The Biodiversity or biological diversity is, according to the International Convention on Biological Diversity , the term by which referred to the wide variety of living things on the Earth and what happens with natural patterns that shape out of thousands of millions of years of evolution according to natural processes and also the growing influence of human activities. Biodiversity also includes the variety of ecosystems and the genetic differences within each species ( genetic diversity) that allow the combination of multiple forms of life, and whose mutual interactions with the rest of the environment base the sustenance of life on the world .
The term "biodiversity" is a carbon copy of the English "biodiversity". This term, in turn, is the contraction of the expression "biological diversity" that was used for the first time in October 1986 as the title of a conference on the subject, the National Forum on BioDiversity , convened by Walter G. Rosen , at who is credited with the idea of the word. [ 1 ]
The Earth Summit held by the United Nations in Rio de Janeiro in 1992 recognized the global need to reconcile the future preservation of biodiversity with human progress according to criteria of sustainability or sustainability promulgated in the International Convention on Biological Diversity which was approved in Nairobi on May 22, 1994, a date later declared by the UN General Assembly as International Biodiversity Day . With this same intention, 2010 was declared the International Year of Biological Diversity by the 61st session of theUnited Nations General Assembly in 2006, coinciding with the 2010 Biodiversity Target date . [ 2 ]
Origin and evolution of the term
However, the concept, due to its intuitive nature, has presented certain difficulties for its precise definition, as Fermín Martín Piera [ 5 ] pointed out when arguing that abuse in its employment could "empty it of content", since in his words: «It usually happens in the history of thought that new paradigms coexist for a time with old ideas», considering along with other authors that the concept of biodiversity was already pointed out by the theory of evolution itself .
At the beginning of the 20th century , the ecologists Jaccard and Gleason proposed in different publications the first statistical indices aimed at comparing the internal diversity of ecosystems. In the mid- 20th century , growing scientific interest allowed the development of the concept to describe complexity and organization, until in 1980, Thomas Lovejoy proposed the term biological diversity . [ 6 ]
If in the field of biology, biodiversity refers to the number of populations of organisms and different species, for ecologists the concept includes the diversity of lasting interactions between species and their immediate environment or biotope , the ecosystem in which organisms live. . In each ecosystem, living organisms are part of a whole interacting with each other, but also with the air, water, and soil that surround them.
Three levels are usually distinguished biodiversity: [ 7 ]
- Genetics or intraspecific diversity, consisting of the diversity of versions of genes ( alleles ) and their distribution, which in turn is the basis of interindividual variations (the variety of genotypes ).
- Specific, understood as systematic diversity, consisting of the plurality of genetic systems or genomes that distinguish species .
- Ecosystem, the diversity of biological communities ( biocenosis ) whose integrated sum constitutes the biosphere .
The internal diversity of ecosystems must also be included, to which the term ecological diversity traditionally refers .
