The gray bat once flourished in caves all over the southeastern United States, but due to human disturbance, gray bat populations declined during the early and mid portion of the 20th century. At one cave alone, the Georgetown Cave in northwestern Alabama, populations declined from 150,000 gray bats to 10,000 by 1969. 95% of gray bats now only roost in 9 caves. M. grisescens has been listed as federally endangered by the U. S. Fish and Wildlife Service since 1976, is protected under the Endangered Species Act. Gray bat populations were estimated at 2 million bats around the time they were placed on the Endangered Species list. By the early 1980s populations of gray bats dropped to 1.6 million. With conservation efforts in place, in 2002, gray bat populations were estimated to have reached 2.3 million. M. grisescens are the largest members of their genus in the eastern United States. Of all U. S. mammals, gray bats are the most cave-dependent. Gray bats have uni-colored dark gray fur on their backs that may bleach to a russet or chestnut brown after the molting season.
Unlike in other species of Myotis, where the wing membrane connects to the toe, in M. grisescens, the wing membrane connects to the ankle. Gray bats weigh between 7 and 16 grams. Gray bats can live up to 17 years. Sexual maturity occurs at about age 2. Although an adult gray bat's forearm measures only about 40–46 mm, Gray bats with forearm lengths of 39.5 mm or less cannot fly. The flight speed of the gray bat, M. grisescens, has been calculated at 20.3 km/h during migration. While foraging, gray bats have been clocked at a flying rate of anywhere between 17 km/h and 39 km/h. Gray bats live in limestone karst areas in Alabama, northern Arkansas, Missouri, northwestern Florida, western Georgia, southern Kansas, southern Indiana and southwestern Illinois, northeastern Oklahoma, northeastern Mississippi, western Virginia, western North Carolina. Gray bats are cave obligate bats, meaning that with few exceptions gray bats only live in caves, not in abandoned barns or other structures as other species of bats are known to do.
Less than 5% of all available caves are inhabited by gray bats. Thus, any disturbance to these cave habitats can be detrimental to gray bat populations. Fall migration occurs in the same order as spring emergence, with females departing first and juveniles leaving last. Gray bats may migrate as far as 500 km from summer caves to reach hibernation caves; the annual activity period of gray bats is April to October, though female gray bats enter hibernation in September. After arriving at winter caves, copulation occurs. Females enter hibernation, while males may remain active for a few more weeks. Males use this extra time before entering hibernation to replenish fat reserves used during breeding. Males begin hibernation by early November. During hibernation, the body temperature of gray bats drops close to the ambient temperature, allowing the body to conserve fat; these fat reserves must last the six months of hibernation and spring migration. Adult mortality is high during spring migration, as bats that do not have sufficient fat reserves have difficulties surviving the stress and energy-intensive migration period.
After copulation, females store sperm in their uteri, ovulating only after they have emerged from hibernation. Gestation in gray bats lasts 60 to 70 days, with birth occurring in early June. Gray bat females give birth to one offspring per clutch, thus giving birth to one offspring per year. Therefore, gray bats demonstrate an iteroparous life-history strategy; the young clings to the mother for about a week, after which they remain in the maternity colony until they are able to fly. Most young take flight by four weeks of age. Annual molting occurs between early June and early August, during which gray bats eat larger amounts of hair than at other times during the activity season. During grooming, gray bats ingest ectoparasites such as chiggers that live in their fur. Gray bats are believed to groom extensively before beginning their nightly hunt, they spend the nighttime hours hunting and digesting. Although the habitat range of the gray bat incorporates much of the southeastern United States, the largest summer colonies of gray bats are located within the Guntersville Reservoir.
