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88-438: Alepis is a genus of flowering plants belonging to the family Loranthaceae . It is monotypic, being represented by the single species Alepis flavida . This mistletoe was first described in 1852 as Loranthus flavidus by Joseph Dalton Hooker , but in 1894 Philippe Édouard Léon Van Tieghem transferred it to the genus, Alepis . Its native range is New Zealand. It is currently (2017) declared "At Risk - Declining" under

176-590: A 2022 study published in Frontiers in Ecology and the Environment , a survey of more than 3,000 experts says that the extent of the mass extinction might be greater than previously thought, and estimates that roughly 30% of species "have been globally threatened or driven extinct since the year 1500." In a 2022 report, IPBES listed unsustainable fishing, hunting, and logging as some of the primary drivers of

264-1852: A molecular phylogeny of plants placed the flowering plants in their evolutionary context: Bryophytes [REDACTED] Lycophytes [REDACTED] Ferns [REDACTED] [REDACTED] [REDACTED] The main groups of living angiosperms are: Amborellales [REDACTED] 1 sp. New Caledonia shrub Nymphaeales [REDACTED] c. 80 spp. water lilies & allies Austrobaileyales [REDACTED] c. 100 spp. woody plants Magnoliids [REDACTED] c. 10,000 spp. 3-part flowers, 1-pore pollen, usu. branch-veined leaves Chloranthales [REDACTED] 77 spp. Woody, apetalous Monocots [REDACTED] c. 70,000 spp. 3-part flowers, 1 cotyledon , 1-pore pollen, usu. parallel-veined leaves   Ceratophyllales [REDACTED] c. 6 spp. aquatic plants Eudicots [REDACTED] c. 175,000 spp. 4- or 5-part flowers, 3-pore pollen, usu. branch-veined leaves Amborellales Melikyan, Bobrov & Zaytzeva 1999 Nymphaeales Salisbury ex von Berchtold & Presl 1820 Austrobaileyales Takhtajan ex Reveal 1992 Chloranthales Mart. 1835 Canellales Cronquist 1957 Piperales von Berchtold & Presl 1820 Magnoliales de Jussieu ex von Berchtold & Presl 1820 Laurales de Jussieu ex von Berchtold & Presl 1820 Acorales Link 1835 Alismatales Brown ex von Berchtold & Presl 1820 Petrosaviales Takhtajan 1997 Dioscoreales Brown 1835 Pandanales Brown ex von Berchtold & Presl 1820 Liliales Perleb 1826 Asparagales Link 1829 Arecales Bromhead 1840 Poales Small 1903 Zingiberales Grisebach 1854 Commelinales de Mirbel ex von Berchtold & Presl 1820 Holocene extinction The Holocene extinction follows

352-442: A woody stem ), grasses and grass-like plants, a vast majority of broad-leaved trees , shrubs and vines , and most aquatic plants . Angiosperms are distinguished from the other major seed plant clade, the gymnosperms , by having flowers , xylem consisting of vessel elements instead of tracheids , endosperm within their seeds, and fruits that completely envelop the seeds. The ancestors of flowering plants diverged from

440-615: A 2006 report by the Food and Agriculture Organization (FAO) of the United Nations, Livestock's Long Shadow , also found that the livestock sector is a "leading player" in biodiversity loss. More recently, in 2019, the IPBES Global Assessment Report on Biodiversity and Ecosystem Services attributed much of this ecological destruction to agriculture and fishing, with the meat and dairy industries having

528-514: A combined 50 billion years of Earth's evolutionary history (defined as phylogenetic diversity ) and driving to extinction some of the "most unique animals on the planet," among them the Aye-aye lemur, the Chinese crocodile lizard and the pangolin . Said lead author Rikki Gumbs: We know from all the data we have for threatened species, that the biggest threats are agriculture expansion and

616-496: A fringe theory. Contemporary human overpopulation and continued population growth , along with per-capita consumption growth, prominently in the past two centuries, are regarded as the underlying causes of extinction. Inger Andersen , the executive director of the United Nations Environment Programme , stated that "we need to understand that the more people there are, the more we put

704-680: A global mass extinction of wildlife. We ignore the decline of other species at our peril – for they are the barometer that reveals our impact on the world that sustains us. A 2023 study published in Current Biology concluded that current biodiversity loss rates could reach a tipping point and inevitably trigger a total ecosystem collapse. Recent extinctions are more directly attributable to human influences, whereas prehistoric extinctions can be attributed to other factors. The International Union for Conservation of Nature (IUCN) characterizes 'recent' extinction as those that have occurred past