Biodiversity and evolution
Although the origin of life could not be dated accurately, the evidence suggests that may have arisen ago 3800 [ 9 ] [ 10 ] [ 11 ] to 3235 million years. [ 12 ] Some more recent research has opened the possibility that it began as much as 4.1 billion years ago [ 13 ] although they are not yet conclusive. Until about 600 million years ago, all life consisted of bacteria and microorganisms. [ 9 ]
The history of biological diversity during the Phanerozoic — last 540 million years — begins with rapid growth during the Cambrian explosion , a period during which the phyla of multicellular organisms first appeared . [ 14 ] During the next 400 million years, global biodiversity showed a relative advance, but it was marked by specific events of mass extinctions . [ 15 ]
The apparent biodiversity shown in the fossil record suggests that a few million recent years include the most biodiverse period in Earth's history . However, not all scientists hold this point of view, since it is not easy to determine whether the abundant fossil record is due to an explosion in biodiversity, or - simply - to the better availability and conservation of the most recent geological strata. [ citation required ]
Some, like Alroy and others [ 16 ] think that by improving sampling, modern biodiversity does not differ too much from that of 300 million years ago. Estimates of current macroscopic species range from 2 to 100 million, with an estimated logical value of approximately 10 million species. [ 14 ]
However, most biologists agree that the period since the appearance of man is part of a new mass extinction, the Holocene extinction event , caused especially by the impact that humans have on the development of the ecosystem. It is estimated that the species extinct due to human activity is still smaller than those observed during the mass extinctions of previous geological eras. [ citation needed ] However, many believe that the current rate of extinction is sufficient to create a major mass extinction within less than 100 years. [ citation required ]Those who disagree with this hypothesis argue that the current rate of extinction can be sustained for several thousand years before the loss of biodiversity exceeds the 20% observed in mass extinctions of the past. [ citation required ]
New species are discovered regularly - an average of three birds per year [ citation needed ] and many already discovered have not yet been classified: it is estimated that 40% of fish freshwater in South America remain unclassified. [ citation required ]
Importance of biodiversity
The essential and fundamental value of biodiversity resides in the fact that it is the result of a natural historical process of great antiquity. For this reason alone, biological diversity has the inalienable right to continue its existence. Man and his culture, as a product and part of this diversity, must ensure that it is protected and respected.
In addition, biodiversity is a guarantor of well-being and balance in the biosphere . The diverse elements that make up biodiversity make up true functional units that provide and ensure many of the basic “services” for our survival.
Finally from our human condition, diversity also represents a natural capital . [ 17 ] The use and benefit of biodiversity has contributed in many ways to the development of human culture, and represents a potential source to meet future needs.
Considering biological diversity from the point of view of its present and potential uses and benefits, it is possible to group the arguments into three main categories.
The ecological aspect
It refers to the role of biological diversity from a systemic and functional point of view ( ecosystems ). Being indispensable to our own survival, many of these functions are often called " services ."
The elements that constitute the biological diversity of an area are the natural regulators of the flows of energy and matter . They play an important role in the regulation and stabilization of land and coastal areas . For example, in mountain slopes, the diversity of species in the actual plant tissue layer formed to protect the underlying layers of inert mechanical action of the elements such as wind and water runoff. Biodiversity plays a determining role in atmospheric and climatic processes. Many exchanges and effects of the continental masses and the oceans with the atmosphere are the product of living elements ( albedo effect , evapotranspiration, carbon cycle , etc.).
The biotic diversity of a natural system is one of the determining factors in the processes of recovery and reconversion of waste and nutrients. In addition, some ecosystems have organisms or communities capable of degrading toxins , or of fixing and stabilizing dangerous compounds in a natural way.
Even with the development of agriculture and the domestication of animals, biological diversity is essential to maintain a good functioning of agroecosystems, since it guarantees the fertility of the land, the natural pollination of several domestic species, the effective control of pests, etc. The trophodynamic regulation of biological populations is only possible by respecting the delicate networks that are established in nature. The imbalance in these relationships has already been shown to have significant negative consequences. [ 18 ] This is even more evident with marine resources, where most of the food sources consumed in the world are caught directly in the middle. The response to disturbances (natural oranthropic ) takes place at the systemic level, through response pathways that tend to return to the initial equilibrium situation. However, human activities have dramatically increased in intensity, irremediably affecting the biological diversity of some ecosystems and in many cases undermining this response capacity with catastrophic results.
Research suggests that a more diverse ecosystem can better resist environmental stress and is therefore more productive. The loss of a species is likely to diminish the system's ability to maintain or recover from damage or disturbance. Like a species with high genetic diversity, a highly biodiverse ecosystem may have more opportunities to adapt to environmental change. In other words: the more species an ecosystem comprises, the more likely the ecosystem is to be stable and resilient. The mechanisms underlying these effects are complex and hotly contested. However, in recent years it has become clear that there really are ecological effects of biodiversity.
