A graduate school is a school that awards advanced academic degrees with the general requirement that students must have earned a previous undergraduate degree with a high grade point average. A distinction is made between graduate schools and professional schools, which offer specialized advanced degrees in professional fields such as medicine, business, speech-language pathology, or law; the distinction between graduate schools and professional schools is not absolute, as various professional schools offer graduate degrees and vice versa. Many universities award graduate degrees. While the term "graduate school" is typical in the United States and used elsewhere, "postgraduate education" is used in English-speaking countries to refer to the spectrum of education beyond a bachelor's degree; those attending graduate schools are called "graduate students", or in British English as "postgraduate students" and, colloquially, "postgraduates" and "postgrads". Degrees awarded to graduate students include master's degrees, doctoral degrees, other postgraduate qualifications such as graduate certificates and professional degrees.
Producing original research is a significant component of graduate studies in the humanities, natural sciences and social sciences. This research leads to the writing and defense of a thesis or dissertation. In graduate programs that are oriented towards professional training, the degrees may consist of coursework, without an original research or thesis component; the term "graduate school" is North American. Additionally, in North America, the term does not refer to medical school, only refers to law school or business school. Graduate students in the humanities and social sciences receive funding from the school and/or a teaching assistant position or other job. Although graduate school programs are distinct from undergraduate degree programs, graduate instruction is offered by some of the same senior academic staff and departments who teach undergraduate courses. Unlike in undergraduate programs, however, it is less common for graduate students to take coursework outside their specific field of study at graduate or graduate entry level.
At the Ph. D. level, though, it is quite common to take courses from a wider range of study, for which some fixed portion of coursework, sometimes known as a residency, is required to be taken from outside the department and college of the degree-seeking candidate, to broaden the research abilities of the student. Some institutions denote other divisions. Graduate degrees in Brazil are called "postgraduate" degrees, can be taken only after an undergraduate education has been concluded". Lato sensu graduate degrees: degrees that represent a specialization in a certain area, take from 1 to 2 years to complete. Sometimes it can be used to describe a specialization level between a master's degree and a MBA. In that sense, the main difference is that the Lato Sensu courses tend to go deeper into the scientific aspects of the study field, while MBA programs tend to be more focused on the practical and professional aspects, being used more to Business and Administration areas. However, since there are no norms to regulate this, both names are used indiscriminately most of the time.
Stricto sensu graduate degrees: degrees for those who wish to pursue an academic career. Masters: 2 years for completion. Serves as additional qualification for those seeking a differential on the job market, or for those who want to pursue a PhD. Most doctoral programs in Brazil require a master's degree, meaning that a Lato Sensu Degree is insufficient to start a doctoral program. Doctors / PhD: 3–4 years for completion. Used as a stepping stone for academic life. In Canada, the Schools and Faculties of Graduate Studies are represented by the Canadian Association of Graduate Studies or Association canadienne pour les études supérieures; the Association brings together 58 Canadian universities with graduate programs, two national graduate student associations, the three federal research-granting agencies and organizations having an interest in graduate studies. Its mandate is to promote and foster excellence in graduate education and university research in Canada. In addition to an annual conference, the association prepares briefs on issues related to graduate studies including supervision and professional development.
Admission to a master's program requires a bachelor's degree in a related field, with sufficiently high grades ranging from B+ and higher, recommendations from professors. Some schools require samples of the student's writing as well as a research proposal. At English-speaking universities, applicants from countries where English is not the primary language are requir
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
Ecology is the branch of biology which studies the interactions among organisms and their environment. Objects of study include interactions of organisms that include biotic and abiotic components of their environment. Topics of interest include the biodiversity, distribution and populations of organisms, as well as cooperation and competition within and between species. Ecosystems are dynamically interacting systems of organisms, the communities they make up, the non-living components of their environment. Ecosystem processes, such as primary production, nutrient cycling, niche construction, regulate the flux of energy and matter through an environment; these processes are sustained by organisms with specific life history traits. Biodiversity means the varieties of species and ecosystems, enhances certain ecosystem services. Ecology is not synonymous with natural history, or environmental science, it overlaps with the related sciences of evolutionary biology and ethology. An important focus for ecologists is to improve the understanding of how biodiversity affects ecological function.