792-466: A global scale and eliminate billions of years of phylogenetic diversity . 189 countries, which are signatory to the Convention on Biological Diversity (Rio Accord), have committed to preparing a Biodiversity Action Plan , a first step at identifying specific endangered species and habitats, country by country . For the first time since the demise of the dinosaurs 65 million years ago, we face

880-566: A global scale, and when these alterations caused changes to global climate. Using chemical proxies from Antarctic ice cores, researchers have estimated the fluctuations of carbon dioxide (CO 2 ) and methane (CH 4 ) gases in the Earth's atmosphere during the Late Pleistocene and Holocene epochs. Estimates of the fluctuations of these two gases in the atmosphere, using chemical proxies from Antarctic ice cores, generally indicate that

968-542: A great deal of influence over food webs and climatic systems worldwide. Although significant debate exists as to how much human predation and indirect effects contributed to prehistoric extinctions, certain population crashes have been directly correlated with human arrival. Human activity has been the main cause of mammalian extinctions since the Late Pleistocene. A 2018 study published in PNAS found that since

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1056-737: A longer Holocene extinction. The Holocene–Anthropocene boundary is contested, with some commentators asserting significant human influence on climate for much of what is normally regarded as the Holocene Epoch . Some experts mark the transition from the Holocene to the Anthropocene at the onset of the industrial revolution . They also note that the official use of this term in the near future will heavily rely on its usefulness, especially for Earth scientists studying late Holocene periods. It has been suggested that human activity has made

1144-445: A mass extinction event, the sixth in roughly 540 million years, wherein many current life forms could be extirpated or at least committed to extinction by the end of this century." The World Wide Fund for Nature 's 2020 Living Planet Report says that wildlife populations have declined by 68% since 1970 as a result of overconsumption , population growth , and intensive farming , which is further evidence that humans have unleashed

1232-424: A number of human-derived factors are recognized as contributing to rising atmospheric concentrations of CH 4 (methane) and CO 2 (carbon dioxide), deforestation and territorial clearance practices associated with agricultural development may have contributed most to these concentrations globally in earlier millennia. Scientists that are employing a variance of archaeological and paleoecological data argue that

1320-821: A similar study drawing on work at the University of Queensland , which found that "more than 1,200 species globally face threats to their survival in more than 90% of their habitat and will almost certainly face extinction without conservation intervention". Since 1970, the populations of migratory freshwater fish have declined by 76%, according to research published by the Zoological Society of London in July 2020. Overall, around one in three freshwater fish species are threatened with extinction due to human-driven habitat degradation and overfishing. Some scientists and academics assert that industrial agriculture and

1408-827: A sixth mass extinction event caused by anthropogenic activity is currently under way. A December 2022 study published in Science Advances states that "the planet has entered the sixth mass extinction" and warns that current anthropogenic trends, particularly regarding climate and land-use changes , could result in the loss of more than a tenth of plant and animal species by the end of the century. 12% of all bird species are threatened with extinction. A 2023 study published in Biological Reviews found that, of 70,000 monitored species, some 48% are experiencing population declines from anthropogenic pressures, whereas only 3% have increasing populations. According to

1496-540: A sixth mass extinction event; however, this finding has been disputed by one 2020 study, which posits that this major decline was primarily driven by a few extreme outlier populations, and that when these outliers are removed, the trend shifts to that of a decline between the 1980s and 2000s, but a roughly positive trend after 2000. A 2021 report in Frontiers in Conservation Science which cites both of

1584-610: A total of 64 angiosperm orders and 416 families. The diversity of flowering plants is not evenly distributed. Nearly all species belong to the eudicot (75%), monocot (23%), and magnoliid (2%) clades. The remaining five clades contain a little over 250 species in total; i.e. less than 0.1% of flowering plant diversity, divided among nine families. The 25 most species-rich of 443 families, containing over 166,000 species between them in their APG circumscriptions, are: The botanical term "angiosperm", from Greek words angeíon ( ἀγγεῖον 'bottle, vessel') and spérma ( σπέρμα 'seed'),

1672-511: A very significant impact. Since the 1970s food production has soared to feed a growing human population and bolster economic growth, but at a huge price to the environment and other species. The report says some 25% of the Earth's ice-free land is used for cattle grazing. A 2020 study published in Nature Communications warned that human impacts from housing, industrial agriculture and in particular meat consumption are wiping out

