100-486: Revueltosaurus ("Revuelto lizard") is an extinct genus of suchian pseudosuchian from Late Triassic (late Carnian to middle Norian stage) deposits of New Mexico , Arizona and North Carolina , United States. Many specimens, mostly teeth, have been assigned to Revueltosaurus over the years. Currently, three species are included in this genus, all of which were originally thought to represent monospecific genera of basal ornithischian dinosaurs . Revueltosaurus
200-438: A food chain who lose their prey. "Species coextinction is a manifestation of one of the interconnectednesses of organisms in complex ecosystems ... While coextinction may not be the most important cause of species extinctions, it is certainly an insidious one." Coextinction is especially common when a keystone species goes extinct. Models suggest that coextinction is the most common form of biodiversity loss . There may be
300-657: A nautilus to the Royal Society that was more than two feet in diameter, and morphologically distinct from any known living species. Hooke theorized that this was simply because the species lived in the deep ocean and no one had discovered them yet. While he contended that it was possible a species could be "lost", he thought this highly unlikely. Similarly, in 1695, Sir Thomas Molyneux published an account of enormous antlers found in Ireland that did not belong to any extant taxa in that area. Molyneux reasoned that they came from
400-415: A species or a population is the variety of genetic information in its living members. A large gene pool (extensive genetic diversity ) is associated with robust populations that can survive bouts of intense selection . Meanwhile, low genetic diversity (see inbreeding and population bottlenecks ) reduces the range of adaptions possible. Replacing native with alien genes narrows genetic diversity within
500-436: A viable population for species preservation and possible future reintroduction to the wild, through use of carefully planned breeding programs . The extinction of one species' wild population can have knock-on effects, causing further extinctions. These are also called "chains of extinction". This is especially common with extinction of keystone species . A 2018 study indicated that the sixth mass extinction started in
600-474: A Lazarus species when extant individuals were described in 2019. Attenborough's long-beaked echidna ( Zaglossus attenboroughi ) is an example of a Lazarus species from Papua New Guinea that had last been sighted in 1962 and believed to be possibly extinct, until it was recorded again in November 2023. Some species currently thought to be extinct have had continued speculation that they may still exist, and in
700-495: A cascade of coextinction across the trophic levels . Such effects are most severe in mutualistic and parasitic relationships. An example of coextinction is the Haast's eagle and the moa : the Haast's eagle was a predator that became extinct because its food source became extinct. The moa were several species of flightless birds that were a food source for the Haast's eagle. Extinction as
800-429: A common ancestor with modern horses. Pseudoextinction is much easier to demonstrate for larger taxonomic groups. A Lazarus taxon or Lazarus species refers to instances where a species or taxon was thought to be extinct, but was later rediscovered. It can also refer to instances where large gaps in the fossil record of a taxon result in fossils reappearing much later, although the taxon may have ultimately become extinct at
900-399: A fact that was accepted by most scientists. The primary debate focused on whether this turnover caused by extinction was gradual or abrupt in nature. Cuvier understood extinction to be the result of cataclysmic events that wipe out huge numbers of species, as opposed to the gradual decline of a species over time. His catastrophic view of the nature of extinction garnered him many opponents in
1000-434: A female householder with no husband present, 41.6% were non-families, and 33.7% of all households were made up of individuals. The average household size was 2.28 and the average family size was 2.94. The median age was 43.0 years. The median income for a household in the county was $ 52,696 and the median income for a family was $ 64,041. Males had a median income of $ 41,703 versus $ 39,215 for females. The per capita income for
1100-708: A higher risk of extinction and die out faster than less sexually dimorphic species, the least sexually dimorphic species surviving for millions of years while the most sexually dimorphic species die out within mere thousands of years. Earlier studies based on counting the number of currently living species in modern taxa have shown a higher number of species in more sexually dimorphic taxa which have been interpreted as higher survival in taxa with more sexual selection, but such studies of modern species only measure indirect effects of extinction and are subject to error sources such as dying and doomed taxa speciating more due to splitting of habitat ranges into more small isolated groups during
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#17329353526271200-405: A large range, a lack of individuals of both sexes (in sexually reproducing species), or other reasons. Pinpointing the extinction (or pseudoextinction ) 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, and from any other closely related species. Extinction of
