Eocene in the context of "Evolution of lemurs"

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⭐ Core Definition: Eocene

The Eocene (IPA: /ˈəsn, ˈ-/ EE-ə-seen, EE-oh-) is a geological epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name "Eocene" comes from Ancient Greek ἠώς (ēṓs), meaning "dawn", and καινός (kainós), meaning "new", and refers to the "dawn" of modern ('new') fauna that appeared during the epoch.

The Eocene spans the time from the end of the Paleocene Epoch to the beginning of the Oligocene Epoch. The start of the Eocene is marked by a brief period in which the concentration of the carbon isotope C in the atmosphere was exceptionally low in comparison with the more common isotope C. The average temperature of Earth at the beginning of the Eocene was about 27 degrees Celsius. The end is set at a major extinction event called the Grande Coupure (the "Great Break" in continuity) or the Eocene–Oligocene extinction event, which may be related to the impact of one or more large bolides in Siberia and in what is now Chesapeake Bay. As with other geologic periods, the strata that define the start and end of the epoch are well identified, though their exact dates are slightly uncertain.

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Eocene in the context of Great Sphinx of Giza

The Great Sphinx of Giza is a limestone statue of a reclining sphinx, a mythical creature with the head of a human and the body of a lion.

The monument was sculpted from the limestone bedrock of the Eocene-aged Mokattam Formation and faces east on the Giza Plateau, on the west bank of the Nile in Giza, Egypt. The oldest known monumental sculpture in Egypt, the Sphinx is part of the Memphite Necropolis and is a UNESCO World Heritage Site.

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Eocene in the context of Mokattam Formation

The Mokattam Formation is a Middle Eocene-aged geological formation in northern Egypt. Consisting of nummulitic marine limestone outcropping across the Mokattam Hills, it has been extensively quarried from Ancient Egypt to the present day, and represents the source material for most of the famous archeological sites of Greater Cairo, most notably the Giza pyramid complex, the Great Sphinx, and much of Historic Cairo.

The age of the formation is thought to span from the late Lutetian to the Bartonian, depending on the member (Building Stone or Giushi). However, some authors treat the Giushi Member as its own geologic formation, which would restrict the Mokattam to just the Lutetian.

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Eocene in the context of Penguin

Penguins are a group of flightless, semi-aquatic, sea birds which live almost exclusively in the Southern Hemisphere. Only one species, the Galápagos penguin, lives at, and slightly north of, the equator. Highly adapted for life in the ocean water, penguins have countershaded dark and white plumage and flippers for swimming. Most penguins feed on krill, fish, squid and other forms of sea life which they catch with their bills and swallow whole while swimming. A penguin has a spiny tongue and powerful jaws to grip slippery prey.

They spend about half of their lives on land and the other half in the sea. The largest living species is the emperor penguin (Aptenodytes forsteri): on average, adults are about 1.1 m (3 ft 7 in) tall and weigh 35 kg (77 lb). The smallest penguin species is the little blue penguin (Eudyptula minor), also known as the fairy penguin, which stands around 30–33 cm (12–13 in) tall and weighs 1.2–1.3 kg (2.6–2.9 lb). Today, larger penguins generally inhabit colder regions, and smaller penguins inhabit regions with temperate or tropical climates. Some prehistoric penguin species were enormous: as tall or heavy as an adult human. There was a great diversity of species in subantarctic regions, and at least one giant species in a region around 2,000 km south of the equator 35 mya, during the Late Eocene, a climate decidedly warmer than today.

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Eocene in the context of Eocene–Oligocene extinction event

The Eocene–Oligocene extinction event, also called the Eocene-Oligocene transition (EOT) or Grande Coupure (French for "great cut"), is the transition between the end of the Eocene and the beginning of the Oligocene, an extinction event and faunal turnover occurring between 33.9 and 33.4 million years ago. It was marked by large-scale extinction and floral and faunal turnover, although it was relatively minor in comparison to the largest mass extinctions.

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Eocene in the context of Guineafowl

Guinea fowl (/ˈɡɪnifl/) are birds of the family Numididae in the order Galliformes. They are endemic to Africa and rank among the oldest of the gallinaceous birds. Phylogenetically, they branched off from the core Galliformes after the Cracidae (chachalacas, guans, and curassows) and before the Odontophoridae (New World quail). An Eocene fossil lineage Telecrex has been associated with guinea fowl; Telecrex inhabited Mongolia, and may have given rise to the oldest of the true phasianids, such as blood pheasants and eared pheasants, which evolved into high-altitude, montane-adapted species with the rise of the Tibetan Plateau. While modern guinea fowl species are endemic to Africa, the helmeted guinea fowl has been introduced as a domesticated bird widely elsewhere.

