Navigation is a field of study that focuses on the process of monitoring and controlling the movement of a craft or vehicle from one place to another. The field of navigation includes four general categories: land navigation, marine navigation, aeronautic navigation, space navigation, it is the term of art used for the specialized knowledge used by navigators to perform navigation tasks. All navigational techniques involve locating the navigator's position compared to known locations or patterns. Navigation, in a broader sense, can refer to any skill or study that involves the determination of position and direction. In this sense, navigation includes pedestrian navigation. In the European medieval period, navigation was considered part of the set of seven mechanical arts, none of which were used for long voyages across open ocean. Polynesian navigation is the earliest form of open-ocean navigation, it was based on memory and observation recorded on scientific instruments like the Marshall Islands Stick Charts of Ocean Swells.
Early Pacific Polynesians used the motion of stars, the position of certain wildlife species, or the size of waves to find the path from one island to another. Maritime navigation using scientific instruments such as the mariner's astrolabe first occurred in the Mediterranean during the Middle Ages. Although land astrolabes were invented in the Hellenistic period and existed in classical antiquity and the Islamic Golden Age, the oldest record of a sea astrolabe is that of Majorcan astronomer Ramon Llull dating from 1295; the perfecting of this navigation instrument is attributed to Portuguese navigators during early Portuguese discoveries in the Age of Discovery. The earliest known description of how to make and use a sea astrolabe comes from Spanish cosmographer Martín Cortés de Albacar's Arte de Navegar published in 1551, based on the principle of the archipendulum used in constructing the Egyptian pyramids. Open-seas navigation using the astrolabe and the compass started during the Age of Discovery in the 15th century.
The Portuguese began systematically exploring the Atlantic coast of Africa from 1418, under the sponsorship of Prince Henry. In 1488 Bartolomeu Dias reached the Indian Ocean by this route. In 1492 the Spanish monarchs funded Christopher Columbus's expedition to sail west to reach the Indies by crossing the Atlantic, which resulted in the Discovery of the Americas. In 1498, a Portuguese expedition commanded by Vasco da Gama reached India by sailing around Africa, opening up direct trade with Asia. Soon, the Portuguese sailed further eastward, to the Spice Islands in 1512, landing in China one year later; the first circumnavigation of the earth was completed in 1522 with the Magellan-Elcano expedition, a Spanish voyage of discovery led by Portuguese explorer Ferdinand Magellan and completed by Spanish navigator Juan Sebastián Elcano after the former's death in the Philippines in 1521. The fleet of seven ships sailed from Sanlúcar de Barrameda in Southern Spain in 1519, crossed the Atlantic Ocean and after several stopovers rounded the southern tip of South America.
Some ships were lost, but the remaining fleet continued across the Pacific making a number of discoveries including Guam and the Philippines. By only two galleons were left from the original seven; the Victoria led by Elcano sailed across the Indian Ocean and north along the coast of Africa, to arrive in Spain in 1522, three years after its departure. The Trinidad sailed east from the Philippines, trying to find a maritime path back to the Americas, but was unsuccessful; the eastward route across the Pacific known as the tornaviaje was only discovered forty years when Spanish cosmographer Andrés de Urdaneta sailed from the Philippines, north to parallel 39°, hit the eastward Kuroshio Current which took its galleon across the Pacific. He arrived in Acapulco on October 8, 1565; the term stems from the 1530s, from Latin navigationem, from navigatus, pp. of navigare "to sail, sail over, go by sea, steer a ship," from navis "ship" and the root of agere "to drive". The latitude of a place on Earth is its angular distance north or south of the equator.
Latitude is expressed in degrees ranging from 0° at the Equator to 90° at the North and South poles. The latitude of the North Pole is 90° N, the latitude of the South Pole is 90° S. Mariners calculated latitude in the Northern Hemisphere by sighting the North Star Polaris with a sextant and using sight reduction tables to correct for height of eye and atmospheric refraction; the height of Polaris in degrees above the horizon is the latitude of the observer, within a degree or so. Similar to latitude, the longitude of a place on Earth is the angular distance east or west of the prime meridian or Greenwich meridian. Longitude is expressed in degrees ranging from 0° at the Greenwich meridian to 180° east and west. Sydney, for example, has a longitude of about 151° east. New York City has a longitude of 74° west. For most of history, mariners struggled to determine longitude. Longitude can be calculated. Lacking that, one can use a sextant to take a lunar distance that, with a nautical almanac, can be used to calculate the time at zero longitude.
