The expression biological diversity was invented by Thomas Lovejoy in 1980 while the term biodiversity itself was invented by Walter G. Rosen in 1985 during the preparation of the National Forum one Biological Diversity organized by the National Research Council in 1986; the word “biodiversity” appears for the first time in 1988 in a publication, when the American entomologist E.O. Wilson makes of it the title of the report of this forum. The word biodiversity had been considered to be more effective in terms of communication than biological diversity .
Since 1986, the term and the concept are very much used among the biologists, the ecologists, the ecologists, the leaders and the Citoyen S. the use of the term coincides with the awakening of the extinction of Espèce S during the last decades of the 20th century.
In June 1992, the planetary top of Rio de Janeiro marked the entry forces some on the international scene of concerns and covetousnesses with respect to the diversity of the alive world. During the Convention on the biological diversity which was held on June 5th, 1992, biological diversity was defined like:
Biodiversity, contraction of “biological diversity”, expression indicating the variety and the diversity of the alive world. In its broadest direction, this word is quasi synonymous with “life on ground”.
Three levelsBiological diversity is the diversity of all the forms of the alive one. It is usually subdivided in three levels:
the genetic Diversity, which corresponds to the diversity of the Gène S within a species (intraspecific diversity).
- the specific diversity, which corresponds to the diversity of the Espèce S (interspecific diversity), to see Taxinomie.
- the ecosystemic diversity, which corresponds to the diversity of the ecosystem S present on Ground, of the interactions of the natural populations and their physical environments.
The gene is the fundamental unit of the Natural selection, therefore of the evolution, and some, like E.O. Wilson, estimate that the only useful biodiversity is genetic diversity. However, in practice, when one studies the biodiversity on the ground, the species is the most accessible unit.
Origins of life, and evolution of the biodiversity
Appearance of the life
There exist multiple assumptions to explain its appearance there is approximately 3,5 billion years, but the Paléontologie, the Stratigraphie and the Biochimie convergent towards a marine origin of the Vie.
The first living being (called éobionte, protobionte, or biogénote) would have appeared starting from many the Molécule S organic present in the medium, resulting from the chemical reactions of the paramount Océan. As of this moment (and perhaps even front), the Natural selection, engine of the evolution, will involve the appearance of multiple forms of life, certainly initially heterotrophic, then photosynthetic. The three great fields of the alive world (Eubactérie S, Archéobactérie S and Eucaryote S) are set up, structuring the diversity of the Vie such as we currently know it.
These Procaryote S, commonly called bacteria , although of very simple organization, represents the fundamental base of the biodiversity, so much from the functional point of view (diversity of the Métabolisme S) that Génétique (the separation of the lines of the archeobacteries and the Eubactérie S could be deepest of the Arbre of alive the).
The exit of water
It is with the Silurien that Bactérie S, Cyanobactérie S, Algue S, Lichen S (association of algae and mushrooms) and foams, gained the terrestrial environment and started to take part in the formation of the first grounds. The grounds, resulting from the interaction between living beings, bed rocks and climate, are of a very great diversity; they are not only one physicochemical support, but a medium of life, where the biodiversity is very large, and different from a place to another.
For example, a ground of moderate area will contain in kilograms per hectare
- 1.000 to 7.000 kg of bacteria
- 100 to 1.000 kg of mushrooms
- 10 to 30 kg of algae
- 5 to 10 kg of protists
- 1.000 kg of arthropods
- 350 to 1.000 kg of ground worms (Lombric S)
In comparison a tropical ground will be able to contain 10% of Fourmi S, 33% of worms of ground, 6% of myriapodes, 4% of Coléoptère S, 4% of Termite S.
Major changes occurred at the time of the passage of the aquatic life to the terrestrial life. They relate to in particular the breathing apparatuses, circulatory and skeletal.
Indeed, 400 million years ago, the aquatic animals had:
- to adapt to atmospheric gases (oxygen and carbon dioxide). The oxygen content of the air medium is higher than in aqueous medium, requiring less energy.
- to adapt to the Viscosity and the Density of the medium, with the adaptations in terms of skeleton and blood circulation. These constraints limited the development of the terrestrial animals (the largest terrestrial mammal, the Mammouth, made up to 20 tons whereas the blue whale reaches 200 tons).
- and finally to face the problems of dissipation of calorific energy and dehydration. Indeed, the air constitutes a good heat insulator: some of the animals became with the Mesozoic Homéotherme S like the reptiles, whereas the aquatic animals remained Poïkilotherme S.
