Anatomy is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is inherently tied to embryology, comparative anatomy, evolutionary biology, Human anatomy is one of the basic essential sciences of medicine. The discipline of anatomy is divided into macroscopic and microscopic anatomy, macroscopic anatomy, or gross anatomy, is the examination of an animals body parts using unaided eyesight. Gross anatomy includes the branch of superficial anatomy, microscopic anatomy involves the use of optical instruments in the study of the tissues of various structures, known as histology, and in the study of cells. The history of anatomy is characterized by an understanding of the functions of the organs. Anatomy and physiology, which study the structure and function of organisms and their parts, make a pair of related disciplines. Derived from the Greek ἀνατομή anatomē dissection, anatomy is the study of the structure of organisms including their systems, organs.
It includes the appearance and position of the parts, the materials from which they are composed, their locations. Anatomy is quite distinct from physiology and biochemistry, which deal respectively with the functions of those parts, the discipline of anatomy can be subdivided into a number of branches including gross or macroscopic anatomy and microscopic anatomy. Gross anatomy is the study of large enough to be seen with the naked eye, and includes superficial anatomy or surface anatomy. Microscopic anatomy is the study of structures on a scale, including histology. Anatomy can be studied using both invasive and non-invasive methods with the goal of obtaining information about the structure and organization of organs, angiography using X-rays or magnetic resonance angiography are methods to visualize blood vessels. The term anatomy is commonly taken to refer to human anatomy, substantially the same structures and tissues are found throughout the rest of the animal kingdom and the term includes the anatomy of other animals.
The term zootomy is used to specifically refer to animals. The structure and tissues of plants are of a dissimilar nature, the kingdom Animalia or metazoa, contains multicellular organisms that are heterotrophic and motile. Most animals have bodies differentiated into separate tissues and these animals are known as eumetazoans. They have a digestive chamber, with one or two openings, the gametes are produced in multicellular sex organs, and the zygotes include a blastula stage in their embryonic development. Metazoans do not include the sponges, which have undifferentiated cells, unlike plant cells, animal cells have neither a cell wall nor chloroplasts
The Online Computer Library Center is a US-based nonprofit cooperative organization dedicated to the public purposes of furthering access to the worlds information and reducing information costs. It was founded in 1967 as the Ohio College Library Center, OCLC and its member libraries cooperatively produce and maintain WorldCat, the largest online public access catalog in the world. OCLC is funded mainly by the fees that libraries have to pay for its services, the group first met on July 5,1967 on the campus of the Ohio State University to sign the articles of incorporation for the nonprofit organization. The group hired Frederick G. Kilgour, a former Yale University medical school librarian, Kilgour wished to merge the latest information storage and retrieval system of the time, the computer, with the oldest, the library. The goal of network and database was to bring libraries together to cooperatively keep track of the worlds information in order to best serve researchers and scholars. The first library to do online cataloging through OCLC was the Alden Library at Ohio University on August 26,1971 and this was the first occurrence of online cataloging by any library worldwide.
Membership in OCLC is based on use of services and contribution of data, between 1967 and 1977, OCLC membership was limited to institutions in Ohio, but in 1978, a new governance structure was established that allowed institutions from other states to join. In 2002, the structure was again modified to accommodate participation from outside the United States. As OCLC expanded services in the United States outside of Ohio, it relied on establishing strategic partnerships with networks, organizations that provided training, support, by 2008, there were 15 independent United States regional service providers. OCLC networks played a key role in OCLC governance, with networks electing delegates to serve on OCLC Members Council, in early 2009, OCLC negotiated new contracts with the former networks and opened a centralized support center. OCLC provides bibliographic and full-text information to anyone, OCLC and its member libraries cooperatively produce and maintain WorldCat—the OCLC Online Union Catalog, the largest online public access catalog in the world.
WorldCat has holding records from public and private libraries worldwide. org, in October 2005, the OCLC technical staff began a wiki project, WikiD, allowing readers to add commentary and structured-field information associated with any WorldCat record. The Online Computer Library Center acquired the trademark and copyrights associated with the Dewey Decimal Classification System when it bought Forest Press in 1988, a browser for books with their Dewey Decimal Classifications was available until July 2013, it was replaced by the Classify Service. S. The reference management service QuestionPoint provides libraries with tools to communicate with users and this around-the-clock reference service is provided by a cooperative of participating global libraries. OCLC has produced cards for members since 1971 with its shared online catalog. OCLC commercially sells software, e. g. CONTENTdm for managing digital collections, OCLC has been conducting research for the library community for more than 30 years.