Reliable marine chronometers were unavailable until the late 18th century and not affordable until the 19th century. For about a hundred years, from about 1767 until about 1850, mariners lacking a chronometer used the method of lunar distances to determine Greenwich time to find their longitude. A mariner with a chronometer could check its reading using a lunar determination of Greenwich tim
Wilderness or wildland is a natural environment on Earth that has not been modified by human activity. It may be defined as: "The most intact, undisturbed wild natural areas left on our planet—those last wild places that humans do not control and have not developed with roads, pipelines or other industrial infrastructure." The term has traditionally referred to terrestrial environments, though growing attention is being placed on marine wilderness. Recent maps of wilderness suggest it covers one quarter of Earth's terrestrial surface, but is being degraded by human activity. Less wilderness remains in the ocean, with only 13.2% free from intense human activity. Some governments establish them by law or administrative acts in land tracts that have not been modified by human action in great measure; the main feature of them is that human motorized activity is restricted. These actions seek not only to preserve what exists, but to promote and advance a natural expression and development. Wilderness areas can be found in preserves, conservation preserves, National Forests, National Parks and in urban areas along rivers, gulches or otherwise undeveloped areas.
These areas are considered important for the survival of certain species, ecological studies, conservation and recreation. Wilderness is valued for cultural, spiritual and aesthetic reasons; some nature writers believe wilderness areas are vital for creativity. They may preserve historic genetic traits and provide habitat for wild flora and fauna that may be difficult to recreate in zoos, arboretums or laboratories; the word wilderness derives from the notion of "wildness"—in other words, that, not controlled by humans. The mere presence or activity of people does not disqualify an area from being "wilderness." Many ecosystems that are, or have been, inhabited or influenced by activities of people may still be considered "wild." This way of looking at wilderness includes areas within which natural processes operate without human interference. The WILD Foundation states that wilderness areas have two dimensions: they must be biologically intact and protected; the World Conservation Union classifies wilderness at Ia and Ib.
Activities on the margins of specific wilderness areas, such as fire suppression and the interruption of animal migration affect the interior of wildernesses. In wealthier, industrialized nations, it has a specific legal meaning as well: as land where development is prohibited by law. Many nations have designated wilderness, including the United States, Canada, New Zealand, South Africa. Many new parks are being planned and passed by various Parliaments and Legislatures at the urging of dedicated individuals around the globe who believe that "in the end, inspired people empowered by effective legislation will ensure that the spirit and services of wilderness will thrive and permeate our society, preserving a world that we are proud to hand over to those who come after us." Looked at through the lens of the visual arts and wildness have been important subjects in various epochs of world history. An early tradition of landscape art occurred in the Tang Dynasty; the tradition of representing nature as it is became one of the aims of Chinese painting and was a significant influence in Asian art.
Artists in the tradition of Shan shui, learned to depict mountains and rivers "from the perspective of nature as a whole and on the basis of their understanding of the laws of nature… as if seen through the eyes of a bird." In the 13th century, Shih Erh Chi recommended avoiding painting "scenes lacking any places made inaccessible by nature."For most of human history, the greater part of the Earth's terrain was wilderness, human attention was concentrated in settled areas. The first known laws to protect parts of nature date back to the Babylonian Empire and Chinese Empire. Ashoka, the Great Mauryan King, defined the first laws in the world to protect flora and fauna in Edicts of Ashoka around 3rd Century B. C. In the Middle Ages, the Kings of England initiated one of the world’s first conscious efforts to protect natural areas, they were motivated by a desire to be able to hunt wild animals in private hunting preserves rather than a desire to protect wilderness. In order to have animals to hunt they would have to protect wildlife from subsistence hunting and the land from villagers gathering firewood.
