Corals are marine invertebrates within the class Anthozoa of the phylum Cnidaria. They live in compact colonies of many identical individual polyps. Corals species include the important reef builders that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton. A coral "group" is a colony of myriad genetically identical polyps; each polyp is a sac-like animal only a few millimeters in diameter and a few centimeters in length. A set of tentacles surround a central mouth opening. An exoskeleton is excreted near the base. Over many generations, the colony thus creates a large skeleton characteristic of the species. Individual heads grow by asexual reproduction of polyps. Corals breed sexually by spawning: polyps of the same species release gametes over a period of one to several nights around a full moon. Although some corals are able to catch small fish and plankton using stinging cells on their tentacles, most corals obtain the majority of their energy and nutrients from photosynthetic unicellular dinoflagellates in the genus Symbiodinium that live within their tissues.
These are known as zooxanthellae. Such corals require sunlight and grow in clear, shallow water at depths less than 60 metres. Corals are major contributors to the physical structure of the coral reefs that develop in tropical and subtropical waters, such as the enormous Great Barrier Reef off the coast of Queensland, Australia. Other corals do not rely on zooxanthellae and can live in much deeper water, with the cold-water genus Lophelia surviving as deep as 3,300 metres; some have been found on the Darwin Mounds, northwest of Cape Wrath and others as far north as off the coast of Washington State and the Aleutian Islands. Aristotle's pupil Theophrastus described the red coral, korallion, in his book on stones, implying it was a mineral, but he described it as a deep-sea plant in his Enquiries on Plants, where he mentions large stony plants that reveal bright flowers when under water in the Gulf of Heroes. Pliny the Elder stated boldly that several sea creatures including sea nettles and sponges "are neither animals nor plants, but are possessed of a third nature".
Petrus Gyllius copied Pliny, introducing the term zoophyta for this third group in his 1535 book On the French and Latin Names of the Fishes of the Marseilles Region. Gyllius further noted, following Aristotle, how hard it was to define what was a plant and what was an animal; the Persian polymath Al-Biruni classified sponges and corals as animals, arguing that they respond to touch. People believed corals to be plants until the eighteenth century, when William Herschel used a microscope to establish that coral had the characteristic thin cell membranes of an animal. Presently, corals are classified as certain species of animals within the sub-classes Hexacorallia and Octocorallia of the class Anthozoa in the phylum Cnidaria. Hexacorallia includes the stony corals and these groups have polyps that have a 6-fold symmetry. Octocorallia includes blue coral and soft corals and species of Octocorallia have polyps with an eightfold symmetry, each polyp having eight tentacles and eight mesenteries.
Fire corals are not true corals. Corals are sessile animals and differ from most other cnidarians in not having a medusa stage in their life cycle; the body unit of the animal is a polyp. Most corals are colonial, the initial polyp budding to produce another and the colony developing from this small start. In stony corals known as hard corals, the polyps produce a skeleton composed of calcium carbonate to strengthen and protect the organism; this is deposited by the coenosarc, the living tissue that connects them. The polyps sit in cup-shaped depressions in the skeleton known as corallites. Colonies of stony coral are variable in appearance. In soft corals, there is no stony skeleton but the tissues are toughened by the presence of tiny skeletal elements known as sclerites, which are made from calcium carbonate. Soft corals are variable in form and most are colonial. A few soft corals are stolonate. In some species this is thick and the polyps are embedded; some soft corals are form lobes. Others have a central axial skeleton embedded in the tissue matrix.