1300-592: A later point. The coelacanth , a fish related to lungfish and tetrapods , is an example of a Lazarus taxon that was known only from the fossil record and was considered to have been extinct since the end of the Cretaceous Period . In 1938, however, a living specimen was found off the Chalumna River (now Tyolomnqa) on the east coast of South Africa. Calliostoma bullatum , a species of deepwater sea snail originally described from fossils in 1844 proved to be
1400-587: A mathematical model that falls in all positions. By contrast, conservation biology uses the extinction vortex model to classify extinctions by cause. When concerns about human extinction have been raised, for example in Sir Martin Rees ' 2003 book Our Final Hour , those concerns lie with the effects of climate change or technological disaster. Human-driven extinction started as humans migrated out of Africa more than 60,000 years ago. Currently, environmental groups and some governments are concerned with
1500-456: A natural part of the evolutionary process. Only recently 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
1600-441: A new mega-predator or by transporting animals and plants from one part of the world to another. Such introductions have been occurring for thousands of years, sometimes intentionally (e.g. livestock released by sailors on islands as a future source of food) and sometimes accidentally (e.g. rats escaping from boats). In most cases, the introductions are unsuccessful, but when an invasive alien species does become established,
1700-610: A population a higher chance in the short term of surviving an adverse change in conditions. Effects that cause or reward a loss in genetic diversity can increase the chances of extinction of a species. Population bottlenecks can dramatically reduce genetic diversity by severely limiting the number of reproducing individuals and make inbreeding more frequent. Extinction sometimes results for species evolved to specific ecologies that are subjected to genetic pollution —i.e., uncontrolled hybridization , introgression and genetic swamping that lead to homogenization or out-competition from
1800-407: A race of animals to become extinct. A series of fossils were discovered in the late 17th century that appeared unlike any living species. As a result, the scientific community embarked on a voyage of creative rationalization, seeking to understand what had happened to these species within a framework that did not account for total extinction. In October 1686, Robert Hooke presented an impression of
1900-502: A reduction in agricultural productivity. Furthermore, increased erosion contributes to poorer water quality by elevating the levels of sediment and pollutants in rivers and streams. Habitat degradation through toxicity can kill off a species very rapidly, by killing all living members through contamination or sterilizing them. It can also occur over longer periods at lower toxicity levels by affecting life span, reproductive capacity, or competitiveness. Habitat degradation can also take
2000-486: A result of climate change has been confirmed by fossil studies. Particularly, the extinction of amphibians during the Carboniferous Rainforest Collapse , 305 million years ago. A 2003 review across 14 biodiversity research centers predicted that, because of climate change, 15–37% of land species would be "committed to extinction" by 2050. The ecologically rich areas that would potentially suffer
2100-479: A species (or replacement by a daughter species) plays a key role in the punctuated equilibrium hypothesis of Stephen Jay Gould and Niles Eldredge . In ecology , extinction is sometimes used informally to refer to local extinction , in which a species ceases to exist in the chosen area of study, despite still existing elsewhere. Local extinctions may be made good by the reintroduction of individuals of that species taken from other locations; wolf reintroduction
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#17329353526272200-439: A species may come suddenly when an otherwise healthy species is wiped out completely, as when toxic pollution renders its entire habitat unliveable; or may occur gradually over thousands or millions of years, such as when a species gradually loses out in competition for food to better adapted competitors. Extinction may occur a long time after the events that set it in motion, a phenomenon known as extinction debt . Assessing
2300-404: A species or group of species. "Just as each species is unique", write Beverly and Stephen C. Stearns , "so is each extinction ... the causes for each are varied—some subtle and complex, others obvious and simple". Most simply, any species that cannot survive and reproduce in its environment and cannot move to a new environment where it can do so, dies out and becomes extinct. Extinction of
2400-518: A subsequent report, IPBES listed unsustainable fishing, hunting and logging as being some of the primary drivers of the global extinction crisis. In June 2019, one million species of plants and animals were at risk of extinction. At least 571 plant species have been lost since 1750, but likely many more. The main cause of the extinctions is the destruction of natural habitats by human activities, such as cutting down forests and converting land into fields for farming. A dagger symbol (†) placed next to
2500-526: Is Santa Fe , the state capital. Santa Fe County includes the Santa Fe metropolitan statistical area , which is also included in the Albuquerque–Santa Fe–Las Vegas combined statistical area . According to the U.S. Census Bureau , the county has a total area of 1,911 square miles (4,950 km ), of which 1,909 square miles (4,940 km ) is land and 1.5 square miles (3.9 km ) (0.08%)