The animals thus had to be accustomed during the geological eras with the modifications of their medium of life, that the constraints are of a climatic nature (climate change) or biological (diseases, predation). They thus slowly evolved/moved to the world living current. --->
To evaluate the biodiversity
How to measure the biodiversity?According to the point of view previously definite, there cannot be of objective single measurement of the biodiversity, but only of measurements relative to precise objectives of use or application.
For conservationnistes, this measurement must to quantify value, which is at the same time largely recognized by the people for whom they make this estimate, but also to be regarded as needing protection. For others, a definition broader and more easily justifiable from an economic point of view is a measurement which makes it possible to guarantee the maintenance of its use, to support the upgrading capabilities of this biodiversity, to guarantee its use for the future generations, while ensuring the protection of the Environnement in a world in constant evolution. Consequently of what the biologists support that this measurement must be associated with the notion of variety of the Gène S. Cependant, as it is difficult to indicate which genes are most likely to be beneficial, the best choice of conservation of the biodiversity consists in ensuring the safeguard of the greatest possible number of genes.
The ecologists regard this approach as being often inadequate and too restrictive.
A recent study shows that the decline of the butterfly S in a given zone is related to that of the biodiversity in this same zone. The presence or the absence of butterflies would be thus an good indicator of measurement of the biodiversity.
Various dimensions of the biodiversity
The biodiversity can on the one hand be considered according to its temporal dimension : it is not static. The biodiversity is a system in constant evolution, from the point of view of the species as much as that of the individual. The average Demi-vie of a species is of approximately a million years and 99% of the species which lived on ground are extinct today.
It can also be considered in its space component : the biodiversity is not distributed systematically on ground. The Flora and the fauna differ according to many criteria like the Climat, altitude, the grounds or the other species.
The inventory of the species
The Systématique is a manner of analyzing the biodiversity in its capacity to distinguish an organization from another. This method is confronted with the problems of time and number: 1,75 million species was described, however, the estimates of the true number of alive species go from 3,6 to more than 100 million. Beside that, some say that the knowledge of the species and the families became insufficient and must be supplemented by a greater comprehension of the functions, interactions and communities.
See also: Contenu=Pour more information on [[insecte#Biodiversity]], [[the biodiversity of the insects]].
Estimates of the number of speciesCertain groups, like the viruses, the bacteria and the algae are very badly known. To make estimates, even careful, is then very delicate.
The rate/rhythm of the discoveriesThe number of the species to be discovered, as we have just seen it, is extremely important. But the rate/rhythm of these discoveries is different according to the zoological groups. Thus, in the birds (graph 3, to see below), it took 87 years to discover half of the species now known and 125 years for other half. What indicates that the species are increasingly difficult to discover. In the case of Arachnida and of the shellfish (graph 4, to see below), one discovered in only ten years (of 1960 to 1970), as many species as since 1758, that is to say 202 years. That indicates that there exist still many still unknown common species but also that to discover news of them will be increasingly difficult.
Examples of country rich in biodiversity
the Brésil is regarded as representative of a fifth of the world biodiversity, with 50.000 species of plants, 5.000 vertebrate, 10 to 15 million insects and million micro-organisms.
- the India would account for 8% of the known species, with 47.000 species from plants and 81.000 of animal species.
Abundant services by the biodiversity
The biodiversity is the source first services rendered by the ecosystems. It is also the engine of the ecological Résilience because it is a natural resource self-sustained (in certain conditions).
It provides all the oxygen, vital, which we consume, all that we eat (food crops, cattle, fish…); it contributes to the purification and the cycle of water, like with biogeochemical major cycle and the climatic regulation.
Elle provides fiber S for clothing, of the Bois - energy for the Chauffage, the construction of Habitation S, the paper mill. It produces or inspires by the Médicament S.
L' Agrobiodiversité indicates the uses of the biodiversity associated with the agro-alimentary one.
The biodiversity contributed in many ways to the development of the human cultures. And conversely, the man played an important role in terms of evolution of diversity at the genetic, specific and ecosystemic levels.
Among the examples of the utility of diversity vis-a-vis the genetic homogenization of the varieties of crop plants, one can quote two of them:
- In 1970,85% of corn cultivated in the United States was almost homogeneous. The resistance of this plant to the Helminthosporiose, cryptogamic disease, was overcome by mushroom and the epidemic caused considerable damage.