Similar measures were introduced in other European countries. The idea of wilderness having intrinsic value emerged in the Western world in the 19th century. British artists John Constable and J. M. W. Turner turned their attention to capturing the beauty of the natural world in their paintings. Prior to that, paintings had been of religious scenes or of human beings. William Wordsworth’s poetry described the wonder of the natural world, viewed as a threatening place; the valuing of nature became an aspect of Western culture. By the mid-19th century, in Germany, "Scientific Conservation," as it was called, advocated "the efficient utilization of natural resources through the application of science and technology." Concepts of forest management based on the German approach were applied in other parts of the world, but with varying degrees of success. Over the course of the 19th century wilderness became viewed not as a place to fear but a place to enjoy and protect, hence came the conservation movement in the latter half of the 19th century.
Rivers were rafted and mountains were climbed for the sake of recreation, not to determine th
Machine vision is the technology and methods used to provide imaging-based automatic inspection and analysis for such applications as automatic inspection, process control, robot guidance in industry. Machine vision is a term encompassing a large number of technologies and hardware products, integrated systems, actions and expertise. Machine vision as a systems engineering discipline can be considered distinct from computer vision, a form of computer science, it attempts to integrate existing technologies in new ways and apply them to solve real world problems. The term is the prevalent one for these functions in industrial automation environments but is used for these functions in other environments such as security and vehicle guidance; the overall machine vision process includes planning the details of the requirements and project, creating a solution. During run-time, the process starts with imaging, followed by automated analysis of the image and extraction of the required information. Definitions of the term "Machine vision" vary, but all include the technology and methods used to extract information from an image on an automated basis, as opposed to image processing, where the output is another image.
The information extracted can be a simple good-part/bad-part signal, or more a complex set of data such as the identity and orientation of each object in an image. The information can be used for such applications as automatic inspection and robot and process guidance in industry, for security monitoring and vehicle guidance; this field encompasses a large number of technologies and hardware products, integrated systems, actions and expertise. Machine vision is the only term used for these functions in industrial automation applications. Machine vision as a systems engineering discipline can be considered distinct from computer vision, a form of basic computer science; the term is used in a broader sense by trade shows and trade groups such as the Automated Imaging Association and the European Machine Vision Association. This broader definition encompasses products and applications most associated with image processing; the primary uses for machine vision are automatic inspection and industrial robot/process guidance.
See glossary of machine vision. The primary uses for machine vision are imaging-based automatic inspection and sorting and robot guidance.. The overall process includes planning the details of the requirements and project, creating a solution; this section describes the technical process that occurs during the operation of the solution. The first step in the automatic inspection sequence of operation is acquisition of an image using cameras and lighting, designed to provide the differentiation required by subsequent processing. MV software packages and programs developed in them employ various digital image processing techniques to extract the required information, make decisions based on the extracted information; the components of an automatic inspection system include lighting, a camera or other imager, a processor and output devices. The imaging device can either be separate from the main image processing unit or combined with it in which case the combination is called a smart camera or smart sensor.
When separated, the connection may be made to specialized intermediate hardware, a custom processing appliance, or a frame grabber within a computer using either an analog or standardized digital interface. MV implementations use digital cameras capable of direct connections to a computer via FireWire, USB or Gigabit Ethernet interfaces. While conventional imaging is most used in MV, alternatives include multispectral imaging, hyperspectral imaging, imaging various infrared bands, line scan imaging, 3D imaging of surfaces and X-ray imaging. Key differentiations within MV 2D visible light imaging are monochromatic vs. color, frame rate and whether or not the imaging process is simultaneous over the entire image, making it suitable for moving processes. Though the vast majority of machine vision applications are solved using two-dimensional imaging, machine vision applications utilizing 3D imaging are a growing niche within the industry; the most used method for 3D imaging is scanning based triangulation which utilizes motion of the product or image during the imaging process.
