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79-958: In a conference of the Ministers of Forests of Central African Forest Commission (COMIFAC), it had been resolved to establish within the Congo Basin , the Sangha River Tri-National Protected Area (TNS) with a total area of 11,331 km (4,375 sq mi) encompassing the Dzanga Sangha Special Reserve and the Dzanga-Ndoki National Park in the Central African Republic , the Nouabalé-Ndoki National Park in

158-423: A mutation–selection balance . It is predicted that a viral quasispecies at a low but evolutionarily neutral and highly connected (that is, flat) region in the fitness landscape will outcompete a quasispecies located at a higher but narrower fitness peak in which the surrounding mutants are unfit, "the quasispecies effect" or the "survival of the flattest". There is no suggestion that a viral quasispecies resembles

237-405: A ring species . Also, among organisms that reproduce only asexually , the concept of a reproductive species breaks down, and each clone is potentially a microspecies. Although none of these are entirely satisfactory definitions, and while the concept of species may not be a perfect model of life, it is still a useful tool to scientists and conservationists for studying life on Earth, regardless of

316-400: A "classical" method of determining species, such as with Linnaeus, early in evolutionary theory. However, different phenotypes are not necessarily different species (e.g. a four-winged Drosophila born to a two-winged mother is not a different species). Species named in this manner are called morphospecies . In the 1970s, Robert R. Sokal , Theodore J. Crovello and Peter Sneath proposed

395-424: A 'smallest clade' idea" (a phylogenetic species concept). Mishler and Wilkins and others concur with this approach, even though this would raise difficulties in biological nomenclature. Wilkins cited the ichthyologist Charles Tate Regan 's early 20th century remark that "a species is whatever a suitably qualified biologist chooses to call a species". Wilkins noted that the philosopher Philip Kitcher called this

474-428: A connected series of neighbouring populations, each of which can sexually interbreed with adjacent related populations, but for which there exist at least two "end" populations in the series, which are too distantly related to interbreed, though there is a potential gene flow between each "linked" population. Such non-breeding, though genetically connected, "end" populations may co-exist in the same region thus closing

553-432: A different species from its ancestors. Viruses have enormous populations, are doubtfully living since they consist of little more than a string of DNA or RNA in a protein coat, and mutate rapidly. All of these factors make conventional species concepts largely inapplicable. A viral quasispecies is a group of genotypes related by similar mutations, competing within a highly mutagenic environment, and hence governed by

632-508: A genetic boundary suitable for defining a species concept is present. DNA barcoding has been proposed as a way to distinguish species suitable even for non-specialists to use. One of the barcodes is a region of mitochondrial DNA within the gene for cytochrome c oxidase . A database, Barcode of Life Data System , contains DNA barcode sequences from over 190,000 species. However, scientists such as Rob DeSalle have expressed concern that classical taxonomy and DNA barcoding, which they consider

711-440: A humid climate and gets, on an average, 1,250 mm (49 in) of rain a year. The rainy season is August to November and the dry season is December to February. The plants include a collection of different types of mahoganies . Numerous providers run safaris into the park in order to fund conservation efforts and raise awareness about the wildlife and natural gems within. Congo Travel and Tours (www.congotravelandtours.com)

790-492: A misnomer, need to be reconciled, as they delimit species differently. Genetic introgression mediated by endosymbionts and other vectors can further make barcodes ineffective in the identification of species. A phylogenetic or cladistic species is "the smallest aggregation of populations (sexual) or lineages (asexual) diagnosable by a unique combination of character states in comparable individuals (semaphoronts)". The empirical basis – observed character states – provides

869-449: A particular species, including which genus (and higher taxa) it is placed in, is a hypothesis about the evolutionary relationships and distinguishability of that group of organisms. As further information comes to hand, the hypothesis may be corroborated or refuted. Sometimes, especially in the past when communication was more difficult, taxonomists working in isolation have given two distinct names to individual organisms later identified as

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948-400: A short way of saying that something applies to many species within a genus, but not to all. If scientists mean that something applies to all species within a genus, they use the genus name without the specific name or epithet. The names of genera and species are usually printed in italics . However, abbreviations such as "sp." should not be italicised. When a species' identity is not clear,