1760-858: Is starting to impact plants and is likely to cause many species to become extinct by 2100. Angiosperms are terrestrial vascular plants; like the gymnosperms, they have roots , stems , leaves , and seeds . They differ from other seed plants in several ways. The largest angiosperms are Eucalyptus gum trees of Australia, and Shorea faguetiana , dipterocarp rainforest trees of Southeast Asia, both of which can reach almost 100 metres (330 ft) in height. The smallest are Wolffia duckweeds which float on freshwater, each plant less than 2 millimetres (0.08 in) across. Considering their method of obtaining energy, some 99% of flowering plants are photosynthetic autotrophs , deriving their energy from sunlight and using it to create molecules such as sugars . The remainder are parasitic , whether on fungi like

1848-524: Is a big risk. The 2011 study by Barnosky et al. confirms that "current extinction rates are higher than would be expected from the fossil record" and adds that anthropogenic ecological stressors, including climate change, habitat fragmentation , pollution, overfishing, overhunting, invasive species, and expanding human biomass , will intensify and accelerate extinction rates in the future without significant mitigation efforts. In The Future of Life (2002), Edward Osborne Wilson of Harvard calculated that, if

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1936-477: Is impacting larger mammals and birds to a much greater extent than smaller ones, with the body mass of such animals expected to shrink by 25% over the next century. Another 2019 study published in Biology Letters found that extinction rates are perhaps much higher than previously estimated, in particular for bird species. The 2019 Global Assessment Report on Biodiversity and Ecosystem Services lists

2024-555: Is primarily driven by human activity. This has resulted in empty forests , ecological communities depleted of large vertebrates. This is not to be confused with extinction, as it includes both the disappearance of species and declines in abundance. Defaunation effects were first implied at the Symposium of Plant-Animal Interactions at the University of Campinas, Brazil in 1988 in the context of Neotropical forests . Since then,

2112-514: Is the current geological epoch . There is no general agreement on when the Holocene , or anthropogenic , extinction begins, and the Quaternary extinction event , which includes climate change resulting in the end of the last ice age , ends, or if they should be considered separate events at all. The Holocene extinction is mainly caused by human activities. Some authors have argued that

2200-491: The Alismatales grow in marine environments, spreading with rhizomes that grow through the mud in sheltered coastal waters. Some specialised angiosperms are able to flourish in extremely acid or alkaline habitats. The sundews , many of which live in nutrient-poor acid bogs , are carnivorous plants , able to derive nutrients such as nitrate from the bodies of trapped insects. Other flowers such as Gentiana verna ,

2288-597: The Atlantic , and of the leatherback sea turtle in Malaysia. Since the Late Pleistocene, humans (together with other factors) have been rapidly driving the largest vertebrate animals towards extinction, and in the process interrupting a 66-million-year-old feature of ecosystems, the relationship between diet and body mass, which researchers suggest could have unpredictable consequences. A 2019 study published in Nature Communications found that rapid biodiversity loss

2376-760: The Ordovician–Silurian extinction events , the Late Devonian extinction , the Permian–Triassic extinction event , the Triassic–Jurassic extinction event , and the Cretaceous–Paleogene extinction event . If the Capitanian extinction event is included among the first-order mass extinctions, the Holocene extinction would correspondingly be known as the "seventh extinction". The Holocene

2464-621: The UNDP 's 2020 Human Development Report , The Next Frontier: Human Development and the Anthropocene : The planet's biodiversity is plunging, with a quarter of species facing extinction, many within decades. Numerous experts believe we are living through, or on the cusp of, a mass species extinction event, the sixth in the history of the planet and the first to be caused by a single organism—us. The 2022 Living Planet Report found that vertebrate wildlife populations have plummeted by an average of almost 70% since 1970, with agriculture and fishing being

2552-593: The United States Chamber of Commerce , have been pushing back against legislation that could address the extinction crisis. A 2022 report by the climate think tank InfluenceMap stated that "although industry associations, especially in the US, appear reluctant to discuss the biodiversity crisis, they are clearly engaged on a wide range of policies with significant impacts on biodiversity loss." The loss of animal species from ecological communities, defaunation ,

