1.
French Polynesia
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It is composed of 118 geographically dispersed islands and atolls stretching over an expanse of more than 2,000 kilometres in the South Pacific Ocean. Its total land area is 4,167 square kilometres, among its 118 islands and atolls,67 are inhabited. Tahiti, which is located within the Society Islands, is the most populous island and it has more than 68% of the population of the islands in 2012. Although not a part of its territory, Clipperton Island was administered from French Polynesia until 2007. Following the Great Polynesian Migration, European explorers visited the islands of French Polynesia on several occasions, traders and whaling ships also visited. In 1842, the French took over the islands and established a French protectorate they called Etablissements des français en Océanie, in 1946, the EFOs became an overseas territory under the constitution of the French Fourth Republic, and Polynesians were granted the right to vote through citizenship. In 1957, the EFOs were renamed French Polynesia, French Polynesia as we know it today was one of the last places on Earth to be settled by humans. Scientists believe the Great Polynesian Migration happened around 1500 BC as Austronesian people went on a journey using celestial navigation to find islands in the South Pacific Ocean, the first islands of French Polynesia to be settled were the Marquesas Islands in about 200 BC. The Polynesians later ventured southwest and discovered the Society Islands around AD300, European encounters began in 1521 when Portuguese explorer Ferdinand Magellan, sailing at the service of the Spanish Crown, sighted Puka-Puka in the Tuāmotu-Gambier Archipelago. Over a century later, British explorer Samuel Wallis visited Tahiti in 1767, French explorer Louis Antoine de Bougainville also visited Tahiti in 1768, while British explorer James Cook arrived in 1769. A short-lived Spanish settlement was created in 1774, and for a time some maps bore the name Isla de Amat after Viceroy Amat, in 1772, Dutchman Jakob Roggeveen came across Bora Bora in the Society Islands. Christian missions began with Spanish priests who stayed in Tahiti for a year, protestants from the London Missionary Society settled permanently in Polynesia in 1797. King Pōmare II of Tahiti was forced to flee to Moorea in 1803, he, French Catholic missionaries arrived on Tahiti in 1834, their expulsion in 1836 caused France to send a gunboat in 1838. In 1842, Tahiti and Tahuata were declared a French protectorate, the capital of Papeetē was founded in 1843. In 1880, France annexed Tahiti, changing the status from that of a protectorate to that of a colony, the island groups were not officially united until the establishment of the French protectorate in 1889. In the 1880s, France claimed the Tuamotu Archipelago, which belonged to the Pōmare Dynasty. Having declared a protectorate over Tahuata in 1842, the French regarded the entire Marquesas Islands as French, in 1885, France appointed a governor and established a general council, thus giving it the proper administration for a colony. The islands of Rimatara and Rūrutu unsuccessfully lobbied for British protection in 1888, postage stamps were first issued in the colony in 1892
2.
Philippines
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The Philippines, officially the Republic of the Philippines, is a sovereign island country in Southeast Asia situated in the western Pacific Ocean. It consists of about 7,641 islands that are categorized broadly under three main geographical divisions from north to south, Luzon, Visayas, and Mindanao, the capital city of the Philippines is Manila and the most populous city is Quezon City, both part of Metro Manila. The Philippines has an area of 300,000 square kilometers, and it is the eighth-most populated country in Asia and the 12th most populated country in the world. As of 2013, approximately 10 million additional Filipinos lived overseas, multiple ethnicities and cultures are found throughout the islands. In prehistoric times, Negritos were some of the archipelagos earliest inhabitants and they were followed by successive waves of Austronesian peoples. Exchanges with Chinese, Malay, Indian, and Islamic nations occurred, then, various competing maritime states were established under the rule of Datus, Rajahs, Sultans or Lakans. The arrival of Ferdinand Magellan in Homonhon, Eastern Samar in 1521 marked the beginning of Hispanic colonization, in 1543, Spanish explorer Ruy López de Villalobos named the archipelago Las Islas Filipinas in honor of Philip II of Spain. With the arrival of Miguel López de Legazpi from Mexico City, in 1565, the Philippines became part of the Spanish Empire for more than 300 years. This resulted in Roman Catholicism becoming the dominant