2600-417: Is a pseudosuchian. According to William Parker, "we have pretty much erased the record of Triassic ornithischian dinosaurs from North America, Europe and worldwide, except for South America." His co-author Randall Irmis said, "because the teeth look like those we know from herbivorous ornithischians, people assigned them to the dinosaurs. We think we've shown that you can't rely on the dentition to determine what
2700-401: Is a pseudosuchian. In response to the report that R. callenderi was not an ornithischian, Heckert (2005) erected a new genus for R. hunti , Krzyzanowskisaurus . He suggested that the denticulated shelf on the teeth represented a cingulum . Irmis et al. (2007) and Nesbitt et al. (2007) synonymized Krzyzanowskisaurus with Revueltosaurus , and argued that this condition of the dentation
2800-517: Is also evidence to suggest that this event was preceded by another mass extinction, known as Olson's Extinction . The Cretaceous–Paleogene extinction event (K–Pg) occurred 66 million years ago, at the end of the Cretaceous period; it is best known for having wiped out non-avian dinosaurs , among many other species. According to a 1998 survey of 400 biologists conducted by New York 's American Museum of Natural History , nearly 70% believed that
2900-410: Is an autapomorphy of R. hunti and is not homologous to the ornithischian asymmetric swelling or a mammalian cingulum. R. olseni was named by Hunt and Lucas in 1994 as a basal ornithischian, under the generic name Pekinosaurus . The generic name honors Pekin, North Carolina , where its type series was collected. The specific name honours the paleontologist Paul E. Olsen. Hunt and Lucas named
3000-477: Is an early dinosaur, which casts doubt on all the ornithischians from the Triassic of North America". Nearly complete specimens of R. callenderi were tested in a broad phylogenetic analysis of basal archosaurs for the first time when Sterling J. Nesbitt included the specimens PEFO 34561 and PEFO 34269 (a complete and a nearly complete skeleton, respectively) in his 2011 phylogenetic analysis. Revueltosaurus
3100-444: Is an example of this. Species that are not globally extinct are termed extant . Those species that are extant, yet are threatened with extinction, are referred to as threatened or endangered species . Currently, 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" (EW) . Species listed under this status by
Revueltosaurus - Misplaced Pages Continue
3200-585: 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 , which was 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 typically leave no genetic material behind, one cannot say whether Hyracotherium evolved into more modern horse species or merely evolved from
3300-417: Is estimated as 100 to 1,000 times "background" rates (the average extinction rates in the evolutionary time scale of planet Earth), faster than at any other time in human history, while future rates are likely 10,000 times higher. However, some groups are going extinct much faster. Biologists Paul R. Ehrlich and Stuart Pimm , among others, contend that human population growth and overconsumption are
3400-520: Is extremely similar to R. callenderi , however they found that Pekinosaurus teeth have slightly different proportions and outline than R. callenderi . They provided a differential diagnosis for that species and referred it to Revueltosaurus , under the new combination R. olseni . All species of Revueltosaurus were thought to represent monospecific genera of basal ornithischian dinosaurs based on their teeth . New discoveries of skeletal material of R. callenderi have suggested that Revueltosaurus
3500-479: Is known and a full description of it is being prepared. R. hunti was named by Andrew B. Heckert in 2002 as a basal ornithischian. The specific name honours the paleontologist Adrian P. Hunt for his contributions to the Triassic paleontology. It is known from the holotype NMMNH P-29357, a nearly complete tooth crown, the paratypes NMMNH P-29358-9 and topotypes P-29347-54 (and aff. R. hunti specimens NMMNH P-29355, P-29359) which were collected in
3600-592: Is the destruction of ocean floors by bottom trawling . Diminished resources or introduction of new competitor species also often accompany habitat degradation. Global warming has allowed some species to expand their range, bringing competition to other species that previously occupied that area. Sometimes these new competitors are predators and directly affect prey species, while at other times they may merely outcompete vulnerable species for limited resources. Vital resources including water and food can also be limited during habitat degradation, leading to extinction. In
3700-525: Is the most important determinant of genus extinction at background rates but becomes increasingly irrelevant as mass extinction arises. Limited geographic range is a cause both of small population size and of greater vulnerability to local environmental catastrophes. Extinction rates can be affected not just by population size, but by any factor that affects evolvability , including balancing selection , cryptic genetic variation , phenotypic plasticity , and robustness . A diverse or deep gene pool gives
3800-457: Is the termination of a taxon by the death of its last member . A taxon may become functionally extinct before the death of its last member if it loses the capacity to reproduce and recover. Because a species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively. This difficulty leads to phenomena such as Lazarus taxa , where a species presumed extinct abruptly "reappears" (typically in