2640-584: The clade Angiospermae ( / ˌ æ n dʒ i ə ˈ s p ər m iː / ). The term 'angiosperm' is derived from the Greek words ἀγγεῖον / angeion ('container, vessel') and σπέρμα / sperma ('seed'), meaning that the seeds are enclosed within a fruit. The group was formerly called Magnoliophyta . Angiosperms are by far the most diverse group of land plants with 64 orders , 416 families , approximately 13,000 known genera and 300,000 known species . They include all forbs (flowering plants without

2728-404: The decline of insect populations are associated with intensive farming practices, along with pesticide use and climate change. The world's insect population decreases by around 1 to 2% per year. We have driven the rate of biological extinction, the permanent loss of species, up several hundred times beyond its historical levels, and are threatened with the loss of a majority of all species by

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2816-460: The orchids for part or all of their life-cycle, or on other plants , either wholly like the broomrapes, Orobanche , or partially like the witchweeds, Striga . In terms of their environment, flowering plants are cosmopolitan, occupying a wide range of habitats on land, in fresh water and in the sea. On land, they are the dominant plant group in every habitat except for frigid moss-lichen tundra and coniferous forest . The seagrasses in

2904-433: The "Anthropocene extinction". Anthropocene is a term introduced in 2000. Some now postulate that a new geological epoch has begun, with the most abrupt and widespread extinction of species since the Cretaceous–Paleogene extinction event 66 million years ago. The term "anthropocene" is being used more frequently by scientists, and some commentators may refer to the current and projected future extinctions as part of

2992-723: The "Big Five" extinction events in Earth's history, only the Cretaceous–Paleogene extinction event had occurred while angiosperms dominated plant life on the planet. Today, the Holocene extinction affects all kingdoms of complex life on Earth, and conservation measures are necessary to protect plants in their habitats in the wild ( in situ ), or failing that, ex situ in seed banks or artificial habitats like botanic gardens . Otherwise, around 40% of plant species may become extinct due to human actions such as habitat destruction , introduction of invasive species , unsustainable logging , land clearing and overharvesting of medicinal or ornamental plants . Further, climate change

3080-404: The Earth under heavy pressure. As far as biodiversity is concerned, we are at war with nature." Some scholars assert that the emergence of capitalism as the dominant economic system has accelerated ecological exploitation and destruction, and has also exacerbated mass species extinction. CUNY professor David Harvey , for example, posits that the neoliberal era "happens to be the era of

3168-446: The Holocene extinction can be linked to the human impact on the environment . The Holocene extinction continues into the 21st century, with anthropogenic global warming , human population growth , increasing per capita consumption (especially by the super- affluent ), and meat production and consumption , among others, being the primary drivers of mass extinction. Deforestation , overfishing , ocean acidification ,

3256-502: The New Zealand Threatened species system, with the qualifier C(1) implying that there are greater than 10000 mature individuals with an expected decline of from 10% to 70%, and with an area of occupancy which is less than 10,000 ha which is expected to decline by from 10% to 50%. Flowering plant Basal angiosperms Core angiosperms Flowering plants are plants that bear flowers and fruits , and form

3344-477: The activities of earlier archaic humans have also resulted in extinctions, though the evidence for this is equivocal; this is supported by rapid megafaunal extinction following recent human colonization in Australia , New Zealand , and Madagascar . In many cases, it is suggested that even minimal hunting pressure was enough to wipe out large fauna, particularly on geographically isolated islands. Only during

3432-536: The aforementioned studies, says "population sizes of vertebrate species that have been monitored across years have declined by an average of 68% over the last five decades, with certain population clusters in extreme decline, thus presaging the imminent extinction of their species," and asserts "that we are already on the path of a sixth major extinction is now scientifically undeniable." A January 2022 review article published in Biological Reviews builds upon previous studies documenting biodiversity decline to assert that

3520-407: The atmosphere was the growth of human agriculture during the Holocene. One of the main theories explaining early Holocene extinctions is historic climate change . The climate change theory has suggested that a change in climate near the end of the late Pleistocene stressed the megafauna to the point of extinction. Some scientists favor abrupt climate change as the catalyst for the extinction of

3608-593: The biomass of insect life in Germany had declined by three-quarters in the previous 25 years. Participating researcher Dave Goulson of Sussex University stated that their study suggested that humans are making large parts of the planet uninhabitable for wildlife. Goulson characterized the situation as an approaching "ecological Armageddon", adding that "if we lose the insects then everything is going to collapse." A 2019 study found that over 40% of insect species are threatened with extinction. The most significant drivers in