Ecologists seek to explain: Life processes and adaptations The movement of materials and energy through living communities The successional development of ecosystems The abundance and distribution of organisms and biodiversity in the context of the environment. Ecology has practical applications in conservation biology, wetland management, natural resource management, city planning, community health, economics and applied science, human social interaction. For example, the Circles of Sustainability approach treats ecology as more than the environment'out there', it is not treated as separate from humans. Organisms and resources compose ecosystems which, in turn, maintain biophysical feedback mechanisms that moderate processes acting on living and non-living components of the planet. Ecosystems sustain life-supporting functions and produce natural capital like biomass production, the regulation of climate, global biogeochemical cycles, water filtration, soil formation, erosion control, flood protection, many other natural features of scientific, economic, or intrinsic value.
The word "ecology" was coined in 1866 by the German scientist Ernst Haeckel. Ecological thought is derivative of established currents in philosophy from ethics and politics. Ancient Greek philosophers such as Hippocrates and Aristotle laid the foundations of ecology in their studies on natural history. Modern ecology became a much more rigorous science in the late 19th century. Evolutionary concepts relating to adaptation and natural selection became the cornerstones of modern ecological theory; the scope of ecology contains a wide array of interacting levels of organization spanning micro-level to a planetary scale phenomena. Ecosystems, for example, contain interacting life forms. Ecosystems are dynamic, they do not always follow a linear successional path, but they are always changing and sometimes so that it can take thousands of years for ecological processes to bring about certain successional stages of a forest. An ecosystem's area can vary from tiny to vast. A single tree is of little consequence to the classification of a forest ecosystem, but critically relevant to organisms living in and on it.
Several generations of an aphid population can exist over the lifespan of a single leaf. Each of those aphids, in turn, support diverse bacterial communities; the nature of connections in ecological communities cannot be explained by knowing the details of each species in isolation, because the emergent pattern is neither revealed nor predicted until the ecosystem is studied as an integrated whole. Some ecological principles, however, do exhibit collective properties where the sum of the components explain the properties of the whole, such as birth rates of a population being equal to the sum of individual births over a designated time frame; the main subdisciplines of ecology, population ecology and ecosystem ecology, exhibit a difference not only of scale, but of two contrasting paradigms in the field. The former focus on organisms distribution and abundance, while the focus on materials and energy fluxes; the scale of ecological dynamics can operate like a closed system, such as aphids migrating on a single tree, while at the same time remain open with regard to broader scale influences, such as atmosphere or climate.
Hence, ecologists classify ecosystems hierarchically by analyzing data collected from finer scale units, such as vegetation associations and soil types, integrate this information to identify emergent patterns of uniform organization and processes that operate on local to regional and chronological scales. To structure the study of ecology into a conceptually manageable framework, the biological world is organized into a nested hierarchy, ranging in scale from genes, to cells, to tissues, to organs, to organisms, to species, to populations, to communities, to ecosystems, to biomes, up to the level of the biosphere; this framework exhibits non-linear behaviors.
Lizards are a widespread group of squamate reptiles, with over 6,000 species, ranging across all continents except Antarctica, as well as most oceanic island chains. The group is paraphyletic as it excludes Amphisbaenia. Lizards range in size from chameleons and geckos a few centimeters long to the 3 meter long Komodo dragon. Most lizards are quadrupedal. Others are legless, have long snake-like bodies; some such as the forest-dwelling Draco lizards are able to glide. They are territorial, the males fighting off other males and signalling with brightly colours, to attract mates and to intimidate rivals. Lizards are carnivorous being sit-and-wait predators. Lizards make use of a variety of antipredator adaptations, including venom, reflex bleeding, the ability to sacrifice and regrow their tails; the adult length of species within the suborder ranges from a few centimeters for chameleons such as Brookesia micra and geckos such as Sphaerodactylus ariasae to nearly 3 m in the case of the largest living varanid lizard, the Komodo dragon.