3900-606: Is water. It is the fifth-smallest county in New Mexico by area. The highest point in the county is the summit of Santa Fe Baldy at 3,847 meters (12,621 ft). It is drained by the Rio Grande and several of its small tributaries. As of the 2000 census , The population density was 68 people per square mile (26 people/km ). There were 57,701 housing units at an average density of 30 per square mile (12/km ). There were 52,482 households, out of which 30.4% had children under
4000-511: The Placerias /Downs quarry near St Johns, Arizona, to Tecovasaurus . Heckert listed the referred specimens CMNH PR1697-1699 originally described by Padian (1990) and the topotypes NMMNH P-4960, P-16573, P-33783-798. Four teeth were referred to aff. Revueltosaurus callenderi (NMMNH P-17362, P-17382 and P-17187). R. callenderi is known to date only from the Revueltian (early-mid Norian,
4100-474: The International Union for Conservation of Nature (IUCN) are not known to have any living specimens in the wild and 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 ever be restored to the wild. When possible, modern zoological institutions try to maintain
Revueltosaurus - Misplaced Pages Continue
4200-477: The Late Pleistocene could take up to 5 to 7 million years to restore 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. Effectively, the old taxon vanishes, transformed ( anagenesis ) into a successor, or split into more than one ( cladogenesis ). Pseudoextinction
4300-619: The fossil record ) after a period of apparent absence. More than 99% of all species that ever lived on Earth , amounting to over five billion species, are estimated to have died out. It is estimated that there are currently around 8.7 million species of eukaryotes globally, and possibly many times more if microorganisms , such as bacteria , are included. Notable extinct animal species include non-avian dinosaurs , saber-toothed cats , dodos , mammoths , ground sloths , thylacines , trilobites , golden toads , and passenger pigeons . Through evolution , species arise through
4400-410: The slender-billed curlew ( Numenius tenuirostris ), not seen since 2007. As long as species have been evolving, species have been going extinct. It is estimated that over 99.9% of all species that ever lived are extinct. The average lifespan of a species is 1–10 million years, although this varies widely between taxa. A variety of causes can contribute directly or indirectly to the extinction of
4500-484: The strata of the Paris basin. They saw alternating saltwater and freshwater deposits, as well as patterns of the appearance and disappearance of fossils throughout the record. From these patterns, Cuvier inferred historic cycles of catastrophic flooding, extinction, and repopulation of the earth with new species. Cuvier's fossil evidence showed that very different life forms existed in the past than those that exist today,
4600-619: The 20 biodiversity goals laid out by the Aichi Biodiversity Targets in 2010, only 6 were "partially achieved" by the deadline of 2020. The report warned that biodiversity will continue to decline if the status quo is not changed, in particular the "currently unsustainable patterns of production and consumption, population growth and technological developments". In a 2021 report published in the journal Frontiers in Conservation Science , some top scientists asserted that even if
4700-451: The Aichi Biodiversity Targets set for 2020 had been achieved, it would not have resulted in a significant mitigation of biodiversity loss. They added that failure of the global community to reach these targets is hardly surprising given that biodiversity loss is "nowhere close to the top of any country's priorities, trailing far behind other concerns such as employment, healthcare, economic growth, or currency stability." For much of history,
4800-658: The Cumnock Formation a Carnian age. Most recent work, however, demonstrates that much of it is in fact Norian in age. Therefore, the strata exposed at the Moncure locality are probably early Norian in age. The Moncure locality have yielded many referred specimens of R. olseni including NCSM 21647, NCSM 23539, 41-46, 48-50, 52-57, NCSM 24722, 58-62 and NCSM 25194-227. NCSM 24728, 25192-3 and 25228 were referred to ? Revueltosaurus . Some osteoderms were referred to it to, as they very similar to those seen in
4900-605: The Earth is currently in the early stages of a human-caused mass extinction, known as the Holocene extinction . In that survey, the same proportion of respondents agreed with the prediction that up to 20% of all living populations could become extinct within 30 years (by 2028). A 2014 special edition of Science declared there is widespread consensus on the issue of human-driven mass species extinctions. A 2020 study published in PNAS stated that
5000-791: The NMMNH locality 1171, Santa Fe County , New Mexico from the Los Esteros Member of the Santa Rosa Formation , Chinle Group, dating to the latest Carnian stage (Adamanian). Other isolated teeth (which Long and Murry (1995) assigned to R. callenderi ) were collected two localities in the Blue Hills, east-central Arizona, from the Blue Mesa Member of the Chinle Formation, dating also to the latest Carnian. UCMP locality V92048 have yielded
5100-570: The North American moose and that the animal had once been common on the British Isles . Rather than suggest that this indicated the possibility of species going extinct, he argued that although organisms could become locally extinct, they could never be entirely lost and would continue to exist in some unknown region of the globe. The antlers were later confirmed to be from the extinct deer Megaloceros . Hooke and Molyneux's line of thinking