religion, during this time, Manila became the western hub of the trans-Pacific trade connecting Asia with Acapulco in the Americas using Manila galleons. Aside from the period of Japanese occupation, the United States retained sovereignty over the islands until after World War II, since then, the Philippines has often had a tumultuous experience with democracy, which included the overthrow of a dictatorship by a non-violent revolution. It is a member of the United Nations, World Trade Organization, Association of Southeast Asian Nations, the Asia-Pacific Economic Cooperation forum. It also hosts the headquarters of the Asian Development Bank, the Philippines was named in honor of King Philip II of Spain. Spanish explorer Ruy López de Villalobos, during his expedition in 1542, named the islands of Leyte, eventually the name Las Islas Filipinas would be used to cover all the islands of the archipelago. Before that became commonplace, other such as Islas del Poniente. The official name of the Philippines has changed several times in the course of its history, during the Philippine Revolution, the Malolos Congress proclaimed the establishment of the República Filipina or the Philippine Republic. From the 1898 Treaty of Paris, the name Philippines began to appear, since the end of World War II, the official name of the country has been the Republic of the Philippines. The metatarsal of the Callao Man, reliably dated by uranium-series dating to 67,000 years ago is the oldest human remnant found in the archipelago to date and this distinction previously belonged to the Tabon Man of Palawan, carbon-dated to around 26,500 years ago. Negritos were also among the archipelagos earliest inhabitants, but their first settlement in the Philippines has not been reliably dated, there are several opposing theories regarding the origins of ancient Filipinos
3.
Fish market
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For the Sydney station, see Fish Market tram stop. A fish market is a marketplace for selling fish products and it can be dedicated to wholesale trade between fishermen and fish merchants, or to the sale of seafood to individual consumers, or to both. Retail fish markets, a type of wet market, often sell street food as well. Fish markets range in size from small stalls, such as the one in the photo at the right, to the great Tsukiji fish market in Tokyo. The term fish market can refer to the process of fish marketing in general. Fish markets were known in antiquity and they served as a public space where large numbers of people could gather and discuss current events and local politics. Because seafood is quick to spoil, fish markets are historically most often found in seaside towns, once ice or other simple cooling methods became available, some were also established in large inland cities that had good trade routes to the coast. Since refrigeration and rapid transport became available in the 19th and 20th century, consequently, most major fish markets now mainly deal with wholesale trade, and the existing major fish retail markets continue to operate as much for traditional reasons as for commercial ones. Both types of markets are often tourist attractions as well. The following is an incomplete list of fish markets. Tsukiji fish market, Tokyo, Japan, the worlds largest fish market, la Nueva Viga Market, Mexico City, Mexico, the worlds second largest fish market. Marketing from 250,000 up to 550,000 tons of seafood a year. C, bestor TC Tsukiji, the fish market at the center of the world In PE Lilienthal, California studies, Volume 11, University of California Press, ISBN 978-0-520-22024-9. Le Blanch J The Global fish market and the need for multilateral fishing disciplines In, Leonard B Overfishing, A Global Challenge, Diane Publishing, la Nueva Viga, paseo marino en el DF fuera de las guías turísticas. A Fishmongers Guide to Greatness Berrett-koehler Series, Berrett-Koehler Publishers, ISBN 978-1-57675-323-1, graddy K The Fulton fish market Journal of Economic Perspectives,20, 207–220. Kirman, Alan P. and Vriend, Nicolaas J. Learning to be loyal, in, Domenico Delli Gatti, Mauro Gallegati, Alan P. Kirman, Interaction and market structure, essays on heterogeneity in economics, Volume 484. Maniatis GC The Organizational Setup and Functioning of the Fish Market in Tenth-Century Constantinople Dumbarton Oaks Papers,54, porcù Leide Fishy business, Humor in a Sardinian fish market International Journal of Humor Research,18, 69–102. Doi,10. 1515/humr.2005.18.1.69 Sophie S and Håkan H Behind the fish market facade The IMP Journal,3, 50-74. Sancar Seckiners new book DZ Uzerine Notlar, published Dec.2014, a film clip of a fish market in New York in 1903 is available at the Internet Archive Fish out of water, A guide to city fishmongers New York Magazine,10 April 1978
4.