Most lizards are small animals. Lizards have four legs and external ears, though some are legless, while snakes lack these characteristics. Lizards and snakes share a movable quadrate bone, distinguishing them from the rhynchocephalians, which have more rigid diapsid skulls; some lizards such as chameleons have prehensile tails. As in other reptiles, the skin of lizards is covered in overlapping scales made of keratin; this reduces water loss through evaporation. This adaptation enables lizards to thrive in some of the driest deserts on earth; the skin is tough and leathery, is shed as the animal grows. Unlike snakes which shed the skin in a single piece, lizards slough their skin in several pieces; the scales may be modified into spines for display or protection, some species have bone osteoderms underneath the scales. The dentitions of lizards reflect their wide range of diets, including carnivorous, omnivorous, herbivorous and molluscivorous. Species have uniform teeth suited to their diet, but several species have variable teeth, such as cutting teeth in the front of the jaws and crushing teeth in the rear.
Most species are pleurodont, though chameleons are acrodont. The tongue can be extended outside the mouth, is long. In the beaded lizards and monitor lizards, the tongue is forked and used or to sense the environment, continually flicking out to sample the environment, back to transfer molecules to the vomeronasal organ responsible for chemosensation, analogous to but different from smell or taste. In geckos, the tongue is used to lick the eyes clean: they have no eyelids. Chameleons have long sticky tongues which can be extended to catch their insect prey. Three lineages, the geckos and chameleons, have modified the scales under their toes to form adhesive pads prominent in the first two groups; the pads are composed of millions of tiny setae which fit to the substrate to adhere using van der Waals forces. In addition, the toes of chameleons are divided into two opposed groups on each foot, enabling them to perch on branches as birds do. Aside from legless lizards, most lizards are quadrupedal and move using gaits with alternating movement of the right and left limbs with substantial body bending.
This body bending prevents significant respiration during movement, limiting their endurance, in a mechanism called Carrier's constraint. Several species can run bipedally, a few can prop themselves up on their hindlimbs and tail while stationary. Several small species such as those in the genus Draco can glide: some can attain a distance of 60 metres, losing 10 metres in height; some species, like chameleons, adhere to vertical surfaces including glass and ceilings. Some species, like the common basilisk, can run across water. Lizards make use of their senses of sight, touch and hearing like other vertebrates; the balance of these varies with the habitat of different species. Monitor lizards have acute vision and olfactory senses; some lizards make unusual use of their sense organs: chameleons can steer their eyes in different directions, sometimes providing non-overlapping fields of view, such as forwards and backwards at once. Lizards lack external ears, having instead a circular opening in which the tympanic membrane can be seen.
Many species rely on hearing for early warning of predators, flee at the slightest sound. As in snakes and many mammals, all lizards have a specialised olfactory system, the vomeronasal organ, used to detect pheromones. Monitor lizards transfer scent from the tip of their tongue to the organ; some lizards iguanas, have retained a photosensory organ on the top of their heads called the parietal eye, a basal feature present in the tuatara. This "eye" has only a rudimentary retina and lens and cannot form images, but is sensitive to changes in light and dark and can detect movemen
Carl Linnaeus known after his ennoblement as Carl von Linné, was a Swedish botanist and zoologist who formalised binomial nomenclature, the modern system of naming organisms. He is known as the "father of modern taxonomy". Many of his writings were in Latin, his name is rendered in Latin as Carolus Linnæus. Linnaeus was born in the countryside of Småland in southern Sweden, he received most of his higher education at Uppsala University and began giving lectures in botany there in 1730. He lived abroad between 1735 and 1738, where he studied and published the first edition of his Systema Naturae in the Netherlands, he returned to Sweden where he became professor of medicine and botany at Uppsala. In the 1740s, he was sent on several journeys through Sweden to find and classify plants and animals. In the 1750s and 1760s, he continued to collect and classify animals and minerals, while publishing several volumes, he was one of the most acclaimed scientists in Europe at the time of his death. Philosopher Jean-Jacques Rousseau sent him the message: "Tell him I know no greater man on earth."