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Eocene in the context of Strepsirrhini

Strepsirrhini or Strepsirhini (/ˌstrɛpsəˈrni/ ; STREP-sə-RY-nee) is a suborder of primates that includes the lemuriform primates, which consist of the lemurs of Madagascar, galagos ("bushbabies") and pottos from Africa, and the lorises from India and Southeast Asia. Collectively they are referred to as strepsirrhines.

Also belonging to the suborder are the extinct adapiform primates, which thrived during the Eocene in Europe, North America, and Asia, but disappeared from most of the Northern Hemisphere as the climate cooled. Adapiforms are sometimes referred to as being "lemur-like", although the diversity of both lemurs and adapiforms does not support this comparison.

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Eocene in the context of Tarsiiformes

Tarsiiformes /ˈtɑːrsi.ɪfɔːrmz/ are a group of primates that once ranged across Europe, northern Africa, Asia, and North America, but whose extant species are all found in the islands of Southeast Asia. Tarsiers (family Tarsiidae) are the only living members of the infraorder; other members of Tarsiidae include the extinct Tarsius eocaenus from the Eocene, and Tarsius thailandicus from the Miocene. Two extinct genera, Xanthorhysis and Afrotarsius, are considered to be close relatives of the living tarsiers, and are generally classified within Tarsiiformes, with the former grouped within family Tarsiidae, and the latter listed as incertae sedis (undefined). Omomyids are generally considered to be extinct relatives, or even ancestors, of the living tarsiers, and are often classified within Tarsiiformes.

Other fossil primates, including Microchoeridae, Carpolestidae, and Eosimiidae, have been included in this classification, although the fossil evidence is debated. Eosimiidae has also been classified under the infraorder Simiiformes (with monkeys and apes), and most experts now consider Eosimiidae to be stem simians. Likewise, Carpolestidae is often classified within the order Plesiadapiformes, a very close, extinct relative of primates.

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Eocene in the context of Vespidae

The Vespidae are a large (nearly 5000 species), diverse, cosmopolitan family of wasps, including nearly all the known eusocial wasps (such as Polistes fuscatus, Vespa orientalis, and Vespula germanica) and many solitary wasps. Each social wasp colony includes a queen and a number of female workers with varying degrees of sterility relative to the queen. In temperate social species, colonies usually last only one year, dying at the onset of winter. New queens and males (drones) are produced towards the end of the summer, and after mating, the queens hibernate over winter in cracks or other sheltered locations. The nests of most species are constructed out of mud, but polistines and vespines use plant fibers, chewed to form a sort of paper (also true of some stenogastrines). Many species are pollen vectors contributing to the pollination of several plants, being potential or even effective pollinators, while others are notable predators of pest insect species, and a few species are invasive pests.

The subfamilies Polistinae and Vespinae are composed solely of eusocial species, while the Eumeninae, Euparagiinae, Gayellinae, Masarinae and Zethinae are all solitary with the exception of a few communal and several subsocial species. The Stenogastrinae are facultatively eusocial, considering nests may have one or several adult females; in cases where the nest is shared by multiple females (typically, a mother and her daughters) there is reproductive division of labor and cooperative brood care.

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Eocene in the context of Charles Lyell

Sir Charles Lyell, 1st Baronet, FRS (14 November 1797 – 22 February 1875) was a Scottish geologist who demonstrated the power of known natural causes in explaining the earth's history. He is best known today for his association with Charles Darwin and as the author of Principles of Geology (1830–33), which presented to a wide public audience the idea that the earth was shaped by the same natural processes still in operation today, operating at similar intensities. The philosopher William Whewell dubbed this gradualistic view "uniformitarianism" and contrasted it with catastrophism, which had been championed by Georges Cuvier and was better accepted in Europe. The combination of evidence and eloquence in Principles convinced a wide range of readers of the significance of "deep time" for understanding the earth and environment.

Lyell's scientific contributions included a pioneering explanation of climate change, in which shifting boundaries between oceans and continents could be used to explain long-term variations in temperature and rainfall. Lyell also gave influential explanations of earthquakes and developed the theory of gradual "backed up-building" of volcanoes. In stratigraphy his division of the Tertiary period into the Pliocene, Miocene, and Eocene was highly influential. He incorrectly conjectured that icebergs were the impetus behind the transport of glacial erratics, and that silty loess deposits might have settled out of flood waters. His creation of a separate period for human history, entitled the 'Recent', is widely cited as providing the foundations for the modern discussion of the Anthropocene.

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