This is an accepted version of this page
109-460: The California grizzly bear ( Ursus arctos californicus ), also known as the California golden bear , is an extinct population of the brown bear , generally known (together with other North American brown bear populations) as the grizzly bear . "Grizzly" could have meant "grizzled" – that is, with golden and grey tips of the hair – or "fear-inspiring" (as
218-438: 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
327-669: 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
436-415: 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
545-436: 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
654-474: A 20 year period in the areas surrounding present day Humboldt County . One prospector in Southern California, William F. Holcomb (nicknamed "Grizzly Bill" Holcomb), was particularly well known for hunting grizzly bears in what is now San Bernardino County . During September 1897, in the mountains between Inwood and Mt. Lassen, Shasta County , 21-year-old Elias Weigart and his dog encountered
763-479: 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
872-503: 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
981-429: 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
1090-399: 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
1199-532: A fight, and supposedly gave the modern stock market its " bear " and " bull " nicknames based on the fighting styles of the two animals: the bear swipes downward while the bull hooks upward. In truth, the phrase's origins predate Greeley's 1859 journey to California by at least 100 years, but the myth of the California connection persists. The Monterey County Herald noted on July 4, 1874: Last Monday, Captain A. Smith, who resides about ten miles from town, in
SECTION 10
#17327935132941308-708: 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
1417-468: A huge California grizzly whose front track measured 11 inches and the rear, 19. The bear died after Weigart emptied his Winchester 38-55 into the beast at close range. In 1920, the Shuteye Peak area of Madera County was home to one of the last California grizzlies, nicknamed 'Two Toes,' who lost part of his front foot in a trap and evaded hunters for years. The last hunted California grizzly bear
1526-405: 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
1635-607: 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
1744-650: A mainstay on restaurant menus in the San Gabriel area; according to Mike Davis , “The paws from adult bears and the flesh from young cubs were deemed particular delicacies.” European settlers paid bounties on the bears who regularly preyed on livestock until the early 20th century. Absolom (Rocky) Beasley hunted grizzly bears throughout the Santa Lucia Mountains and claimed to have killed 139 bears in his lifetime. Noted California mountain man Seth Kinman claimed to have shot over 800 grizzly bears in
1853-594: 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
1962-456: 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
2071-441: 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,
2180-738: A permanent part of the state seal in 1849. The California grizzly bear was designated the official state animal in 1953. The bear is celebrated in name and as mascot of the sports teams of the University of California, Berkeley (the California Golden Bears ), and of the University of California, Los Angeles (the UCLA Bruins ) and in the mascot of University of California, Riverside (the UC Riverside Highlanders ). The California Maritime Academy operates
2289-456: A phonetic spelling of "grisly"). Nonetheless, after careful study, naturalist George Ord formally classified it in 1815 – not for its hair, but for its character – as Ursus horribilis ("terrifying bear"). Genetically, North American brown bears are closely related; in size and coloring, the California grizzly bear was much like the Kodiak bear of the southern coast of Alaska. The grizzly became
SECTION 20
#17327935132942398-610: 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
2507-407: 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
2616-502: 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
2725-499: 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
2834-609: A rumor that the Spanish intended to use the Japanese Christian minority to overthrow the shogunate and take control of Japan. After taking his leave in 1612, he surveyed the east coast of Japan and searched for two mythical islands called Rico de Oro and Rico de Plata. Failing to find them, he returned to Japan. In 1613, Vizcaíno accompanied the Japanese embassy led by Hasekura Tsunenaga to Mexico. In Acapulco, Vizcaíno
2943-528: A second expedition: to locate safe harbors in Alta California for Spanish galleons to use on their return voyage to Acapulco from Manila . He was also given the mandate to map in detail the California coastline that Juan Rodríguez Cabrillo had first reconnoitered 60 years earlier. He departed Acapulco with three ships on May 5, 1602. His flagship was the San Diego and the other two ships were
3052-479: 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
3161-439: 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
3270-404: 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
3379-518: 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
California grizzly bear - Misplaced Pages Continue