In accordance with its mission, OCLC makes its research outcomes known through various publications and these publications, including journal articles, reports and presentations, are available through the organizations website. The most recent publications are displayed first, and all archived resources, membership Reports – A number of significant reports on topics ranging from virtual reference in libraries to perceptions about library funding
Paleontology or palaeontology is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene Epoch. It includes the study of fossils to determine organisms evolution and interactions with each other, paleontological observations have been documented as far back as the 5th century BC. The science became established in the 18th century as a result of Georges Cuviers work on comparative anatomy, and developed rapidly in the 19th century. The term itself originates from Greek παλαιός, palaios, i. e. old, ancient, ὄν, on, i. e. being, creature and λόγος, logos, i. e. speech, study. Paleontology lies on the border between biology and geology, but differs from archaeology in that it excludes the study of modern humans. It now uses techniques drawn from a range of sciences, including biochemistry, mathematics. The final quarter of the 20th century saw the development of molecular phylogenetics, molecular phylogenetics has been used to estimate the dates when species diverged, but there is controversy about the reliability of the molecular clock on which such estimates depend.
The simplest definition is the study of ancient life, paleontology is one of the historical sciences, along with archaeology, astronomy, cosmology and history itself. This means that it aims to describe phenomena of the past, hence it has three main elements, description of the phenomena, developing a general theory about the causes of various types of change, and applying those theories to specific facts. Sometimes the smoking gun is discovered by an accident during other research. Paleontology lies on the boundary between biology and geology since paleontology focuses on the record of past life but its source of evidence is fossils. In addition paleontology often uses techniques derived from other sciences, including biology, ecology, techniques developed in engineering have been used to analyse how ancient organisms might have worked, for example how fast Tyrannosaurus could move and how powerful its bite was. As knowledge has increased, paleontology has developed specialised subdivisions, vertebrate paleontology concentrates on fossils of vertebrates, from the earliest fish to the immediate ancestors of modern mammals.
Invertebrate paleontology deals with fossils of such as molluscs, arthropods. Paleobotany focuses on the study of plants, but traditionally includes the study of fossil algae. Palynology, the study of pollen and spores produced by plants and protists. Micropaleontology deals with all microscopic fossil organisms, regardless of the group to which they belong, one example is the development of oxygenic photosynthesis by bacteria, which hugely increased the productivity and diversity of ecosystems. This caused the oxygenation of the atmosphere, these were a prerequisite for the evolution of the most complex eukaryotic cells, from which all multicellular organisms are built
A cephalopod is any member of the molluscan class Cephalopoda. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, fishermen sometimes call them inkfish, referring to their common ability to squirt ink. The study of cephalopods is a branch of known as teuthology. Cephalopods became dominant during the Ordovician period, represented by primitive nautiloids, the class now contains two, only distantly related, extant subclasses, which includes octopuses and cuttlefish, and Nautiloidea, represented by Nautilus and Allonautilus. In the Coleoidea, the shell has been internalized or is absent, whereas in the Nautiloidea. About 800 living species of cephalopods have been identified, two important extinct taxa are the Ammonoidea and Belemnoidea. There are over 800 extant species of cephalopod, although new species continue to be described, an estimated 11,000 extinct taxa have been described, although the soft-bodied nature of cephalopods means they are not easily fossilised.
Cephalopods are found in all the oceans of Earth, none of them can tolerate freshwater, but the brief squid, Lolliguncula brevis, found in Chesapeake Bay, is a notable partial exception in that it tolerates brackish water. Cephalopods are thought to be unable to live in due to multiple biochemical constraints. Cephalopods occupy most of the depth of the ocean, from the plain to the sea surface. Their diversity is greatest near the equator and decreases towards the poles, Cephalopods are widely regarded as the most intelligent of the invertebrates, and have well developed senses and large brains. The nervous system of cephalopods is the most complex of the invertebrates, the brain is protected in a cartilaginous cranium. Cephalopods have known to climb out of their aquaria, maneuver a distance of the lab floor, enter another aquarium to feed on the crabs. Cephalopods are social creatures, when isolated from their own kind, some cephalopods are able to fly through the air for distances of up to 50 m.