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#17329353526275200-535: The Painted Desert, including the nearly complete specimen PEFO 34561 which have been fully reconstructed recently. According to Sterling J. Nesbitt (2011), much of the Revueltosaurus cranial and postcranial material originates from a monotypic bonebed. Some specimens occur as isolated bones, while others are completely associated and even fully articulated. Thus, nearly the entire skeleton of R. callenderi
5300-518: The Paris basin, could be formed by a slow rise and fall of sea levels . The concept of extinction was integral to Charles Darwin 's On the Origin of Species , with less fit lineages disappearing over time. For Darwin, extinction was a constant side effect of competition . Because of the wide reach of On the Origin of Species , it was widely accepted that extinction occurred gradually and evenly (a concept now referred to as background extinction ). It
5400-655: The Petrified Forest material of R. callenderi . R. olseni is thought to be one of the most common tetrapods from its assemblage. Irmis et al. (2007) and Nesbitt et al. (2007) tentatively synonymized Pekinosaurus (and Galtonia ) with Revueltosaurus , and refer its type series to Revueltosaurus sp . They noted that Hunt and Lucas (1994) did not provide any differential diagnosis, autapomorphies, or unique combination of characters for Pekinosaurus . Furthermore, they argued that it cannot be differentiated from R. callenderi . Heckert et al. (2012) agreed that R. olseni
5500-568: The United States government, to force the removal of Native Americans , many of whom relied on the bison for food. Santa Fe County Santa Fe County ( Spanish : Condado de Santa Fe ; meaning Holy faith in Spanish) is a county located in the U.S. state of New Mexico . As of the 2020 census , the population was 154,823, making it New Mexico's third-most populous county, after Bernalillo County and Doña Ana County . Its county seat
5600-429: The accumulation of slightly deleterious mutations , then a population will go extinct. Smaller populations have fewer beneficial mutations entering the population each generation, slowing adaptation. It is also easier for slightly deleterious mutations to fix in small populations; the resulting positive feedback loop between small population size and low fitness can cause mutational meltdown . Limited geographic range
5700-422: The age of 18 living with them, 45.5% were married couples living together, 11.7% had a female householder with no husband present, and 37.5% were non-families. 29.4% of all households were made up of individuals, and 7.4% had someone living alone who was 65 years of age or older. The average household size was 2.42 and the average family size was 3.01. In the county, the population was spread out, with 24.1% under
5800-461: The age of 18, 8.1% from 18 to 24, 29.7% from 25 to 44, 27.3% from 45 to 64, and 10.8% who were 65 years of age or older. The median age was 38 years. For every 100 females there were 95.8 males. For every 100 females age 18 and over, there were 93.4 males. The median income for a household in the county was $ 42,207, and the median income for a family was $ 50,000. Males had a median income of $ 33,287 versus $ 27,780 for females. The per capita income for
5900-600: The consequences can be catastrophic. Invasive alien species can affect native species directly by eating them, competing with them, and introducing pathogens or parasites that sicken or kill them; or indirectly by destroying or degrading their habitat. Human populations may themselves act as invasive predators. According to the "overkill hypothesis", the swift extinction of the megafauna in areas such as Australia (40,000 years before present), North and South America (12,000 years before present), Madagascar , Hawaii (AD 300–1000), and New Zealand (AD 1300–1500), resulted from
6000-418: The contemporary extinction crisis "may be the most serious environmental threat to the persistence of civilization, because it is irreversible." Biologist E. O. Wilson estimated in 2002 that if current rates of human destruction of the biosphere continue, one-half of all plant and animal species of life on earth will be extinct in 100 years. More significantly, the current rate of global species extinctions
6100-492: The county was $ 23,594. About 9.4% of families and 12% of the population were below the poverty line , including 15.2% of those under age 18 and 9.7% of those age 65 or over. As of the 2010 census , there were 144,170 people, 61,963 households, and 36,183 families residing in the county. The population density was 75.5 inhabitants per square mile (29.2/km ). There were 71,267 housing units at an average density of 37.3 per square mile (14.4/km ). The racial makeup of
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#17329353526276200-588: The county was $ 32,188. About 10.0% of families and 14.4% of the population were below the poverty line , including 21.4% of those under age 18 and 7.3% of those age 65 or over. The county is governed by a five-member county commission , whose members are elected from single-member districts ( see map ). Elections are partisan and all five seats are currently held by Democrats . County commissioners serve four-year terms, with term limits preventing them from serving more than two full terms. Current commissioners are: As well, there are five elected officials taking on