Taxonomy (biology)
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Taxonomy is the science of defining groups of biological organisms on the basis of shared characteristics and giving names to those groups. The exact definition of taxonomy varies from source to source, but the core of the remains, the conception, naming. There is some disagreement as to whether biological nomenclature is considered a part of taxonomy, the broadest meaning of taxonomy is used here. The word taxonomy was introduced in 1813 by Candolle, in his Théorie élémentaire de la botanique, the term alpha taxonomy is primarily used today to refer to the discipline of finding, describing, and naming taxa, particularly species. In earlier literature, the term had a different meaning, referring to morphological taxonomy, ideals can, it may be said, never be completely realized. They have, however, a value of acting as permanent stimulants. Some of us please ourselves by thinking we are now groping in a beta taxonomy, turrill thus explicitly excludes from alpha taxonomy various areas of study that he includes within taxonomy as a whole, such as ecology, physiology, genetics, and cytology. He further excludes phylogenetic reconstruction from alpha taxonomy, thus, Ernst Mayr in 1968 defined beta taxonomy as the classification of ranks higher than species. This activity is what the term denotes, it is also referred to as beta taxonomy. How species should be defined in a group of organisms gives rise to practical and theoretical problems that are referred to as the species problem. The scientific work of deciding how to define species has been called microtaxonomy, by extension, macrotaxonomy is the study of groups at higher taxonomic ranks, from subgenus and above only, than species. While some descriptions of taxonomic history attempt to date taxonomy to ancient civilizations, earlier works were primarily descriptive, and focused on plants that were useful in agriculture or medicine. There are a number of stages in scientific thinking. Early taxonomy was based on criteria, the so-called artificial systems. Later came systems based on a complete consideration of the characteristics of taxa, referred to as natural systems, such as those of de Jussieu, de Candolle and Bentham. The publication of Charles Darwins Origin of Species led to new ways of thinking about classification based on evolutionary relationships and this was the concept of phyletic systems, from 1883 onwards. This approach was typified by those of Eichler and Engler, the advent of molecular genetics and statistical methodology allowed the creation of the modern era of phylogenetic systems based on cladistics, rather than morphology alone. Taxonomy has been called the worlds oldest profession, and naming and classifying our surroundings has likely been taking place as long as mankind has been able to communicate
5.
Animal
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Animals are multicellular, eukaryotic organisms of the kingdom Animalia. The animal kingdom emerged as a clade within Apoikozoa as the group to the choanoflagellates. Animals are motile, meaning they can move spontaneously and independently at some point in their lives and their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later in their lives. All animals are heterotrophs, they must ingest other organisms or their products for sustenance, most known animal phyla appeared in the fossil record as marine species during the Cambrian explosion, about 542 million years ago. Animals can be divided broadly into vertebrates and invertebrates, vertebrates have a backbone or spine, and amount to less than five percent of all described animal species. They include fish, amphibians, reptiles, birds and mammals, the remaining animals are the invertebrates, which lack a backbone. These include molluscs, arthropods, annelids, nematodes, flatworms, cnidarians, ctenophores, the study of animals is called zoology. The word animal comes from the Latin animalis, meaning having breath, the biological definition of the word refers to all members of the kingdom Animalia, encompassing creatures as diverse as sponges, jellyfish, insects, and humans. Aristotle divided the world between animals and plants, and this was followed by Carl Linnaeus, in the first hierarchical classification. In Linnaeuss original scheme, the animals were one of three kingdoms, divided into the classes of Vermes, Insecta, Pisces, Amphibia, Aves, and Mammalia. Since then the last four have all been subsumed into a single phylum, in 1874, Ernst Haeckel divided the animal kingdom into two subkingdoms, Metazoa and Protozoa. The protozoa were later moved to the kingdom Protista, leaving only the metazoa, thus Metazoa is now considered a synonym of Animalia. Animals have several characteristics that set apart from other living things. Animals are eukaryotic and multicellular, which separates them from bacteria and they are heterotrophic, generally digesting food in an internal chamber, which separates them from plants and algae. They are also distinguished from plants, algae, and fungi by lacking cell walls. All animals are motile, if only at life stages. In most animals, embryos pass through a stage, which is a characteristic exclusive to animals. With a few exceptions, most notably the sponges and Placozoa and these include muscles, which are able to contract and control locomotion, and nerve tissues, which send and process signals
6.