This is composed either of a fibrous protein called gorgonin or of a calcified material. In both stony and soft corals, the polyps can be retracted, with stony corals relying on their hard skeleton and cnidocytes for defence against predators, soft corals relying on chemical defences in the form of toxic substances present in the tissues known as terpenoids; the polyps of stony corals have six-fold symmetry. The mouth of each polyp is surrounded by a ring of tentacles. In stony corals these are cylindrical and taper to a point, but in soft corals they are pinnate with side branches known as pinnules. In some tropical species these are reduced to mere stubs and in some they are fused to give a paddle-like appearance. In most corals, the tentacles are retracted by day and spread out at night to catch plankton and other small organisms. Shallow water species of both stony and soft corals can be zooxanthellate, the corals supplementing their plankton diet with t
Natural history is a domain of inquiry involving organisms including animals and plants in their environment. A person who studies natural history is called natural historian. Natural history is not limited to it, it involves the systematic study of any category of natural organisms. So while it dates from studies in the ancient Greco-Roman world and the mediaeval Arabic world, through to European Renaissance naturalists working in near isolation, today's natural history is a cross discipline umbrella of many specialty sciences; the meaning of the English term "natural history" has narrowed progressively with time. In antiquity, "natural history" covered anything connected with nature, or which used materials drawn from nature, such as Pliny the Elder's encyclopedia of this title, published circa 77 to 79 AD, which covers astronomy, geography and their technology and superstition, as well as animals and plants. Medieval European academics considered knowledge to have two main divisions: the humanities and divinity, with science studied through texts rather than observation or experiment.
The study of nature revived in the Renaissance, became a third branch of academic knowledge, itself divided into descriptive natural history and natural philosophy, the analytical study of nature. In modern terms, natural philosophy corresponded to modern physics and chemistry, while natural history included the biological and geological sciences; the two were associated. During the heyday of the gentleman scientists, many people contributed to both fields, early papers in both were read at professional science society meetings such as the Royal Society and the French Academy of Sciences – both founded during the seventeenth century. Natural history had been encouraged by practical motives, such as Linnaeus' aspiration to improve the economic condition of Sweden; the Industrial Revolution prompted the development of geology to help find useful mineral deposits. Modern definitions of natural history come from a variety of fields and sources, many of the modern definitions emphasize a particular aspect of the field, creating a plurality of definitions with a number of common themes among them.
For example, while natural history is most defined as a type of observation and a subject of study, it can be defined as a body of knowledge, as a craft or a practice, in which the emphasis is placed more on the observer than on the observed. Definitions from biologists focus on the scientific study of individual organisms in their environment, as seen in this definition by Marston Bates: "Natural history is the study of animals and Plants – of organisms.... I like to think of natural history as the study of life at the level of the individual – of what plants and animals do, how they react to each other and their environment, how they are organized into larger groupings like populations and communities" and this more recent definition by D. S. Wilcove and T. Eisner: "The close observation of organisms—their origins, their evolution, their behavior, their relationships with other species"; this focus on organisms in their environment is echoed by H. W. Greene and J. B. Losos: "Natural history focuses on where organisms are and what they do in their environment, including interactions with other organisms.
It encompasses changes in internal states insofar as they pertain to what organisms do". Some definitions go further, focusing on direct observation of organisms in their environment, both past and present, such as this one by G. A. Bartholomew: "A student of natural history, or a naturalist, studies the world by observing plants and animals directly; because organisms are functionally inseparable from the environment in which they live and because their structure and function cannot be adequately interpreted without knowing some of their evolutionary history, the study of natural history embraces the study of fossils as well as physiographic and other aspects of the physical environment". A common thread in many definitions of natural history is the inclusion of a descriptive component, as seen in a recent definition by H. W. Greene: "Descriptive ecology and ethology". Several authors have argued for a more expansive view of natural history, including S. Herman, who defines the field as "the scientific study of plants and animals in their natural environments.
It is concerned with levels of organization from the individual organism to the ecosystem, stresses identification, life history, distribution and inter-relationships. It and appropriately includes an esthetic component", T. Fleischner, who defines the field more broadly, as "A practice of intentional, focused attentiveness and receptivity to the more-than-human world, guided by honesty and accuracy"; these definitions explicitly include the arts in the field of natural history, are aligned with the broad definition outlined by B. Lopez, who defines the field as the "Patient interrogation of a landscape" while referring to the natural history knowledge of the Eskimo. A different framework for natural history, covering a similar range of themes, is implied in the scope of work encompassed by many leading natural history museums, which include elements of anthropology, geology and astronomy along with botany and zoology, or include both cultural and natural components of the world; the pl
A snail is, in loose terms, a shelled gastropod. The name is most applied to land snails, terrestrial pulmonate gastropod molluscs. However, the common name snail is used for most of the members of the molluscan class Gastropoda that have a coiled shell, large enough for the animal to retract into; when the word "snail" is used in this most general sense, it includes not just land snails but numerous species of sea snails and freshwater snails. Gastropods that lack a shell, or have only an internal shell, are called slugs, land snails that have only a small shell are called semi-slugs. Snails have considerable human relevance, including as food items, as pests, as vectors of disease, their shells are used as decorative objects and are incorporated into jewelry; the snail has had some cultural significance, has been used as a metaphor. Snails that respire using a lung belong to the group Pulmonata; as traditionally defined, the Pulmonata were found to be polyphyletic in a molecular study per Jörger et al. dating from 2010.
