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51-397: Thus, for a period of 53 million years India retained a degree of isolation, 11 of which it was a complete island continent. This allowed its local biota to follow the typical patterns seen in islands and diversify in unique ways, much as in modern Madagascar, its sister landmass. Faunal interchanges with other landmasses, like Africa and Europe (then an archipelago of islands across

102-479: A fossorial mode of life, indicating that this lifestyle may have saved them from the extinction's impacts. Several mammal genera also survived the event, although they went extinct during the Paleocene . Invertebrate fauna, especially soil invertebrates such as centipedes , were likely less affected by the extinction, and several lineages that persist today are thought to have Gondwanan ancestry. The Parreysiinae ,

153-474: A microbiome is a mix of organisms that coexist in a defined space on a much smaller scale. For example, the human microbiome is the collection of bacteria, viruses, and other microorganisms that are present on or in a human body. A biota is the total collection of organisms of a geographic region or a time period, from local geographic scales and instantaneous temporal scales all the way up to whole-planet and whole-timescale spatiotemporal scales. The biotas of

204-639: A family of freshwater crabs widespread throughout much of tropical Asia, is thought to have originated in India, despite not being of ancient Gondwanan origins themselves. Divergence estimates indicate that the Gecarcinucidae originate from Southeast Asian ancestors that dispersed to Insular India and diverged there during the middle Eocene, before India collided with Asia. As India drifted northwards, it may have come into close enough proximity to Southeast Asia to allow for dispersing lineages to colonize it. Notably, as

255-597: A gradient (2), the moisture gradient, to express the above conclusions in what is known as the Whittaker classification scheme. The scheme graphs average annual precipitation (x-axis) versus average annual temperature (y-axis) to classify biome-types. The multi-authored series Ecosystems of the World , edited by David W. Goodall , provides a comprehensive coverage of the major "ecosystem types or biomes" on Earth: The eponymously named Heinrich Walter classification scheme considers

306-575: A mainland Asian origin and colonized India during the Paleogene . The fossil record of the Paleocene of India, when the continent was a fully isolated landmass, is dubious and thus most inferrals about its fauna are somewhat speculative. It is known for certain that Deccanolestes and Bharattherium survived the K-Pg event, though for how further long did non-placental eutherians and gondwanatheres live in India

357-674: A particularly catastrophic effect in India, wiping out almost all terrestrial vertebrate lineages on the continent. It is thought that the effects of the Deccan Traps volcanism may have compounded the extinction event's impacts, making it especially devastating there. Only three extant tetrapod groups have representatives that can be verified as descending from Gondwanan endemics of Insular India: one family of frogs ( Nasikabatrachidae ), several families of caecilians ( Grandisoniidae , Chikilidae and Ichthyophiidae ), and 1 family of blindsnakes ( Gerrhopilidae ). Notably, all three lineages have

408-499: A simplification of Holdridge's; more readily accessible, but missing Holdridge's greater specificity. Whittaker based his approach on theoretical assertions and empirical sampling. He had previously compiled a review of biome classifications. Whittaker's distinction between biome and formation can be simplified: formation is used when applied to plant communities only, while biome is used when concerned with both plants and animals. Whittaker's convention of biome-type or formation-type

459-675: A subfamily of the freshwater mussel family Unionidae , are thought to have originated in East Gondwana during the Jurassic , and survived on both Africa and Insular India throughout the Cretaceous. Several different tribes ( Indochinellini , Lamellidentini , and Parreysiini ) of the Parreysiinae evolved in isolation on Insular India. These endemic tribes managed to survive the K-Pg extinction, and colonized mainland Asia via both Insular India and

510-457: A swamp, can create different kinds of communities within the same biome. Schultz (1988, 2005) defined nine ecozones (his concept of ecozone is more similar to the concept of biome than to the concept of ecozone of BBC): Robert G. Bailey nearly developed a biogeographical classification system of ecoregions for the United States in a map published in 1976. He subsequently expanded