This reservoir, found in northeastern Alabama, contains the Sauta and Hambrick caves which can accommodate over 100,000 gray bats. Gray bats use caves differently at different times of the year. For example, populations of gray bats tend to cluster in caves known as hibernacula to prepare for winter hibernation. In contrast, their populations disperse during the spring to establish sexually segregated colonies. Females form maternity colonies; these bachelor colonies house yearlings of both sexes. Gray bats utilize a third type of cave, the dispersal cave, which they inhabit only during migration. For their hibernacula, gray bats prefer deep, cool caves with average temperatures ranging from 5 to 11 °C. Multiple entrances and good airflow comprise the other characteristics that gray bats find desirable. Winter hibernacula are cold when gray bats begin arriving in September. Summer caves are located along rivers and have temperatures that range from 14 to 25 °C. Summer caves cont
International Union for Conservation of Nature
The International Union for Conservation of Nature is an international organization working in the field of nature conservation and sustainable use of natural resources. It is involved in data gathering and analysis, field projects and education. IUCN's mission is to "influence and assist societies throughout the world to conserve nature and to ensure that any use of natural resources is equitable and ecologically sustainable". Over the past decades, IUCN has widened its focus beyond conservation ecology and now incorporates issues related to sustainable development in its projects. Unlike many other international environmental organisations, IUCN does not itself aim to mobilize the public in support of nature conservation, it tries to influence the actions of governments and other stakeholders by providing information and advice, through building partnerships. The organization is best known to the wider public for compiling and publishing the IUCN Red List of Threatened Species, which assesses the conservation status of species worldwide.
IUCN has a membership of over 1400 non-governmental organizations. Some 16,000 scientists and experts participate in the work of IUCN commissions on a voluntary basis, it employs 1000 full-time staff in more than 50 countries. Its headquarters are in Switzerland. IUCN has observer and consultative status at the United Nations, plays a role in the implementation of several international conventions on nature conservation and biodiversity, it was involved in establishing the World Wide Fund for Nature and the World Conservation Monitoring Centre. In the past, IUCN has been criticized for placing the interests of nature over those of indigenous peoples. In recent years, its closer relations with the business sector have caused controversy. IUCN was established in 1948, it was called the International Union for the Protection of Nature and the World Conservation Union. Establishment IUCN was established on 5 October 1948, in Fontainebleau, when representatives of governments and conservation organizations signed a formal act constituting the International Union for the Protection of Nature.
The initiative to set up the new organisation came from UNESCO and from its first Director General, the British biologist Julian Huxley. The objectives of the new Union were to encourage international cooperation in the protection of nature, to promote national and international action and to compile and distribute information. At the time of its founding IUPN was the only international organisation focusing on the entire spectrum of nature conservation Early years: 1948–1956 IUPN started out with 65 members, its secretariat was located in Brussels. Its first work program focused on saving species and habitats and applying knowledge, advancing education, promoting international agreements and promoting conservation. Providing a solid scientific base for conservation action was the heart of all activities. IUPN and UNESCO were associated, they jointly organized the 1949 Conference on Protection of Nature. In preparation for this conference a list of gravely endangered species was drawn up for the first time, a precursor of the IUCN Red List of Threatened Species.
In the early years of its existence IUCN depended entirely on UNESCO funding and was forced to temporarily scale down activities when this ended unexpectedly in 1954. IUPN was successful in engaging prominent scientists and identifying important issues such as the harmful effects of pesticides on wildlife but not many of the ideas it developed were turned into action; this was caused by unwillingness to act on the part of governments, uncertainty about the IUPN mandate and lack of resources. In 1956, IUPN changed its name to International Union for Conservation of Nature and Natural Resources. Increased profile and recognition: 1956–1965 In the 1950s and 1960s Europe entered a period of economic growth and formal colonies became independent. Both developments had impact on the work of IUCN. Through the voluntary involvement of experts in its Commissions IUCN was able to get a lot of work done while still operating on a low budget, it established links with the Council of Europe. In 1961, at the request of United Nations Economic and Social Council, the United Nations Economic and Social Council, IUCN published the first global list of national parks and protected areas which it has updated since.