But snails with gills form a polyphyletic group. Both snails that have lungs and snails that have gills have diversified so over geological time that a few species with gills can be found on land and numerous species with lungs can be found in freshwater. A few marine species have lungs. Snails can be found in a wide range of environments, including ditches and the abyssal depths of the sea. Although land snails may be more familiar to laymen, marine snails constitute the majority of snail species, have much greater diversity and a greater biomass. Numerous kinds of snail can be found in fresh water. Most snails have thousands of microscopic tooth-like structures located on a banded ribbon-like tongue called a radula; the radula works like a file. Many snails are herbivorous, eating plants or rasping algae from surfaces with their radulae, though a few land species and many marine species are omnivores or predatory carnivores. Snails cannot absorb colored pigments when eating paper or cardboard so their feces are colored.
Several species of the genus Achatina and related genera are known as giant African land snails. The largest living species of sea snail is Syrinx aruanus; the snail Lymnaea makes decisions by using only two types of neuron: one deciding whether the snail is hungry, the other deciding whether there is food in the vicinity. The largest known land gastropod is the African giant snail Achatina achatina, the largest recorded specimen of which measured 39.3 centimetres from snout to tail when extended, with a shell length of 27.3 cm in December 1978. It weighed 900 g. Named Gee Geronimo, this snail was owned by Christopher Hudson of Hove, East Sussex, UK, was collected in Sierra Leone in June 1976. Gastropods that lack a conspicuous shell are called slugs rather than snails; some species of slug have a red shell, some have only an internal vestige that serves as a calcium repository, others have no shell at all. Other than that there is little morphological difference between slugs and snails. There are however important differences in habitats and behavior.
A shell-less animal is much more maneuverable and compressible, so quite large land slugs can take advantage of habitats or retreats with little space, retreats that would be inaccessible to a similar-sized snail. Slugs squeeze themselves into confined spaces such as under loose bark on trees or under stone slabs, logs or wooden boards lying on the ground. In such retreats they are in less danger from either predators or desiccation, those are suitable places for laying their eggs. Slugs as a group are far from monophyletic; the reduction or loss of the shell has evolved many times independently within several different lineages of gastropods. The various taxa of land and sea gastropods with slug morphology occur within numerous higher taxonomic groups of shelled species. Land snails are known as an agricultural and garden pest but some species are an edible delicacy and household pets. There are a variety of snail-control measures that gardeners and farmers use in an attempt to reduce damage to valuable plants.
Traditional pesticides are still used, as are many less toxic control options such as concentrated garlic or wormwood solutions. Copper metal is a snail repellent, thus a copper band around the trunk of a tree will prevent snails from climbing up and reaching the foliage and fruit. Placing crushed egg shells on the soil around garden plants can deter snails from coming to the plants; the decollate snail will capture and eat garden snails, because of this it has sometimes been introduced as a biological pest control agent. However, this is not without problems, as the decollate snail is just as to attack and devour other gastropods that may represent a valuable part of the native fauna of the region. In French cuisine, edible snails are served for instance in Escargot à la Bourguignonne; the practice of rearing snails for food is known as heliciculture. For purposes of cultivation, the snails are kept in a
Nature, in the broadest sense, is the natural, physical, or material world or universe. "Nature" can refer to the phenomena of the physical world, to life in general. The study of nature is a large, part of science. Although humans are part of nature, human activity is understood as a separate category from other natural phenomena; the word nature is derived from the Latin word natura, or "essential qualities, innate disposition", in ancient times meant "birth". Natura is a Latin translation of the Greek word physis, which related to the intrinsic characteristics that plants and other features of the world develop of their own accord; the concept of nature as a whole, the physical universe, is one of several expansions of the original notion. This usage continued during the advent of modern scientific method in the last several centuries. Within the various uses of the word today, "nature" refers to geology and wildlife. Nature can refer to the general realm of living plants and animals, in some cases to the processes associated with inanimate objects—the way that particular types of things exist and change of their own accord, such as the weather and geology of the Earth.