While cephalopods are not particularly aerodynamic, they achieve these impressive ranges by jet-propulsion, the animals spread their fins and tentacles to form wings and actively control lift force with body posture. Cephalopods have advanced vision, can detect gravity with statocysts, and have a variety of sense organs. Octopuses use their arms to explore their environment and can use them for depth perception, most cephalopods rely on vision to detect predators and prey, and to communicate with one another. Consequently, cephalopod vision is acute, training experiments have shown that the octopus can distinguish the brightness, shape
Morphology is a branch of biology dealing with the study of the form and structure of organisms and their specific structural features. This includes aspects of the appearance, i. e. external morphology, as well as the form and structure of the internal parts like bones and organs. This is in contrast to physiology, which deals primarily with function, Morphology is a branch of life science dealing with the study of gross structure of an organism or taxon and its component parts. The word morphology is from the Ancient Greek don, morphé, meaning form, among other important theorists of morphology are Lorenz Oken, Georges Cuvier, Étienne Geoffroy Saint-Hilaire, Richard Owen, Karl Gegenbaur and Ernst Haeckel. In English-speaking countries, the term molecular morphology has been used for time for describing the structure of compound molecules, such as polymers. Comparative Morphology is analysis of the patterns of the locus of structures within the plan of an organism. Functional Morphology is the study of the relationship between the structure and function of morphological features, experimental Morphology is the study of the effects of external factors upon the morphology of organisms under experimental conditions, such as the effect of genetic mutation.
Anatomy is a branch of morphology that deals with the structure of organisms, most taxa differ morphologically from other taxa. Typically, closely related taxa differ much less than more distantly related ones, cryptic species are species which look very similar, or perhaps even outwardly identical, but are reproductively isolated. Conversely, sometimes unrelated taxa acquire a similar appearance as a result of convergent evolution or even mimicry, in addition, there can be morphological differences within a species, such as in Apoica flavissima where queens are significantly smaller than workers. A further problem with relying on morphological data is that what may appear, morphologically speaking, the significance of these differences can be examined through the use of allometric engineering in which one or both species are manipulated to phenocopy the other species. Invention and development of microscopy enable the observation of 3-D cell morphology with both spatial and temporal resolution.
The dynamic processes of cell morphology which are controlled by a complex system play an important role in varied important biological process, such as immune. Comparative anatomy Insect morphology Morphometrics Neuromorphology Phenetics Phenotype Phenotypic plasticity Plant morphology
Biochemistry, sometimes called biological chemistry, is the study of chemical processes within and relating to living organisms. By controlling information flow through biochemical signaling and the flow of energy through metabolism. Biochemistry is closely related to biology, the study of the molecular mechanisms by which genetic information encoded in DNA is able to result in the processes of life. Depending on the definition of the terms used, molecular biology can be thought of as a branch of biochemistry, or biochemistry as a tool with which to investigate. The chemistry of the cell depends on the reactions of smaller molecules. These can be inorganic, for water and metal ions, or organic, for example the amino acids. The mechanisms by which cells harness energy from their environment via chemical reactions are known as metabolism, the findings of biochemistry are applied primarily in medicine and agriculture. In medicine, biochemists investigate the causes and cures of diseases, in nutrition, they study how to maintain health and study the effects of nutritional deficiencies.
In agriculture, biochemists investigate soil and fertilizers, and try to discover ways to improve crop cultivation, crop storage and pest control. However, biochemistry as a scientific discipline has its beginning sometime in the 19th century, or a little earlier. Gowland Hopkins on enzymes and the nature of biochemistry. The term biochemistry itself is derived from a combination of biology, the German chemist Carl Neuberg however is often cited to have coined the word in 1903, while some credited it to Franz Hofmeister. Then, in 1828, Friedrich Wöhler published a paper on the synthesis of urea and these techniques allowed for the discovery and detailed analysis of many molecules and metabolic pathways of the cell, such as glycolysis and the Krebs cycle. Another significant historic event in biochemistry is the discovery of the gene and this part of biochemistry is often called molecular biology. In the 1950s, James D. Watson, Francis Crick, Rosalind Franklin, in 1958, George Beadle and Edward Tatum received the Nobel Prize for work in fungi showing that one gene produces one enzyme.