1027-404: A specialist may use "cf." before the epithet to indicate that confirmation is required. The abbreviations "nr." (near) or "aff." (affine) may be used when the identity is unclear but when the species appears to be similar to the species mentioned after. With the rise of online databases, codes have been devised to provide identifiers for species that are already defined, including: The naming of

1106-523: A species as groups of actually or potentially interbreeding natural populations, which are reproductively isolated from other such groups. It has been argued that this definition is a natural consequence of the effect of sexual reproduction on the dynamics of natural selection. Mayr's use of the adjective "potentially" has been a point of debate; some interpretations exclude unusual or artificial matings that occur only in captivity, or that involve animals capable of mating but that do not normally do so in

1185-400: A species as determined by a taxonomist. A typological species is a group of organisms in which individuals conform to certain fixed properties (a type), so that even pre-literate people often recognise the same taxon as do modern taxonomists. The clusters of variations or phenotypes within specimens (such as longer or shorter tails) would differentiate the species. This method was used as

1264-491: A species. All species definitions assume that an organism acquires its genes from one or two parents very like the "daughter" organism, but that is not what happens in HGT. There is strong evidence of HGT between very dissimilar groups of prokaryotes , and at least occasionally between dissimilar groups of eukaryotes , including some crustaceans and echinoderms . The evolutionary biologist James Mallet concludes that there

1343-685: A species. Generally the term includes the unknown element of a distinct act of creation. Many authors have argued that a simple textbook definition, following Mayr's concept, works well for most multi-celled organisms , but breaks down in several situations: Species identification is made difficult by discordance between molecular and morphological investigations; these can be categorised as two types: (i) one morphology, multiple lineages (e.g. morphological convergence , cryptic species ) and (ii) one lineage, multiple morphologies (e.g. phenotypic plasticity , multiple life-cycle stages). In addition, horizontal gene transfer (HGT) makes it difficult to define

1422-528: A taxonomic decision at the discretion of cognizant specialists, is not governed by the Codes of Zoological or Botanical Nomenclature, in contrast to the PhyloCode , and contrary to what is done in several other fields, in which the definitions of technical terms, like geochronological units and geopolitical entities, are explicitly delimited. The nomenclatural codes that guide the naming of species, including

1501-517: A traditional biological species. The International Committee on Taxonomy of Viruses has since 1962 developed a universal taxonomic scheme for viruses; this has stabilised viral taxonomy. Most modern textbooks make use of Ernst Mayr 's 1942 definition, known as the Biological Species Concept as a basis for further discussion on the definition of species. It is also called a reproductive or isolation concept. This defines

1580-588: A transboundary collaborative project. It also involved a progression of interaction with local, regional and national authorities. It was finally established in September 1993 covering an area of 392,169 ha (969,070 acres) between the North-eastern Sangha Department and the north-western Likouala Department of Congo. In 1999, the timber company CIB (Congolaise Industrielle du Bois) and the local community joined hands with WCS and

1659-447: A variation on the morphological species concept, a phenetic species, defined as a set of organisms with a similar phenotype to each other, but a different phenotype from other sets of organisms. It differs from the morphological species concept in including a numerical measure of distance or similarity to cluster entities based on multivariate comparisons of a reasonably large number of phenotypic traits. A mate-recognition species

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1738-515: A variety of reasons. Viruses are a special case, driven by a balance of mutation and selection , and can be treated as quasispecies . Biologists and taxonomists have made many attempts to define species, beginning from morphology and moving towards genetics . Early taxonomists such as Linnaeus had no option but to describe what they saw: this was later formalised as the typological or morphological species concept. Ernst Mayr emphasised reproductive isolation, but this, like other species concepts,

1817-463: A very well established infrastructure, skilled personnel, and substantial economic backing. In the past, protection technology had been limited for rangers . However, now, they have been using detectors to catch criminals hurting the park. The rangers of Nouabalé-Ndoki National Park have a group known as 'eco-guards'. The 'eco-guards' are under the supervision of the MFEE (Ministry of Forestry Economy and