It is taken to mean the "natural environment" or wilderness—wild animals, forest, in general those things that have not been altered by human intervention, or which persist despite human intervention. For example, manufactured objects and human interaction are not considered part of nature, unless qualified as, for example, "human nature" or "the whole of nature"; this more traditional concept of natural things which can still be found today implies a distinction between the natural and the artificial, with the artificial being understood as that, brought into being by a human consciousness or a human mind. Depending on the particular context, the term "natural" might be distinguished from the unnatural or the supernatural. Earth is the only planet known to support life, its natural features are the subject of many fields of scientific research. Within the solar system, it is third closest to the sun, its most prominent climatic features are its two large polar regions, two narrow temperate zones, a wide equatorial tropical to subtropical region.
Precipitation varies with location, from several metres of water per year to less than a millimetre. 71 percent of the Earth's surface is covered by salt-water oceans. The remainder consists of continents and islands, with most of the inhabited land in the Northern Hemisphere. Earth has evolved through geological and biological processes that have left traces of the original conditions; the outer surface is divided into several migrating tectonic plates. The interior remains active, with a thick layer of plastic mantle and an iron-filled core that generates a magnetic field; this iron core is composed of a solid inner phase, a fluid outer phase. Convective motion in the core generates electric currents through dynamo action, these, in turn, generate the geomagnetic field; the atmospheric conditions have been altered from the original conditions by the presence of life-forms, which create an ecological balance that stabilizes the surface conditions. Despite the wide regional variations in climate by latitude and other geographic factors, the long-term average global climate is quite stable during interglacial periods, variations of a degree or two of average global temperature have had major effects on the ecological balance, on the actual geography of the Earth.
Geology is the study of the solid and liquid matter that constitutes the Earth. The field of geology encompasses the study of the composition, physical properties and history of Earth materials, the processes by which they are formed and changed; the field is a major academic discipline, is important for mineral and hydrocarbon extraction, knowledge about and mitigation of natural hazards, some Geotechnical engineering fields, understanding past climates and environments. The geology of an area evolves through time as rock units are deposited and inserted and deformational processes change their shapes and locations. Rock units are first emplaced either by deposition onto the surface or intrude into the overlying rock. Deposition can occur when sediments settle onto the surface of the Earth and lithify into sedimentary rock, or when as volcanic material such as volcanic ash or lava flows, blanket the surface. Igneous intrusions such as batholiths, laccoliths and sills, push upwards into the overlying rock, crystallize as they intrude.
After the initial sequence of rocks has been deposited, the rock units can be deformed and/or metamorphosed. Deformation occurs as a result of horizontal shortening, horizontal extension, or side-to-side motion; these structural regimes broadly relate to convergent boundaries, divergent boundaries, transform boundaries between tectonic plates. Earth is estimated to have formed 4.54 billion years ago from the solar nebula, along with the Sun and other planets. The moon formed 20 million years later. Molten, the outer layer of the Earth cooled, resulting in the solid crust. Outgassing and volcanic activity produced the primordial atmosphere. Condensing water vapor, most or all of which came from ice delivered by comets, produced the oceans and other water sources; the energetic chemistry is believed to have produced a self-replicat
A monarch is a sovereign head of state in a monarchy. A monarch may exercise the highest authority and power in the state, or others may wield that power on behalf of the monarch. A monarch either inherits the lawful right to exercise the state's sovereign rights or is selected by an established process from a family or cohort eligible to provide the nation's monarch. Alternatively, an individual may become monarch by acclamation or a combination of means. A monarch reigns for life or until abdication. If a young child is crowned the monarch, a regent is appointed to govern until the monarch reaches the requisite adult age to rule. Monarchs' actual powers vary from one monarchy in different eras. A monarch can reign in multiple monarchies simultaneously. For example, the monarchy of Canada and the monarchy of the United Kingdom are separate states, but they share the same monarch through personal union. Monarchs, as such, bear a variety of titles – king or queen, prince or princess, emperor or empress, duke or grand duke, emir or sultan.
