Misplaced Pages

#736263

120-672: The cape, known by geologists as the Yehliu Promontory , forms part of the Daliao Miocene Formation. It stretches approximately 1,700 metres (5,600 ft) into the ocean and was formed as geological forces pushed the Datun Mountains out of the sea. A distinctive feature of the cape is the hoodoo stones that dot its surface. These shapes can be viewed at the Yehliu Geopark operated by

240-542: A broader aridification trend. The EMCI ended 18 million years ago, giving way to the Middle Miocene Warm Interval (MMWI), the warmest part of which was the MMCO that began 16 million years ago. As the world transitioned into the MMCO, carbon dioxide concentrations varied between 300 and 500 ppm. Global annual mean surface temperature during the MMCO was about 18.4 °C. MMCO warmth was driven by

360-529: A clade of large terrestrial predatory crocodyliformes distantly related to modern crocodilians, from which they likely diverged over 180 million years ago, are known from the Miocene of South America. The last Desmostylians thrived during this period before becoming the only extinct marine mammal order. The pinnipeds , which appeared near the end of the Oligocene, became more aquatic. A prominent genus

480-497: A common ancestor about 660,000 years ago. However, a sequencing of the Neanderthal genome in 2010 indicated that Neanderthals did indeed interbreed with anatomically modern humans c. 45,000-80,000 years ago, around the time modern humans migrated out from Africa, but before they dispersed throughout Europe, Asia and elsewhere. The genetic sequencing of a 40,000-year-old human skeleton from Romania showed that 11% of its genome

600-570: A cooler, drier climate. C 4 grasses, which are able to assimilate carbon dioxide and water more efficiently than C 3 grasses, expanded to become ecologically significant near the end of the Miocene between 6 and 7 million years ago, although they did not expand northward during the Late Miocene. The expansion of grasslands and radiations among terrestrial herbivores correlates to fluctuations in CO 2 . One study, however, has attributed

720-486: A good analogue for future warmer climates caused by anthropogenic global warming , with this being especially true of the global climate during the Middle Miocene Climatic Optimum (MMCO), because the last time carbon dioxide levels were comparable to projected future atmospheric carbon dioxide levels resulting from anthropogenic climate change was during the MMCO. The Ross Sea margin of

840-435: A good model for a "living fossil". Eucalyptus fossil leaves occur in the Miocene of New Zealand , where the genus is not native today, but have been introduced from Australia . Both marine and continental fauna were fairly modern, although marine mammals were less numerous. Only in isolated South America and Australia did widely divergent fauna exist. In Eurasia, genus richness shifted southward to lower latitudes from

960-608: A higher rate of depression. The flow of genes from Neanderthal populations to modern humans was not all one way. Sergi Castellano of the Max Planck Institute for Evolutionary Anthropology reported in 2016 that while Denisovan and Neanderthal genomes are more related to each other than they are to us, Siberian Neanderthal genomes show more similarity to modern human genes than do European Neanderthal populations. This suggests Neanderthal populations interbred with modern humans around 100,000 years ago, probably somewhere in

1080-598: A major expansion of Antarctic glaciers. This severed the connection between the Indian Ocean and the Mediterranean Sea and formed the present land connection between Afro-Arabia and Eurasia. The subsequent uplift of mountains in the western Mediterranean region and a global fall in sea levels combined to cause a temporary drying up of the Mediterranean Sea (known as the Messinian salinity crisis ) near

1200-480: A major expansion of grass-grazer ecosystems . Herds of large, swift grazers were hunted by predators across broad sweeps of open grasslands , displacing desert, woodland, and browsers . The higher organic content and water retention of the deeper and richer grassland soils , with long-term burial of carbon in sediments, produced a carbon and water vapor sink. This, combined with higher surface albedo and lower evapotranspiration of grassland, contributed to

1320-485: A number of clear anatomical differences between anatomically modern humans (AMH) and Neanderthal specimens, many relating to the superior Neanderthal adaptation to cold environments. Neanderthal surface to volume ratio was even lower than that among modern Inuit populations, indicating superior retention of body heat. Neanderthals also had significantly larger brains, as shown from brain endocasts, casting doubt on their intellectual inferiority to modern humans. However,

SECTION 10

#1732772700737

1440-480: A related lineage. In September 2019, scientists reported the computerized determination, based on 260 CT scans , of a virtual skull shape of the last common human ancestor to modern humans ( H. sapiens ), representative of the earliest modern humans, and suggested that modern humans arose between 260,000 and 350,000 years ago through a merging of populations in East and South Africa. Between 400,000 years ago and

1560-602: A significant drop in atmospheric carbon dioxide levels. Both continental and oceanic thermal gradients in mid-latitudes during the Early Miocene were very similar to those in the present. Global cooling caused the East Asian Summer Monsoon (EASM) to begin to take on its modern form during the Early Miocene. From 22.1 to 19.7 Ma, the Xining Basin experienced relative warmth and humidity amidst

1680-700: A significant local decline along the northeastern coast of Australia during the Tortonian, most likely due to warming seawater. Cetaceans attained their greatest diversity during the Miocene, with over 20 recognized genera of baleen whales in comparison to only six living genera. This diversification correlates with emergence of gigantic macro-predators such as megatoothed sharks and raptorial sperm whales . Prominent examples are O. megalodon and L. melvillei . Other notable large sharks were O. chubutensis , Isurus hastalis , and Hemipristis serra . Crocodilians also showed signs of diversification during

1800-469: A study of the life history of Ar. ramidus that the species provides evidence for a suite of anatomical and behavioral adaptations in very early hominins unlike any species of extant great ape. This study demonstrated affinities between the skull morphology of Ar. ramidus and that of infant and juvenile chimpanzees, suggesting the species evolved a juvenalised or paedomorphic craniofacial morphology via heterochronic dissociation of growth trajectories. It

1920-463: A woman's head, it took over 4,000 years to form. The length of its neck is 125 centimetres (49 in) and has been weathered at a rate of 0.2 to 0.5 centimetres (0.079 to 0.197 in) per year. The popularity of the site draws increasing numbers of international tourists. There is a successor to Queen's Head Rock, which is called the Princess’ Head in the park. The successor is chosen to distract