A high availability of resources in the environment favors a higher biomass , but also ecological dominance and ecosystems that are relatively poor in nutrients often present greater diversity, something that is systematically true in aquatic ecosystems. Greater biodiversity allows an ecosystem to better resist major environmental changes, making it less vulnerable, more resilient since the state of the system depends on the interrelationships between species and the disappearance of any of them is less crucial for the stability of the whole than in ecosystems. less diverse and more marked by dominance.
The economic aspect
For all humans, biodiversity is the first resource for daily life. An important aspect is the diversity of the crop, which is also called agrobiodiversity .
Biodiversity is seen by most people as a useful resource repository for the manufacture of food, pharmaceuticals, and cosmetics. This concept of biological resources explains most of the fears of the disappearance of resources. However, it is also the origin of new conflicts over the division and appropriation of natural resources.
Some of the important economic items that biodiversity provides to humanity are:
- Food: crops, livestock, forestry, fish farming, medicine. Wild plants have been used for medicinal purposes since prehistoric times. For example, quinine comes from the cinchona tree (it treats malaria ); the digital one, from the Digitalia plant (chronic arrhythmia problems); and morphine , from the poppy(anesthesia). Animals can also play a role, particularly in research. It is estimated that of the 250,000 known plant species, only 5,000 have been investigated for possible medical applications. But maintaining biodiversity is not only important in case there are "new" species, not yet discovered, that can be exploited economically; It is also important to keep it as a "gene mine", a reserve of interesting characteristics (resistance to droughts, pests, soil salinity ) that can be incorporated, if deemed convenient, into current agricultural species ( wheat , barley , corn , vine ) by genetic engineering.
- Industry: for example, textile fibers, wood for coverings and heat. Biodiversity can be a source of energy (like biomass). Biological diversity also contains the largest reserve of biochemical compounds imaginable, due to the variety of metabolic adaptations of organisms. Other industrial products that we currently obtain are oils , lubricants, perfumes , dyes, paper , waxes , rubber , latex , resins , poisons , cork .
- Health: in addition to being a very rich source of molecules, some of which have medicinal effects, greater biodiversity leads to less extension and severity of infectious diseases, [ 20 ] and therefore the high costs associated with them. [ 21 ]
- Animal-based supplies include wool , silk , fur, meat , leather , lubricants, and waxes . Animals can also be used for transportation.
- Tourism and recreation: Biodiversity is a source of cheap wealth for many areas, such as parks and forests where wild nature and animals are a source of beauty and joy for many people. Ecotourism, in particular, is growing in outdoor recreation. Likewise, a large part of the human cultural heritage in various fields (gastronomic, educational, spiritual) is closely linked to local or regional diversity and will surely continue to be so.
Ecologists and ecological activists were the first to insist on the economic aspect of protecting biological diversity.
Estimating the value of biodiversity is a necessary precondition for any discussion on the distribution of its wealth. This value can be discriminated between use value (direct like tourism or indirect like pollination) and intrinsic value.
If biological resources represent an ecological interest for the community, their economic value is also increasing. New products are developed due to biotechnologies and new markets. For society, biodiversity is also a field of activity and profit. It requires an appropriate management arrangement to determine how these resources will be used.
The current and future economic importance of most species has yet to be assessed. However, we must be aware that we still have a long way to go to know how to accurately calculate, not only the economic but, much more important, the value that each species has for its ecosystem.
The demographic and economic expansion of the human species is generally considered to be setting in motion a mass extinction , of incomparably greater dimensions than any previous extinction. The concrete causes are in the indiscriminate disappearance of ecosystems , by cutting down forests , soil degradation , environmental pollution , excessive hunting and fishing , etc. The scientific community generally judges that such extinction represents a threat to the ability of the biosphere to sustain human life through various natural services andrenewable resources .