Prince is sometimes used as a generic term to refer to any monarch regardless of title in older texts. A king can be a queen's husband and a queen can be a king's wife. If both of the couple reign, neither person is considered to be a consort. Monarchy is political or sociocultural in nature, is associated with hereditary rule. Most monarchs, both and in the present day, have been born and brought up within a royal family and trained for future duties. Different systems of succession have been used, such as proximity of blood, agnatic seniority, Salic law, etc. While traditionally most monarchs have been male, female monarchs have ruled, the term queen regnant refers to a ruling monarch, as distinct from a queen consort, the wife of a reigning king; some monarchies are non-hereditary. In an elective monarchy, the monarch otherwise serves as any other monarch. Historical examples of elective monarchy include the Holy Roman Emperors and the free election of kings of the Polish–Lithuanian Commonwealth.
Modern examples include the Yang di-Pertuan Agong of Malaysia, appointed by the Conference of Rulers every five years or after the king's death, the pope of the Roman Catholic Church, who serves as sovereign of the Vatican City State and is elected to a life term by the College of Cardinals. In recent centuries, many states have become republics. Advocacy of government by a republic is called republicanism, while advocacy of monarchy is called monarchism. A principal advantage of hereditary monarchy is the immediate continuity of national leadership, as illustrated in the classic phrase "The King is dead. Long live the King!". In cases where the monarch serves as a ceremonial figure real leadership does not depend on the monarch. A form of government may in fact be hereditary without being considered monarchy, such as a family dictatorship. Monarchies take a wide variety of forms, such as the two co-princes of Andorra, positions held by the Roman Catholic Bishop of Urgel and the elected President of France.
The Yang di-Pertuan Agong of Malaysia is considered a monarch despite only holding the position for five years at a time. Hereditary succession within one patrilineal family has been most common, with preference for children over siblings, sons over daughters. In Europe, some peoples practiced equal division of land and regalian rights among sons or brothers, as in the Germanic states of the Holy Roman Empire, until after the medieval era and sometimes into the 19th century. Other European realms practice one form or another of primogeniture, whereunder a lord was succeeded by his eldest son or, if he had none, by his brother, his daughters or sons of daughters; the system of tanistry was semi-elective and gave weight to ability and merit. The Salic law, practiced in France and in the Italian territories of the House of Savoy, stipulated that only men could inherit the crown. In most fiefs, in the event of the demise of all legitimate male members of the patrilineage, a female of the family could succeed.
In most realms and sisters were eligible to succeed a ruling kinsman before more distant male relatives, but sometimes the husband of the heiress became the ruler, most also received the title, jure uxoris. Spain today continues this model of succession law, in the form of cognatic primogeniture. In more complex medieval cases, the sometimes conflicting principles of proximity and primogeniture battled, outcomes were idiosyncratic; as the average life span increased, an eldest son was more to reach majority age before the death of his father, primogeniture became favoured over proximity, tanistry and election. In 19
The Tegetthoff class was a class of four dreadnought battleships built for the Austro-Hungarian Navy. Named for Austrian Admiral Wilhelm von Tegetthoff, the class was composed of SMS Viribus Unitis, SMS Tegetthoff, SMS Prinz Eugen, SMS Szent István. Construction started on the ships shortly before World War I. Three of the four warships were built in the Stabilimento Tecnico Triestino shipyard in Trieste; the Tegetthoff-class ships hold the distinction for being the first and only dreadnought battleships of the Austro-Hungarian Navy. Viribus Unitis and Tegetthoff were commissioned into the fleet in December 1912 and July 1913, respectively. Prinz Eugen followed in July 1914; the smaller shipyards in Fiume resulted in a slower construction, further delayed by the outbreak of the war, with Szent István commissioned into the fleet in December 1915. This was too late for her to take part in the Bombardment of Ancona in which the remaining ships in the class saw action following Italy's declaration of war on Austria-Hungary in May 1915.