2040-651: A zone of low rainfall in the Late Miocene. The Indian Plate continued to collide with the Eurasian Plate , creating new mountain ranges and uplifting the Tibetan Plateau , resulting in the rain shadowing and aridification of the Asian interior. The Tian Shan experienced significant uplift in the Late Miocene, blocking westerlies from coming into the Tarim Basin and drying it as a result. At

2160-600: Is Kamoyapithecus from the uppermost Oligocene at Eragaleit in the northern Great Rift Valley in Kenya, dated to 24 million years ago. Its ancestry is thought to be species related to Aegyptopithecus , Propliopithecus , and Parapithecus from the Faiyum, at around 35 mya. In 2010, Saadanius was described as a close relative of the last common ancestor of the crown catarrhines, and tentatively dated to 29–28 mya, helping to fill an 11-million-year gap in

2280-445: Is claimed to have been discovered living at the same time period of A. afarensis . There is debate whether A. deyiremeda is a new species or is A. afarensis . Australopithecus prometheus , otherwise known as Little Foot has recently been dated at 3.67 million years old through a new dating technique, making the genus Australopithecus as old as afarensis . Given the opposable big toe found on Little Foot, it seems that

2400-461: Is consistent with recent studies indicating that the divergence of some human alleles dates to one Ma, although this interpretation has been questioned. Neanderthals and AMH Homo sapiens could have co-existed in Europe for as long as 10,000 years, during which AMH populations exploded, vastly outnumbering Neanderthals, possibly outcompeting them by sheer numbers. In 2008, archaeologists working at

2520-706: Is evidence of a wide diversity of forms across Africa and the Mediterranean basin during the relatively warm and equable climatic regimes of the Early and Middle Miocene. The youngest of the Miocene hominoids, Oreopithecus , is from coal beds in Italy that have been dated to 9 million years ago. Molecular evidence indicates that the lineage of gibbons diverged from the line of great apes some 18–12 mya, and that of orangutans (subfamily Ponginae ) diverged from

SECTION 20

#1732772700737

2640-486: Is intriguing both for its size and its age, being an example of a recent species of the genus Homo that exhibits derived traits not shared with modern humans. In other words, H. floresiensis shares a common ancestor with modern humans, but split from the modern human lineage and followed a distinct evolutionary path. The main find was a skeleton believed to be a woman of about 30 years of age. Found in 2003, it has been dated to approximately 18,000 years old. The living woman

2760-405: Is limited; both poor preservation – rain forest soils tend to be acidic and dissolve bone – and sampling bias probably contribute to this problem. Other hominins probably adapted to the drier environments outside the equatorial belt; and there they encountered antelope, hyenas, dogs, pigs, elephants, horses, and others. The equatorial belt contracted after about 8 million years ago, and there

2880-682: Is of particular interest to geologists and palaeoclimatologists because major phases of the geology of the Himalaya occurred during that epoch, affecting monsoonal patterns in Asia, which were interlinked with glacial periods in the northern hemisphere. The Miocene faunal stages from youngest to oldest are typically named according to the International Commission on Stratigraphy : Regionally, other systems are used, based on characteristic land mammals; some of them overlap with

3000-715: Is seen most completely in the Upper Eocene and lowermost Oligocene fossil beds of the Faiyum depression southwest of Cairo —gave rise to all extant primate species, including the lemurs of Madagascar , lorises of Southeast Asia, galagos or "bush babies" of Africa, and to the anthropoids , which are the Platyrrhines or New World monkeys, the Catarrhines or Old World monkeys, and the great apes, including humans and other hominids. The earliest known catarrhine

3120-523: Is still some debate among academics whether certain African hominid species of this time, such as A. robustus and A. boisei , constitute members of the same genus; if so, they would be considered to be "robust australopiths" while the others would be considered "gracile australopiths". However, if these species do indeed constitute their own genus, then they may be given their own name, Paranthropus . A new proposed species Australopithecus deyiremeda

3240-693: Is supported in part, because some modern humans who live on Flores , the Indonesian island where the skeleton was found, are pygmies . This, coupled with pathological dwarfism, could have resulted in a significantly diminutive human. The other major attack on H. floresiensis as a separate species is that it was found with tools only associated with H. sapiens . The hypothesis of pathological dwarfism, however, fails to explain additional anatomical features that are unlike those of modern humans (diseased or not) but much like those of ancient members of our genus. Aside from cranial features, these features include

3360-595: Is the first geological epoch of the Neogene Period and extends from about 23.03 to 5.333 million years ago (Ma). The Miocene was named by Scottish geologist Charles Lyell ; the name comes from the Greek words μείων ( meíōn , "less") and καινός ( kainós , "new") and means "less recent" because it has 18% fewer modern marine invertebrates than the Pliocene has. The Miocene followed

3480-408: Is very little fossil evidence for the split—thought to have occurred around that time—of the hominin lineage from the lineages of gorillas and chimpanzees. The earliest fossils argued by some to belong to the human lineage are Sahelanthropus tchadensis (7 Ma) and Orrorin tugenensis (6 Ma), followed by Ardipithecus (5.5–4.4 Ma), with species Ar. kadabba and Ar. ramidus . It has been argued in

3600-629: The Gorillini tribe between 8 and 9 mya; Australopithecine (including the extinct biped ancestors of humans) separated from the Pan genus (containing chimpanzees and bonobos ) 4–7 mya. The Homo genus is evidenced by the appearance of H. habilis over 2 mya, while anatomically modern humans emerged in Africa approximately 300,000 years ago. The evolutionary history of primates can be traced back 65 million years. One of

3720-625: The Late Cretaceous period, with their earliest fossils appearing over 55 mya, during the Paleocene . Primates produced successive clades leading to the ape superfamily, which gave rise to the hominid and the gibbon families; these diverged some 15–20 mya. African and Asian hominids (including orangutans ) diverged about 14 mya. Hominins (including the Australopithecine and Panina subtribes) parted from