Chordate
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Chordates are deuterostomes, as during the embryo development stage the anus forms before the mouth. They are also bilaterally symmetric coelomates, in the case of vertebrate chordates, the notochord is usually replaced by a vertebral column during development, and they may have body plans organized via segmentation. There are also additional extinct taxa, the Vertebrata are sometimes considered as a subgroup of the clade Craniata, consisting of chordates with a skull, the Craniata and Tunicata compose the clade Olfactores. Of the more than 65,000 living species of chordates, the worlds largest and fastest animals, the blue whale and peregrine falcon respectively, are chordates, as are humans. Fossil chordates are known from at least as early as the Cambrian explosion, Hemichordata, which includes the acorn worms, has been presented as a fourth chordate subphylum, but it now is usually treated as a separate phylum. The Hemichordata, along with the Echinodermata, form the Ambulacraria, the Chordata and Ambulacraria form the superphylum Deuterostomia, composed of the deuterostomes. Attempts to work out the relationships of the chordates have produced several hypotheses. All of the earliest chordate fossils have found in the Early Cambrian Chengjiang fauna. Because the fossil record of early chordates is poor, only molecular phylogenetics offers a prospect of dating their emergence. However, the use of molecular phylogenetics for dating evolutionary transitions is controversial and it has also proved difficult to produce a detailed classification within the living chordates. Attempts to produce family trees shows that many of the traditional classes are paraphyletic. While this has been known since the 19th century, an insistence on only monophyletic taxa has resulted in vertebrate classification being in a state of flux. Although the name Chordata is attributed to William Bateson, it was already in prevalent use by 1880, ernst Haeckel described a taxon comprising tunicates, cephalochordates, and vertebrates in 1866. Though he used the German vernacular form, it is allowed under the ICZN code because of its subsequent latinization, among the vertebrate sub-group of chordates the notochord develops into the spine, and in wholly aquatic species this helps the animal to swim by flexing its tail. In fish and other vertebrates, this develops into the spinal cord, the pharynx is the part of the throat immediately behind the mouth. In fish, the slits are modified to form gills, a muscular tail that extends backwards behind the anus. This is a groove in the wall of the pharynx. In filter-feeding species it produces mucus to gather food particles, which helps in transporting food to the esophagus and it also stores iodine, and may be a precursor of the vertebrate thyroid gland
7.
Actinopterygii
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Actinopterygii /ˌæktᵻnˌɒptəˈrɪdʒi. aɪ/, or the ray-finned fishes, constitute a class or subclass of the bony fishes. These actinopterygian fin rays attach directly to the proximal or basal skeletal elements, the radials, numerically, actinopterygians are the dominant class of vertebrates, comprising nearly 99% of the over 30,000 species of fish. They are ubiquitous throughout freshwater and marine environments from the sea to the highest mountain streams. Extant species can range in size from Paedocypris, at 8 mm, to the ocean sunfish, at 2,300 kg. Ray-finned fishes occur in variant forms. The main features of a typical ray-finned fish are shown in the diagram at the left. In nearly all ray-finned fish, the sexes are separate, development then proceeds with a free-swimming larval stage. However other patterns of ontogeny exist, with one of the commonest being sequential hermaphroditism, in most cases this involves protogyny, fish starting life as females and converting to males at some stage, triggered by some internal or external factor. This may be advantageous as females become less prolific as they age while male fecundity increases with age, protandry, where a fish converts from male to female, is much less common than protogyny. Most families use external rather than internal fertilization, of the oviparous teleosts, most do not provide parental care. Viviparity is relatively rare and is found in about 6% of teleost species, male territoriality preadapts a species for evolving male parental care. There are a few examples of fish that self-fertilise, the mangrove rivulus is an amphibious, simultaneous hermaphrodite, producing both eggs and spawn and having internal fertilisation. This mode of reproduction may be related to the habit of spending long periods out of water in the mangrove forests it inhabits. Males are occasionally produced at temperatures below 19 °C and can fertilise eggs that are spawned by the female. This maintains genetic variability in a species that is otherwise highly inbred, the earliest known fossil actinopterygiian is Andreolepis hedei, dating back 420 million years. Remains have been found in Russia, Sweden, and Estonia, actinopterygians are divided into the subclasses Chondrostei and Neopterygii. The Neopterygii, in turn, are divided into the infraclasses Holostei and Teleostei, during the Mesozoic and Cenozoic the teleosts in particular diversified widely, and as a result, 96% of all known fish species are teleosts. The cladogram shows the groups of actinopterygians and their relationship to the terrestrial vertebrates that evolved from a related group of fish
8.