All of the Tegetthoffs were members of the 1st Battleship Division at the beginning of the war and were stationed out of the naval base at Pola. Following the Bombardment of Ancona and the commissioning of Szent István, the four ships saw little combat due to the Otranto Barrage which prohibited the Austro-Hungarian Navy from leaving the Adriatic Sea. In June 1918, in an attempt to earn safer passage for German and Austro-Hungarian U-boats through the Strait of Otranto, the Austro-Hungarian Navy attempted to break the Barrage with a major attack on the strait, but it was abandoned after Szent István was sunk by the motor torpedo boat MAS-15 on the morning of 10 June. After the sinking of Szent István, the remaining three ships of the class returned to port in Pola where they remained for the rest of the war; when Austria-Hungary was facing defeat in the war in October 1918, the Austrian government decided to transfer Viribus Unitis to the newly formed State of Slovenes and Serbs in order to avoid having to hand the ship over to the Allied Powers.
Renamed Yugoslavia, the ship was destroyed by an Italian mine in the Raid on Pola a day later. Following the Armistice of Villa Giusti in November 1918, Prinz Eugen was ceded to France where she was sunk as a target ship in 1922, while Tegetthoff was handed over to Italy and scrapped between 1924 and 1925; the wreck of Viribus Unitis was salvaged from Pola harbor and broken up between 1920 and 1930. With the establishment of the Austrian Naval League in September 1904 and the October appointment of Vice-Admiral Rudolf Montecuccoli to the posts of Commander-in-Chief of the Navy and Chief of the Naval Section of the War Ministry, the Austro-Hungarian Navy began an expansion program befitting a Great Power. Montecuccoli pursued the efforts championed by his predecessor, Admiral Hermann von Spaun, pushed for a expanded and modernized navy. Additional motivations existed which led to the development of the Tegetthoff class beyond Montecuccoli's own plans for the navy. New railroads had been constructed through Austria's Alpine passes between 1906 and 1908, linking Trieste and the Dalmatian coastline to the rest of the Empire.
Lower tariffs on the port of Trieste aided the expansion of the city and similar growth in Austria-Hungary's merchant marine. These changes necessitated the development of a new line of battleships capable of more than the defense of Austria-Hungary's coastline. Prior to the turn of the century, sea power had not been a priority in Austrian foreign policy and the navy had little public interest or support. However, the appointment of Archduke Franz Ferdinand – heir to the Austro-Hungarian throne and a prominent and influential supporter of naval expansion – to the position of admiral in September 1902 increased the importance of the navy in the eyes of both the general public and the Austrian and Hungarian Parliaments. Franz Ferdinand's interest in naval affairs stemmed from his belief that a strong navy would be necessary to compete with Italy, which he viewed as Austria-Hungary's greatest regional threat; the Tegetthoff-class battleships were authorized when Austria-Hungary was engaged in a naval arms race with its nominal ally, Italy.
Italy's Regia Marina was considered the most important naval power in the region, which Austria-Hungary measured itself against unfavorably. The disparity between the Austro-Hungarian and Italian navies had existed for decades. While that disparity had been somewhat equalized with the Imperial Russian Navy and German Imperial Navy surpassing the Italian Navy in 1893 and 1894 by 1903 the balance began to shift towards Italy's favor with the Italians claiming 18 pre-dreadnoughts in commission or under construction compared to 6 Austro-Hungarian battleships. Following the construction of the final two Regina Elena-class battleships in 1903, the Italian Navy elected to construct a series of large cruisers rather than additional battleships. Furthermore, a major scandal involving the Terni steelworks' armor contracts led to a government investigation that postponed several naval construction programs for three years; these delays meant that the Italian Navy would not initiate construction on another battleship until 1909, provided the Austro-Hungarian Navy with an opportunity to address the disparity between t
A scientist is someone who conducts scientific research to advance knowledge in an area of interest. In classical antiquity, there was no real ancient analog of a modern scientist. Instead, philosophers engaged in the philosophical study of nature called natural philosophy, a precursor of natural science, it was not until the 19th century that the term scientist came into regular use after it was coined by the theologian and historian of science William Whewell in 1833. The term'scientist' was first coined by him for Mary Somerville because the term "man of science", more custom at that time, was inappropriate here. In modern times, many scientists have advanced degrees in an area of science and pursue careers in various sectors of the economy such as academia, industry and nonprofit environments; the roles of "scientists", their predecessors before the emergence of modern scientific disciplines, have evolved over time. Scientists of different eras have had different places in society, the social norms, ethical values, epistemic virtues associated with scientists—and expected of them—have changed over time as well.
