometimes infeasible. For example, destruction of rare or endangered species' habitats sometimes requires Ex-situ Conservation efforts. Furthermore, ex-situ conservation can provide a backup solution to in-situ conservation projects. Some believe both types of conservation are required to ensure proper preservation. An example of an in-situ conservation effort is the setting-up of protection areas. Examples of ex-situ conservation efforts, by contrast, would be planting germplasts in Seedbank s, or growing the Wollemi Pine in nurseries. Such efforts allow the preservation of large populations of plants with minimal genetic erosion. At national levels a Biodiversity Action Plan is sometimes prepared to state the protocols necessary to protect an individual species. Usually this plan also details extant data on the species and its habitat. In the USA such a plan is called a Recovery Plan . The threat to biological diversity was among the hot topics discussed at the UN World Summit for Sustainable Development, in hope of seeing the foundation of a Global Conservation Trust to help maintain plant collections. JUDICIAL STATUS OF BIOLOGICAL DIVERSITY Biodiversity is beginning to be evaluated and its evolution analysed (through observations, inventories, conservation...) as well as being taken into account in political and judicial decisions .
The 1972 UNESCO convention established that biological resources, such as plants, were the common heritage of mankind. These rules probably inspired the creation of great public banks of genetic resources, located outside the source-countries. New global agreements (e.g. Convention On Biological Diversity ), now give sovereign national rights over biological resources (not property). The idea of static conservation of biodiversity is disappearing and being replaced by the idea of dynamic conservation, through the notion of resource and innovation. The new agreements commit countries to conserve biodiversity, '''develop resources for sustainability''' and '''share the benefits''' resulting from their use. Under new rules, it is expected that Bioprospecting or collection of natural products has to be allowed by the biodiversity-rich country, in exchange for a share of the benefits. Sovereignty principles can rely upon what is better known as Access And Benefit Sharing Agreements (ABAs). The Convention On Biodiversity spirit implies a prior Informed Consent between the source country and the collector, to establish which resource will be used and for what, and to settle on a Fair Agreement On Benefit Sharing . Bioprospecting can become a type of Biopiracy when those principles are not respected. Uniform approval for use of biodiversity as a legal standard has not been achieved, however. At least one legal commentator has argued that biodiversity should not be used as a legal standard, arguing that the multiple layers of scientific uncertainty inherent in the concept of biodiversity will cause administrative waste and increase litigation without promoting preservation goals. See Fred Bosselman, A Dozen Biodiversity Puzzles, 12 N.Y.U. Environmental Law Journal 364 (2004) CRITICISMS OF THE BIODIVERSITY PARADIGM .]] Food The notion that there is 'vast untapped potential' for reducing mankinds dependence on a relatively small number of domesticated plant and animal species should be challenged. Jared Diamond ,Diamond, J.(1998), ''Guns, Germs and Steel''. Vintage. ISBN 0 09 930278 0 (pbk.) based on studies of the domestication of plants and animals, argued that the rarity of species suitable for domestication and their occurrence in just a few parts of the world, determined the limited number of locations in which major civilizations could arise. In recent times there have been many studies of minor food sources, but none of these sources have subsequently become major food crops. The founder effect The field of biodiversity research (inevitably) suffers from natural human than for inaccessible, species-poor deep sea areas. It has been easier to mobilise public opinion and national legislation for the terrestrial realm, which has higher visibility and falls within countries' territorial boundaries. Marine Conservation involves having to pioneer new and international mechanisms of protection as well as solving methodological problems in Marine Biology relating to marine ecosystem classification and data-gathering on some of the earth's most difficult species to access and monitor. Size bias Biodiversity researcher , visible life consists of barely noticeable twigs. This should not be surprising — invisible life had at least three billion years to diversify and explore evolutionary space before the 'visibles' arrived". The size bias is not restricted to consideration of microbes. Entomologist Nigel Stork states that "to a first approximation, all multicellular species on Earth are insects" N. E. Stork 2007. ''Biodiversity: world of Insects''. Nature 448, 657-658 (9 August 2007). The reply to this, however, is that biodiversity conservation has never focused exclusively on visible (in this sense) species. From the very beginning, the classification and conservation of natural communities or ecosystem types has been a central part of the effort. The thought behind this has been that since invisible (in this sense) diversity is, due to lack of taxonomy, impossible to treat in the same manner as visible diversity, the best that can be done is to preserve a diversity of ecosystem types, thereby preserving as well as possible the diversity of invisible organisms. REFERENCES NEWS
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