Therefore, understanding cultural biodiversity in its relationship with ecosystems is key, provided that natural resources are not dissociated from their cultural, historical and geographical context.
The scientific aspect
Biodiversity is important as each species can give scientists a clue about the evolution of life. In addition, biodiversity helps science understand how the life process works and the role that each species has in ecosystems.
The assessment of biodiversity
Diversity is a phenomenological property that tries to express the variety of different elements. As a fundamental quality of our perception, we feel the need to quantify it. The development of a measure that allows the expression of biological diversity in a clear and comparable way presents difficulties and limitations. It is not simply a matter of measuring a variation of one or more common elements, but of quantifying and weighing how many different elements or groups of elements exist. The existing diversity measures, then, are nothing more than quantitative or semi-quantitative models of a qualitative reality with very clear limits in terms of their applications and scope. The development of a logical and coherent mathematical concept for the modeling of biological diversity at the specific and genetic levelIt has been extensively explored and features a robust synthetic body. Diversity modeling at the ecosystem level is more recent, and has benefited from technological advances (such as GIS ). [ 22 ] The simplest measures of diversity consist of mathematical indices that express the amount of information and the degree of organization of it. Basically the metric expressions of diversity take into account three aspects:
- Wealth : It is the number of elements. Depending on the level, it is the number of alleles or heterozygosity (genetic level), number of species (specific level), or the number of different habitats or environmental units (ecosystem level).
- Relative abundance : It is the relative incidence of each of the elements in relation to the others.
- Differentiation: It is the degree of genetic, taxonomic or functional differentiation of the elements.
Each of these diversity indices is one-dimensional and limited readability. Comparisons and assessments of biological diversity are necessarily incomplete in these terms. They are used for their practical and synthetic nature, but insufficient compared to alternative multiscale and multidimensional analytical models that better respond to specific conservation and management needs. Thus, two-dimensional modeling (richness and relative abundance) can be considered as the “classical” standard for the measurement and expression of diversity. According to the spatial scale in which biological diversity is measured, we speak of alpha diversity (punctual diversity, represented by α), beta(diversity between habitats, represented by β) and gamma (diversity on a regional scale, represented by γ). These terms were coined by Robert Whittaker in 1960 and are generally widely accepted.
Biodiversity is not static: it is a system in constant evolution, both in each species, as well as in each individual organism. A current species may have started one to four million years ago, and 99% of the species that have ever existed on Earth are extinct.
Biodiversity is not evenly distributed on earth. It is richer in the tropics, and as you approach the polar regions you will find larger populations and fewer species. The flora and fauna vary, depending on the climate, altitude, soil and the presence of other species.
Spatial units and biodiversity
The distribution of current biological diversity is the result of evolutionary, biogeographic and ecological processes over time since the appearance of life on earth. Its existence, conservation and evolution depend on the environmental factors that make it possible. Each species has specific environmental requirements without which it cannot survive. Although orographic and oceanographic, altitudinal and latitudinal changes make it possible to define landscape units fairly roughly, the specific component of the species present is what finally allows the identification of relatively homogeneous areas in terms of the characteristics that they present or offer for biological populations.
These biosphere units can be identified as biodiversity units according to different evaluation criteria: for example, the number of endemisms, specific wealth, ecosystems or phylogenetics. Although it is common to argue that this or that country has certain biodiversity indices, the spatial units of biological diversity are by definition independent of geopolitical limits or barriers.
Two of the current spatial units of the biosphere, where the biodiversity factor precedes in importance, are the Global 200 ecoregions [ 23 ] identified by the WWF and the biodiversity hotspots or hotspots of the International Union for the Conservation of Nature . [ 24 ]
Global 200 identifies the most important ecoregions on the planet , both marine and continental - freshwater and terrestrial bodies - according to their specific richness, the number of endemisms and their conservation status. [ 25 ]
The term "biodiversity hotspot" was coined by Norman Myers in 1998 and identifies important terrestrial biogeographic regions based on the number of endemisms and the degree of threat to biodiversity. [ 26 ] In its latest review Conservation International proposes 34 hotspots .