1896-438: Is "an entity composed of organisms which maintains its identity from other such entities through time and over space, and which has its own independent evolutionary fate and historical tendencies". This differs from the biological species concept in embodying persistence over time. Wiley and Mayden stated that they see the evolutionary species concept as "identical" to Willi Hennig 's species-as-lineages concept, and asserted that

1975-570: Is a great source of travel information about the park and current travel and weather conditions, and has budget and more upscale itineraries into the park starting from $ 1,799 for 8 days, per person. There are many kinds of species living in the park. The National Geographic Society has observed that the park may have the largest concentration of wild life per square mile of any place in Africa. The most prominent species are primates . There are colobus monkeys (black-and-white colobus, red colobus),

2054-400: Is a group of sexually reproducing organisms that recognise one another as potential mates. Expanding on this to allow for post-mating isolation, a cohesion species is the most inclusive population of individuals having the potential for phenotypic cohesion through intrinsic cohesion mechanisms; no matter whether populations can hybridise successfully, they are still distinct cohesion species if

2133-458: Is a set of organisms adapted to a particular set of resources, called a niche, in the environment. According to this concept, populations form the discrete phenetic clusters that we recognise as species because the ecological and evolutionary processes controlling how resources are divided up tend to produce those clusters. A genetic species as defined by Robert Baker and Robert Bradley is a set of genetically isolated interbreeding populations. This

2212-594: Is a supra-annual seed crop and it is “thought that mast fruiting may have occurred to combat seed production through predator satiation.” Its characteristics are defined as “79% of its stems above 10 cm at breast height and 88% of the basal area.” These seeds are destroyed by beetles. However, they form the major food source for a large number of mammals such as rodents , duikers (cephelophus spp.), pigs ( Putamoechoerus porcus and hylochoerus meinertzhagen ), buffalo ( Syncerus caffer ), elephants, and particularly gorillas. Conservation efforts undertaken are not limited to

2291-404: Is a very lush rainforest . It is home to 24 distinct types of vegetation. However, the dominant vegetation is of Gilbertiodendron dewervei ( G. dewevevri in the upland region and away from water courses in large areas; mixed and swamp forests are also a feature. The forest has many “bais” meaning ”cleared areas”. Over 1000 different plant and tree species have been identified. G. dewevevri

2370-574: Is an intergovernmental organisation in Central Africa. Its goal is to manage the forests of Central Africa in a sustainable manner and is supported by the wildlife trade monitoring network TRAFFIC. The secretariat is based in Yaoundé , Cameroon . Raymond Mbitikon serves as its Executive Secretary. Its four official languages are French, English, Spanish and Portuguese. The Central African Forest Commission's eleven member states are: COMIFAC

2449-414: Is between 8 and 8.7 million. About 14% of these had been described by 2011. All species (except viruses ) are given a two-part name , called a "binomial". The first part of a binomial is the genus to which the species belongs. The second part is called the specific name or the specific epithet (in botanical nomenclature , also sometimes in zoological nomenclature ). For example, Boa constrictor

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2528-414: Is called speciation . Charles Darwin was the first to describe the role of natural selection in speciation in his 1859 book The Origin of Species . Speciation depends on a measure of reproductive isolation , a reduced gene flow. This occurs most easily in allopatric speciation, where populations are separated geographically and can diverge gradually as mutations accumulate. Reproductive isolation

2607-403: Is described formally, in a publication that assigns it a unique scientific name. The description typically provides means for identifying the new species, which may not be based solely on morphology (see cryptic species ), differentiating it from other previously described and related or confusable species and provides a validly published name (in botany) or an available name (in zoology) when

2686-671: Is further weakened by the existence of microspecies , groups of organisms, including many plants, with very little genetic variability, usually forming species aggregates . For example, the dandelion Taraxacum officinale and the blackberry Rubus fruticosus are aggregates with many microspecies—perhaps 400 in the case of the blackberry and over 200 in the dandelion, complicated by hybridisation , apomixis and polyploidy , making gene flow between populations difficult to determine, and their taxonomy debatable. Species complexes occur in insects such as Heliconius butterflies, vertebrates such as Hypsiboas treefrogs, and fungi such as