3488-544: A symbol of the Bear Flag Republic , a moniker that was attached to the short-lived attempt by a group of U.S. settlers to break away from Mexico in 1846. Later, this rebel flag became the basis for the state flag of California , and then California was known as the "Bear State". A 1953 researcher stated, "The specific status of North American brown bears (or grizzly bears) is one of the most complex problems of mammalian taxonomy. The difficulty stems directly from
3597-427: A training ship named Golden Bear . [REDACTED] Data related to Ursus arctos californicus at Wikispecies Extinct Extinction 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
3706-400: A whale carcass stranded on the beach. However, his reports were not widely circulated, so the existence of grizzlies in California was not well-known to Europeans until the eighteenth century. Western Europeans' first well-circulated encounters with California grizzly bears are found in diaries kept by several members of the 1769 Portola expedition , the first European land exploration of what
3815-523: 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
3924-444: 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
4033-585: 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
4142-794: 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 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 , like 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
4251-417: 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
4360-437: Is now the state of California. Several place names that include the Spanish word for bear ( oso ) trace their origins back to that first overland expedition (e.g. Los Osos ). As the settled frontier of New Spain was extended northward, settlers began to populate California and establish large cattle herds as the main industry. The ranchers' livestock were easy prey for the largely herbivorous-omnivorous grizzly bears found across
4469-592: 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
California grizzly bear - Misplaced Pages Continue
4578-525: 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
4687-642: The Gulf of California was transferred to Vizcaíno. He succeeded in sailing with three ships to La Paz, Baja California Sur , in 1596. He gave this site (known to Hernándo Cortés as Santa Cruz) its modern name and attempted to establish a settlement. However, problems of resupply, declining morale, and a fire soon forced its abandonment. In 1601, the Spanish viceroy in Mexico City , Gaspar de Zúñiga, 5th Count of Monterrey , appointed Vizcaíno general-in-charge of
4796-483: 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
4905-485: 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
5014-671: The San Tomás and the Tres Reyes . On November 10, 1602, Vizcaíno entered and named San Diego Bay . Sailing up the coast, Vizcaíno named many prominent features such as the Santa Barbara Channel Islands , Point Conception , the Santa Lucia Mountains , Point Lobos , Carmel River and Monterey Bay (obliterating some of the names given these same features by Cabrillo in 1542). He was the first person in recorded history to note certain ecological features of
5123-536: The Spanish invasion of Portugal during 1580–1583. Coming to New Spain in 1583, he sailed as a merchant on a Manila galleon to the Spanish East Indies in 1586–1589. In 1587, he was on board the Santa Ana as one of the merchants when Thomas Cavendish captured it, robbing him and others of their personal cargoes of gold. In 1593, the disputed concession for pearl fishing on the western shores of
5232-474: The U.S. Fish and Wildlife Service received, and subsequently rejected, a petition to reintroduce grizzly bears to California. In 2015, the Center for Biological Diversity launched a petition aimed at the California state legislature to reintroduce the grizzly bear to the state. In anticipation of the 2024 centennial marking the final recorded sighting of a wild grizzly bear in California, a collaborative effort
5341-418: The ranchos of California provided an abundant food source for the bears, allowing the grizzly population to expand rapidly. However, the cattle population was greatly diminished following extreme drought and flooding in the 1860s and 1870s, leading to a reduction in the number of grizzlies. This coincided with an increased interest in bear hunting, both for sport and commercial purposes. Grizzly bear meat became
5450-410: 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
5559-488: 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,
SECTION 50
#17327935132945668-639: 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
5777-451: 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,
5886-493: The California coast such as the Monterey cypress forest at Point Lobos. The commander of the Tres Reyes , Martín de Aguilar , became separated from Vizcaíno and continued up the coast to present-day Oregon as far as Cape Blanco and possibly to Coos Bay . After Vizcaíno passed Cape Mendocino , he turned back, with some of his men suffering from scurvy and starvation. Half of the crew members, some 45 men, died during
5995-426: The California grizzly bear was diverse, ranging from plant sources like grasses, seeds, berries, and acorns, to animal sources such as elk, deer, salmon , steelhead , and carrion. Isotopic study indicates that the majority of the diet consisted of plant matter, as with other grizzly bear populations. Anecdotal reports from Spanish explorers reported California grizzly bears scavenging on beached whale carcasses. After
6104-479: The Carmel Valley, succeeded in poisoning a large grizzly bear. Bruin had been annoying the neighborhood by destroying cattle, etc., for several years past, and all efforts to exterminate him seem futile. In some manner, however, he was induced partake of that "cold pizen" the captain had prepared for his special benefit. He is not likely to repeat his experiment. In the early to mid 19th century, livestock from