In 1988, Colin Pitchfork was the first person convicted of murder with DNA evidence, mello received the 2006 Nobel Prize for discovering the role of RNA interference, in the silencing of gene expression. Around two dozen of the 92 naturally occurring elements are essential to various kinds of biological life. Most rare elements on Earth are not needed by life, while a few common ones are not used, most organisms share element needs, but there are a few differences between plants and animals
Stephen Jay Gould
Stephen Jay Gould was an American paleontologist, evolutionary biologist, and historian of science. He was one of the most influential and widely read writers of science of his generation. Gould spent most of his teaching at Harvard University and working at the American Museum of Natural History in New York. In 1996 Gould was appointed as the Vincent Astor Visiting Research Professor of Biology at New York University, Goulds most significant contribution to evolutionary biology was the theory of punctuated equilibrium, which he developed with Niles Eldredge in 1972. The theory proposes that most evolution is characterized by periods of evolutionary stability. The theory was contrasted against phyletic gradualism, the idea that evolutionary change is marked by a pattern of smooth. Most of Goulds empirical research was based on the land snail genera Poecilozonites and he contributed to evolutionary developmental biology, and received wide praise for his book Ontogeny and Phylogeny. In evolutionary theory he opposed strict selectionism, sociobiology as applied to humans and he campaigned against creationism and proposed that science and religion should be considered two distinct fields whose authorities do not overlap.
Gould was known by the public mainly from his 300 popular essays in the magazine Natural History. In April 2000, the US Library of Congress named him a Living Legend, Stephen Jay Gould was born and raised in the community of Bayside, a neighborhood of the northeastern section of Queens in New York City. His father Leonard was a stenographer and a World War II veteran in the United States Navy. His mother Eleanor was an artist whose parents were Jewish immigrants living and working in the citys Garment District, when Gould was five years old his father took him to the Hall of Dinosaurs in the American Museum of Natural History, where he first encountered Tyrannosaurus rex. I had no idea there were such things—I was awestruck, Gould once recalled and it was in that moment that he decided to become a paleontologist. Raised in a secular Jewish home, Gould did not formally practice religion, when asked directly if he was an agnostic in Skeptic magazine, he responded, If you absolutely forced me to bet on the existence of a conventional anthropomorphic deity, of course Id bet no.
But, Huxley was right when he said that agnosticism is the honorable position because we really cannot know. Id be real surprised if there turned out to be a conventional God, though he had been brought up by a Marxist father, he stated that his fathers politics were very different from his own. In describing his own views, he has said they tend to the left of center. According to Gould the most influential political books he read were C. Wright Mills The Power Elite, while attending Antioch College in the early 1960s, Gould was active in the civil rights movement and often campaigned for social justice
The dodo is an extinct flightless bird that was endemic to the island of Mauritius, east of Madagascar in the Indian Ocean. The dodos closest genetic relative was the extinct Rodrigues solitaire, the closest living relative of the dodo is the Nicobar pigeon. A white dodo was once thought to have existed on the island of Réunion. Subfossil remains show the dodo was about 1 metre tall and may have weighed 10. 6–21.1 kg, the dodos appearance in life is evidenced only by drawings and written accounts from the 17th century. Though the dodo has historically been considered fat and clumsy, it is now thought to have been well-adapted for its ecosystem. It has been depicted with brownish-grey plumage, yellow feet, a tuft of feathers, a grey, naked head, and a black, yellow. It used gizzard stones to help digest its food, which is thought to have included fruits, one account states its clutch consisted of a single egg. It is presumed that the dodo became flightless because of the availability of abundant food sources.