2765-726: Is hard or even impossible to test. Later biologists have tried to refine Mayr's definition with the recognition and cohesion concepts, among others. Many of the concepts are quite similar or overlap, so they are not easy to count: the biologist R. L. Mayden recorded about 24 concepts, and the philosopher of science John Wilkins counted 26. Wilkins further grouped the species concepts into seven basic kinds of concepts: (1) agamospecies for asexual organisms (2) biospecies for reproductively isolated sexual organisms (3) ecospecies based on ecological niches (4) evolutionary species based on lineage (5) genetic species based on gene pool (6) morphospecies based on form or phenotype and (7) taxonomic species,

2844-403: Is no easy way to tell whether related geographic or temporal forms belong to the same or different species. Species gaps can be verified only locally and at a point of time. One is forced to admit that Darwin's insight is correct: any local reality or integrity of species is greatly reduced over large geographic ranges and time periods. The botanist Brent Mishler argued that the species concept

2923-478: Is not valid, notably because gene flux decreases gradually rather than in discrete steps, which hampers objective delimitation of species. Indeed, complex and unstable patterns of gene flux have been observed in cichlid teleosts of the East African Great Lakes . Wilkins argued that "if we were being true to evolution and the consequent phylogenetic approach to taxa, we should replace it with

3002-400: Is one of the species of the genus Boa , with constrictor being the species' epithet. While the definitions given above may seem adequate at first glance, when looked at more closely they represent problematic species concepts. For example, the boundaries between closely related species become unclear with hybridisation , in a species complex of hundreds of similar microspecies , and in

3081-586: Is similar to Mayr's Biological Species Concept, but stresses genetic rather than reproductive isolation. In the 21st century, a genetic species could be established by comparing DNA sequences. Earlier, other methods were available, such as comparing karyotypes (sets of chromosomes ) and allozymes ( enzyme variants). An evolutionarily significant unit (ESU) or "wildlife species" is a population of organisms considered distinct for purposes of conservation. In palaeontology , with only comparative anatomy (morphology) and histology from fossils as evidence,

3160-434: Is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity . Other ways of defining species include their karyotype , DNA sequence, morphology , behaviour, or ecological niche . In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes

3239-594: Is threatened by hybridisation, but this can be selected against once a pair of populations have incompatible alleles of the same gene, as described in the Bateson–Dobzhansky–Muller model . A different mechanism, phyletic speciation, involves one lineage gradually changing over time into a new and distinct form (a chronospecies ), without increasing the number of resultant species. Horizontal gene transfer between organisms of different species, either through hybridisation , antigenic shift , or reassortment ,

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3318-874: The Congo-Brazzaville , and the Lobéké National Park in Cameroon . In 2012, all three national parks were awarded World Heritage Site -status as the Sangha Trinational . The Nouabalé-Ndoki National Park is managed under a Public-Private Partnership (PPP) agreement, signed in 2013 between the RoC Government and the WCS . The agreement creates the Fondation Nouabalé-Ndoki (FNN), of which WCS has been delegated as

3397-530: The ICZN for animals and the ICN for plants, do not make rules for defining the boundaries of the species. Research can change the boundaries, also known as circumscription, based on new evidence. Species may then need to be distinguished by the boundary definitions used, and in such cases the names may be qualified with sensu stricto ("in the narrow sense") to denote usage in the exact meaning given by an author such as

3476-399: The fly agaric . Natural hybridisation presents a challenge to the concept of a reproductively isolated species, as fertile hybrids permit gene flow between two populations. For example, the carrion crow Corvus corone and the hooded crow Corvus cornix appear and are classified as separate species, yet they can hybridise where their geographical ranges overlap. A ring species is

3555-507: The jaguar ( Panthera onca ) of Latin America or the leopard ( Panthera pardus ) of Africa and Asia. In contrast, the scientific names of species are chosen to be unique and universal (except for some inter-code homonyms ); they are in two parts used together : the genus as in Puma , and the specific epithet as in concolor . A species is given a taxonomic name when a type specimen

3634-406: The "cynical species concept", and arguing that far from being cynical, it usefully leads to an empirical taxonomy for any given group, based on taxonomists' experience. Other biologists have gone further and argued that we should abandon species entirely, and refer to the "Least Inclusive Taxonomic Units" (LITUs), a view that would be coherent with current evolutionary theory. The species concept