IUCN's best known publication, the Red Data Book on the conservation status of species, was first published in 1964. IUCN began to play a part in the development of international treaties and conventions, starting with the African Convention on the Conservation of Nature and Natural Resources. Environmental law and policy making became a new area of expertise. Africa was the focus of many of the early IUCN conservation field projects. IUCN supported the ‘Yellowstone model’ of protected area management, which restricted human presence and activity in order to protect nature. IUCN and other conservation organisations were criticized for protecting nature against people rather than with people; this model was also applied in Africa and played a role in the decision to remove the Maasai people from Serengeti National Park and the Ngorongoro Conservation Area. To establish a stable financial basis for its work, IUCN participated in setting up the World Wildlife Fund
Extinct in the wild
A species, extinct in the wild is one, categorized by the International Union for Conservation of Nature as known only by living members kept in captivity or as a naturalized population outside its historic range due to massive habitat loss. Examples of species and subspecies that are extinct in the wild include: Alagoas curassow Beloribitsa Black soft-shell turtle Cachorrito de charco palmal Escarpment cycad Franklinia Golden skiffia Guam kingfisher Guam rail Hawaiian crow or ʻalalā Kihansi spray toad Oahu deceptor bush cricket Pedder galaxias Père David's deer Scimitar oryx Socorro dove Socorro isopod South China tiger Spix's macaw Wyoming toad The Pinta Island tortoise had only one living individual, named Lonesome George, until his death in June 2012; the tortoise was believed to be extinct in the mid-20th century, until Hungarian malacologist József Vágvölgyi spotted Lonesome George on the Galapagos island of Pinta on 1 December 1971. Since Lonesome George has been a powerful symbol for conservation efforts in general and for the Galapagos Islands in particular.
With his death on 24 June 2012, the subspecies is again believed to be extinct. With the discovery of 17 hybrid Pinta tortoises located at nearby Wolf Volcano a plan has been made to attempt to breed the subspecies back into a pure state. Not all species that are extinct in the wild are rare. For example, Ameca splendens, though extinct in the wild, was a popular fish among aquarists for some time, but hobbyist stocks have declined quite a lot more placing its survival in jeopardy. However, the ultimate purpose of preserving biodiversity is to maintain ecological function; when a species exists only in captivity, it is ecologically extinct. Reintroduction is the deliberate release of species into the wild, from captivity or relocated from other areas where the species survives; this may be an option for certain species that are extinct in the wild. However, it may be difficult to reintroduce EW species into the wild if their natural habitats were restored, because survival techniques, which are passed from parents to offspring during parenting, may be lost.
While conservation efforts may preserve some of the genetics of a species, the species may never recover due to the loss of the natural memetics of the species. An example of a successful reintroduction of an EW species is Przewalski's horse, which as of 2018 is considered to be an Endangered species, following reintroduction started in the 1990s. IUCN Red List extinct in the wild species for a list by taxonomy Category:IUCN Red List extinct in the wild species for an alphabetical list Extinction List of Extinct in the Wild species as identified by the IUCN Red List of Threatened Species
In biology, extinction is the termination of an organism or of a group of organisms a species. The moment of extinction is considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point; because a species' potential range may be large, determining this moment is difficult, is done retrospectively. This difficulty leads to phenomena such as Lazarus taxa, where a species presumed extinct abruptly "reappears" after a period of apparent absence. More than 99 percent of all species, amounting to over five billion species, that lived on Earth are estimated to have died out. Estimates on the number of Earth's current species range from 10 million to 14 million, of which about 1.2 million have been documented and over 86 percent have not yet been described. In 2016, scientists reported that 1 trillion species are estimated to be on Earth with only one-thousandth of one percent described. Through evolution, species arise through the process of speciation—where new varieties of organisms arise and thrive when they are able to find and exploit an ecological niche—and species become extinct when they are no longer able to survive in changing conditions or against superior competition.