6300-423: The county was 67.2% white, 3.1% American Indian, 1.2% Asian, 0.9% black or African American, 0.1% Pacific islander, 15.1% from other races, and 3.6% from two or more races. Those of Hispanic or Latino origin made up 50.6% of the population. The largest ancestry groups were: Of the 61,963 households, 26.9% had children under the age of 18 living with them, 42.1% were married couples living together, 11.0% had
6400-471: The deliberate destruction of some species, such as dangerous viruses , and the total destruction of other problematic species has been suggested. Other species were deliberately driven to extinction, or nearly so, due to poaching or because they were "undesirable", or to push for other human agendas. One example was the near extinction of the American bison , which was nearly wiped out by mass hunts sanctioned by
6500-530: The director of the New Mexico Museum of Natural History Jonathan F. Callender . R. callenderi was originally described as a basal ornithischian on the basis of 32 teeth: the holotype NMMNH P-4957 a nearly complete premaxillary ( incisiform ) tooth, the paratypes (NMMNH P-4958-9, a nearly complete maxillary or dentary tooth crown with root and a nearly complete premaxillary tooth crown) and 28 referred specimens. All specimens were collected from
6600-403: The endangered wild water buffalo is most threatened with extinction by genetic pollution from the abundant domestic water buffalo ). Such extinctions are not always apparent from morphological (non-genetic) observations. Some degree of gene flow is a normal evolutionary process; nevertheless, hybridization (with or without introgression) threatens rare species' existence. The gene pool of
6700-575: The event of rediscovery would be considered Lazarus species. Examples include the thylacine , or Tasmanian tiger ( Thylacinus cynocephalus ), the last known example of which died in Hobart Zoo in Tasmania in 1936; the Japanese wolf ( Canis lupus hodophilax ), last sighted over 100 years ago; the American ivory-billed woodpecker ( Campephilus principalis ), with the last universally accepted sighting in 1944; and
6800-443: The extinction crisis. According to the International Union for Conservation of Nature (IUCN), 784 extinctions have been recorded since the year 1500, the arbitrary date selected to define "recent" extinctions, up to the year 2004; with many more likely to have gone unnoticed. Several species have also been listed as extinct since 2004. If adaptation increasing population fitness is slower than environmental degradation plus
6900-475: The extinction of species caused by humanity, and they try to prevent further extinctions through a variety of conservation programs. Humans can cause extinction of a species through overharvesting , pollution , habitat destruction , introduction of invasive species (such as new predators and food competitors ), overhunting, and other influences. Explosive, unsustainable human population growth and increasing per capita consumption are essential drivers of
7000-533: The field of zoology , and biology in general, and has also become an area of concern outside the scientific community. A number of organizations, such as the Worldwide Fund for Nature , have been created with the goal of preserving species from extinction. Governments have attempted, through enacting laws, to avoid habitat destruction, agricultural over-harvesting, and pollution . While many human-caused extinctions have been accidental, humans have also engaged in
7100-435: The form of a physical destruction of niche habitats. The widespread destruction of tropical rainforests and replacement with open pastureland is widely cited as an example of this; elimination of the dense forest eliminated the infrastructure needed by many species to survive. For example, a fern that depends on dense shade for protection from direct sunlight can no longer survive without forest to shelter it. Another example
7200-487: The genus on the basis of the teeth series YPM 7666-9. Note that they designed the holotype to be YPM 8545, but the correct designation is YPM 7666 following Heckert et al. (2012). The type series of R. olseni was thought to originate from the Pekin Formation of Montgomery County . Heckert et al. (2012) noted that recent field work has shown that strata formerly assigned to that formation, including
7300-580: The habitat retreat of taxa approaching extinction. Possible causes of the higher extinction risk in species with more sexual selection shown by the comprehensive fossil studies that rule out such error sources include expensive sexually selected ornaments having negative effects on the ability to survive natural selection , as well as sexual selection removing a diversity of genes that under current ecological conditions are neutral for natural selection but some of which may be important for surviving climate change. There have been at least five mass extinctions in
7400-660: The heaviest losses include the Cape Floristic Region and the Caribbean Basin . These areas might see a doubling of present carbon dioxide levels and rising temperatures that could eliminate 56,000 plant and 3,700 animal species. Climate change has also been found to be a factor in habitat loss and desertification . Studies of fossils following species from the time they evolved to their extinction show that species with high sexual dimorphism , especially characteristics in males that are used to compete for mating, are at
7500-447: The history of life on earth, and four in the last 350 million years in which many species have disappeared in a relatively short period of geological time. A massive eruptive event that released large quantities of tephra particles into the atmosphere is considered to be one likely cause of the " Permian–Triassic extinction event " about 250 million years ago, which is estimated to have killed 90% of species then existing. There