The first recorded mention of the dodo was by Dutch sailors in 1598, in the following years, the bird was hunted by sailors and invasive species, while its habitat was being destroyed. The last widely accepted sighting of a dodo was in 1662 and its extinction was not immediately noticed, and some considered it to be a mythical creature. In the 19th century, research was conducted on a quantity of remains of four specimens that had been brought to Europe in the early 17th century. Among these is a head, the only soft tissue of the dodo that remains today. Since then, an amount of subfossil material has been collected on Mauritius. The extinction of the dodo within less than a century of its discovery called attention to the previously unrecognised problem of human involvement in the disappearance of entire species. The dodo was variously declared a small ostrich, a rail, Strickland stated that although not identical, these birds shared many distinguishing features of the leg bones, otherwise known only in pigeons.
Strickland and Melville established that the dodo was anatomically similar to pigeons in many features and they pointed to the very short keratinous portion of the beak, with its long, naked basal part. Other pigeons have bare skin around their eyes, almost reaching their beak, the forehead was high in relation to the beak, and the nostril was located low on the middle of the beak and surrounded by skin, a combination of features shared only with pigeons. The legs of the dodo were generally similar to those of terrestrial pigeons than of other birds
A primate is a mammal of the order Primates. In taxonomy, primates include two distinct lineages and haplorhines, Primates arose from ancestors that lived in the trees of tropical forests, many primate characteristics represent adaptations to life in this challenging three-dimensional environment. Most primate species remain at least partly arboreal, with the exception of humans, who inhabit every continent except for Antarctica, most primates live in tropical or subtropical regions of the Americas and Asia. Based on fossil evidence, the earliest known true primates, represented by the genus Teilhardina, an early close primate relative known from abundant remains is the Late Paleocene Plesiadapis, c. Molecular clock studies suggest that the branch may be even older. The order Primates was traditionally divided into two groupings and anthropoids. Prosimians have characteristics more like those of the earliest primates, and include the lemurs of Madagascar, simians include monkeys and hominins.
Simians are divided into two groups, catarrhine monkeys and apes of Africa and Southeast Asia and platyrrhine or New World monkeys of South, catarrhines consist of Old World monkeys and great apes, New World monkeys include the capuchin and squirrel monkeys. Humans are the only extant catarrhines to have spread successfully outside of Africa, South Asia, New primate species are still being discovered. More than 25 species were described in the decade of the 2000s. Considered generalist mammals, primates exhibit a range of characteristics. Some primates are primarily terrestrial rather than arboreal, but all species possess adaptations for climbing trees, locomotion techniques used include leaping from tree to tree, walking on two or four limbs, knuckle-walking, and swinging between branches of trees. Primates are characterized by large brains relative to other mammals, as well as a reliance on stereoscopic vision at the expense of smell. These features are developed in monkeys and apes and noticeably less so in lorises.
Three-color vision has developed in some primates, most have opposable thumbs and some have prehensile tails. Many species are dimorphic, differences include body mass, canine tooth size. Primates have slower rates of development than other similarly sized mammals and reach maturity later, depending on the species, adults may live in solitude, in mated pairs, or in groups of up to hundreds of members. The relationships among the different groups of primates were not clearly understood until relatively recently, for example, ape has been used either as an alternative for monkey or for any tailless, relatively human-like primate
Therefore, members of a group are assumed to share a common history and are considered to be closely related. The techniques and nomenclature of cladistics have been applied to other disciplines, Cladistics in the original sense refers to a particular set of methods used in phylogenetic analysis, although it is now sometimes used to refer to the whole field. What is now called the cladistic method appeared as early as 1901 with a work by Peter Chalmers Mitchell for birds and subsequently by Robert John Tillyard in 1921, Hennig referred to his own approach as phylogenetic systematics. Phenetics was championed at this time by the numerical taxonomists Peter Sneath and Robert Sokal, originally conceived, if only in essence, by Willi Hennig in a book published in 1950, cladistics did not flourish until its translation into English in 1966. Today, cladistics is the most popular method for constructing phylogenies from morphological, unlike phenetics, cladistics is specifically aimed at reconstructing evolutionary histories.