Thomas C. Jerdon
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Thomas Caverhill Jerdon was a British physician, zoologist and botanist. He was a pioneering ornithologist who described numerous species of birds in India, several species of plants and birds including the rare Jerdons courser are named after him. Thomas was the eldest son of Archibald Jerdon of Bonjedward, near Jedburgh and his early education was at Bishopton Grove near Ripon and later at Bawtry near Doncaster. Thomas joined Edinburgh University in 1828 as a student but attended classes in natural history by Professor Robert Jameson. He joined the Plinian Society, an association of naturalists, on 23 June 1829 and he graduated as a medical student in 1829-1830 and continued medical studies before obtaining an assistant surgeonship in the East India Companys service. He was appointed on 11 September 1835 and he arrived at Madras on 21 February 1836 and his initial work in India was in dealing with fever and dysentery that affected the troops posted in the Ganjam district. During this posting, he described the birds of the Eastern Ghats, on 1 March 1837 he moved to the 2nd Light Cavalry and was posted at Trichinopoly and moved with the regiment to Jalnah in central India. He remained in the Deccan region for the four years. In 1841 he visited the Nilgiri Hills on leave and in July of the year he married Flora Alexandrina Matilda Macleod. Flora had an interest in art and took an interest in orchids. She was also an excellent guitarist, around 1845 the Jerdons lived in their Ooty home Woodside, and their children were baptised at the local St. Stephens church. Six months later he was appointed Civil Surgeon of Nellore, at Nellore, he interacted with the Yanadi tribes and obtained information on local names of birds and studied the natural history of the area. On 25 October 1844 he was transferred to Fort St. George as Garrison Assistant-Surgeon, during this time he took an interest in the fishes of the Bay of Bengal. On 12 February 1847 he was appointed Civil Surgeon of Tellicherry and this position led him to describe many species from the Malabar region including ants such as the distinctive Harpegnathos saltator. He resigned from civil charge on 3 June 1851 and was promoted as Surgeon with the 4th Light Cavalry in Sagar on 29 February 1852, after peace regained following the 1857 revolts, he was made Surgeon Major on 1 October 1858. Around 1861 a mission to Tibet was to be conducted by Captain E. Smythe and Jerdon was to accompany the group as botanist but failure to obtain passports from Pekin led to the mission being cancelled. Around the same time Lord Canning enabled him to special duty that would allow him to work on the publication of a series of books on the vertebrates of India. This began with his works on the Birds of India, followed by works on the mammals, reptiles, on 28 February 1868 he retired from service and he was given the honorary position of Deputy Inspector-General of hospitals in Madras on 28 October 1868
9.