A laser is projected onto the surfaces of an object and viewed from a different angle. In machine vision this is accomplished with a scanning motion, either by moving the workpiece, or by moving the camera & laser imaging system; the line is viewed by a camera from a different angle. Lines from multiple scans are assembled into a depth map or point cloud. Stereoscopic vision is used in special cases involving unique features present in both views of a pair of cameras. Other 3D methods used for machine vision are time of flight and grid based. One method is grid array based systems using pseudorandom structured light system as employed by the Microsoft Kinect system circa 2012. After an image is acquired, it is processed. Multiple stages of processing are used in a sequence that ends up as a desired result. A t
In architecture and building engineering, a floor plan is a drawing to scale, showing a view from above, of the relationships between rooms, traffic patterns, other physical features at one level of a structure. Dimensions are drawn between the walls to specify room sizes and wall lengths. Floor plans may include details of fixtures like sinks, water heaters, etc. Floor plans may include notes for construction to specify finishes, construction methods, or symbols for electrical items, it is called a plan, a measured plane projected at the floor height of 4 ft, as opposed to an elevation, a measured plane projected from the side of a building, along its height, or a section or cross section where a building is cut along an axis to reveal the interior structure. Similar to a map the orientation of the view is downward from above, but unlike a conventional map, a plan is drawn at a particular vertical position. Objects below this level are seen, objects at this level are shown'cut' in plan-section, objects above this vertical position within the structure are omitted or shown dashed.
Plan view or planform is defined as a vertical orthographic projection of an object on a horizontal plane, like a map. The term may be used in general to describe any drawing showing the physical layout of objects. For example, it may denote the arrangement of the displayed objects at an exhibition, or the arrangement of exhibitor booths at a convention. Drawings are now reproduced using large format xerographic copiers. A reflected ceiling plan shows a view of the room as if looking from above, through the ceiling, at a mirror installed one foot below the ceiling level, which shows the reflected image of the ceiling above; this convention maintains the same orientation of the floor and ceilings plans - looking down from above. RCPs are used by designers and architects to demonstrate lighting, visible mechanical features, ceiling forms as part of the documents provided for construction. A floor plan is not a top view or birds eye view, it is a measured drawing to scale of the layout of a floor in a building.
A top view or bird's eye view does not show an orthogonally projected plane cut at the typical four foot height above the floor level. A floor plan could show: Interior walls and hallways Restrooms Windows and doors Appliances such as stoves, water heater etc. Interior features such as fireplaces and whirlpools The use of all rooms A plan view is an orthographic projection of a three-dimensional object from the position of a horizontal plane through the object. In other words, a plan is a section viewed from the top. In such views, the portion of the object above the plane is omitted to reveal. In the case of a floor plan, the roof and upper portion of the walls may be omitted. Whenever an interior design project is being approached, a floor plan is the typical starting point for any further design considerations and decisions. Roof plans are orthographic projections, but they are not sections as their viewing plane is outside of the object. A plan is a common method of depicting the internal arrangement of a three-dimensional object in two dimensions.
It is used in technical drawing and is traditionally crosshatched. The style of crosshatching indicates the type of material. A 3D floor plan can be defined as a virtual model of a building floor plan, it is used to better convey architectural plans to individuals not familiar with floor plans. Despite the purpose of floor plans being to depict 3D layouts in a 2D manner, technological expansion has made rendering 3D models much more cost effective. 3D plans show a better depth of image and are complimented by 3D furniture in the room. This allows a greater appreciation of scale than with traditional 2D floor plans. 3D printing 3D scanner Architect's scale Architectural drawing List of floor plan software House House plan Indoor positioning system Room number Media related to floor plans at Wikimedia Commons
Automotive navigation system
An automotive navigation system is part of the automobile controls or a third party add-on used to find direction in an automobile. It uses a satellite navigation device to get its position data, correlated to a position on a road; when directions are needed routing can be calculated. On the fly traffic information can be used to adjust the route. Dead reckoning using distance data from sensors attached to the drivetrain, a gyroscope and an accelerometer can be used for greater reliability, as GPS signal loss and/or multipath can occur due to urban canyons or tunnels. Mathematically, automotive navigation is based on the shortest path problem, within graph theory, which examines how to identify the path that best meets some criteria between two points in a large network. Automotive navigation system is a key technology that can be improved when develop the self-driving cars. Automotive navigation systems represent a convergence of a number of diverse technologies many of which have been available for many years, but were too costly or inaccessible.