561-433: A way to recognize the irreversible coupling of human and ecological systems at global scales and manage Earth's biosphere and anthropogenic biomes. Major anthropogenic biomes: The endolithic biome, consisting entirely of microscopic life in rock pores and cracks, kilometers beneath the surface, has only recently been discovered, and does not fit well into most classification schemes. Anthropogenic climate change has

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612-503: Is woody plant encroachment , which can change grass savanna into shrub savanna. Average temperatures have risen more than twice the usual amount in both arctic and mountainous biomes, which leads to the conclusion that arctic and mountainous biomes are currently the most vulnerable to climate change. South American terrestrial biomes have been predicted to go through the same temperature trends as arctic and mountainous biomes. With its annual average temperature continuing to increase,

663-485: Is a broader method to categorize similar communities. Whittaker used what he called "gradient analysis" of ecocline patterns to relate communities to climate on a worldwide scale. Whittaker considered four main ecoclines in the terrestrial realm. Along these gradients, Whittaker noted several trends that allowed him to qualitatively establish biome-types: Whittaker summed the effects of gradients (3) and (4) to get an overall temperature gradient and combined this with

714-407: Is a distinct geographical region with specific climate , vegetation , and animal life . It consists of a biological community that has formed in response to its physical environment and regional climate . Biomes may span more than one continent. A biome encompasses multiple ecosystems within its boundaries. It can also comprise a variety of habitats . While a biome can cover small areas,

765-747: Is also known, extending the range of this clade into the Late Cretaceous and the southern continents. The herpetofauna of India in the Cretaceous is a mosaic of indigenous groups and forms that rafted their way from Asia. Neobatrachians are an indigenous clade and locally well represented as they are in Madagascar in the form of ranids , hylids , leptodactylids , pelobatids and discoglossids , as are madtsoiid snakes like Sanajeh and possibly Indophis and iguanian lizards, while anguids are from Laurasia . Caecillians are an indigenous Gondwanan clade, but their absence in Madagascar suggests that

816-488: Is either the most basal Euarchontan, as the earliest known Adapisoriculid , or as a stem- afrotherian . Deccanolestes hislopi is based on an isolated first upper molar (VPL/JU/NKIM/10). A third molar, a lower third premolar, various other isolated teeth, and some postcranial remains have been referred to it. Deccanolestes robustus is based on an isolated lower first molar. Isolated teeth and some ankle remains have also been referred to it. Deccanolestes narmadensis

867-631: Is the presence of stegosaurs , the last remaining members of this lineage; if these aren't misidentified remains of herbivorous notosuchians and sauropods, then these relics would be the only indigenous ornithischians in the entire Indo-Malagasy landmass. Another possible deviation is the presence of a troodontid , a lineage more typically associated with Laurasia and thus possibly indicating interchange with Europe or even mainland Asia , but these remains are controversial and could belong either other theropods or notosuchians. The mammalian fauna of India also bears similarities with that of Madagascar, with

918-420: Is unknown, and by the time the landmass makes contact with Asia they are most likely extinct. During this epoch, unambiguous placental mammals make their way into India in spite of its isolation, probably by rafting like the many placental groups in Madagascar, or perhaps brief connections with Africa and Europe (the latter still an archipelago). Hyaenodonts are an endemic African clade, first showing outside of

969-566: Is used as an international, non-regional, terminology—irrespectively of the continent in which an area is present, it takes the same biome name—and corresponds to his "zonobiome", "orobiome" and "pedobiome" (biomes determined by climate zone, altitude or soil). In the Brazilian literature, the term biome is sometimes used as a synonym of biogeographic province , an area based on species composition (the term floristic province being used when plant species are considered), or also as synonym of

1020-596: The Burma Terrane , the latter of which collided with and was pushed north by Insular India during the Paleogene. They are now found throughout much of India and Southeast Asia. Similarly, numerous lineages of mantises (clade Cernomantodea ) are thought to have originated on the Antarctic -Indian landmass after the breakup of Gondwana, and persisted on Insular India after it broke away. This massive diversity of mantises survived