Accordingly, many different historical figures can be identified as early scientists, depending on which characteristics of modern science are taken to be essential. Some historians point to the Scientific Revolution that began in 16th century as the period when science in a recognizably modern form developed, it wasn't until the 19th century that sufficient socioeconomic changes occurred for scientists to emerge as a major profession. Knowledge about nature in classical antiquity was pursued by many kinds of scholars. Greek contributions to science—including works of geometry and mathematical astronomy, early accounts of biological processes and catalogs of plants and animals, theories of knowledge and learning—were produced by philosophers and physicians, as well as practitioners of various trades; these roles, their associations with scientific knowledge, spread with the Roman Empire and, with the spread of Christianity, became linked to religious institutions in most of European countries.
Astrology and astronomy became an important area of knowledge, the role of astronomer/astrologer developed with the support of political and religious patronage. By the time of the medieval university system, knowledge was divided into the trivium—philosophy, including natural philosophy—and the quadrivium—mathematics, including astronomy. Hence, the medieval analogs of scientists were either philosophers or mathematicians. Knowledge of plants and animals was broadly the province of physicians. Science in medieval Islam generated some new modes of developing natural knowledge, although still within the bounds of existing social roles such as philosopher and mathematician. Many proto-scientists from the Islamic Golden Age are considered polymaths, in part because of the lack of anything corresponding to modern scientific disciplines. Many of these early polymaths were religious priests and theologians: for example, Alhazen and al-Biruni were mutakallimiin. During the Italian Renaissance scientists like Leonardo Da Vinci, Galileo Galilei and Gerolamo Cardano have been considered as the most recognizable polymaths.
During the Renaissance, Italians made substantial contributions in science. Leonardo Da Vinci made significant discoveries in anatomy; the Father of modern Science,Galileo Galilei, made key improvements on the thermometer and telescope which allowed him to observe and describe the solar system. Descartes was not only a pioneer of analytic geometry but formulated a theory of mechanics and advanced ideas about the origins of animal movement and perception. Vision interested the physicists Young and Helmholtz, who studied optics and music. Newton extended Descartes' mathematics by inventing calculus, he investigated light and optics. Fourier founded a new branch of mathematics — infinite, periodic series — studied heat flow and infrared radiation, discovered the greenhouse effect. Girolamo Cardano, Blaise Pascal Pierre de Fermat, Von Neumann, Khinchin and Wiener, all mathematicians, made major contributions to science and probability theory, including the ideas behind computers, some of the foundations of statistical mechanics and quantum mechanics.
Many mathematically inclined scientists, including Galileo, were musicians. There are many compelling stories in medicine and biology, such as the development of ideas about the circulation of blood from Galen to Harvey. During the age of Enlightenment, Luigi Galvani, the pioneer of the bioelectromagnetics, discovered the animal electricity, he discovered that a charge applied to the spinal cord of a frog could generate muscular spasms throughout its body. Charges could make frog legs jump if the legs were no longer attached to a frog. While cutting a frog leg, Galvani's steel scalpel touched a brass hook, holding the leg in place; the leg twitched. Further experiments confirmed this effect, Galvani was convinced that he was seeing the effects of what he called animal electricity, the life force within the muscles of the frog. At the University of Pavia, Galvani's colleague Alessandro Volta was able to reproduce the results, but was sceptical o