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3696-430: The case that early farmers involved in systems of agriculture used more land per capita than growers later in the Holocene, who intensified their labor to produce more food per unit of area (thus, per laborer); arguing that agricultural involvement in rice production implemented thousands of years ago by relatively small populations created significant environmental impacts through large-scale means of deforestation. While

3784-560: The common ancestor of all living gymnosperms before the end of the Carboniferous , over 300 million years ago. In the Cretaceous , angiosperms diversified explosively , becoming the dominant group of plants across the planet. Agriculture is almost entirely dependent on angiosperms, and a small number of flowering plant families supply nearly all plant-based food and livestock feed. Rice , maize and wheat provide half of

3872-553: The current rate of human disruption of the biosphere continues, one-half of Earth's higher lifeforms will be extinct by 2100. A 1998 poll conducted by the American Museum of Natural History found that 70% of biologists acknowledge an ongoing anthropogenic extinction event. In a pair of studies published in 2015, extrapolation from observed extinction of Hawaiian snails led to the conclusion that 7% of all species on Earth may have been lost already. A 2021 study published in

3960-527: The cut-off point of 1500, and at least 875 plant and animal species have gone extinct since that time and 2009. Some species, such as the Père David's deer and the Hawaiian crow , are extinct in the wild, and survive solely in captive populations. Other populations are only locally extinct (extirpated), still existent elsewhere, but reduced in distribution, as with the extinction of gray whales in

4048-467: The dawn of human civilization, the biomass of wild mammals has decreased by 83%. The biomass decrease is 80% for marine mammals, 50% for plants, and 15% for fish. Currently, livestock make up 60% of the biomass of all mammals on Earth, followed by humans (36%) and wild mammals (4%). As for birds, 70% are domesticated, such as poultry, whereas only 30% are wild. Extinction of animals, plants, and other organisms caused by human actions may go as far back as

4136-430: The destruction of wetlands , and the decline in amphibian populations , among others, are a few broader examples of global biodiversity loss . Mass extinctions are characterized by the loss of at least 75% of species within a geologically short period of time (i.e., less than 2 million years). The Holocene extinction is also known as the "sixth extinction", as it is possibly the sixth mass extinction event, after

4224-455: The destruction of habitats, the consumption of animals as resources, and the elimination of species that humans view as threats or competitors. Rising extinction trends impacting numerous animal groups including mammals, birds, reptiles, and amphibians have prompted some scientists to declare a biodiversity crisis. The description of recent extinction as a mass extinction has been debated among scientists. Stuart Pimm , for example, asserts that

4312-441: The end of the 21st century. Various species are predicted to become extinct in the near future , among them some species of rhinoceros , primates , and pangolins . Others, including several species of giraffe, are considered " vulnerable " and are experiencing significant population declines from anthropogenic impacts including hunting, deforestation and conflict. Hunting alone threatens bird and mammalian populations around

4400-435: The estimate put forward in the 2019 IPBES report. According to a 2023 study published in PNAS , at least 73 genera of animals have gone extinct since 1500. If humans had never existed, the study estimates it would have taken 18,000 years for the same genera to have disappeared naturally, leading the authors to conclude that "the current generic extinction rates are 35 times higher than expected background rates prevailing in

4488-462: The exception of Africa. Over the past 130,000 years, avian functional diversity has declined precipitously and disproportionately relative to phylogenetic diversity losses. Human civilization was founded on and grew from agriculture. The more land used for farming, the greater the population a civilization could sustain, and subsequent popularization of farming led to widespread habitat conversion. Habitat destruction by humans , thus replacing

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4576-482: The extinction event include deforestation , hunting, pollution, the introduction in various regions of non-native species , and the widespread transmission of infectious diseases spread through livestock and crops. Recent investigations into the practice of landscape burning during the Neolithic Revolution have a major implication for the current debate about the timing of the Anthropocene and

4664-545: The extinction of the majority of large (megafaunal) animals during the preceding Late Pleistocene . Some of these extinctions were likely in part due to human hunting pressure. The most popular theory is that human overhunting of species added to existing stress conditions as the Holocene extinction coincides with human colonization of many new areas around the world. Although there is debate regarding how much human predation and habitat loss affected their decline, certain population declines have been directly correlated with