6213-618: 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
6322-584: 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
6431-522: 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
6540-664: The United States government, to force the removal of Native Americans , many of whom relied on the bison for food. Sebasti%C3%A1n Vizca%C3%ADno Sebastián Vizcaíno (c. 1548–1624) was a Spanish soldier, entrepreneur, explorer, and diplomat whose varied roles took him to New Spain , the Baja California peninsula , the California coast and Asia . Vizcaíno was born in 1548, in Extremadura , Crown of Castile ( Spain ). He saw military service in
6649-429: 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
SECTION 60
#17327935132946758-673: The bear, but differ as to its exact size.) Her telling of that bear is part of the oral history of "Bear Valley", the original name for Valley Center. The bear was prominent in the Big Sur region of the central California coast. Frank Post , born in 1859 on the Soberanes Ranch in Big Sur, remembered when his family lived at Soberanes Creek, during the American Civil War – recalling the "Great Sur Bears". Inhabiting most of
6867-514: The bears lived across almost the entirety of the state, save its most southeastern and northeastern corners. Probably the southernmost records for this subspecies are from the Sierra de Juárez , during the 18th century. The bear was most abundant in chaparral, oak woodland, and hardwood forests. The first documented sighting of a grizzly bear in California occurred in 1603 when a Spanish explorer near Monterey described how bears came down to feed on
6976-600: 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
7085-418: 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
7194-476: 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
7303-403: 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
7412-591: 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
7521-507: The expedition. Much of what we know about Vizcaíno's Pacific Coast voyage is from the diary of Antonio de la Ascensión, a Carmelite friar, chronicler and cosmographer who traveled with the expedition. One result of Vizcaíno's voyage was a flurry of enthusiasm for establishing a Spanish settlement at Monterey , but this was ultimately deferred for another 167 years after the Conde de Monterrey left to become Viceroy of Peru and his successor
7630-443: 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
7739-475: 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
7848-540: 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
7957-435: 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
8066-580: 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
8175-676: 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
8284-447: 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
8393-475: 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
8502-431: 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,
8611-414: The introduction of European livestock, California grizzly bears increasingly incorporated cattle into their diets. California grizzly bears were primarily solitary, except for mothers with cubs, but foraging groups of up to 40 have been reported. Prior to Spanish settlement in the second half of the 1700s , it is estimated that 10,000 grizzly bears inhabited what is modern-day California. It is thought that
8720-488: 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
8829-421: 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
8938-490: 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
9047-469: 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
9156-410: 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
9265-464: The only genetically anomalous grouping of grizzly bears is the ABC Islands bear , implying that previous grizzly bear subspecies designations are unwarranted. However, a formal taxonomic synonymy was not performed, and mitochondrial introgression is known to be an issue in brown bears. Pending further taxonomic resolution, the subspecies is provisionally accepted as separate. The California grizzly
9374-399: 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
9483-702: 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
9592-406: The reintroduction in California as an intolerable threat, regardless of individual risk. The California grizzly bear is one of the state's most visible and enduring symbols, adorning both the state flag and seal. The Bear Flag first flew in 1846 as a symbol of the short-lived California Republic . A second version was adopted as the state flag by the state legislature in 1911. The bear symbol became
9701-410: 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
9810-460: 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
9919-405: The state is growing. Despite having one of the largest American black bear populations in the nation, California still has habitat that can sustain about 500 grizzlies; it is thought that the presence of an additional large mammal could curb overpopulation of the smaller black bear, which often is involved in human-bear conflicts, as it enters human settlements in pursuit of food and trash. In 2014,