1071-576: The Seychelles still retain an indigenous herpetofauna , presumably an echo of the amphibian and reptile species seen in India as an island. The Burma Terrane or West Burma block , an isolated island arc that was present in the Tethys Sea during the Cretaceous, collided with Insular India during the Paleocene and was pushed northwards, eventually colliding with mainland Asia independent of Insular India's own collision. Much of western Myanmar consists of

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1122-594: The World Wildlife Fund (WWF) developed a scheme that divided the world's land area into biogeographic realms (called "ecozones" in a BBC scheme), and these into ecoregions (Olson & Dinerstein, 1998, etc.). Each ecoregion is characterized by a main biome (also called major habitat type). This classification is used to define the Global 200 list of ecoregions identified by the WWF as priorities for conservation. For

1173-621: The gondwanathere Bharattherium , one of the most common mammals, being extremely similar to the malagasy Lavanify . The most diverse mammals in the Maastrichtian of India are eutherians , a clade normally associated with northern continents and also found in Madagascar in this epoch , which combined with their ambiguous phylogenetic positions renders them extremely important in the understanding of placental evolution. Some like Deccanolestes have been variously interpreted as euarchontans , adapisoriculids , or stem- afrotherians , though

1224-550: The terrestrial ecoregions , there is a specific EcoID, format XXnnNN (XX is the biogeographic realm , nn is the biome number, NN is the individual number). The applicability of the realms scheme above - based on Udvardy (1975)—to most freshwater taxa is unresolved. According to the WWF, the following are classified as freshwater biomes: Biomes of the coastal and continental shelf areas ( neritic zone ): Example: Pruvot (1896) zones or "systems": Longhurst (1998) biomes : Other marine habitat types (not covered yet by

1275-420: The "morphoclimatic and phytogeographical domain" of Ab'Sáber , a geographic space with subcontinental dimensions, with the predominance of similar geomorphologic and climatic characteristics, and of a certain vegetation form. Both include many biomes in fact. To divide the world into a few ecological zones is difficult, notably because of the small-scale variations that exist everywhere on earth and because of

1326-755: The Asian species have descended from African species that colonized India as it drifted north. The divergence between African and Asian groups has been estimated at 120 million years ago, indicating that this likely happened during the Cretaceous. Several fish taxa are known from estuarine locales; most are marine species, but there are also forms like lepisosteids , which do also occur in Africa but are otherwise rare in Gondwanan landmasses. Cichlids and other forms suspected of having had an Indian Gondwanan origin were most likely present. The Cretaceous-Paleogene extinction event had

1377-489: The Earth make up the biosphere . The term was suggested in 1916 by Clements , originally as a synonym for biotic community of Möbius (1877). Later, it gained its current definition, based on earlier concepts of phytophysiognomy , formation and vegetation (used in opposition to flora ), with the inclusion of the animal element and the exclusion of the taxonomic element of species composition . In 1935, Tansley added

1428-523: The Gecarcinucidae are a freshwater group that could not disperse via marine habitats, this indicates that temporary land bridges may have formed in the Eocene between India and Southeast Asia, allowing for the dispersal of freshwater organisms to India while it was still isolated. Following the India-Asia collision, the Gecarcinucidae dispersed back into mainland Asia. The giant madtsoiid snake Vasuki indicus

1479-639: The Global 200/WWF scheme): Humans have altered global patterns of biodiversity and ecosystem processes. As a result, vegetation forms predicted by conventional biome systems can no longer be observed across much of Earth's land surface as they have been replaced by crop and rangelands or cities. Anthropogenic biomes provide an alternative view of the terrestrial biosphere based on global patterns of sustained direct human interaction with ecosystems, including agriculture , human settlements , urbanization , forestry and other uses of land . Anthropogenic biomes offer

1530-499: The Indian Subcontinent until the evolution of the marine " protocetids ". Eocene India is also rich in bat remains, including many representatives of modern groups, though its unclear if this Indian chiropteran fauna represents an adaptive radiation or simply that bat fossils elsewhere are rare. During this time, lagomorphs and hyaenodonts disperse out of India, establishing their cosmopolitan ranges. The Gecarcinucidae ,