7600-475: The human era since the Late Pleistocene would require 5 to 7 million years to recover. According to the 2019 Global Assessment Report on Biodiversity and Ecosystem Services by IPBES , the biomass of wild mammals has fallen by 82%, natural ecosystems have lost about half their area and a million species are at risk of extinction—all largely as a result of human actions. Twenty-five percent of plant and animal species are threatened with extinction. In
7700-431: The introduced ( or hybrid ) species. Endemic populations can face such extinctions when new populations are imported or selectively bred by people, or when habitat modification brings previously isolated species into contact. Extinction is likeliest for rare species coming into contact with more abundant ones; interbreeding can swamp the rarer gene pool and create hybrids, depleting the purebred gene pool (for example,
7800-485: The main drivers of the modern extinction crisis. In January 2020, the UN's Convention on Biological Diversity drafted a plan to mitigate the contemporary extinction crisis by establishing a deadline of 2030 to protect 30% of the Earth's land and oceans and reduce pollution by 50%, with the goal of allowing for the restoration of ecosystems by 2050. The 2020 United Nations ' Global Biodiversity Outlook report stated that of
7900-421: The modern understanding of extinction as the end of a species was incompatible with the prevailing worldview. Prior to the 19th century, much of Western society adhered to the belief that the world was created by God and as such was complete and perfect. This concept reached its heyday in the 1700s with the peak popularity of a theological concept called the great chain of being , in which all life on earth, from
8000-490: The name of a species or other taxon normally indicates its status as extinct. Examples of species and subspecies that are extinct include: A species is extinct when the last existing member dies. 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, age, sparse distribution over
8100-469: The natural course of events, species become extinct for a number of reasons, including but not limited to: extinction of a necessary host, prey or pollinator, interspecific competition , inability to deal with evolving diseases and changing environmental conditions (particularly sudden changes) which can act to introduce novel predators, or to remove prey. Recently in geological time, humans have become an additional cause of extinction of some species, either as
8200-410: The newly emerging school of uniformitarianism . Jean-Baptiste Lamarck , a gradualist and colleague of Cuvier, saw the fossils of different life forms as evidence of the mutable character of species. While Lamarck did not deny the possibility of extinction, he believed that it was exceptional and rare and that most of the change in species over time was due to gradual change. Unlike Cuvier, Lamarck
8300-399: The original population, thereby increasing the chance of extinction. Habitat degradation is currently the main anthropogenic cause of species extinctions. The main cause of habitat degradation worldwide is agriculture, with urban sprawl , logging, mining, and some fishing practices close behind. The degradation of a species' habitat may alter the fitness landscape to such an extent that
8400-702: 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 firmly established. A typical species becomes extinct within 10 million years of its first appearance, although some species, called living fossils , survive with little to no morphological change for hundreds of millions of years. Mass extinctions are relatively rare events; however, isolated extinctions of species and clades are quite common, and are
8500-410: The relative importance of genetic factors compared to environmental ones as the causes of extinction has been compared to the debate on nature and nurture . The question of whether more extinctions in the fossil record have been caused by evolution or by competition or by predation or by disease or by catastrophe is a subject of discussion; Mark Newman, the author of Modeling Extinction , argues for
8600-456: The roles of assessor, clerk, probate judge, sheriff, and treasurer: The New Mexico Corrections Department and the Penitentiary of New Mexico are located in an unincorporated area in the county. Santa Fe County is a Democratic Party stronghold, rivaling Taos County as the most Democratic county in New Mexico. The last Republican to carry the county in a presidential election
8700-460: The species is no longer able to survive and becomes extinct. This may occur by direct effects, such as the environment becoming toxic , or indirectly, by limiting a species' ability to compete effectively for diminished resources or against new competitor species. Habitat destruction, particularly the removal of vegetation that stabilizes soil, enhances erosion and diminishes nutrient availability in terrestrial ecosystems. This degradation can lead to
8800-430: The sudden introduction of human beings to environments full of animals that had never seen them before and were therefore completely unadapted to their predation techniques. Coextinction refers to the loss of a species due to the extinction of another; for example, the extinction of parasitic insects following the loss of their hosts. Coextinction can also occur when a species loses its pollinator , or to predators in