10028-588: The state, both inland and coastally, it is likely the California grizzly's southernmost range in the state overlapped with that of the now-extinct Mexican grizzly bear , as well. In the late 1700s, Spanish ranchers placed a poisoned "bait ball" made of suet or swine entrails filled with a lethal dose of strychnine which they hung from the branches of a tree within reach of the bear but out of reach of dogs and children. Mexican settlers captured bears for bear and bull fights and they also sold their skins for 6 to 10 pesos to trading ships. Bear Trap Canyon near Bixby Creek
10137-401: The state. In turn, grizzly populations increased around human settlements. By eating their livelihood, and scaring them, the grizzlies became enemies of the rancheros . Vaqueros hunted the grizzlies, often roping and capturing them alive to be pitted against other animals in public battles ( bloodsports ). In 1866, a grizzly bear described as weighing as much as 2,200 pounds (1,000 kg)
10246-430: 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
10355-412: 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
10464-567: 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
10573-581: 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
10682-530: The work of Merriam (1918), who concluded that there are 86 forms of grizzlies (and brown bears) in North America." North American brown bears were taxonomically grouped as a species apart from other bear species, until DNA testing revealed that they should properly be grouped in the same species as the other brown bears. Grizzlies living in California had been classified by Merriam into many subspecies. A recent study based on mitochondrial DNA suggests that
10791-491: 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
10900-558: Was historically considered an enormous bear. Father Pedro Font , an early missionary, described the local grizzly bears, writing, "He was horrible, fierce, large, and fat." In the 1800s, multiple newspaper accounts mentioned bears weighing well over 1,000 pounds (450 kg); the hind foot of one particular adult male grizzly was measured at 12 inches (300 mm) long by 8 inches (200 mm) wide, and claws were often 2 inches (51 mm) wide by 3.5 inches (89 mm) long. Measurements of museum specimens, however, demonstrate that this bear
11009-704: Was initiated by scientists affiliated with the Research Network, prominent leaders from California Tribes, and advocates associated with conservation nonprofits. This initiative resulted in the establishment of the California Grizzly Alliance. Despite these efforts, however, their reintroduction remains controversial. Arguments against grizzly bear reintroduction emphasize the potential for rare but significant harm, such as attacks causing injuries or fatalities. Those who deem any harm, especially loss of human life, as morally unacceptable view
11118-481: Was killed in what is present-day Valley Center, California , in the north-central area of San Diego County . The incident was recalled in 1932 by Catherine E. Lovett Smith, who witnessed the bear's killing on her family's ranch when she was just six years old. If its measurements are accurate, this particular bear was the biggest bear ever found in California and one of the largest specimens of any bear species ever recorded. (Other sources confirm Lovett Smith's account of
11227-485: Was less favorable. A colonizing expedition was authorized in 1606 for 1607, but was delayed and then canceled in 1608. In 1611, Vizcaíno carried a Japanese delegation led by Tanaka Shōsuke from Mexico back to Japan. In an ambassadorial capacity, Vizcaíno met with the shōgun Tokugawa Hidetada and his father, the retired first shōgun, Tokugawa Ieyasu , founder of the Tokugawa dynasty. However, diplomacy soured due to
11336-412: Was no larger than those present in the rest of North America, with average body size estimates ranging from 104 kilograms (229 lb) to 252 kilograms (556 lb) depending on methodology. The fur of the California grizzly bear has been described as golden brown, leading to the occasional name "California golden bear". The captive individual "Monarch" had a dark brown, almost black, pelt. The diet of
11445-430: 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
11554-608: Was one of their favorite sites for trapping grizzly bears along the central California coast. These bears were even turned into furniture, such as a chair gifted to President Andrew Johnson in 1865. Bear-baiting events flourished as popular spectacles in 19th century California. Bloody fights that pitted bears against bulls often inspired betting as to whether the bear or the bull would win. One persistently popular, but false phrase origin story related to these fights stems from famous 19th-century newspaperman Horace Greeley . While visiting California, Greeley allegedly witnessed such
11663-468: Was seriously injured in a fight with the Japanese, as recorded by 17th-century Aztec historian Chimalpahin in his journal, "Annals of His Time". The Japanese entourage continued to Mexico City, and embarked a ship at Veracruz bound for Europe. In October 1615, Vizcaíno commanded 200 men at the port of Salagua against an attack by 200 Dutch pirates led by Joris van Spilbergen . In the afternoon, both sides ran out of ammunition. Vizcaíno's men retreated after
11772-627: Was shot in Tulare County, California , in August 1922, although no body, skeleton or pelt was ever produced. Less than 75 years after the discovery of gold in 1848, almost every grizzly bear in California had been tracked down and killed. In 1924, what was thought to be a grizzly was spotted in Sequoia National Park for the last time and thereafter, grizzlies were never seen again in California. Support to reintroduce grizzlies to
11881-571: 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
#293706