Johann Wolfgang von Goethe wrote: "With the exception of Shakespeare and Spinoza, I know no one among the no longer living who has influenced me more strongly." Swedish author August Strindberg wrote: "Linnaeus was in reality a poet who happened to become a naturalist." Linnaeus has been called Princeps botanicorum and "The Pliny of the North". He is considered as one of the founders of modern ecology. In botany and zoology, the abbreviation L. is used to indicate Linnaeus as the authority for a species' name. In older publications, the abbreviation "Linn." is found. Linnaeus's remains comprise the type specimen for the species Homo sapiens following the International Code of Zoological Nomenclature, since the sole specimen that he is known to have examined was himself. Linnaeus was born in the village of Råshult in Småland, Sweden, on 23 May 1707, he was the first child of Christina Brodersonia. His siblings were Anna Maria Linnæa, Sofia Juliana Linnæa, Samuel Linnæus, Emerentia Linnæa, his father taught him Latin as a small child.
One of a long line of peasants and priests, Nils was an amateur botanist, a Lutheran minister, the curate of the small village of Stenbrohult in Småland. Christina was the daughter of the rector of Samuel Brodersonius. A year after Linnaeus's birth, his grandfather Samuel Brodersonius died, his father Nils became the rector of Stenbrohult; the family moved into the rectory from the curate's house. In his early years, Linnaeus seemed to have a liking for plants, flowers in particular. Whenever he was upset, he was given a flower, which calmed him. Nils spent much time in his garden and showed flowers to Linnaeus and told him their names. Soon Linnaeus was given his own patch of earth. Carl's father was the first in his ancestry to adopt a permanent surname. Before that, ancestors had used the patronymic naming system of Scandinavian countries: his father was named Ingemarsson after his father Ingemar Bengtsson; when Nils was admitted to the University of Lund, he had to take on a family name. He adopted the Latinate name Linnæus after a giant linden tree, lind in Swedish, that grew on the family homestead.
This name was spelled with the æ ligature. When Carl was born, he was named Carl Linnæus, with his father's family name; the son always spelled it with the æ ligature, both in handwritten documents and in publications. Carl's patronymic would have been Nilsson, as in Carl Nilsson Linnæus. Linnaeus's father began teaching him basic Latin and geography at an early age; when Linnaeus was seven, Nils decided to hire a tutor for him. The parents picked a son of a local yeoman. Linnaeus did not like him, writing in his autobiography that Telander "was better calculated to extinguish a child's talents than develop them". Two years after his tutoring had begun, he was sent to the Lower Grammar School at Växjö in 1717. Linnaeus studied going to the countryside to look for plants, he reached the last year of the Lower School when he was fifteen, taught by the headmaster, Daniel Lannerus, interested in botany. Lannerus gave him the run of his garden, he introduced him to Johan Rothman, the state doctor of Småland and a teacher at Katedralskolan in Växjö.
A botanist, Rothman broadened Linnaeus's interest in botany and helped him develop an interest in medicine. By the age of 17, Linnaeus had become well acquainted with the existing botanical literature, he remarks in his journal that he "read day and night, knowing like the back of my hand, Arvidh Månsson's Rydaholm Book of Herbs, Tillandz's Flora Åboensis, Palmberg's Serta Florea Suecana, Bromelii Chloros Gothica and Rudbeckii Hortus Upsaliensis...."Linnaeus entered the Växjö Katedralskola in 1724, where he studied Greek, Hebrew and mathematics, a curriculum designed for boys preparing for the priesthood. In the last year at the gymnasium, Linnaeus's father visited to ask the professors how his son's studies were progressing. Rothman believed otherwise; the doctor offered to have Linnaeus live with his family in Växjö and to teach him physiology and botany. Nils accepted this offer. Rothman showed Linnaeus that botany was a serious sub
Tuatara are reptiles endemic to New Zealand. Although resembling most lizards, they are part of the order Rhynchocephalia, their name derives from the Māori language, means "peaks on the back". The single species of tuatara is the only surviving member of its order, which flourished around 200 million years ago, their most recent common ancestor with any other extant group is with the squamates. For this reason, tuatara are of interest in the study of the evolution of lizards and snakes, for the reconstruction of the appearance and habits of the earliest diapsids, a group of amniote tetrapods that includes dinosaurs and crocodilians. Tuatara are greenish brown and grey, measure up to 80 cm from head to tail-tip and weigh up to 1.3 kg with a spiny crest along the back pronounced in males. They have two rows of teeth in the upper jaw overlapping one row on the lower jaw, unique among living species, they are unusual in having a pronounced photoreceptive eye, the third eye, thought to be involved in setting circadian and seasonal cycles.