Yehliu - Misplaced Pages Continue

3840-493: The Late Pliocene or Early Pleistocene , 2.5–2 Ma, when it diverged from the australopithecines with the development of smaller molars and larger brains. One of the first known hominins, it made tools from stone and perhaps animal bones, leading to its name homo habilis (Latin 'handy man') bestowed by discoverer Louis Leakey . Some scientists have proposed moving this species from Homo into Australopithecus due to

3960-559: The Middle Miocene Climate Transition (MMCT). Abrupt increases in opal deposition indicate this cooling was driven by enhanced drawdown of carbon dioxide via silicate weathering. The MMCT caused a sea surface temperature (SST) drop of approximately 6 °C in the North Atlantic. The drop in benthic foraminiferal δ O values was most noticeable in the waters around Antarctica, suggesting cooling

4080-631: The North Coast and Guanyinshan National Scenic Area administration. A number of rock formations have been given imaginative names based on their shapes. The best known is the "Queen's Head" (女王頭), an iconic image in Taiwan and an unofficial emblem for the town of Wanli. Other formations include the "Fairy Shoe", the "Beehive", the "Ginger Rocks", and the "Sea Candles". Queens Head Rock is a natural formation in Yehliu, Taiwan. Named after its resemblance to

4200-522: The Oligocene and preceded the Pliocene. As Earth went from the Oligocene through the Miocene and into the Pliocene, the climate slowly cooled towards a series of ice ages . The Miocene boundaries are not marked by distinct global events but by regionally defined transitions from the warmer Oligocene to the cooler Pliocene Epoch. During the Early Miocene, Afro-Arabia collided with Eurasia, severing

4320-468: The Pleistocene played a significant role in human evolution observed via human transitions between subsistence systems. The most significant of these adaptations are bipedalism, increased brain size, lengthened ontogeny (gestation and infancy), and decreased sexual dimorphism . The relationship between these changes is the subject of ongoing debate. Other significant morphological changes included

4440-560: The carbon cycle occurred approximately 6 Ma, causing continental carbon reservoirs to no longer expand during cold spells, as they had done during cold periods in the Oligocene and most of the Miocene. At the end of the Miocene, global temperatures rose again as the amplitude of Earth's obliquity increased, which caused increased aridity in Central Asia. Around 5.5 Ma, the EAWM underwent a period of rapid intensification. Life during

4560-466: The fossil record , cranial capacity had doubled to 850 cm . (Such an increase in human brain size is equivalent to each generation having 125,000 more neurons than their parents.) It is believed that H. erectus and H. ergaster were the first to use fire and complex tools, and were the first of the hominin line to leave Africa, spreading throughout Africa, Asia, and Europe between 1.3 to 1.8 million years ago . According to

4680-458: The history of primates that led to the emergence of Homo sapiens as a distinct species of the hominid family that includes all the great apes . This process involved the gradual development of traits such as human bipedalism , dexterity , and complex language , as well as interbreeding with other hominins (a tribe of the African hominid subfamily), indicating that human evolution

4800-525: The Australopithecine and Panina subtribes) parted from the Gorillini tribe (gorillas) between 8 and 9 mya; Australopithecine (including the extinct biped ancestors of humans) separated from the Pan genus (containing chimpanzees and bonobos) 4–7 mya. The Homo genus is evidenced by the appearance of H. habilis over 2 mya, while anatomically modern humans emerged in Africa approximately 300,000 years ago. Species close to

4920-710: The Central Paratethys, cut off from sources of freshwater input by its separation from the Eastern Paratethys. From 13.36 to 12.65 Ma, the Central Paratethys was characterised by open marine conditions, before the reopening of the Bârlad Strait resulted in a shift to brackish-marine conditions in the Central Paratethys, causing the Badenian-Sarmatian Extinction Event. As a result of the Bârlad Strait's reopening,

Yehliu - Misplaced Pages Continue

5040-834: The Early Pleistocene, 1.5–1 Ma, some populations of Homo habilis are thought to have evolved larger brains and to have made more elaborate stone tools; these differences and others are sufficient for anthropologists to classify them as a new species, Homo erectus —in Africa. The evolution of locking knees and the movement of the foramen magnum are thought to be likely drivers of the larger population changes. This species also may have used fire to cook meat. Richard Wrangham notes that Homo seems to have been ground dwelling, with reduced intestinal length, smaller dentition, and "brains [swollen] to their current, horrendously fuel-inefficient size", and hypothesizes that control of fire and cooking, which released increased nutritional value,

5160-785: The Early to the Middle Miocene. Europe's large mammal diversity significantly declined during the Late Miocene. In the Early Miocene, several Oligocene groups were still diverse, including nimravids , entelodonts , and three-toed equids. As in the previous Oligocene Epoch, oreodonts were still diverse, only to disappear in the earliest Pliocene. During the later Miocene mammals were more modern, with easily recognizable canids , bears , red pandas , procyonids , equids , beavers , deer , camelids , and whales , along with now-extinct groups like borophagine canids , certain gomphotheres , three-toed horses , and hornless rhinos like Teleoceras and Aphelos . The late Miocene also marks

5280-720: The East Antarctic Ice Sheet (EAIS) was highly dynamic during the Early Miocene. The Miocene began with the Early Miocene Cool Event (Mi-1) around 23 million years ago, which marked the start of the Early Miocene Cool Interval (EMCI). This cool event occurred immediately after the Oligocene-Miocene Transition (OMT) during a major expansion of Antarctica's ice sheets, but was not associated with

5400-545: The East Asian Winter Monsoon (EAWM) became stronger synchronously with a southward shift of the subarctic front. Greenland may have begun to have large glaciers as early as 8 to 7 Ma, although the climate for the most part remained warm enough to support forests there well into the Pliocene. Zhejiang, China was noticeably more humid than today. In the Great Rift Valley of Kenya , there

5520-518: The Indonesian island of Java. He originally named the material Anthropopithecus erectus (1892–1893, considered at this point as a chimpanzee-like fossil primate) and Pithecanthropus erectus (1893–1894, changing his mind as of based on its morphology, which he considered to be intermediate between that of humans and apes). Years later, in the 20th century, the German physician and paleoanthropologist Franz Weidenreich (1873–1948) compared in detail