- In 1980, for the same reason, 90% of the cuban harvest of tobacco was destroyed by the Mildiou.
One sees thus that the genetic diversity of the natural populations of animals and of plants seems a strategy promoted by the natural selection, in answer to the continual pressures of the parasites evolving/moving quickly.
The ecosystems also provide supports of production (fertility of the ground, sediments, functions of predatory, decomposition and organic waste recycling and nécromasse…) and of the priceless services such as the production and air cleaning, the purification of water, the stabilization and the moderation of the climate, the reduction in the consequences of the drynesses, floods and others environmental disasters.
If the living resources represent an ecological interest for the community, the economic value of the biodiversity is proposed also more and more. New products are developed thanks to the Biotechnologie S, and of new markets created. For the company, the biodiversity is also a branch of industry and profit, and requires a suitable management of the resources.
The biodiversity also became a mirror of our relations with the other alive species , an ethical sight with rights, duties, and an educational need. The educational aspect is often ensured by the school (at the time of exits of education to the environment for example) or by organizations of protection of nature, such as WWF.
The biodiversity, vital natural heritage for each people and country, are strongly dependant on the needs for the man and its health, its food… and its richness. Because it has also an economic aspect: it can be used to manufacture agro-alimentary, medicinal, cosmetic products…
See also : Écotourisme
Which price to grant to the biodiversity?
The ecologists and the environmentalists were the first to insist on the economic aspect of the protection of biological diversity. Thus, Edward Wilson wrote into 1992 that the biodiversity is one of the greatest richnesses of planet, and yet the least recognized like such . Many are those which today regard the biodiversity as a reservoir of resources usable to manufacture products Agro-alimentaire S, pharmaceutical, Cosmétique S… This concept of development of the resources is at the origin of fears of disappearance of the resources related to the erosion of the biodiversity, but also of new the Conflit S bearing on the rules of division and Appropriation of this richness.
A precondition to any discussion on the distribution of the richnesses is necessary: that of the economic evaluation of the biodiversity. This objective must also make it possible to determine financial means to devote to its protection.
Is the biodiversity threatened?
See also: Extinction of Holocene the
The installation of the man in the majority of the territories available modified the ecological balances existing; the climatic fluctuations had an impact on the distribution of the species. These modifications, which had course during several millenia however allowed important a biological diversity of perdurer to the paddle of the industrial era.
These last decades, a erosion of the biodiversity was observed and more half of livable space of planet was modified to a significant degree by the mankind. The majority of the ecologists and biologists estimate that a massive Extinction is in hand. If there is dissension on the figures and the deadlines, the majority of the scientists think that the current rate of extinction higher than it is forever been in last times. Several studies show that approximately a species on eight of the known plants is threatened of extinction. Each year, between 17 000 and 100 000 species disappear from our planet, and a fifth of all the alive species could disappear in 2030. There is consensus on the fact that the man is the cause, in particular by the Fragmentation of the habitats and/or the destruction of the ecosystem S sheltering these species. Without neglecting the evolution even species nor their installation during time in spaces given, one can only note in terms of assessment that the quantitative and especially qualitative losses are enormous, and that with the planetary scales these last are carried out in a regular and pernicious way.
Seas and oceans: a Statistical study published in 2006 based on the analysis during four years of data covering one period thousand years, for 48 zones of fishing in the world shows that the currently fished species (fish and shellfish) could almost all disappear in 2048 without supplementary measure from safeguarding. In 2006,29% of the fished species are already about to disappear, imposing a more important call to the Pisciculture S of which some degrade the environment. The important loss of marine biodiversity weakens the marine ecosystems and consequently the climate and those of whole planet, because the seas and oceans are essential with the biogeochemical cycles, of which that of the Oxygène.
Some estimate that the conversion of old ecosystems (or of substitution, such as meadows, scrap-metal…) in standardized ecosystems (e.g for example, Deforestation followed intensive Monoculture) has effects even more negative on the biodiversity than overexploitation of species or degradation of primary education ecosystems. Others think that it is the absence of property rights or access rules to the resources which led to the anarchistic exploitation of the natural resources.
Among these detractors, some affirm that abusive extrapolations are made and that the current rhythm of disappearance of the species or destruction of the tropical forests, of the coral reefs or of the Mangrove S (three kinds of habitat rich in biodiversity) is not sufficient to speak about extinction of mass . Thus, the majority of the extinctions or the extinctions most important was observed on islands.