They are able to hear, although no external ear is present, have unique features in their skeleton, some of them evolutionarily retained from fish. Tuatara are sometimes referred to as "living fossils", which has generated significant scientific debate. While mapping its genome, researchers have discovered that the species has between five and six billion base pairs of DNA sequence, nearly twice that of humans; the tuatara Sphenodon punctatus has been protected by law since 1895. A second species, S. guntheri, was recognised in 1989, but since 2009 it has been reclassified as a subspecies. Tuatara, like many of New Zealand's native animals, are threatened by habitat loss and introduced predators, such as the Polynesian rat. Tuatara were extinct on the mainland, with the remaining populations confined to 32 offshore islands until the first North Island release into the fenced and monitored Karori Sanctuary in 2005. During routine maintenance work at Karori Sanctuary in late 2008, a tuatara nest was uncovered, with a hatchling found the following autumn.
This is thought to be the first case of tuatara breeding in the wild on the New Zealand North Island in over 200 years. Tuatara, along with other, now-extinct members of the order Sphenodontia, belong to the superorder Lepidosauria, the only surviving taxon within Lepidosauromorpha. Squamates and tuatara both show caudal autotomy, have transverse cloacal slits; the origin of the tuatara lies close to the split between the Lepidosauromorpha and the Archosauromorpha. Though tuatara resemble lizards, the similarity is superficial, because the family has several characteristics unique among reptiles; the typical lizard shape is common for the early amniotes. Tuatara were classified as lizards in 1831 when the British Museum received a skull; the genus remained misclassified until 1867, when Albert Günther of the British Museum noted features similar to birds and crocodiles. He proposed the order Rhynchocephalia for its fossil relatives. Many disparately related species were subsequently added to the Rhynchocephalia, resulting in what taxonomists call a "wastebasket taxon".
Williston proposed the Sphenodontia to include only tuatara and their closest fossil relatives in 1925. Sphenodon is derived from the Greek for "wedge" and "tooth". Tuatara have been referred to as living fossils, which means that they retain many basal characteristics from around the time of the squamate–rhynchocephalian split. Morphometric analyses of variation in jaw morphology among tuatara and extinct Rhynchocephalian relatives have been argued to demonstrate morphological conservatism and support for the classification of tuatara as a'living fossil', but the reliability of these results has been criticised and debated. Taxonomic research on Sphenodontia indicates that the group has undergone a variety of changes throughout the Mesozoic, the rate of molecular evolution for tuatara has been estimated to be among the fastest of any animal yet examined. Many of the niches occupied by lizards today were held by sphenodontians. There was a successful group of aquatic sphenodontians known as pleurosaurs, which differed markedly from living tuatara.
Tuatara show cold-weather adaptations. For instance, Palaeopleurosaurus appears to have had a much shorter lifespan compared to the modern tuatara. A species of sphenodontine is known from the Miocene Saint Bathans Fauna. Whether it is referable to Sphenodon proper is not clear, but is assumed to be related to tuataras. While there is considered to be only one living species of tuatara, two species were identified: Sphenodon punctatus, or northern tuatara, the much rarer Sphenodon guntheri, or Brothers Island tuatara, confined to North Brother Island in Cook Strait; the specific name punctatus is Latin for "spotted", guntheri refers to German-born British herpetologist Albert Günther. A 2009 paper re-examined the genetic bases used to distinguish the two supposed species of tuatara, concluded they only represent geographic variants, only one species should be recognized; the northern tuatara was classified as Sphenodon punctatus punctatus and the Brothers Island tuatara as Sphenodon punctatus guntheri.