5640-460: The LMC; extratropical sea surface temperatures dropped substantially by approximately 7–9 °C. 41 kyr obliquity cycles became the dominant orbital climatic control 7.7 Ma and this dominance strengthened 6.4 Ma. Benthic δ O values show significant glaciation occurred from 6.26 to 5.50 Ma, during which glacial-interglacial cycles were governed by the 41 kyr obliquity cycle. A major reorganisation of

5760-526: The Late Cretaceous, are known from the Miocene of Patagonia, represented by the mole-like Necrolestes . The youngest known representatives of metatherians (the broader grouping to which marsupials belong) in Europe, Asia and Africa are known from the Miocene, including the European herpetotheriid Amphiperatherium , the peradectids Siamoperadectes and Sinoperadectes from Asia, and

5880-705: The Late Miocene, the Earth's climate began to display a high degree of similarity to that of the present day . The 173 kyr obliquity modulation cycle governed by Earth's interactions with Saturn became detectable in the Late Miocene. By 12 Ma, Oregon was a savanna akin to that of the western margins of the Sierra Nevada of northern California . Central Australia became progressively drier, although southwestern Australia experienced significant wettening from around 12 to 8 Ma. The South Asian Winter Monsoon (SAWM) underwent strengthening ~9.2–8.5 Ma. From 7.9 to 5.8 Ma,

6000-574: The Miocene Epoch was mostly supported by the two newly formed biomes , kelp forests and grasslands . Grasslands allow for more grazers, such as horses , rhinoceroses , and hippos . Ninety-five percent of modern plants existed by the end of this epoch . Modern bony fish genera were established. A modern-style latitudinal biodiversity gradient appeared ~15 Ma. The coevolution of gritty , fibrous, fire-tolerant grasses and long-legged gregarious ungulates with high-crowned teeth , led to

6120-449: The Miocene. The largest form among them was a gigantic caiman Purussaurus which inhabited South America. Another gigantic form was a false gharial Rhamphosuchus , which inhabited modern age India . A strange form, Mourasuchus also thrived alongside Purussaurus . This species developed a specialized filter-feeding mechanism, and it likely preyed upon small fauna despite its gigantic size. The youngest members of Sebecidae ,

SECTION 50

#1732772700737

6240-635: The Miocene–Pliocene boundary, the Strait of Gibraltar opened, and the Mediterranean refilled. That event is referred to as the " Zanclean flood ". Also during the early Miocene (specifically the Aquitanian and Burdigalian Stages), the apes first evolved, began diversifying, and became widespread throughout the Old World . Around the end of this epoch, the ancestors of humans had split away from

6360-455: The Near East. Studies of a Neanderthal child at Gibraltar show from brain development and tooth eruption that Neanderthal children may have matured more rapidly than Homo sapiens . H. floresiensis , which lived from approximately 190,000 to 50,000 years before present (BP), has been nicknamed the hobbit for its small size, possibly a result of insular dwarfism . H. floresiensis

6480-550: The North American Great Plains and in Argentina . The global trend was towards increasing aridity caused primarily by global cooling reducing the ability of the atmosphere to absorb moisture, particularly after 7 to 8 million years ago. Uplift of East Africa in the late Miocene was partly responsible for the shrinking of tropical rain forests in that region, and Australia got drier as it entered

6600-656: The Oligocene–Miocene transgression. As the southern Andes rose in the Middle Miocene (14–12 million years ago) the resulting rain shadow originated the Patagonian Desert to the east. Far northern Australia was monsoonal during the Miocene. Although northern Australia is often believed to have been much wetter during the Miocene, this interpretation may be an artefact of preservation bias of riparian and lacustrine plants; this finding has itself been challenged by other papers. Western Australia, like today,

6720-561: The Qiongdongnan Basin in the northern South China Sea indicates the Pearl River was a major source of sediment flux into the sea during the Early Miocene and was a major fluvial system as in the present. During the Oligocene and Early Miocene, the coast of northern Brazil, Colombia, south-central Peru , central Chile and large swathes of inland Patagonia were subject to a marine transgression . The transgressions in

6840-608: The Toba catastrophe; however, nearby H. floresiensis survived it. The early phase of H. erectus , from 1.8 to 1.25 Ma, is considered by some to be a separate species, H. ergaster , or as H. erectus ergaster , a subspecies of H. erectus . Many paleoanthropologists now use the term Homo ergaster for the non-Asian forms of this group, and reserve H. erectus only for those fossils that are found in Asia and meet certain skeletal and dental requirements which differ slightly from H. ergaster . In Africa in

6960-471: The absence of aggressive canine morphology in Ar. ramidus and the implications this has for the evolution of hominin social psychology, they wrote: Of course Ar. ramidus differs significantly from bonobos, bonobos having retained a functional canine honing complex. However, the fact that Ar. ramidus shares with bonobos reduced sexual dimorphism, and a more paedomorphic form relative to chimpanzees, suggests that

7080-497: The activity of the Columbia River Basalts and enhanced by decreased albedo from the reduction of deserts and expansion of forests. Climate modelling suggests additional, currently unknown, factors also worked to create the warm conditions of the MMCO. The MMCO saw the expansion of the tropical climatic zone to much larger than its current size. The July ITCZ, the zone of maximal monsoonal rainfall, moved to

7200-531: The ancestors of the chimpanzees and had begun following their own evolutionary path during the final Messinian Stage (7.5–5.3 Ma) of the Miocene. As in the Oligocene before it, grasslands continued to expand, and forests to dwindle. In the seas of the Miocene, kelp forests made their first appearance and soon became one of Earth's most productive ecosystems. The plants and animals of the Miocene were recognizably modern. Mammals and birds were well established. Whales , pinnipeds , and kelp spread. The Miocene

7320-439: The ancestral hominin line. There is yet no consensus as to which of these groups should be considered a separate species and which should be subspecies; this may be due to the dearth of fossils or to the slight differences used to classify species in the genus Homo . The Sahara pump theory (describing an occasionally passable "wet" Sahara desert) provides one possible explanation of the intermittent migration and speciation in