8900-412: The tiniest microorganism to God, is linked in a continuous chain. The extinction of a species was impossible under this model, as it would create gaps or missing links in the chain and destroy the natural order. Thomas Jefferson was a firm supporter of the great chain of being and an opponent of extinction, famously denying the extinction of the woolly mammoth on the grounds that nature never allows
9000-398: The topotypes UCMPV 173839-41, and the referred teeth UCMPV 139563-75 are from UCMP locality V7307. Parker et al. (2005) confirmed that R. hunti may be assignable to Revueltosaurus , on the basis of undescribed squamosal collected from its referred locality that is nearly identical to that seen in the Petrified Forest material of R. callenderi , thus suggesting that R. hunti
9100-555: The total extinction of the dodo and the extirpation of indigenous horses to the British Isles. He similarly argued against mass extinctions , believing that any extinction must be a gradual process. Lyell also showed that Cuvier's original interpretation of the Parisian strata was incorrect. Instead of the catastrophic floods inferred by Cuvier, Lyell demonstrated that patterns of saltwater and freshwater deposits , like those seen in
9200-585: The type locality dates back to the early Norian) of Bull Canyon Formation ( Dockum Group , New Mexico) and the Painted Desert of the Petrified Forest Member (Chinle Formation, Arizona). Parker et al. (2005) described several partially complete skeletons of R. callenderi (PEFO 33787-95), including a nearly complete and a partial skulls , from the Revueltosaurus Quarry, Petrified Forest National Park . Other skeletons were discovered from
9300-577: The type locality of R. olseni , actually pertain to the overlying Cumnock Formation (located in the Sanford Subbasin, Deep River Basin). Hence, the type locality and the newly discovered Moncure locality are from the same stratigraphic interval. The Cumnock Formation belongs to the Chathan Group (of the Newark Supergroup ), which is recognized as Late Triassic in age. Most workers have assigned
9400-595: The type locality, from the Bull Canyon Formation , dating to the Norian stage. Later, other teeth were described by Padian (1990), Kaye and Padian (1994) and Hunt and Lucas (1994), from Chinle Formation of Arizona . Andrew B. Heckert (2002) redescribed the genus in detail and named a second species, R. hunti on the basis of teeth described by Hunt and Lucas (1994). He referred MNA V3690, an isolated tooth assigned by Kaye and Padian (1994) to R. callenderi from
9500-577: The wider scientific community of his theory. Cuvier was a well-regarded geologist, lauded for his ability to reconstruct the anatomy of an unknown species from a few fragments of bone. His primary evidence for extinction came from mammoth skulls found in the Paris basin . Cuvier recognized them as distinct from any known living species of elephant, and argued that it was highly unlikely such an enormous animal would go undiscovered. In 1812, Cuvier, along with Alexandre Brongniart and Geoffroy Saint-Hilaire , mapped
9600-465: Was about 1 meter (3.3 feet) long. R. callenderi was named by Adrian P. Hunt in 1989 and it is the type species of the genus. The generic name honors its type locality, Revuelto Creek, Quay County of New Mexico. Revuelto is derived from Spanish revuelta , "revolution", in reference to the importance of the Late Triassic period for terrestrial vertebrate evolution. The specific name honours
9700-483: Was difficult to disprove. When parts of the world had not been thoroughly examined and charted, scientists could not rule out that animals found only in the fossil record were not simply "hiding" in unexplored regions of the Earth. Georges Cuvier is credited with establishing the modern conception of extinction in a 1796 lecture to the French Institute , though he would spend most of his career trying to convince
9800-430: Was not until 1982, when David Raup and Jack Sepkoski published their seminal paper on mass extinctions, that Cuvier was vindicated and catastrophic extinction was accepted as an important mechanism . The current understanding of extinction is a synthesis of the cataclysmic extinction events proposed by Cuvier, and the background extinction events proposed by Lyell and Darwin. Extinction is an important research topic in
9900-880: Was placed at the base of the clade Suchia as the sister taxon to the armored and herbivorous aetosaurs . However, Revueltosaurus itself is not an aetosaur, since Aetosauria was redefined to exclude it. The analysis found Gracilisuchus , Turfanosuchus and the Revueltosaurus + Aetosauria clade to nest in a large polytomy with Ticinosuchus + Paracrocodylomorpha . The cladogram below follows Nesbitt (2011). Avemetatarsalia Ornithosuchidae Gracilisuchus Turfanosuchus Revueltosaurus Aetosaurus Longosuchus Stagonolepis Ticinosuchus Poposauroidea Prestosuchus Saurosuchus Batrachotomus Fasolasuchus Rauisuchus Polonosuchus Postosuchus Crocodylomorpha [REDACTED] [REDACTED] [REDACTED] [REDACTED] Extinct Extinction
10000-571: Was skeptical that catastrophic events of a scale large enough to cause total extinction were possible. In his geological history of the earth titled Hydrogeologie, Lamarck instead argued that the surface of the earth was shaped by gradual erosion and deposition by water, and that species changed over time in response to the changing environment. Charles Lyell , a noted geologist and founder of uniformitarianism , believed that past processes should be understood using present day processes. Like Lamarck, Lyell acknowledged that extinction could occur, noting
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