4752-444: The fastest mass extinction of species in the Earth's recent history". Ecologist William E. Rees concludes that the "neoliberal paradigm contributes significantly to planetary unraveling" by treating the economy and the ecosphere as totally separate systems, and by neglecting the latter. Major lobbying organizations representing corporations in the agriculture, fisheries, forestry and paper, mining, and oil and gas industries, including

4840-659: The flowering plants as an unranked clade without a formal Latin name (angiosperms). A formal classification was published alongside the 2009 revision in which the flowering plants rank as the subclass Magnoliidae. From 1998, the Angiosperm Phylogeny Group (APG) has reclassified the angiosperms, with updates in the APG II system in 2003, the APG III system in 2009, and the APG IV system in 2016. In 2019,

4928-546: The global extinction crisis. A 2022 study published in Science Advances suggests that if global warming reaches 2.7 °C (4.9 °F) or 4.4 °C (7.9 °F) by 2100, then 13% and 27% of terrestrial vertebrate species will go extinct by then, largely due to climate change (62%), with anthropogenic land conversion and co-extinctions accounting for the rest. A 2023 study published in PLOS One shows that around two million species are threatened with extinction, double

5016-598: The growing demand for meat is contributing to significant global biodiversity loss as this is a significant driver of deforestation and habitat destruction; species-rich habitats, such as the Amazon region and Indonesia being converted to agriculture. A 2017 study by the World Wildlife Fund (WWF) found that 60% of biodiversity loss can be attributed to the vast scale of feed crop cultivation required to rear tens of billions of farm animals. Moreover,

5104-408: The history of Earth. One scientist estimates the current extinction rate may be 10,000 times the background extinction rate , although most scientists predict a much lower extinction rate than this outlying estimate. Theoretical ecologist Stuart Pimm stated that the extinction rate for plants is 100 times higher than normal. Some contend that contemporary extinction has yet to reach the level of

5192-511: The illegal wildlife trade. Populations of brown bears have experienced similar population decline. The term pollinator decline refers to the reduction in abundance of insect and other animal pollinators in many ecosystems worldwide beginning at the end of the twentieth century, and continuing into the present day. Pollinators, which are necessary for 75% of food crops, are declining globally in both abundance and diversity. A 2017 study led by Radboud University's Hans de Kroon indicated that

5280-646: The journal Frontiers in Forests and Global Change found that only around 3% of the planet's terrestrial surface is ecologically and faunally intact, meaning areas with healthy populations of native animal species and little or no human footprint. The 2019 Global Assessment Report on Biodiversity and Ecosystem Services , published by the United Nations' Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), posits that out of around eight million species of plants and animals, roughly one million species face extinction within decades as

5368-734: The last 126,000 years, which is double previous estimates. In the twentieth century, human numbers quadrupled, and the size of the global economy increased twenty-five-fold. This Great Acceleration or Anthropocene epoch has also accelerated species extinction. Ecologically , humanity is now an unprecedented "global superpredator", which consistently preys on the adults of other apex predators , takes over other species' essential habitats and displaces them, and has worldwide effects on food webs . There are many famous examples of extinctions within Africa , Asia , Europe , Australia , North and South America , and on smaller islands. Overall,

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5456-419: The last million years under the absence of human impacts" and that human civilization is causing the "rapid mutilation of the tree of life." We are currently, in a systematic manner, exterminating all non-human living beings. — Anne Larigauderie , IPBES executive secretary There is widespread consensus among scientists that human activity is accelerating the extinction of many animal species through

5544-416: The late Pleistocene , over 12,000 years ago. There is a correlation between megafaunal extinction and the arrival of humans. Megafauna that are still extant also suffered severe declines that were highly correlated with human expansion and activity. Over the past 125,000 years, the average body size of wildlife has fallen by 14% as actions by prehistoric humans eradicated megafauna on all continents with

5632-440: The leading cause in the next several decades. A June 2020 study published in PNAS posits that the contemporary extinction crisis "may be the most serious environmental threat to the persistence of civilization, because it is irreversible" and that its acceleration "is certain because of the still fast growth in human numbers and consumption rates." The study found that more than 500 vertebrate species are poised to be lost in

5720-518: The manner of vines or lianas . The number of species of flowering plants is estimated to be in the range of 250,000 to 400,000. This compares to around 12,000 species of moss and 11,000 species of pteridophytes . The APG system seeks to determine the number of families , mostly by molecular phylogenetics . In the 2009 APG III there were 415 families. The 2016 APG IV added five new orders (Boraginales, Dilleniales, Icacinales, Metteniusales and Vahliales), along with some new families, for