SECTION 60

#1732772700737

7440-405: The ancient forest and woodland ecosystems of late Miocene and early Pliocene Africa. Consequently, they argue that humans may not represent evolution from a chimpanzee-like ancestor as has traditionally been supposed. This suggests many modern human adaptations represent phylogenetically deep traits and that the behavior and morphology of chimpanzees may have evolved subsequent to the split with

7560-472: The aridity of the former. Unequivocally-recognizable dabbling ducks , plovers , typical owls , cockatoos and crows appear during the Miocene. By the epoch's end, all or almost all modern bird groups are believed to have been present; the few post-Miocene bird fossils which cannot be placed in the evolutionary tree with full confidence are simply too badly preserved, rather than too equivocal in character. Marine birds reached their highest diversity ever in

7680-639: The attention of the Queen's Head and prevent the Queen's Head Rock from being touched by tourists and accelerate the damage. Since the Queen's Head Rock is fragile, it has been protected by a stone necklace. 25°12′47″N 121°41′53″E  /  25.2131°N 121.698°E  / 25.2131; 121.698 This article about a location in Taiwan is a stub . You can help Misplaced Pages by expanding it . Miocene The Miocene ( / ˈ m aɪ . ə s iː n , - oʊ -/ MY -ə-seen, -⁠oh- )

7800-583: The beginning of the Miocene, the northern margin of the Arabian plate, then part of the African landmass, collided with Eurasia; as a result, the Tethys seaway continued to shrink and then disappeared as Africa collided with Eurasia in the Turkish – Arabian region. The first step of this closure occurred 20 Ma, reducing water mass exchange by 90%, while the second step occurred around 13.8 Ma, coincident with

7920-513: The characters of Dubois' Java Man , then named Pithecanthropus erectus , with the characters of the Peking Man , then named Sinanthropus pekinensis . Weidenreich concluded in 1940 that because of their anatomical similarity with modern humans it was necessary to gather all these specimens of Java and China in a single species of the genus Homo , the species H. erectus . Homo erectus lived from about 1.8 Ma to about 70,000 years ago – which would indicate that they were probably wiped out by

8040-401: The common ancestor they share with humans. The genus Australopithecus evolved in eastern Africa around 4 million years ago before spreading throughout the continent and eventually becoming extinct 2 million years ago. During this time period various forms of australopiths existed, including Australopithecus anamensis , A. afarensis , A. sediba , and A. africanus . There

8160-422: The connection between the Mediterranean and Indian Oceans, and allowing the interchange of fauna between Eurasia and Africa, including the dispersal of proboscideans and hominoids into Eurasia. During the late Miocene, the connections between the Atlantic and Mediterranean closed, causing the Mediterranean Sea to almost completely evaporate. This event is referred to as the " Messinian salinity crisis ". Then, at

8280-460: The course of this epoch . The youngest representatives of Choristodera , an extinct order of aquatic reptiles that first appeared in the Middle Jurassic , are known from the Miocene of Europe, belonging to the genus Lazarussuchus , which had been the only known surviving genus of the group since the beginning of the Eocene. The last known representatives of the archaic primitive mammal order Meridiolestida , which dominated South America during

8400-408: The developmental and social adaptations evident in bonobos may be of assistance in future reconstructions of early hominin social and sexual psychology. In fact the trend towards increased maternal care, female mate selection and self-domestication may have been stronger and more refined in Ar. ramidus than what we see in bonobos. The authors argue that many of the basic human adaptations evolved in

8520-402: The distribution of stone tools), and faster spread of social and technological innovations. All these may have all contributed to modern Homo sapiens replacing Neanderthal populations by 28,000 BP. Earlier evidence from sequencing mitochondrial DNA suggested that no significant gene flow occurred between H. neanderthalensis and H. sapiens , and that the two were separate species that shared

8640-478: The divergence point of the mtDNA was unexpectedly deep in time, the full genomic sequence suggested the Denisovans belonged to the same lineage as Neanderthals, with the two diverging shortly after their line split from the lineage that gave rise to modern humans. Modern humans are known to have overlapped with Neanderthals in Europe and the Near East for possibly more than 40,000 years, and the discovery raises

8760-472: The earlier dispersed H. erectus . This migration and origin theory is usually referred to as the "recent single-origin hypothesis" or "out of Africa" theory. H. sapiens interbred with archaic humans both in Africa and in Eurasia, in Eurasia notably with Neanderthals and Denisovans. The Toba catastrophe theory , which postulates a population bottleneck for H. sapiens about 70,000 years ago,

8880-554: The early to mid Miocene (23–15 Ma). Oceans cooled partly due to the formation of the Antarctic Circumpolar Current , and about 15 million years ago the ice cap in the southern hemisphere started to grow to its present form. The Greenland ice cap developed later, in the Middle Pliocene time, about 3 million years ago. Human evolution Human evolution is the evolutionary process within

9000-578: The end of the Miocene due to increased habitat uniformity. The expansion of grasslands in North America also led to an explosive radiation among snakes. Previously, snakes were a minor component of the North American fauna, but during the Miocene, the number of species and their prevalence increased dramatically with the first appearances of vipers and elapids in North America and the significant diversification of Colubridae (including

9120-422: The end of the Miocene. The Paratethys underwent a significant transgression during the early Middle Miocene. Around 13.8 Ma, during a global sea level drop, the Eastern Paratethys was cut off from the global ocean by the closure of the Bârlad Strait, effectively turning it into a saltwater lake. From 13.8 to 13.36 Ma, an evaporite period similar to the later Messinian salinity crisis in the Mediterranean ensued in

9240-637: The enigmatic Saint Bathans Mammal . Microbial life in the igneous crust of the Fennoscandian Shield shifted from being dominated by methanogens to being primarily composed of sulphate-reducing prokaryotes . The change resulted from fracture reactivation during the Pyrenean-Alpine orogeny, enabling sulphate-reducing microbes to permeate into the Fennoscandian Shield via descending surficial waters. Diatom diversity