The relationship between animals and their ecological niches has been established. A typical species becomes extinct within 10 million years of its first appearance, although some species, called living fossils, survive with no morphological change for hundreds of millions of years. Mass extinctions are rare events. Only have extinctions been recorded and scientists have become alarmed at the current high rate of extinctions. Most species that become extinct are never scientifically documented; some scientists estimate that up to half of presently existing plant and animal species may become extinct by 2100. A 2018 report indicated that the phylogenetic diversity of 300 mammalian species erased during the human era since the Late Pleistocene would require 5 to 7 million years to recover. A dagger symbol placed next to the name of a species or other taxon indicates its status as extinct. A species is extinct. Extinction therefore becomes a certainty when there are no surviving individuals that can reproduce and create a new generation.
A species may become functionally extinct when only a handful of individuals survive, which cannot reproduce due to poor health, sparse distribution over a large range, a lack of individuals of both sexes, or other reasons. Pinpointing the extinction of a species requires a clear definition of that species. If it is to be declared extinct, the species in question must be uniquely distinguishable from any ancestor or daughter species, from any other related species. Extinction of a species plays a key role in the punctuated equilibrium hypothesis of Stephen Jay Gould and Niles Eldredge. In ecology, extinction is used informally to refer to local extinction, in which a species ceases to exist in the chosen area of study, but may still exist elsewhere; this phenomenon is known as extirpation. Local extinctions may be followed by a replacement of the species taken from other locations. Species which are not extinct are termed extant; those that are extant but threatened by extinction are referred to as threatened or endangered species.
An important aspect of extinction is human attempts to preserve critically endangered species. These are reflected by the creation of the conservation status "extinct in the wild". Species listed under this status by the International Union for Conservation of Nature are not known to have any living specimens in the wild, are maintained only in zoos or other artificial environments; some of these species are functionally extinct, as they are no longer part of their natural habitat and it is unlikely the species will be restored to the wild. When possible, modern zoological institutions try to maintain a viable population for species preservation and possible future reintroduction to the wild, through use of planned breeding programs; the extinction of one species' wild population can have knock-on effects, causing further extinctions. These are called "chains of extinction"; this is common with extinction of keystone species. A 2018 study indicated that the 6th mass extinction started in the Late Pleistocene could take up to 5 to 7 million years to restore 2.5 billion years of unique mammal diversity to what it was before the human era.
Extinction of a parent species where daughter species or subspecies are still extant is called pseudoextinction or phyletic extinction. The old taxon vanishes, transformed into a successor, or split into more than one. Pseudoextinction is difficult to demonstrate unless one has a strong chain of evidence linking a living species to members of a pre-existing species. For example, it is sometimes claimed that the extinct Hyracotherium, an early horse that shares a common ancestor with the modern horse, is pseudoextinct, rather than extinct, because there are several extant species of Equus, including zebra and donkey. However, as fossil species leave no genetic material behind, one cannot say whether Hyracotherium evolved into more modern horse species or evolved from a common ancestor with modern horses. Pseudoextinction is much easier to demonstrate for larger taxonomic groups; the coelacanth, a fish related to lungfish and tetrapods, was consi
Lists of organisms by population
This is a collection of lists of organisms by their population. While most of the numbers are estimates, they have been made by the experts in their fields. Species population is a science falling under the purview of population biogeography. Individuals are counted by census. More than 99 percent of all species, amounting to over five billion species, that lived on Earth are estimated to be extinct. Estimates on the number of Earth's current species range from 10 million to 14 million, of which about 1.2 million have been documented and over 86 percent have not yet been described. According to another study, the number of described species has been estimated at 1,899,587. 2000–2009 saw 17,000 species described per year. The total number of undescribed organisms is unknown, but marine microbial species alone could number 20,000,000; the number of quantified species will ipso facto always lag behind the number of described species, species contained in these lists tend to be on the K side of the r/K selection continuum.