5808-674: The megafauna at the end of the Pleistocene, most who believe increased hunting from early modern humans also played a part, with others even suggesting that the two interacted. In the Americas, a controversial explanation for the shift in climate is presented under the Younger Dryas impact hypothesis , which states that the impact of comets cooled global temperatures. Despite its popularity among nonscientists, this hypothesis never been accepted by relevant experts, who dismiss it as

5896-424: The most recent parts of the extinction have plants also suffered large losses . The contemporary rate of extinction of species is estimated at 100 to 1,000 times higher than the background extinction rate , the historically typical rate of extinction (in terms of the natural evolution of the planet); also, the current rate of extinction is 10 to 100 times higher than in any of the previous mass extinctions in

5984-411: The next two decades. Biomass of mammals on Earth as of 2018 Humans both create and destroy crop cultivar and domesticated animal varieties. Advances in transportation and industrial farming has led to monoculture and the extinction of many cultivars. The use of certain plants and animals for food has also resulted in their extinction, including silphium and the passenger pigeon . It

6072-727: The onset of human activity, such as the extinction events of New Zealand , Madagascar, and Hawaii . Aside from humans, climate change may have been a driving factor in the megafaunal extinctions, especially at the end of the Pleistocene . Over the course of the Late Holocene, there were hundreds of extinctions of birds on islands across the Pacific, driven by human settlement of the previously uninhabited islands, with extinctions peaking around 1300 AD. Roughly 12% of avian species have been driven to extinction by human activity over

6160-424: The original local ecosystems, is a major driver of extinction. The sustained conversion of biodiversity rich forests and wetlands into poorer fields and pastures (of lesser carrying capacity for wild species), over the last 10,000 years, has considerably reduced the Earth's carrying capacity for wild birds and mammals, among other organisms, in both population size and species count. Other, related human causes of

6248-431: The patterns of the significant decline of CO 2 levels during the last ice age of the Pleistocene inversely correlate to the Holocene where there have been dramatic increases of CO 2 around 8000 years ago and CH 4 levels 3000 years after that. The correlation between the decrease of CO 2 in the Pleistocene and the increase of it during the Holocene implies that the causation of this spark of greenhouse gases into

6336-527: The peak of the Anthropocene occurred within the previous two centuries: typically beginning with the Industrial Revolution , when the highest greenhouse gas levels were recorded. A 2015 article in Science suggested that humans are unique in ecology as an unprecedented "global superpredator", regularly preying on large numbers of fully grown terrestrial and marine apex predators , and with

6424-605: The period starting from the mid-20th century different enough from the rest of the Holocene to consider it a new geological epoch , known as the Anthropocene, a term which was considered for inclusion in the timeline of Earth's history by the International Commission on Stratigraphy in 2016, but the proposal was rejected in 2024. To constitute the Holocene as an extinction event , scientists must determine exactly when anthropogenic greenhouse gas emissions began to measurably alter natural atmospheric levels on

6512-461: The previous five mass extinctions, and that this comparison downplays how severe the first five mass extinctions were. John Briggs argues that there is inadequate data to determine the real rate of extinctions, and shows that estimates of current species extinctions varies enormously, ranging from 1.5 species to 40,000 species going extinct due to human activities each year. Both papers from Barnosky et al. (2011) and Hull et al. (2015) point out that

6600-470: The primary causes of contemporary extinctions in descending order: (1) changes in land and sea use (primarily agriculture and overfishing respectively); (2) direct exploitation of organisms such as hunting; (3) anthropogenic climate change; (4) pollution and (5) invasive alien species spread by human trade. This report, along with the 2020 Living Planet Report by the WWF, both project that climate change will be

6688-621: The primary drivers of this decline. Some scientists, including Rodolfo Dirzo and Paul R. Ehrlich , contend that the sixth mass extinction is largely unknown to most people globally and is also misunderstood by many in the scientific community. They say it is not the disappearance of species, which gets the most attention, that is at the heart of the crisis, but "the existential threat of myriad population extinctions." The abundance of species extinctions considered anthropogenic , or due to human activity, has sometimes (especially when referring to hypothesized future events) been collectively called

6776-436: The processes contributing to substantial human modification of the environment spanned many thousands of years on a global scale and thus, not originating as late as the Industrial Revolution . Palaeoclimatologist William Ruddiman has argued that in the early Holocene 11,000 years ago, atmospheric carbon dioxide and methane levels fluctuated in a pattern which was different from the Pleistocene epoch before it. He argued that