9360-484: The evolution of a power and precision grip , a change first occurring in H. erectus . Bipedalism , (walking on two legs), is the basic adaptation of the hominid and is considered the main cause behind a suite of skeletal changes shared by all bipedal hominids. The earliest hominin, of presumably primitive bipedalism, is considered to be either Sahelanthropus or Orrorin , both of which arose some 6 to 7 million years ago. The non-bipedal knuckle-walkers,

9480-461: The evolution of both groups into modern representatives. The early Miocene Saint Bathans Fauna is the only Cenozoic terrestrial fossil record of the landmass, showcasing a wide variety of not only bird species, including early representatives of clades such as moa , kiwi and adzebills , but also a diverse herpetofauna of sphenodontians , crocodiles and turtles as well as a rich terrestrial mammal fauna composed of various species of bats and

9600-499: The expansion of grasslands not to a CO 2 drop but to the increasing seasonality and aridity, coupled with a monsoon climate, which made wildfires highly prevalent compared to before. The Late Miocene expansion of grasslands had cascading effects on the global carbon cycle, evidenced by the imprint it left in carbon isotope records. Cycads between 11.5 and 5 million years ago began to rediversify after previous declines in variety due to climatic changes, and thus modern cycads are not

9720-718: The extinction of the last-surviving members of the hyaenodonts . Islands began to form between South and North America in the Late Miocene, allowing ground sloths like Thinobadistes to island-hop to North America. The expansion of silica-rich C 4 grasses led to worldwide extinctions of herbivorous species without high-crowned teeth . Mustelids diversified into their largest forms as terrestrial predators like Ekorus , Eomellivora , and Megalictis and bunodont otters like Enhydriodon and Sivaonyx appeared. Eulipotyphlans were widespread in Europe, being less diverse in Southern Europe than farther north due to

9840-629: The findings of marine invertebrate fossils of both Atlantic and Pacific affinity in La Cascada Formation . Connection would have occurred through narrow epicontinental seaways that formed channels in a dissected topography . The Antarctic Plate started to subduct beneath South America 14 million years ago in the Miocene, forming the Chile Triple Junction . At first the Antarctic Plate subducted only in

9960-550: The forerunner of anatomically modern humans , evolved in the Middle Paleolithic between 400,000 and 250,000 years ago. Recent DNA evidence suggests that several haplotypes of Neanderthal origin are present among all non-African populations, and Neanderthals and other hominins, such as Denisovans, may have contributed up to 6% of their genome to present-day humans, suggestive of a limited interbreeding between these species . According to some anthropologists,

10080-594: The form of bones in the wrist, forearm, shoulder, knees, and feet. Additionally, this hypothesis fails to explain the find of multiple examples of individuals with these same characteristics, indicating they were common to a large population, and not limited to one individual. In 2016, fossil teeth and a partial jaw from hominins assumed to be ancestral to H. floresiensis were discovered at Mata Menge , about 74 km (46 mi) from Liang Bua. They date to about 700,000 years ago and are noted by Australian archaeologist Gerrit van den Bergh for being even smaller than

10200-1002: The fossil record. In the Early Miocene , about 22 million years ago, the many kinds of arboreally -adapted (tree-dwelling) primitive catarrhines from East Africa suggest a long history of prior diversification. Fossils at 20 million years ago include fragments attributed to Victoriapithecus , the earliest Old World monkey. Among the genera thought to be in the ape lineage leading up to 13 million years ago are Proconsul , Rangwapithecus , Dendropithecus , Limnopithecus , Nacholapithecus , Equatorius , Nyanzapithecus , Afropithecus , Heliopithecus , and Kenyapithecus , all from East Africa. The presence of other generalized non-cercopithecids of Middle Miocene from sites far distant, such as Otavipithecus from cave deposits in Namibia, and Pierolapithecus and Dryopithecus from France, Spain and Austria,

10320-538: The genomes of modern humans outside Africa. HLA haplotypes from Denisovans and Neanderthal represent more than half the HLA alleles of modern Eurasians, indicating strong positive selection for these introgressed alleles. Corinne Simoneti at Vanderbilt University, in Nashville and her team have found from medical records of 28,000 people of European descent that the presence of Neanderthal DNA segments may be associated with

10440-641: The genus Homo . Based on archaeological and paleontological evidence, it has been possible to infer, to some extent, the ancient dietary practices of various Homo species and to study the role of diet in physical and behavioral evolution within Homo . Some anthropologists and archaeologists subscribe to the Toba catastrophe theory , which posits that the supereruption of Lake Toba on Sumatra in Indonesia some 70,000 years ago caused global starvation, killing

10560-820: The higher body mass of Neanderthals may have required larger brain mass for body control. Also, recent research by Pearce, Stringer , and Dunbar has shown important differences in brain architecture. The larger size of the Neanderthal orbital chamber and occipital lobe suggests that they had a better visual acuity than modern humans, useful in the dimmer light of glacial Europe. Neanderthals may have had less brain capacity available for social functions . Inferring social group size from endocranial volume (minus occipital lobe size) suggests that Neanderthal groups may have been limited to 120 individuals, compared to 144 possible relationships for modern humans. Larger social groups could imply that modern humans had less risk of inbreeding within their clan, trade over larger areas (confirmed in

10680-411: The human lineage) appeared in Africa at the very end of the Miocene, including Sahelanthropus , Orrorin , and an early form of Ardipithecus ( A. kadabba ). The chimpanzee–human divergence is thought to have occurred at this time. The evolution of bipedalism in apes at the end of the Miocene instigated an increased rate of faunal turnover in Africa. In contrast, European apes met their end at

10800-606: The lake levels of the Eastern Paratethys dropped as it once again became a sea. The Fram Strait opened during the Miocene and acted as the only throughflow for Atlantic Water into the Arctic Ocean until the Quaternary period. Due to regional uplift of the continental shelf, this water could not move through the Barents Seaway in the Miocene. The modern day Mekong Delta took shape after 8 Ma. Geochemistry of