3713-573: The Cameroon. This organizational effort has ensured appropriate actions being implemented related to anti-poaching, research and the promotion of tourism to the rain forests. A regular feature of this effort is the meetings that are held at regular intervals of the three park-administrations, as well as the prefects of the three countries. Patrolling of the parks is carried out by regular joint patrols to ensure that poaching, smuggling of ivory and unauthorized fishing and carriage fire arms do not happen in

3792-655: The Environment). With the MFEE/eco-guards, it has been ensured that no illegal human activities take place in the park such as poaching . Apart from the rangers, the local community of the Ba’Aka also provide their local knowledge base inputs to promote sustainable preservation and conservation of the forests in the park. Central African Forest Commission The Central African Forest Commission ( French : Commission des Forêts d'Afrique Centrale , or COMIFAC )

3871-595: The Government of Congo to create an entity that would minimise the negative impacts of logging on the national park. In 2001, the park area was extended with part of a neighbouring logging concession known as the Gouloago triangle getting annexed to this park. The German logging firm surrendered its rights over 100 km (39 sq mi) of the Goualougo Triangle under its lease hold to be merged with

3950-676: The Nouabale-Ndoki National Park alone but also to the two other parks of the tri region, and also the entire Sangha River Tri-national Protected Area that encompasses more than 96% of the land area. The countries who have formed the tri-national organization under a trans-boundary program through the efforts of the World Wide Fund for Nature (WWF) are the Central African Republic, the Congo and

4029-600: The Park Management Unit until 2038. The concept of creating reserved parks emerged in the 1980s with the realization that wild roaming elephants which moved freely in the entire region of the three parks needed to be protected from poachers and the logging industry. Plans to establish the Nouabale-Ndoki National Park were initiated in 1991 by the Wildlife Conservation Society (WCS) and the Government of Congo with support from USAID as

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4108-405: The abbreviation "sp." in the singular or "spp." (standing for species pluralis , Latin for "multiple species") in the plural in place of the specific name or epithet (e.g. Canis sp.). This commonly occurs when authors are confident that some individuals belong to a particular genus but are not sure to which exact species they belong, as is common in paleontology . Authors may also use "spp." as

4187-455: The aim of informing policy-making and to promote better governance and sustainable management of natural resources. This article about a forestry agency is a stub . You can help Misplaced Pages by expanding it . Species A species ( pl. : species) is a population of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring , typically by sexual reproduction . It

4266-570: The amount of hybridisation is insufficient to completely mix their respective gene pools . A further development of the recognition concept is provided by the biosemiotic concept of species. In microbiology , genes can move freely even between distantly related bacteria, possibly extending to the whole bacterial domain. As a rule of thumb, microbiologists have assumed that members of Bacteria or Archaea with 16S ribosomal RNA gene sequences more similar than 97% to each other need to be checked by DNA–DNA hybridisation to decide if they belong to

4345-474: The biological species concept, "the several versions" of the phylogenetic species concept, and the idea that species are of the same kind as higher taxa are not suitable for biodiversity studies (with the intention of estimating the number of species accurately). They further suggested that the concept works for both asexual and sexually-reproducing species. A version of the concept is Kevin de Queiroz 's "General Lineage Concept of Species". An ecological species

4424-505: The biological species concept, a cladistic species does not rely on reproductive isolation – its criteria are independent of processes that are integral in other concepts. Therefore, it applies to asexual lineages. However, it does not always provide clear cut and intuitively satisfying boundaries between taxa, and may require multiple sources of evidence, such as more than one polymorphic locus, to give plausible results. An evolutionary species, suggested by George Gaylord Simpson in 1951,

4503-433: The concept of a chronospecies can be applied. During anagenesis (evolution, not necessarily involving branching), some palaeontologists seek to identify a sequence of species, each one derived from the phyletically extinct one before through continuous, slow and more or less uniform change. In such a time sequence, some palaeontologists assess how much change is required for a morphologically distinct form to be considered