The way for computational phylogenetics was paved by phenetics, a set of commonly used from the 1950s to 1980s. Phenetics did not try to reconstruct phylogenetic trees, rather, it tried to build dendrograms from similarity data, the cladistic method interprets each character state transformation implied by the distribution of shared character states among taxa as a potential piece of evidence for grouping. The outcome of an analysis is a cladogram – a tree-shaped diagram that is interpreted to represent the best hypothesis of phylogenetic relationships. Cladists contend that these models are unjustified, every cladogram is based on a particular dataset analyzed with a particular method. Different datasets and different methods, not to mention violations of the mentioned assumptions, only scientific investigation can show which is more likely to be correct. Since the cladograms provide competing accounts of events, at most one of them is correct. Within the primates, all anthropoids are hypothesized to have had a common ancestor all of whose descendants were anthropoids, the prosimians, on the other hand, form a paraphyletic taxon.
When two or more taxa that are not nested within each other share a plesiomorphy, it is a symplesiomorphy, symplesiomorphies do not mean that the taxa that exhibit that character state are necessarily closely related. For example, Reptilia is traditionally characterized by being cold-blooded, whereas birds are warm-blooded, an apomorphy or derived state is an innovation. It can thus be used to diagnose a clade – or even to help define a clade name in phylogenetic nomenclature, features that are derived in individual taxa are called autapomorphies. Autapomorphies express nothing about relationships among groups, clades are identified by synapomorphies, for example, the possession of digits that are homologous with those of Homo sapiens is a synapomorphy within the vertebrates. The tetrapods can be singled out as consisting of the first vertebrate with such digits homologous to those of Homo sapiens together with all descendants of this vertebrate and it is therefore inferred to have evolved by convergence or reversal.
Both mammals and birds are able to maintain a constant body temperature
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, 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
Astrobiology is the study of the origin, evolution and future of life in the universe, extraterrestrial life and life on Earth. Astrobiology addresses the question of whether life exists beyond Earth, the origin and early evolution of life is an inseparable part of the discipline of astrobiology. Although speculation is entertained to give context, astrobiology concerns itself primarily with hypotheses that fit firmly into existing scientific theories. The chemistry of life may have begun shortly after the Big Bang,13.8 billion years ago, according to the panspermia hypothesis, microscopic life—distributed by meteoroids and other small Solar System bodies—may exist throughout the universe. According to research published in August 2015, very large galaxies may be favorable to the creation. Nonetheless, Earth is the place in the universe humans know to harbor life. The search for evidence of habitability and organic molecules on the planet Mars is now a primary NASA and ESA objective. Astrobiology is etymologically derived from the Greek ἄστρον, constellation, star, βίος, life, the synonyms of astrobiology are diverse, the synonyms were structured in relation to the most important sciences implied in its development and biology.
A close synonym is exobiology from the Greek Έξω, external, Βίος, life, the term exobiology was coined by molecular biologist Joshua Lederberg. Another term used in the past is xenobiology, a used in 1954 by science fiction writer Robert Heinlein in his work The Star Beast. The term xenobiology is now used in a more specialized sense, to mean biology based on foreign chemistry, since alternate chemistry analogs to some life-processes have been created in the laboratory, xenobiology is now considered as an extant subject. While it is an emerging and developing field, the question of whether life exists elsewhere in the universe is a verifiable hypothesis, though once considered outside the mainstream of scientific inquiry, astrobiology has become a formalized field of study. Planetary scientist David Grinspoon calls astrobiology a field of philosophy, grounding speculation on the unknown. NASAs interest in exobiology first began with the development of the U. S, in 1959, NASA funded its first exobiology project, and in 1960, NASA founded an Exobiology Program, which is now one of four main elements of NASAs current Astrobiology Program.
NASAs Viking missions to Mars, launched in 1976, included three biology experiments designed to look for metabolism of present life on Mars, a particular focus of current astrobiology research is the search for life on Mars due to its proximity to Earth and geological history. Missions specifically designed to search for current life on Mars were the Viking program, the Viking results were inconclusive, and Beagle 2 failed minutes after landing. In late 2008, the Phoenix lander probed the environment for past and present planetary habitability of microbial life on Mars, in November 2011, NASA launched the Mars Science Laboratory mission carrying the Curiosity rover, which landed on Mars at Gale Crater in August 2012. The Curiosity rover is currently probing the environment for past and present planetary habitability of microbial life on Mars, the European Space Agency is currently collaborating with the Russian Federal Space Agency and developing the ExoMars astrobiology rover, which is to be launched in 2018