10920-602: The last common ancestor of gorillas, chimpanzees and humans may be represented by Nakalipithecus fossils found in Kenya and Ouranopithecus found in Greece. Molecular evidence suggests that between 8 and 4 million years ago, first the gorillas, and then the chimpanzees (genus Pan ) split off from the line leading to the humans. Human DNA is approximately 98.4% identical to that of chimpanzees when comparing single nucleotide polymorphisms (see human evolutionary genetics ). The fossil record, however, of gorillas and chimpanzees

11040-413: The later fossils. A small number of specimens from the island of Luzon , dated 50,000 to 67,000 years ago, have recently been assigned by their discoverers, based on dental characteristics, to a novel human species, H. luzonensis . H. sapiens (the adjective sapiens is Latin for "wise" or "intelligent") emerged in Africa around 300,000 years ago, likely derived from H. heidelbergensis or

11160-598: The majority of humans and creating a population bottleneck that affected the genetic inheritance of all humans today. The genetic and archaeological evidence for this remains in question however. A 2023 genetic study suggests that a similar human population bottleneck of between 1,000 and 100,000 survivors occurred "around 930,000 and 813,000 years ago ... lasted for about 117,000 years and brought human ancestors close to extinction." Homo habilis lived from about 2.8 to 1.4 Ma. The species evolved in South and East Africa in

11280-494: The morphology of its skeleton being more adapted to living in trees rather than walking on two legs like later hominins. In May 2010, a new species, Homo gautengensis , was discovered in South Africa. These are proposed species names for fossils from about 1.9–1.6 Ma, whose relation to Homo habilis is not yet clear. The first fossils of Homo erectus were discovered by Dutch physician Eugene Dubois in 1891 on

11400-547: The north, increasing precipitation over southern China whilst simultaneously decreasing it over Indochina during the EASM. Western Australia was at this time characterised by exceptional aridity. In Antarctica, average summer temperatures on land reached 10 °C. In the oceans, the lysocline shoaled by approximately half of a kilometre during warm phases that corresponded to orbital eccentricity maxima. The MMCO ended around 14 million years ago, when global temperatures fell in

11520-654: The oldest known primate-like mammal species, the Plesiadapis , came from North America; another, Archicebus , came from China . Other similar basal primates were widespread in Eurasia and Africa during the tropical conditions of the Paleocene and Eocene . David R. Begun concluded that early primates flourished in Eurasia and that a lineage leading to the African apes and humans, including to Dryopithecus , migrated south from Europe or Western Asia into Africa. The surviving tropical population of primates—which

11640-523: The origin of many modern genera such as Nerodia , Lampropeltis , Pituophis and Pantherophis ). Arthropods were abundant, including in areas such as Tibet where they have traditionally been thought to be undiverse. Neoisopterans diversified and expanded into areas they previously were absent from, such as Madagascar and Australia. In the oceans, brown algae , called kelp , proliferated, supporting new species of sea life, including otters , fish and various invertebrates . Corals suffered

11760-486: The other great apes at about 12 million years; there are no fossils that clearly document the ancestry of gibbons, which may have originated in a so-far-unknown Southeast Asian hominoid population, but fossil proto-orangutans may be represented by Sivapithecus from India and Griphopithecus from Turkey, dated to around 10 mya. Hominidae subfamily Homininae (African hominids) diverged from Ponginae (orangutans) about 14 mya. Hominins (including humans and

11880-764: The possibility that Neanderthals, Denisovans, and modern humans may have co-existed and interbred. The existence of this distant branch creates a much more complex picture of humankind during the Late Pleistocene than previously thought. Evidence has also been found that as much as 6% of the DNA of some modern Melanesians derive from Denisovans, indicating limited interbreeding in Southeast Asia. Alleles thought to have originated in Neanderthals and Denisovans have been identified at several genetic loci in

12000-463: The possible herpetotheriid Morotodon from the late Early Miocene of Uganda. Approximately 100 species of apes lived during this time , ranging throughout Africa, Asia and Europe and varying widely in size, diet, and anatomy. Due to scanty fossil evidence it is unclear which ape or apes contributed to the modern hominid clade, but molecular evidence indicates this ape lived between 18 and 13 million years ago. The first hominins ( bipedal apes of

12120-846: The preceding Oligocene and following Pliocene Epochs: Continents continued to drift toward their present positions. Of the modern geologic features, only the land bridge between South America and North America was absent, although South America was approaching the western subduction zone in the Pacific Ocean , causing both the rise of the Andes and a southward extension of the Meso-American peninsula. Mountain building took place in western North America , Europe , and East Asia . Both continental and marine Miocene deposits are common worldwide with marine outcrops common near modern shorelines. Well studied continental exposures occur in

12240-477: The recent African origin theory, modern humans evolved in Africa possibly from H. heidelbergensis , H. rhodesiensis or H. antecessor and migrated out of the continent some 50,000 to 100,000 years ago, gradually replacing local populations of H. erectus , Denisova hominins , H. floresiensis , H. luzonensis and H. neanderthalensis , whose ancestors had left Africa in earlier migrations. Archaic Homo sapiens ,

12360-583: The second interglacial period in the Middle Pleistocene , around 250,000 years ago, the trend in intra-cranial volume expansion and the elaboration of stone tool technologies developed, providing evidence for a transition from H. erectus to H. sapiens . The direct evidence suggests there was a migration of H. erectus out of Africa , then a further speciation of H. sapiens from H. erectus in Africa. A subsequent migration (both within and out of Africa) eventually replaced

12480-566: The site of Denisova Cave in the Altai Mountains of Siberia uncovered a small bone fragment from the fifth finger of a juvenile member of another human species, the Denisovans. Artifacts, including a bracelet, excavated in the cave at the same level were carbon dated to around 40,000 BP. As DNA had survived in the fossil fragment due to the cool climate of the Denisova Cave, both mtDNA and nuclear DNA were sequenced. While

12600-714: The southernmost tip of Patagonia, meaning that the Chile Triple Junction lay near the Strait of Magellan . As the southern part of Nazca Plate and the Chile Rise became consumed by subduction the more northerly regions of the Antarctic Plate begun to subduct beneath Patagonia so that the Chile Triple Junction advanced to the north over time. The asthenospheric window associated to the triple junction disturbed previous patterns of mantle convection beneath Patagonia inducing an uplift of ca. 1 km that reversed