6864-418: The real rate of extinction during previous mass extinctions is unknown, because only some organisms leave fossil remains, and also the temporal resolution of the fossil layer is larger than the time frame of the extinction events. However, all these authors agree that there is a modern biodiversity crisis with population declines affecting numerous species, and that a future anthropogenic mass extinction event

6952-505: The result of human actions. Organized human existence is jeopardised by increasingly rapid destruction of the systems that support life on Earth, according to the report, the result of one of the most comprehensive studies of the health of the planet ever conducted. Moreover, the 2021 Economics of Biodiversity review, published by the UK government, asserts that "biodiversity is declining faster than at any time in human history." According to

7040-482: The role that humans may have played in the production of greenhouse gases prior to the Industrial Revolution . Studies of early hunter-gatherers raise questions about the current use of population size or density as a proxy for the amount of land clearance and anthropogenic burning that took place in pre-industrial times. Scientists have questioned the correlation between population size and early territorial alterations. Ruddiman and Ellis' research paper in 2009 makes

7128-450: The sixth mass extinction "is something that hasn't happened yet – we are on the edge of it." Several studies posit that the Earth has entered a sixth mass extinction event, including a 2015 paper by Barnosky et al. and a November 2017 statement titled " World Scientists' Warning to Humanity: A Second Notice ", led by eight authors and signed by 15,364 scientists from 184 countries which asserted, among other things, that "we have unleashed

7216-568: The spring gentian, are adapted to the alkaline conditions found on calcium -rich chalk and limestone , which give rise to often dry topographies such as limestone pavement . As for their growth habit , the flowering plants range from small, soft herbaceous plants , often living as annuals or biennials that set seed and die after one growing season, to large perennial woody trees that may live for many centuries and grow to many metres in height. Some species grow tall without being self-supporting like trees by climbing on other plants in

7304-400: The term has gained broader usage in conservation biology as a global phenomenon. Big cat populations have severely declined over the last half-century and could face extinction in the following decades. According to 2011 IUCN estimates: lions are down to 25,000, from 450,000; leopards are down to 50,000, from 750,000; cheetahs are down to 12,000, from 45,000; tigers are down to 3,000 in

7392-538: The wild, from 50,000. A December 2016 study by the Zoological Society of London, Panthera Corporation and Wildlife Conservation Society showed that cheetahs are far closer to extinction than previously thought, with only 7,100 remaining in the wild, existing within only 9% of their historic range. Human pressures are to blame for the cheetah population crash, including prey loss due to overhunting by people, retaliatory killing from farmers, habitat loss and

7480-559: The world's staple calorie intake, and all three plants are cereals from the Poaceae family (colloquially known as grasses). Other families provide important industrial plant products such as wood , paper and cotton , and supply numerous ingredients for beverages , sugar production , traditional medicine and modern pharmaceuticals . Flowering plants are also commonly grown for decorative purposes , with certain flowers playing significant cultural roles in many societies. Out of

7568-655: The world. The direct killing of megafauna for meat and body parts is the primary driver of their destruction, with 70% of the 362 megafauna species in decline as of 2019. Mammals in particular have suffered such severe losses as the result of human activity (mainly during the Quaternary extinction event , but partly during the Holocene) that it could take several million years for them to recover. Contemporary assessments have discovered that roughly 41% of amphibians, 25% of mammals, 21% of reptiles and 14% of birds are threatened with extinction, which could disrupt ecosystems on

7656-483: Was coined in the form "Angiospermae" by Paul Hermann in 1690, including only flowering plants whose seeds were enclosed in capsules. The term angiosperm fundamentally changed in meaning in 1827 with Robert Brown , when angiosperm came to mean a seed plant with enclosed ovules. In 1851, with Wilhelm Hofmeister 's work on embryo-sacs, Angiosperm came to have its modern meaning of all the flowering plants including Dicotyledons and Monocotyledons. The APG system treats

7744-450: Was estimated in 2012 that 13% of Earth's ice-free land surface is used as row-crop agricultural sites, 26% used as pastures, and 4% urban-industrial areas. In March 2019, Nature Climate Change published a study by ecologists from Yale University , who found that over the next half century, human land use will reduce the habitats of 1,700 species by up to 50%, pushing them closer to extinction. That same month PLOS Biology published

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