1581-494: The K-Pg extinction and invaded mainland Asia following the collision of Insular India with Asia. Following the near-total extirpation of vertebrate life from India during the K-Pg extinction, India's vertebrate fauna was successively rebuilt by dispersing lineages primarily from Asia, first over water during its period of isolation, and later via land when it collided with Asia. Some of India's surviving tetrapod Gondwanan vertebrate lineages were outcompeted by these new arrivals. It

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1632-505: The Tethys) occurred during this period, and a considerable Asian influence can already been seen long before contact was made. This rendered India rather peculiar as not just an isolated continent but also a "stepping stone" in the dispersal of many animal and plant clades across Africa, Europe, Madagascar, Asia and possibly even Oceania . Still, several "archaic" clades managed to survive. The vast majority of India's terrestrial vertebrate life

1683-474: The climatic and soil aspects to the idea, calling it ecosystem . The International Biological Program (1964–74) projects popularized the concept of biome. However, in some contexts, the term biome is used in a different manner. In German literature, particularly in the Walter terminology, the term is used similarly as biotope (a concrete geographical unit), while the biome definition used in this article

1734-634: The continent and diversified. The Dipterocarpaceae are now among the most widespread and dominant tree groups in tropical Asia. Fossil evidence indicates that the other subfamily of Dipterocarpaceae, the Monotoideae (presently found in Africa, Madagasar , and South America ), also colonized India and was present until the Eocene , but ultimately went extinct in India and thus did not disperse to other parts of Asia. Biome A biome ( / ˈ b aɪ . oʊ m / )

1785-591: The continent in the Paleocene of India and Europe. Glires evolved in Asia, but a lineage became isolated in India, where it gave rise to the lagomorphs. For a while it was theorised that ostriches evolved in India during this epoch, under the assumption that European ratites like Palaeotis represented recent Asiatic migrations. However, the first unambiguous ostriches are now thought to have evolved in Africa, with eogruiids having occupied their ecological niche in Asia; likewise, European ratites are now thought to be among

1836-455: The continent. By the time full contact was established, a large percentage of India's old and new indigenous fauna had been outcompeted by Eurasian species. However, several groups like lagomorphs have become widespread across the world, as have floral groups such as dipterocarps , which went on to become dominant tree species throughout much of tropical Asia. A significant portion of Asian mantises also originated on Insular India. The islands of

1887-458: The former Burma Terrane. The Cretaceous fauna of India is well attested in both Coniacian and Maastrichtian aged sites such as the Lameta Formation . Generally speaking, the local dinosaurian and crocodilian fauna is almost identical to that of Madagascar , with clades like abelisaurids , titanosaurs , noasaurids and notosuchians being well represented here. A possible deviation

1938-525: The general consensus appears to be that they are non-placental eutherians and that there are non known Cretaceous placentals . Kharmerungulatum , formerly interpreted as a stem- ungulate , is now known to be a representative of Zhelestidae , a herbivorous non-placental eutherian clade. Regardless of the phylogenetics of these eutherians, they almost certainly reached India and Madagascar through either Europe, Africa or mainland Asia; later they would propagate across Gondwana as far west as Brazil . Probably

1989-401: The gradual changeover from one biome to the other. Their boundaries must therefore be drawn arbitrarily and their characterization made according to the average conditions that predominate in them. A 1978 study on North American grasslands found a positive logistic correlation between evapotranspiration in mm/yr and above-ground net primary production in g/m /yr. The general results from

2040-470: The moisture currently located in forest biomes will dry up. Deccanolestes Deccanolestes is a scansorial , basal Euarchontan from the Late Cretaceous ( Maastrichtian ) and Paleocene Intertrappean Beds of Andhra Pradesh , India . It may be closely related to Sahnitherium . Deccanolestes has been referred to Palaeoryctidae in the past, but recent evidence has shown that it