Limitations such as batteries and processing power had to be overcome before the product became commercially viable. 1961: Hidetsugu Yagi designed a wireless-based navigation system. This design was still intended for military-use. 1966: General Motors Research was working on a non-satellite-based navigation and assistance system called DAIR. After initial tests GM found that it was not a scalable or practical way to provide navigation assistance. Decades however, the concept would be reborn as OnStar. 1973: Japan's Ministry of International Trade and Industry and Fuji Heavy Industries sponsored CATC, a Japanese research project on automobile navigation systems. 1979: MITI established JSK in Japan. 1980: Electronic Auto Compass with new mechanism on the Toyota Crown. 1981: The earlier research of CATC leads to the first generation of automobile navigation systems from Japanese companies Honda and Toyota. They used dead reckoning technology. 1981: Honda's Electro Gyro-Cator was the first commercially available car navigation system.
It used inertial navigation systems, which tracked the distance traveled, the start point, direction headed. It was the first with a map display. 1981: Navigation computer on the Toyota Celica. 1983: Etak was founded. It made an early system. Digital map information was stored on standard cassette tapes. 1987: Toyota introduced the World's first CD-ROM-based navigation system on the Toyota Crown. 1990: Mazda Eunos Cosmo became the first car with built-in GPS-navigation system 1991: Toyota introduced GPS car navigation on the Toyota Soarer. 1991: Mitsubishi introduced GPS car navigation on the Mitsubishi Debonair. 1992: Voice assisted GPS navigation system on the Toyota Celsior. 1993: The Austrian channel ORF airs a presentation of the software company bitMAP and its head Werner Liebig's invention, an electronic city map including street names and house numbers, using a satellite-based navigation system. BitMAP doesn't manage to market itself properly. 1994: BMW 7 series E38 first European model featuring GPS navigation.
The navigation system was developed in cooperation with Philips. 1995: Oldsmobile introduced the first GPS navigation system available in a United States production car, called GuideStar. 1995: Device called "Mobile Assistant" or short, MASS, produced by Munich-based company ComRoad AG, won the title "Best Product in Mobile Computing" on CeBit by magazine Byte. It offered turn-by-turn navigation via wireless internet connection, with both GPS and speed sensor in the car. 1995: Acura introduced the first hard disk drive-based navigation system in the 1996 RL. 1997: Navigation system using Differential GPS developed as a factory-installed option on the Toyota Prius 1998: First DVD-based navigation system introduced on the Toyota Progres. 2000: The United States made a more accurate GPS signal available for civilian use. 2003: Toyota introduced the first Hard disk drive-based navigation system and the industry's first DVD-based navigation system with a built-in Electronic throttle control 2007: Toyota introduced Map on Demand, a technology for distributing map updates to car navigation systems, developed as the first of its kind in the world 2008: World's first navigation system-linked brake assist function and Navigation system linked to Adaptive Variable Suspension System on Toyota Crown The road database is a vector map.
Street names or numbers and house numbers, as well as points of interest, are encoded as geographic coordinates. This enables users to find a desired destination as geographic coordinates. Map database formats are uniformly proprietary, with no industry standards for satellite navigation maps, although some companies are trying to address this with SDAL and Navigation Data Standard. Map data vendors such as Tele Atlas and Navteq create the base map in a GDF format, but each electronics manufacturer compiles it in an optimized proprietary manner. GDF is not a CD standard for car navigation systems. GDF is converted onto the CD-ROM in the internal format of the navigation system. CDF is a proprietary navigation map format created by Philips. SDAL is a proprietary map format developed by Navteq, released royalty free in the hope that it would become an in
In navigation, a radio beacon is a kind of beacon, a device which marks a fixed location and allows direction finding equipment to find relative bearing. Radio beacons transmit a radio signal, picked up by radio direction finding systems on ships and vehicles to determine the direction to the beacon. A radio beacon is a transmitter at a known location, which transmits a continuous or periodic radio signal with limited information content, on a specified radio frequency; the beacon function is combined with some other transmission, like telemetry data or meteorological information. Radio beacons have many applications, including air and sea navigation, propagation research, robotic mapping, radio-frequency identification / Near Field Communication and indoor guidance, as with real-time locating systems like Syledis or simultaneous localization and mapping. A most basic aviation radio navigational aid is the Non-directional Beacon; these are simple low frequency and medium frequency transmitters and they are used to locate airways intersections, airports and to conduct instrument approaches, with the use of a radio direction finder located on the aircraft.