Nevertheless, in addition to the theories of the ecology of the landscape predict that it is indeed initially on the islands that the species must disappear, it is precisely a phenomenon of insularisation écopaysagère which the scientists observe on the continents. Moreover, the inventories showing that a great quantity of species did not completely disappear also show that they often have - in a few decades - considering melting or disappearing their populations on the essence of what was their normal or old surface of distribution. Their genetic diversity was necessarily reduced. Lastly, the speed of quasi-disappearance of formerly common fishing resources and more than 200 fish species in the Lake Victoria (to be compared with 129 species fresh water only for all the Europe), following the introduction of the Perche of the Nile in 1954 shows the possibility, in a short time, of an extinction of mass of human origin. The documentary film the Nightmare of Darwin (2005) also illustrates this aspect.
Lastly, the speed and the night rate of regression of the species S are badly followed and little studied, but the phenomenon known as of luminous Pollution could be underestimated in its impacts in terms of ecological Fragmentation of the night Environnement; however it is in constant progression and rapid since the years 1950.
Management of the biodiversity: conservation, safeguarding and protection
All in all, it is not so much the presence of the man who disturbs the ecological balance of the ecosystems that his increasingly intensive activities which, in particular in the plains, split up the sectors more and more where a certain biodiversity is still expressed. The destruction of the habitats and their fragmentation are thus the two independent factors of the loss of a biological high level of richness.
However, most of the human activities seems compatible with the maintenance of an important biodiversity provided that certain rules of management and installation are complied with and followed, even if some of enter they require deep changes in our economic and sociological perception of the world.
The conservation of the biodiversity became a reason for world concern. Although everyone is not inevitably of agreement on the fact that a massive extinction is in hand, the majority of the observers admit the disappearance of many species, and consider essential that this diversity is preserved, according to the Precaution principle.
There exist two great types of options of conservation of the biodiversity: the conservation in situ i.e. in the natural environment and the conservation ex situ . The in situ conservation is often seen like the ideal strategy. Its installation is however not always possible. For example, the cases of destruction of rare habitats of species or species in the process of disappearance require the installation of strategies of conservation ex situ. Some estimate that the two types of conservation are complementary.
An example of in situ conservation is the installation of protection zones. The gene conservation in banks of seed is an example of conservation ex situ, which allows the safeguard of a great number of species with a genetic minimum of erosion.
In a general way, the safeguarding of the biodiversity implies the safeguarding of ecological great balances, on some scale that it is: habitat, forest, area, world… Balances which, if they are broken, involve serious biological dysfunctions with the often disastrous consequences, sometimes unforeseeable, on the human society in general and their economic base in particular.
The erosion of the biodiversity was one of the subjects most discussed at the time of the Sommet for sustainable development, with Rio de Janeiro, in the hope of the installation of a total bottom of conservation for the maintenance of the species and the collections (academies, banks of seeds, etc…). It is also at the time of this top that the May 22nd was declared international Journée of the biodiversity . The Convention on biological diversity voted in Rio, before being ratified by its Parts - members, engages the states signatories and the European Union to take conservation measures and of durable use of the biodiversity like to the equal share of the benefit rising from the use of the genetic resources.
The convention of 1972 of UNESCO will be used to lead on an agreement right on the division of the resulting benefit. The Bioprospection can become what was called Biopiraterie when these rules are not complied with.
Perspective for a good governance of the Biodiversity : UNO set up FAO to answer the questions of agriculture and breeding and WHO for the health questions, but there is no world Agency for the Biodiversity. An advisory step (IMoSEB which means “International Mechanism Of Scientific Expertise one Biodiversity” ) considers in 2006 the creation of a scientific organization of type IPCC on the topic of the biodiversity, following the recommendations of an international work group ( Leipzig workshop ) on the interfaces Science-Decision makers for good a Gouvernance of the biodiversity ( International Science-Policy Interfaces for Biodiversity Governance ). In February 2007 in Paris, president Jacques Chirac gave the support of France to the idea of creation of a world Agency of the Environment.
The urban biodiversity , and that of the banal natural is also concerns émergeantes, with some experiments of integration in urban management and architecture (Construction with positive biodiversity, Fifteenth target HQE…)
|Random links:||Onésicrite | Blackburn Shark Mk.III | Party of solidarity and progress | Royal company of Arts and Sciences of Mauritius | As long as there will be women|