4582-415: The endangered lowland gorillas , chimpanzees , and moustached guenon monkeys . The park plays host to over 300 different bird species. Some of the important species are the eagles , hawks , owls , scavenging vultures , and wading herons . There are also the rare African forest elephant , forest buffalo , leopard , bongo , and blue duiker . Crocodiles and blood-sucking insects are also part of

4661-435: The evidence to support hypotheses about evolutionarily divergent lineages that have maintained their hereditary integrity through time and space. Molecular markers may be used to determine diagnostic genetic differences in the nuclear or mitochondrial DNA of various species. For example, in a study done on fungi , studying the nucleotide characters using cladistic species produced the most accurate results in recognising

4740-450: The forest's species. Herpetofauna studies have been conducted in four specific areas of the park. These studies have established 20 amphibian and 14 reptile species in the southern edge of the park; of these, the frog species are Aubria masako , Amietophrynus regularis , Cryptothylax greshoffii , Hyperolius balfouri , H. brachiofasciatus , Leptopelis brevirostris and L. calcaratus meridionalis . Parrots are also seen in

4819-682: The forests in the park. The protected area, which is part of the Sangha River Tri-National Protected Area (STN) is drained mainly by the Sangha River , a tributary of the Congo River . Part of the forest is still inaccessible and remains unexplored. It is a swampy tropical forest in lowlands that are part of the Congo River drainage basin. This park, along with the other two reserved parks within

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4898-561: The larger Sangha Reserve, is secluded from all economic activity involving roads and human interference, which has resulted in its maintenance as a pristine rain forest. The park lies within the forest area of Congo which forms 11% of the total area of the country. It has been further demarcated into protected areas, cleared areas known as Bai and Yanga, two seasonal zones for use by nomadic people, hunting areas reserved for employees, protected zones that act as prey zones for hunting, hunting zones for local community, and sacred sites. The park has

4977-488: The national park, and also resolved to ban hunting. While logging operations (particularly of two species of the African mahogany for high-grade timber) have taken place in many forest regions in the northern Congo to a limited scale, this park has been free of any such operations. This has resulted in the fact that it has been beneficial to effective preservation and growth of population of the wild life and natural habitat of

5056-483: The numerous fungi species of all the concepts studied. Versions of the phylogenetic species concept that emphasise monophyly or diagnosability may lead to splitting of existing species, for example in Bovidae , by recognising old subspecies as species, despite the fact that there are no reproductive barriers, and populations may intergrade morphologically. Others have called this approach taxonomic inflation , diluting

5135-593: The paper is accepted for publication. The type material is usually held in a permanent repository, often the research collection of a major museum or university, that allows independent verification and the means to compare specimens. Describers of new species are asked to choose names that, in the words of the International Code of Zoological Nomenclature , are "appropriate, compact, euphonious, memorable, and do not cause offence". Books and articles sometimes intentionally do not identify species fully, using

5214-405: The park area. Forest elephants create space by clearing the forest for other animals to move. Horned antelopes with 12 lb (5.4 kg) tops number 100 per 1 km (0.39 sq mi). According to a Pygmy legend, a Congo-based long-necked reptile, known as Mokele-mbembe killed elephants with its huge frontal horn. Mbeli Bai is a specific 3 km (1.2 sq mi) area within

5293-448: The park which is particularly rich in gorillas, with 180 western lowland gorillas reported here. It also contains many monkey species, and nine of them have a population density of 50 per 1 km (0.39 sq mi). The monkey species found here are the black-and–white and red colobus , mustached and crowned guenon, grey-cheeked mangabeys and many others. The trees and plants flourish within this climate. Nouable-Ndoki National Park

5372-674: The person who named the species, while the antonym sensu lato ("in the broad sense") denotes a wider usage, for instance including other subspecies. Other abbreviations such as "auct." ("author"), and qualifiers such as "non" ("not") may be used to further clarify the sense in which the specified authors delineated or described the species. Species are subject to change, whether by evolving into new species, exchanging genes with other species, merging with other species or by becoming extinct. The evolutionary process by which biological populations of sexually-reproducing organisms evolve to become distinct or reproductively isolated as species