The aviation NDBs the ones marking airways intersections, are decommissioned, as they are replaced with other navigational aids based on newer technologies. Due to low purchase and calibration cost, they are still used to mark locations of smaller aerodromes and important helicopter landing sites. There were marine beacons, based on the same technology and installed at coastal areas, for use by ships at sea. Most of them in the western world, are no longer in service, while some have been converted to telemetry transmitters for differential GPS. In addition to dedicated radio beacons, any AM, VHF, or UHF radio station at a known location can be used as a beacon with direction finding equipment. A marker beacon is a specialized beacon used in aviation in conjunction with an instrument landing system, to give pilots a means to determine distance to the runway. Marker beacons transmit on the dedicated frequency of 75 MHz; this type of beacon is being phased-out and most new ILS installations have no marker beacons.
An amateur radio propagation beacon is used to study the propagation of radio signals. Nearly all of them are part of the amateur radio service. A group of radio beacons with single-letter identifiers transmitting in morse code have been reported on various HF frequencies. There is no official information available about these transmitters and they are not registered with the ITU; some investigators suggest that some of these beacons are radio propagation beacons for naval use. Beacons are used in both geostationary and inclined orbit satellites. Any satellite will emit one or more beacons. A beacon was left on the moon by the last Apollo mission, transmitting FSK telemetry on 2276.0 MHz Driftnet radio buoys are extensively used by fishing boats operating in open seas and oceans. They are useful for collecting long fishing lines or fishing nets, with the assistance of a radio direction finder. According to product information released by manufacturer Kato Electronics Co, Ltd. these buoys transmit on 1600–2850 kHz with a power of 4-15 W.
Some types of driftnet buoys, called "SelCall buoys", answer only when they are called by their own ships. Using this technique the buoy prevents nets and fishing gears from being carried away by other ships, while the battery power consumption remains low. Distress radiobeacons collectively known as distress beacons, emergency beacons, or beacons, are those tracking transmitters that operate as part of the international Cospas-Sarsat Search and Rescue satellite system; when activated, these beacons send out a distress signal that, when detected by non-geostationary satellites, can be located by triangulation. In the case of 406 MHz beacons which transmit digital signals, the beacons can be uniquely identified instantly, furthermore, a GPS position can be encoded into the signal Distress signals from the beacons are homed by Search and Rescue aircraft and ground search parties who can in turn come to the aid of the concerned boat, and/or persons. There are three kinds of distress radiobeacons: EPIRBs signal maritime distress, ELTs signal aircraft distress PLBs are for personal use and are intended to indicate a person in distress, away from normal emergency response capabilities The basic purpose of distress radiobeacons is to get people rescued within the so-called "golden day" when the majority of survivors can still be saved.
In the field of Wi-Fi, the term beacon signifies a specific data transmission from the wireless access point, which carries the SSID, the channel number and security protocols such as Wired Equivalent Privacy or Wi-Fi Protected Access. This transmission does not contain the link layer address of another Wi-Fi device, therefore it can be received by any LAN client. Stations participating in packet radio networks based on the AX.25 link layer
Biology is the natural science that studies life and living organisms, including their physical structure, chemical processes, molecular interactions, physiological mechanisms and evolution. Despite the complexity of the science, there are certain unifying concepts that consolidate it into a single, coherent field. Biology recognizes the cell as the basic unit of life, genes as the basic unit of heredity, evolution as the engine that propels the creation and extinction of species. Living organisms are open systems that survive by transforming energy and decreasing their local entropy to maintain a stable and vital condition defined as homeostasis. Sub-disciplines of biology are defined by the research methods employed and the kind of system studied: theoretical biology uses mathematical methods to formulate quantitative models while experimental biology performs empirical experiments to test the validity of proposed theories and understand the mechanisms underlying life and how it appeared and evolved from non-living matter about 4 billion years ago through a gradual increase in the complexity of the system.