Georges Cuvier
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Jean Léopold Nicolas Frédéric Cuvier, known as Georges Cuvier, was a French naturalist and zoologist, sometimes referred to as the father of paleontology. Cuvier is also known for establishing extinction as a fact—at the time, in his Essay on the Theory of the Earth Cuvier was interpreted to have proposed that new species were created after periodic catastrophic floods. In this way, Cuvier became the most influential proponent of catastrophism in geology in the early 19th century and his study of the strata of the Paris basin with Alexandre Brongniart established the basic principles of biostratigraphy. Cuvier is also remembered for strongly opposing theories of evolution, which at the time were mainly proposed by Jean-Baptiste de Lamarck, Cuvier believed there was no evidence for evolution, but rather evidence for cyclical creations and destructions of life forms by global extinction events such as deluges. Cuvier supported function and rejected Lamarcks thinking and his most famous work is Le Règne Animal. In 1819, he was created a peer for life in honor of his scientific contributions, thereafter, he was known as Baron Cuvier. He died in Paris during an epidemic of cholera, some of Cuviers most influential followers were Louis Agassiz on the continent and in the United States, and Richard Owen in Britain. His name is one of the 72 names inscribed on the Eiffel Tower, Cuvier was born in Montbéliard, France, where his Protestant ancestors had lived since the time of the Reformation. His father, Jean George Cuvier, was a lieutenant in the Swiss Guards, at the time, the town, which was annexed to France on 10 October 1793, belonged to the Duchy of Württemberg. His mother, who was younger than his father, tutored him diligently throughout his early years. During his gymnasium years, he had trouble acquiring Latin and Greek, and was always at the head of his class in mathematics, history. At the age of 10, soon entering the gymnasium, he encountered a copy of Conrad Gessners Historiae Animalium. He then began frequent visits to the home of a relation, all of these he read and reread, retaining so much of the information, that by the age of 12, he was as familiar with quadrupeds and birds as a first-rate naturalist. He remained at the gymnasium for four years, Cuvier spent an additional four years at the Caroline Academy in Stuttgart, where he excelled in all of his coursework. Although he knew no German on his arrival, after nine months of study. Upon graduation, he had no money on which to live as he awaited appointment to an academic office, so in July 1788, he took a job at Fiquainville chateau in Normandy as tutor to the only son of the Comte dHéricy, a Protestant noble. There, during the early 1790s, he began his comparisons of fossils with extant forms, Cuvier regularly attended meetings held at the nearby town of Valmont for the discussion of agricultural topics. There, he acquainted with Henri Alexandre Tessier, who had assumed a false identity
10.
Species
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In biology, a species is the basic unit of biological classification and a taxonomic rank. A species is defined as the largest group of organisms in which two individuals can produce fertile offspring, typically by sexual reproduction. While this definition is often adequate, looked at more closely it is problematic, for example, with hybridisation, in a species complex of hundreds of similar microspecies, or in a ring species, the boundaries between closely related species become unclear. Other ways of defining species include similarity of DNA, morphology, all species are given a two-part name, a binomial. The first part of a binomial is the genus to which the species belongs, the second part is called the specific name or the specific epithet. For example, Boa constrictor is one of four species of the Boa genus, Species were seen from the time of Aristotle until the 18th century as fixed kinds that could be arranged in a hierarchy, the great chain of being. In the 19th century, biologists grasped that species could evolve given sufficient time, Charles Darwins 1859 book The Origin of Species explained how species could arise by natural selection. Genes can sometimes be exchanged between species by horizontal transfer, and species may become extinct for a variety of reasons. In his biology, Aristotle used the term γένος to mean a kind, such as a bird or fish, a kind was distinguished by its attributes, for instance, a bird has feathers, a beak, wings, a hard-shelled egg, and warm blood. A form was distinguished by being shared by all its members, Aristotle believed all kinds and forms to be distinct and unchanging. His approach remained influential until the Renaissance, when observers in the Early Modern period began to develop systems of organization for living things, they placed each kind of animal or plant into a context. Many of these early delineation schemes would now be considered whimsical, animals likewise that differ specifically preserve their distinct species permanently, one species never springs from the seed of another nor vice versa. In the 18th century, the Swedish scientist Carl Linnaeus classified organisms according to shared physical characteristics and he established the idea of a taxonomic hierarchy of classification based upon observable characteristics and intended to reflect natural relationships. At the time, however, it was widely believed that there was no organic connection between species, no matter how similar they appeared. However, whether or not it was supposed to be fixed, by the 19th century, naturalists understood that species could change form over time, and that the history of the planet provided enough time for major changes. Jean-Baptiste Lamarck, in his 1809 Zoological Philosophy, described the transmutation of species, proposing that a species could change over time, in 1859, Charles Darwin and Alfred Russel Wallace provided a compelling account of evolution and the formation of new species. Darwin argued that it was populations that evolved, not individuals and this required a new definition of species. Darwin concluded that species are what appear to be, ideas
11.