5451-492: The purpose of conservation of the parks. The national park has also its several research projects that are financially supported by USAID - CARPE , U.S. Fish & Wildlife Service , Columbus Zoo, and the MacArthur Foundation . Consequent to extensive international support, the park is now considered not only nationally important, but also an internationally recognised conservation area of immense importance, with

5530-590: The reserve park. Visitors can visit the park only in a group as part of an organized tour arranged by professional wild life tour operators. Conservation measures are supported by the German Cooperation of Technical Collaboration (GTC) in Central African Republic and Cameroon, and the World Wildlife Fund for Nature (WWF) and Wildlife Conservation Society (WCS - New York) in the Congo. A trust fund, flush with funds, has also been created for

5609-487: The result of misclassification leading to questions on whether there really are any ring species. The commonly used names for kinds of organisms are often ambiguous: "cat" could mean the domestic cat, Felis catus , or the cat family, Felidae . Another problem with common names is that they often vary from place to place, so that puma, cougar, catamount, panther, painter and mountain lion all mean Puma concolor in various parts of America, while "panther" may also mean

5688-586: The ring. Ring species thus present a difficulty for any species concept that relies on reproductive isolation. However, ring species are at best rare. Proposed examples include the herring gull – lesser black-backed gull complex around the North pole, the Ensatina eschscholtzii group of 19 populations of salamanders in America, and the greenish warbler in Asia, but many so-called ring species have turned out to be

5767-508: The same species. This concept was narrowed in 2006 to a similarity of 98.7%. The average nucleotide identity (ANI) method quantifies genetic distance between entire genomes , using regions of about 10,000 base pairs . With enough data from genomes of one genus, algorithms can be used to categorize species, as for Pseudomonas avellanae in 2013, and for all sequenced bacteria and archaea since 2020. Observed ANI values among sequences appear to have an "ANI gap" at 85–95%, suggesting that

5846-529: The same species. When two species names are discovered to apply to the same species, the older species name is given priority and usually retained, and the newer name considered as a junior synonym, a process called synonymy . Dividing a taxon into multiple, often new, taxa is called splitting . Taxonomists are often referred to as "lumpers" or "splitters" by their colleagues, depending on their personal approach to recognising differences or commonalities between organisms. The circumscription of taxa, considered

5925-506: The species concept and making taxonomy unstable. Yet others defend this approach, considering "taxonomic inflation" pejorative and labelling the opposing view as "taxonomic conservatism"; claiming it is politically expedient to split species and recognise smaller populations at the species level, because this means they can more easily be included as endangered in the IUCN red list and can attract conservation legislation and funding. Unlike

6004-485: The theoretical difficulties. If species were fixed and clearly distinct from one another, there would be no problem, but evolutionary processes cause species to change. This obliges taxonomists to decide, for example, when enough change has occurred to declare that a lineage should be divided into multiple chronospecies , or when populations have diverged to have enough distinct character states to be described as cladistic species. Species and higher taxa were seen from

6083-877: The time of Aristotle until the 18th century as categories that could be arranged in a hierarchy, the great chain of being . In the 19th century, biologists grasped that species could evolve given sufficient time. Charles Darwin 's 1859 book On the Origin of Species explained how species could arise by natural selection . That understanding was greatly extended in the 20th century through genetics and population ecology . Genetic variability arises from mutations and recombination , while organisms themselves are mobile, leading to geographical isolation and genetic drift with varying selection pressures . Genes can sometimes be exchanged between species by horizontal gene transfer ; new species can arise rapidly through hybridisation and polyploidy ; and species may become extinct for

6162-540: The wild. It is difficult to define a species in a way that applies to all organisms. The debate about species concepts is called the species problem. The problem was recognised even in 1859, when Darwin wrote in On the Origin of Species : I was much struck how entirely vague and arbitrary is the distinction between species and varieties. He went on to write: No one definition has satisfied all naturalists; yet every naturalist knows vaguely what he means when he speaks of

6241-606: Was established in March 1999, through the " Declaration of Yaoundé ". In February 2005, the organization adopted a "Convergence Plan for improved management and conservation of forests in Central Africa." Established in 2007, the Central African Forest Observatory (OFAC) is a specialized unit of the COMIFAC, which provides up-to-date and relevant data on the forests and ecosystems of the region, with

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