During the 20th century , the increasingly accelerated erosion of biodiversity has been observed. Estimates of the rates of extinction vary, ranging from a very few to as many as 201 extinct species per day, but all scientists acknowledge that the rate of species loss is higher than at any time in human history.
In the plant kingdom, it is estimated that approximately 12.5% of currently known species are threatened. Everyone agrees that the losses are due to human activity, including the direct destruction of plants and their habitats.
There is also a growing concern about the human introduction of exotic species into certain habitats, altering the food chain. [ 27 ]
Development-directed human activities that can affect biodiversity
Some examples of development activities that can have the most significant negative consequences for biodiversity are:
- Agricultural and livestock projects involving land clearing, removal of wetlands, flooding for reservoirs for irrigation , displacement of wildlife by fences or domestic livestock, the intensive use of pesticides , the introduction of monoculture commercial products places that previously relied on a large assortment of local crops for subsistence farming.
- Fish farming projects that include the conversion, for aquaculture or mariculture, of important natural breeding or breeding sites, excessive fishing, the introduction of exotic species in natural aquatic ecosystems. [ 28 ]
- Forestry projects that include the construction of access roads, intensive forestry exploitation, establishment of industries for forest products that generate further development near the project site.
- Transportation projects that include the construction of main roads, bridges, rural roads, railways or canals, which could facilitate access to natural areas and their population.
- Channeling of rivers.
- Dredging and filling activities in coastal or inland wetlands.
- Hydroelectric projects that imply large diversions of water, floods or other important transformations of natural aquatic or terrestrial areas, producing the reduction or modification of the habitat and the consequent necessary transfer to new areas and the probable violation of the maintenance capacity.
- Irrigation and other drinking water projects that can drain water, drain wetland habitats, or remove vital sources of water.
- Industrial projects that produce air, water or soil pollution.
- Large-scale loss of habitat, due to mining and mineral exploration.
- Conversion of biological resources for fuel or food on an industrial scale.
- Human overpopulation and anthropocentrism.
Cultural biodiversity can be added meaningfully to the above . Work on biological biodiversity is incorporating the study, promotion and protection of cultural biodiversity, in addition to specific biodiversity, ecosystems and genetics.
Eugenio Reyes Naranjo [ 29 ] defines Cultural Biodiversity as the diversity of knowledge that human beings have developed through history in their relationship with biodiversity.
This includes beliefs, myths , dreams, legends, language , scientific knowledge, psychological attitudes in the broadest possible sense, management, exploitation, enjoyment and understanding of the natural environment.
It is about understanding biological evolution taking into account all aspects of human intervention.
- Megadiverse countries
- genetic diversity
- Ecological diversity
- Mass extinction
- Genetic contamination
- Taxonomy and biodiversity crisis
- Conservation biology
- Latitudinal gradient of diversity
- Biodiversity of insects
Notes and references
- Cf. Francisco García Olmedo, «The invisible biodiversity», Book Magazine , 159, May 2009.
- 2010 International Year of Biodiversity.
- "UN Assembly in which Biological Diversity Day is proclaimed." .
- «biodiversity», Dictionary of the Spanish language (twenty-second edition), Royal Spanish Academy, 2001.
- Martín Piera, F., 1991. Systematics, biodiversity and conservation of the natural environment. Conference on the Albacete Natural Environment, 1: 409-413.
- T.E. Lovejoy,Conservation Biology : An evolutionary-ecological perspective(1980) (M. E. SOULÉ et B. A. WILSON, dir.), Sinauer Associates (Sunderland).
- Basic concepts of environmental management and sustainable development . National Institute of Ecology. ISBN 9786077552079 . Retrieved February 14, 2018 .