2091-483: The most spectacular representative of India's Cretaceous fauna is Avashishta , a late surviving haramiyid and the last known non-mammalian synapsid . Non-gondwanathere multituberculates and meridiolestidans can probably also be inferred as having lived in India during this epoch, due to the former's presence in all landmasses including Madagascar and the latter being the dominant mammals in other known Gondwannan sites. An eutriconodont , Indotriconodon magnus ,

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2142-764: The oldest known, and probably evolved independently there, being unrelated to ostriches. Still, India probably had a thriving paleognath fauna; the volant ancestors of kiwis and elephant birds presumably flew from there to Oceania and Madagascar respectively, while the mysterious Hypselornis may represent an indigenous clade. By this time India already has an extensive placental fauna (as well as metatherians like Indodelphis ), but in its isolation there are still high degrees of endemism, with some clades like anthracobunids not being found elsewhere. A study on Cambaytherium suggests that Perissodactyla might have had an insular origin in India. The most notable endemic mammals are cetaceans , which are in fact restricted to

2193-410: The potential to greatly alter the distribution of Earth's biomes. Meaning, biomes around the world could change so much that they would be at risk of becoming new biomes entirely. More specifically, between 54% and 22% of global land area will experience climates that correspond to other biomes. 3.6% of land area will experience climates that are completely new or unusual. An example of a biome shift

2244-418: The seasonality of temperature and precipitation. The system, also assessing precipitation and temperature, finds nine major biome types, with the important climate traits and vegetation types . The boundaries of each biome correlate to the conditions of moisture and cold stress that are strong determinants of plant form, and therefore the vegetation that defines the region. Extreme conditions, such as flooding in

2295-489: The study were that precipitation and water use led to above-ground primary production, while solar irradiation and temperature lead to below-ground primary production (roots), and temperature and water lead to cool and warm season growth habit. These findings help explain the categories used in Holdridge's bioclassification scheme (see below), which were then later simplified by Whittaker. The number of classification schemes and

2346-405: The system to include the rest of North America in 1981, and the world in 1989. The Bailey system, based on climate, is divided into four domains (polar, humid temperate, dry, and humid tropical), with further divisions based on other climate characteristics (subarctic, warm temperate, hot temperate, and subtropical; marine and continental; lowland and mountain). A team of biologists convened by

2397-485: The types of vegetation found in a habitat. Holdridge uses the four axes to define 30 so-called "humidity provinces", which are clearly visible in his diagram. While this scheme largely ignores soil and sun exposure, Holdridge acknowledged that these were important. The principal biome-types by Allee (1949): The principal biomes of the world by Kendeigh (1961): Whittaker classified biomes using two abiotic factors: precipitation and temperature. His scheme can be seen as

2448-475: The variety of determinants used in those schemes, however, should be taken as strong indicators that biomes do not fit perfectly into the classification schemes created. In 1947, the American botanist and climatologist Leslie Holdridge classified climates based on the biological effects of temperature and rainfall on vegetation under the assumption that these two abiotic factors are the largest determinants of

2499-569: Was likely the apex predator of this time and environment. The Dipterocarpoideae , the largest subfamily of the Dipterocarpaceae , is thought to originate from ancestors that dispersed from Africa to India during the Late Cretaceous. Surviving the K-Pg extinction event, the Dipterocarpoideae were isolated on Insular India (aside from some representatives in the Seychelles ) until India's collision with Asia, after which they migrated out of

2550-403: Was previously thought that several major families of Neobatrachia ( Ranidae , Dicroglossidae , Rhacophoridae ) originated in India from an ancestor that colonized the continent from Africa during the Cretaceous. This was supported by closely related families ( Nyctibatrachidae , Ranixalidae , Micrixalidae ) being endemic to India. However, more recent studies hypothesize that these families have

2601-514: Was wiped out in the Cretaceous-Paleogene extinction event ; only 3 extant tetrapod lineages can trace their ancestry to Cretaceous India. Most of India's few other surviving Gondwanan lineages were outcompeted during the Paleogene by newly-arriving lineages. However, plants and invertebrate fauna were less affected. During the Paleogene, dispersing tetrapod lineages from Asia repopulated India, with some, such as lagomorphs , evolving on

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