12720-404: The specimen was a good climber. It is thought given the night predators of the region that he built a nesting platform at night in the trees in a similar fashion to chimpanzees and gorillas. The earliest documented representative of the genus Homo is Homo habilis , which evolved around 2.8  million years ago , and is arguably the earliest species for which there is positive evidence of

12840-668: The transition to behavioral modernity with the development of symbolic culture, language, and specialized lithic technology happened around 50,000 years ago (beginning of the Upper Paleolithic ), although others point to evidence of a gradual change over a longer time span during the Middle Paleolithic. Homo sapiens is the only extant species of its genus, Homo . While some (extinct) Homo species might have been ancestors of Homo sapiens , many, perhaps most, were likely "cousins", having speciated away from

12960-402: The use of stone tools. The brains of these early hominins were about the same size as that of a chimpanzee, although it has been suggested that this was the time in which the human SRGAP2 gene doubled, producing a more rapid wiring of the frontal cortex. During the next million years a process of rapid encephalization occurred, and with the arrival of Homo erectus and Homo ergaster in

13080-604: The west coast of South America are thought to be caused by a regional phenomenon while the steadily rising central segment of the Andes represents an exception. While there are numerous registers of Oligocene–Miocene transgressions around the world it is doubtful that these correlate. It is thought that the Oligocene–Miocene transgression in Patagonia could have temporarily linked the Pacific and Atlantic Oceans, as inferred from

13200-423: Was Allodesmus . A ferocious walrus , Pelagiarctos may have preyed upon other species of pinnipeds including Allodesmus . Furthermore, South American waters witnessed the arrival of Megapiranha paranensis , which were considerably larger than modern age piranhas . New Zealand 's Miocene fossil record is particularly rich. Marine deposits showcase a variety of cetaceans and penguins , illustrating

13320-535: Was Neanderthal, implying the individual had a Neanderthal ancestor 4–6 generations previously, in addition to a contribution from earlier interbreeding in the Middle East. Though this interbred Romanian population seems not to have been ancestral to modern humans, the finding indicates that interbreeding happened repeatedly. All modern non-African humans have about 1% to 4% (or 1.5% to 2.6% by more recent data) of their DNA derived from Neanderthals. This finding

13440-624: Was a gradual and progressive trend of increasing aridification, though it was not unidirectional, and wet humid episodes continued to occur. Between 7 and 5.3 Ma, temperatures dropped sharply again in the Late Miocene Cooling (LMC), most likely as a result of a decline in atmospheric carbon dioxide and a drop in the amplitude of Earth's obliquity, and the Antarctic ice sheet was approaching its present-day size and thickness. Ocean temperatures plummeted to near-modern values during

13560-479: Was also argued that the species provides support for the notion that very early hominins, akin to bonobos ( Pan paniscus ) the less aggressive species of the genus Pan , may have evolved via the process of self-domestication . Consequently, arguing against the so-called "chimpanzee referential model" the authors suggest it is no longer tenable to use chimpanzee ( Pan troglodytes ) social and mating behaviors in models of early hominin social evolution. When commenting on

13680-405: Was arid, particularly so during the Middle Miocene. Climates remained moderately warm, although the slow global cooling that eventually led to the Pleistocene glaciations continued. Although a long-term cooling trend was well underway, there is evidence of a warm period during the Miocene when the global climate rivalled that of the Oligocene . The climate of the Miocene has been suggested as

13800-549: Was controversial from its first proposal in the 1990s and by the 2010s had very little support. Distinctive human genetic variability has arisen as the result of the founder effect , by archaic admixture and by recent evolutionary pressures . Since Homo sapiens separated from its last common ancestor shared with chimpanzees , human evolution is characterized by a number of morphological , developmental , physiological , behavioral , and environmental changes. Environmental (cultural) evolution discovered much later during

13920-411: Was estimated to be one meter in height, with a brain volume of just 380 cm (considered small for a chimpanzee and less than a third of the H. sapiens average of 1400 cm ). However, there is an ongoing debate over whether H. floresiensis is indeed a separate species. Some scientists hold that H. floresiensis was a modern H. sapiens with pathological dwarfism. This hypothesis

14040-688: Was inversely correlated with carbon dioxide levels and global temperatures during the Miocene. Most modern lineages of diatoms appeared by the Late Miocene. There is evidence from oxygen isotopes at Deep Sea Drilling Program sites that ice began to build up in Antarctica about 36 Ma during the Eocene . Further marked decreases in temperature during the Middle Miocene at 15 Ma probably reflect increased ice growth in Antarctica. It can therefore be assumed that East Antarctica had some glaciers during

14160-646: Was most intense there. Around this time the Mi3b glacial event (a massive expansion of Antarctic glaciers) occurred. The East Antarctic Ice Sheet (EAIS) markedly stabilised following the MMCT. The intensification of glaciation caused a decoherence of sediment deposition from the 405 kyr eccentricity cycle. The MMWI ended about 11 Ma, when the Late Miocene Cool Interval (LMCI) started. A major but transient warming occurred around 10.8-10.7 Ma. During

14280-471: Was not linear but weblike. The study of the origins of humans involves several scientific disciplines, including physical and evolutionary anthropology , paleontology , and genetics ; the field is also known by the terms anthropogeny , anthropogenesis , and anthropogony . (The latter two terms are sometimes used to refer to the related subject of hominization .) Primates diverged from other mammals about 85  million years ago ( mya ), in

14400-531: Was the key adaptation that separated Homo from tree-sleeping Australopithecines. These are proposed as species intermediate between H. erectus and H. heidelbergensis . H. heidelbergensis ("Heidelberg Man") lived from about 800,000 to about 300,000 years ago. Also proposed as Homo sapiens heidelbergensis or Homo sapiens paleohungaricus . Homo neanderthalensis , alternatively designated as Homo sapiens neanderthalensis , lived in Europe and Asia from 400,000 to about 28,000 years ago. There are

#736263