More in May 2016, scientists reported that 1 trillion species are estimated to be on Earth with only one-thousandth of one percent described. The total number of related DNA base pairs on Earth is estimated at 5.0 x 1037 and weighs 50 billion tonnes. In comparison, the total mass of the biosphere has been estimated to be as much as 4 TtC. In July 2016, scientists reported identifying a set of 355 genes from the Last Universal Common Ancestor of all organisms living on Earth, it is estimated that the most numerous bacteria are of a species of the Pelagibacterales clade Pelagibacter ubique, the most numerous viruses are bacteriophages infecting these species. It is estimated; the Deep Carbon Observatory has been exploring living forms in the interior of the Earth. "Life in deep Earth totals 15 to 23 billion tons of carbon". Mammals by population Artiodactyla Carnivora Cetacea Chiroptera Perissodactyla Primates Birds by population Anseriformes Apodiformes Caprimulgiformes Charadriiformes Ciconiiformes Columbiformes Coraciiformes Cuculiformes Falconiformes Galliformes Gaviiformes Gruiformes Passeriformes Pelecaniformes Phoenicopteriformes Piciformes Podicipediformes Procellariiformes Psittaciformes Sphenisciformes Strigiformes Struthioniformes Tinamiformes Trogoniformes There are an estimated 3,500,000,000,000 fish in the ocean.
In the last 100 years, the number of small fish – such as pilchards, anchovies and sardines – has more than doubled. It is caused by a major decline in big ‘predator fish’ such as sharks and cod due to over-fishing. Recent figures indicate that there are more than 1.4 billion insects for each human on the planet An article in The New York Times claimed that the world holds 300 pounds of insects for every pound of humans. Ants have colonised every landmass on Earth, their population is estimated as 1016–1017. According to NASA in 2005, there were over 400 billion trees on our globe. However, more in 2015, using better methods, the global tree count has been estimated at about 3 trillion. Other studies show that the Amazonian forest alone yields 430 billion trees. Extrapolations from data compiled over a period of 10 years suggest that greater Amazonia, which includes the Amazon Basin and the Guiana Shield, harbors around 390 billion individual trees
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. While these definitions may seem adequate, when looked at more they represent problematic species concepts. For example, the boundaries between related species become unclear with hybridisation, in a species complex of hundreds of similar microspecies, in a ring species. Among organisms that reproduce only asexually, the concept of a reproductive species breaks down, each clone is a microspecies. All species are given a two-part name, a "binomial"; the first part of a binomial is the genus.
The second part is called the specific epithet. For example, Boa constrictor is one of four species of the genus Boa. None of these is satisfactory definitions, but scientists and conservationists need a species definition which allows them to work, regardless of the theoretical difficulties. If species were fixed and distinct from one another, there would be no problem, but evolutionary processes cause species to change continually, to grade into one another. Species were seen from the time of Aristotle until the 18th century as fixed kinds that could be arranged in a hierarchy, the great chain of being. In the 19th century, biologists grasped. Charles Darwin's 1859 book The Origin of Species explained how species could arise by natural selection; that understanding was 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. Viruses are a special case, driven by a balance of mutation and selection, 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 formalised as the typological or morphological species concept. Ernst Mayr emphasised reproductive isolation, but this, like other species concepts, is hard or impossible to test. 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, the philosopher of science John Wilkins counted 26. Wilkins further grouped the species concepts into seven basic kinds of concepts: agamospecies for asexual organisms biospecies for reproductively isolated sexual organisms ecospecies based on ecological niches evolutionary species based on lineage genetic species based on gene pool morphospecies based on form or phenotype and taxonomic species, a species as determined by a taxonomist.