Extinction
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In biology and ecology, extinction is the end of an organism or of a group of organisms, normally a species. The moment of extinction is considered to be the death of the last individual of the species, although the capacity to breed. Because a species range may be very large, determining this moment is difficult. This difficulty leads to such as Lazarus taxa, where a species presumed extinct abruptly reappears after a period of apparent absence. More than 99 percent of all species, amounting to five billion species. Estimates on the number of Earths current species range from 10 million to 14 million, of which about 1.2 million have been documented and over 86 percent have not yet been described. More recently, in May 2016, scientists reported that 1 trillion species are estimated to be on Earth currently with only one-thousandth of one percent described, the relationship between animals and their ecological niches has been firmly established. Mass extinctions are relatively rare events, however, isolated extinctions are quite common, only recently have extinctions been recorded and scientists have become alarmed at the current high rate of extinctions. Most species that become extinct are never scientifically documented, some scientists estimate that up to half of presently existing plant and animal species may become extinct by 2100. A dagger symbol next to a name is often used to indicate its extinction. A species is extinct when the last existing member dies, Extinction therefore becomes a certainty when there are no surviving individuals that can reproduce and create a new generation. Pinpointing the extinction of a species requires a definition of that species. If it is to be declared extinct, the species in question must be distinguishable from any ancestor or daughter species. Extinction of a plays a key role in the punctuated equilibrium hypothesis of Stephen Jay Gould. In ecology, extinction is often used informally to refer to local extinction, in which a species ceases to exist in the area of study. This phenomenon is known as extirpation. Local extinctions may be followed by a replacement of the species taken from other locations, species which are not extinct are termed extant. Those that are extant but threatened by extinction are referred to as threatened or endangered species, currently an important aspect of extinction is human attempts to preserve critically endangered species
12.
Cretaceous
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The Cretaceous is a geologic period and system that spans 79 million years from the end of the Jurassic Period 145 million years ago to the beginning of the Paleogene Period 66 Mya. It is the last period of the Mesozoic Era, the Cretaceous Period is usually abbreviated K, for its German translation Kreide. The Cretaceous was a period with a warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas. These oceans and seas were populated with now-extinct marine reptiles, ammonites and rudists, during this time, new groups of mammals and birds, as well as flowering plants, appeared. The Cretaceous ended with a mass extinction, the Cretaceous–Paleogene extinction event, in which many groups, including non-avian dinosaurs, pterosaurs. The end of the Cretaceous is defined by the abrupt Cretaceous–Paleogene boundary, the name Cretaceous was derived from Latin creta, meaning chalk. The Cretaceous is divided into Early and Late Cretaceous epochs, or Lower and Upper Cretaceous series, in older literature the Cretaceous is sometimes divided into three series, Neocomian, Gallic and Senonian. A subdivision in eleven stages, all originating from European stratigraphy, is now used worldwide, in many parts of the world, alternative local subdivisions are still in use. As with other geologic periods, the rock beds of the Cretaceous are well identified. No great extinction or burst of diversity separates the Cretaceous from the Jurassic and this layer has been dated at 66.043 Ma. A140 Ma age for the Jurassic-Cretaceous boundary instead of the usually accepted 145 Ma was proposed in 2014 based on a study of Vaca Muerta Formation in Neuquén Basin. Víctor Ramos, one of the authors of the study proposing the 140 Ma boundary age sees the study as a first step toward formally changing the age in the International Union of Geological Sciences, due to the high sea level there was extensive space for such sedimentation. Because of the young age and great thickness of the system. Chalk is a type characteristic for the Cretaceous. It consists of coccoliths, microscopically small calcite skeletons of coccolithophores, the group is found in England, northern France, the low countries, northern Germany, Denmark and in the subsurface of the southern part of the North Sea. Chalk is not easily consolidated and the Chalk Group still consists of sediments in many places. The group also has other limestones and arenites, among the fossils it contains are sea urchins, belemnites, ammonites and sea reptiles such as Mosasaurus. In southern Europe, the Cretaceous is usually a marine system consisting of competent limestone beds or incompetent marls
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Media related to Chanos chanos at Wikimedia Commons
Data related to Chanos chanos at Wikispecies