- Collective of authors. Text translated and synthesized from Earth and Life - origins of biodiversity. Year of Planet Earth: Earth Sciences for society. P. 1.
- "BBC Nature - History of life on Earth" . Retrieved May 19, 2016 .
- «Space & Astronomy News - Is this life? - 07/03/2002». www.abc.net.au. Consultado el 19 de mayo de 2016.
- Ponnamperuma / Molton, Cyril / Peter (August 1, 1981). "The origin of life". SCIENCE AND DEVELOPMENT. SPECIAL ISSUE: THE ORIGIN OF LIFE .
- "Who were the first living beings?" . www.elcultural.com . Retrieved May 19, 2016 .
- Julia Rosen (October 19, 2015). "Scientists may have found the earliest evidence of life on earth . " www.sciencemag.org (in English) . AAAS . Retrieved October 19, 2015 .
- Wagoner, Ben; et al. . "The Cambrian Period" (in English) . University of California Museum of Paleontology . Retrieved March 5, 2010 .
- Orue-Etxebarria, Xavier (March 5, 2013). "Impacts and extinctions: the end of the dinosaurs" (Conference) . In Luis Alfonso Gámez, ed. Asteroids . Bilbao: Bilbao City Council, the Aula Espazio Gela, the Skeptical Circle and the newspaper El Correo . Retrieved August 23, 2014 .
- 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.
- Constanza and others, 1997.
- «62 measures to stop the loss of biodiversity» .
- «Climate change begins to be felt in agricultural production» . The Galician Mail (Galicia, Spain). February 12, 2007 . Retrieved March 18, 2019 .
- Díaz, Ángel (December 2, 2010). "Less biodiversity, more infectious diseases . " The World (Madrid, Spain) . Retrieved March 18, 2019 .
- «Biodiversity reduces the severity of infectious diseases» . ABC (Madrid, Spain). December 4, 2013 . Retrieved March 18, 2019 .
- GIS: Geographic information systems.
- WWF - About Global Ecoregions.
- The biodiversity hotspots.
- "Archived copy" . Archived from the original on July 12, 2006 . Retrieved July 4, 2006 .
- Biodiversity Hotspots - Hotspots by Region.
- Vázquez Manzanares, Víctor Manuel (2014): “Externalities and environment”, Ibero-American Magazine of Business Organization and Marketing, n. 2 (December 2014) 
- Nations, Food and Agriculture Organization of the United (December 30, 2007). State of world aquaculture 2006 . Food & Agriculture Org. ISBN 9789253056316 . Retrieved February 14, 2018 .
- Biodiversity Knowledge Bank of the Macaronesian Bioregion, Canarian Botanical Garden "Viera y Clavijo".
- Fermín Martín Piera (1997). "Notes on Biodiversity and Conservation of Insects: Dilemmas, Fictions and Solutions?" . Monograph The Arthropods and Man (Aragonese Entomological Society, SEA) 20 : 25-55.
- Constanza, R.; d'Arge, R.; de Groot, R.; Farber, S.; de Grasso, M.; Hannon, B.; Limburg, K.; Naeem, S.; O'Neil, R.V.; Paruelo, J.; Raskin, R.G.; Sutton, P.; van der Belt, M. (1997). «The value of the world's ecosystem services and natural capital». Nature 387: 253-260.
- Whittaker, R.H. (1972). «Evolution and measurement of species diversity». Taxón 21: 213-251.
- Benton, M. J. (2001). «Biodiversity on land and in the sea.». Geological Journal 36 (3-4): 211-230.
- Debinski, D. M.; Ray, C.; Saveraid, E. H. (2001). «Species diversity and the scale of the landscape mosaic: do scales of movement and patch size affect diversity?.». Biological Conservation 98: 179-190.
- Wikimedia Commons hosts a multimedia category on Biodiversity .
- Summary in Spanish of the Biodiversity Synthesis Report , made by GreenFacts.