A typological species is a group of organisms in which individuals conform to certain fixed properties, so that pre-literate people recognise the same taxon as do modern taxonomists. The clusters of variations or phenotypes within specimens would differentiate the species; this method was used as a "classical" method of determining species, such as with Linnaeus early in evolutionary theory. However, different phenotypes are not different species. Species named in this manner are called morphospecies. In the 1970s, Robert R. Sokal, Theodore J. Crovello and Peter Sneath proposed a variation on this, 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 is a group of sexually reproducing organisms that recognize 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. A further development of the recognition concept is provided by the biosemiotic concept of species. In microbiology, genes can move even between distantly related bacteria extending to the whole bacterial domain; as a rule of thumb, microbiologists have assumed that kinds 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 the same species or not. This concept was narrowed in 2006 to a similarity of 98.7%. DNA-DNA hybri
An endangered species is a species, categorized as likely to become extinct. Endangered, as categorized by the International Union for Conservation of Nature Red List, is the second most severe conservation status for wild populations in the IUCN's schema after Critically Endangered. In 2012, the IUCN Red List featured 3,079 animal and 2,655 plant species as endangered worldwide; the figures for 1998 were 1,102 and 1,197. Many nations have laws that protect conservation-reliant species: for example, forbidding hunting, restricting land development or creating preserves. Population numbers and species' conservation status can be found at the lists of organisms by population; the conservation status of a species indicates the likelihood. Many factors are considered; the IUCN Red List of Threatened Species is the best-known worldwide conservation status listing and ranking system. Over 50% of the world's species are estimated to be at risk of extinction. Internationally, 199 countries have signed an accord to create Biodiversity Action Plans that will protect endangered and other threatened species.
In the United States, such plans are called Species Recovery Plans. Though labelled a list, the IUCN Red List is a system of assessing the global conservation status of species that includes "Data Deficient" species – species for which more data and assessment is required before their status may be determined – as well species comprehensively assessed by the IUCN's species assessment process; those species of "Near Threatened" and "Least Concern" status have been assessed and found to have robust and healthy populations, though these may be in decline. Unlike their more general use elsewhere, the List uses the terms "endangered species" and "threatened species" with particular meanings: "Endangered" species lie between "Vulnerable" and "Critically Endangered" species, while "Threatened" species are those species determined to be Vulnerable, Endangered or Critically Endangered; the IUCN categories, with examples of animals classified by them, include: Extinct no remaining individuals of the species Extinct in the wild Captive individuals survive, but there is no free-living, natural population.
Critically endangered Faces an high risk of extinction in the immediate future. Endangered Faces a high risk of extinction in the near future. Vulnerable Faces a high risk of endangerment in the medium term. Near-threatened May be considered threatened in the near future. Least concern No immediate threat to species' survival. A) Reduction in population size based on any of the following: An observed, inferred or suspected population size reduction of ≥ 70% over the last 10 years or three generations, whichever is the longer, where the causes of the reduction are reversible AND understood AND ceased, based on any of the following: direct observation an index of abundance appropriate for the taxon a decline in area of occupancy, extent of occurrence or quality of habitat actual or potential levels of exploitation the effects of introduced taxa, pathogens, competitors or parasites. An observed, inferred or suspected population size reduction of ≥ 50% over the last 10 years or three generations, whichever is the longer, where the reduction or its causes may not have ceased OR may not be understood OR may not be reversible, based on any of to under A1.
A population size reduction of ≥ 50%, projected or suspected to be met within the next 10 years or three generations, whichever is the longer, based on any of to under A1. An observed, inferred, projected or suspected population size reduction of ≥ 50% over any 10 year or three generation period, whichever is longer, where the time period must include both the past and the future, where the reduction or its causes may not have ceased OR may not be understood OR may not be reversible, based on any of to under A1. B) Geographic range in the form of either B1 OR B2 OR both: Extent of occurrence estimated to be less than 5,000 km², estimates indicating at least two of a-c: Severely fragmented or known to exist at no more than five locations. Continuing decline, observed or projected, in any of the following: extent of occurrence area of occupancy area, extent or quality of habitat number of locations or subpopulations number of mature individuals Extreme fluctuations in any of the following: extent of occurrence area of occupancy number of locations or subpopulations number of mature individuals Area of occupancy estimated to be less than 500 km², estimates indicating at least two of a-c: Severely fragmented or known to exist at no more than five locations.
Continuing decline, observed or projected, in any of the following: extent of occurrence area of occupancy area, extent or quality of habitat number of locations or subpopulations number of mature individuals Extreme fluctuations in any of the following: extent of occurrence area of occupancy number of locations or subpopulations number of mature individualsC) Population estimated to number fewer than 2,500 mature individuals and either: An estimated continuing decline of at least 20% within five years or two generations, whichever is longer, OR A continuing decline, projected