See branches of biology. The term biology is derived from the Greek word βίος, bios, "life" and the suffix -λογία, -logia, "study of." The Latin-language form of the term first appeared in 1736 when Swedish scientist Carl Linnaeus used biologi in his Bibliotheca botanica. It was used again in 1766 in a work entitled Philosophiae naturalis sive physicae: tomus III, continens geologian, phytologian generalis, by Michael Christoph Hanov, a disciple of Christian Wolff; the first German use, was in a 1771 translation of Linnaeus' work. In 1797, Theodor Georg August Roose used the term in the preface of a book, Grundzüge der Lehre van der Lebenskraft. Karl Friedrich Burdach used the term in 1800 in a more restricted sense of the study of human beings from a morphological and psychological perspective; the term came into its modern usage with the six-volume treatise Biologie, oder Philosophie der lebenden Natur by Gottfried Reinhold Treviranus, who announced: The objects of our research will be the different forms and manifestations of life, the conditions and laws under which these phenomena occur, the causes through which they have been effected.
The science that concerns itself with these objects we will indicate by the name biology or the doctrine of life. Although modern biology is a recent development, sciences related to and included within it have been studied since ancient times. Natural philosophy was studied as early as the ancient civilizations of Mesopotamia, the Indian subcontinent, China. However, the origins of modern biology and its approach to the study of nature are most traced back to ancient Greece. While the formal study of medicine dates back to Hippocrates, it was Aristotle who contributed most extensively to the development of biology. Important are his History of Animals and other works where he showed naturalist leanings, more empirical works that focused on biological causation and the diversity of life. Aristotle's successor at the Lyceum, wrote a series of books on botany that survived as the most important contribution of antiquity to the plant sciences into the Middle Ages. Scholars of the medieval Islamic world who wrote on biology included al-Jahiz, Al-Dīnawarī, who wrote on botany, Rhazes who wrote on anatomy and physiology.
Medicine was well studied by Islamic scholars working in Greek philosopher traditions, while natural history drew on Aristotelian thought in upholding a fixed hierarchy of life. Biology began to develop and grow with Anton van Leeuwenhoek's dramatic improvement of the microscope, it was that scholars discovered spermatozoa, bacteria and the diversity of microscopic life. Investigations by Jan Swammerdam led to new interest in entomology and helped to develop the basic techniques of microscopic dissection and staining. Advances in microscopy had a profound impact on biological thinking. In the early 19th century, a number of biologists pointed to the central importance of the cell. In 1838, Schleiden and Schwann began promoting the now universal ideas that the basic unit of organisms is the cell and that individual cells have all the characteristics of life, although they opposed the idea that all cells come from the division of other cells. Thanks to the work of Robert Remak and Rudolf Virchow, however, by the 1860s most biologists accepted all three tenets of what came to be known as cell theory.
Meanwhile and classification became the focus of natural historians. Carl Linnaeus published a basic taxonomy for the natural world in 1735, in the 1750s introduced scientific names for all his species. Georges-Louis Leclerc, Comte de Buffon, treated species as artificial categories and living forms as malleable—even suggesting the possibility of common descent. Although he was opposed to evolution, Buffon is a key figure in the history of evolutionary thought. Serious evolutionary thinking originated with the works of Jean-Baptiste Lamarck, the first to present a coherent theory of evolution, he posited that evolution was the result of environmental stress on properties of animals, meaning that the more and rigorously an organ was used, the more complex and efficient it would become, thus adapting the animal to its environment. Lamarck believed that these acquired traits could be passed on to the animal's offspring, who would