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Spandrel (biology)
In evolutionary biology, a spandrel is a phenotypic trait that is a byproduct of the evolution of some other characteristic, rather than a direct product of adaptive selection. Stephen Jay Gould and Richard Lewontin brought the term into biology in their 1979 paper " The Spandrels of San Marco and the Panglossian Paradigm: A Critique of the Adaptationist Programme". Adaptationism is a point of view that sees most organismal traits as adaptive products of natural selection. Gould and Lewontin sought to temper what they saw as adaptationist bias by promoting a more structuralist view of evolution. The term "spandrel" originates from architecture, where it refers to the roughly triangular spaces between the top of an arch and the ceiling. Etymology The term was coined by Harvard paleontologist Stephen Jay Gould and population geneticist Richard Lewontin in their paper "The Spandrels of San Marco and the Panglossian Paradigm: A Critique of the Adaptationist Programme" (1979). Ev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spandrel (PSF)
A spandrel is a roughly triangular space, usually found in pairs, between the top of an arch and a rectangular frame; between the tops of two adjacent arches or one of the four spaces between a circle within a square. They are frequently filled with decorative elements. Meaning There are four or five accepted and cognate meanings of the term ''spandrel'' in architectural and art history, mostly relating to the space between a curved figure and a rectangular boundary – such as the space between the curve of an arch and a rectilinear bounding moulding, or the wallspace bounded by adjacent arches in an arcade and the stringcourse or moulding above them, or the space between the central medallion of a carpet and its rectangular corners, or the space between the circular face of a clock and the corners of the square revealed by its hood. Also included is the space under a flight of stairs, if it is not occupied by another flight of stairs. In a building with more than one floor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adaptation
In biology, adaptation has three related meanings. Firstly, it is the dynamic evolutionary process of natural selection that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the population during that process. Thirdly, it is a phenotypic trait or adaptive trait, with a functional role in each individual organism, that is maintained and has evolved through natural selection. Historically, adaptation has been described from the time of the ancient Greek philosophers such as Empedocles and Aristotle. In 18th and 19th century natural theology, adaptation was taken as evidence for the existence of a deity. Charles Darwin proposed instead that it was explained by natural selection. Adaptation is related to biological fitness, which governs the rate of evolution as measured by change in allele frequencies. Often, two or more species co-adapt and co-evolve as they develop adaptations that interlock with those of the o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cladistics
Cladistics (; ) is an approach to biological classification in which organisms are categorized in groups (" clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived characteristics ( synapomorphies'')'' that are not present in more distant groups and ancestors. However, from an empirical perspective, common ancestors are inferences based on a cladistic hypothesis of relationships of taxa whose character states can be observed. Theoretically, a last common ancestor and all its descendants constitute a (minimal) clade. Importantly, all descendants stay in their overarching ancestral clade. For example, if the terms ''worms'' or ''fishes'' were used within a ''strict'' cladistic framework, these terms would include humans. Many of these terms are normally used paraphyletically, outside of cladistics, e.g. as a ' grade', which are fruitless to precisely delineate, especially when including extinct species. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Comparative Anatomy
Comparative anatomy is the study of similarities and differences in the anatomy of different species. It is closely related to evolutionary biology and phylogeny (the evolution of species). The science began in the classical era, continuing in the early modern period with work by Pierre Belon who noted the similarities of the skeletons of birds and humans. Comparative anatomy has provided evidence of common descent, and has assisted in the classification of animals. History The first specifically anatomical investigation separate from a surgical or medical procedure is associated by Alcmaeon of Croton. Leonardo da Vinci made notes for a planned anatomical treatise in which he intended to compare the hands of various animals including bears. Pierre Belon, a French naturalist born in 1517, conducted research and held discussions on dolphin embryos as well as the comparisons between the skeletons of birds to the skeletons of humans. His research led to modern comparative a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spotted Hyena
The spotted hyena (''Crocuta crocuta''), also known as the laughing hyena, is a hyena species, currently classed as the sole extant member of the genus ''Crocuta'', native to sub-Saharan Africa. It is listed as being of least concern by the IUCN on account of its widespread range and large numbers estimated between 27,000 and 47,000 individuals. The species is, however, experiencing declines outside of protected areas due to habitat loss and poaching. The species may have originated in Asia, and once ranged throughout Europe for at least one million years until the end of the Late Pleistocene. The spotted hyena is the largest known member of the Hyaenidae, and is further physically distinguished from other species by its vaguely bear-like build, its rounded ears, its less prominent mane, its spotted pelt, its more dual-purposed dentition, its fewer nipples and the presence of a pseudo-penis in the female. It is the only placental mammalian species where females lack an external ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aesthetics
Aesthetics, or esthetics, is a branch of philosophy that deals with the nature of beauty and taste, as well as the philosophy of art (its own area of philosophy that comes out of aesthetics). It examines aesthetic values, often expressed through judgments of taste. Aesthetics covers both natural and artificial sources of experiences and how we form a judgment about those sources. It considers what happens in our minds when we engage with objects or environments such as viewing visual art, listening to music, reading poetry, experiencing a play, watching a fashion show, movie, sports or even exploring various aspects of nature. The philosophy of art specifically studies how artists imagine, create, and perform works of art, as well as how people use, enjoy, and criticize art. Aesthetics considers why people like some works of art and not others, as well as how art can affect moods or even our beliefs. Both aesthetics and the philosophy of art try to find answers for what exa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Squinch
In architecture, a squinch is a triangular corner that supports the base of a dome. Its visual purpose is to translate a rectangle into an octagon. See also: pendentive. Construction A squinch is typically formed by a masonry arch that spans a square corner. History in the Middle East The dome chamber in the Palace of Ardashir, the Sassanid king, in Firuzabad, Iran is the earliest surviving example of the use of the squinch, suggesting that the squinch may have been invented in Persia. After the rise of Islam, it was used in the Middle East in both eastern Romanesque and Islamic architecture. It remained a feature of Islamic architecture, especially in Iran, and was often covered by corbelled stalactite-like structures known as muqarnas. History in Western Europe It spread to the Romanesque architecture of western Europe, one example being the Normans' 12th-century church of San Cataldo, Palermo in Sicily. This has three domes, each supported by four doubled squinche ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corbel
In architecture, a corbel is a structural piece of stone, wood or metal jutting from a wall to carry a superincumbent weight, a type of bracket. A corbel is a solid piece of material in the wall, whereas a console is a piece applied to the structure. A piece of timber projecting in the same way was called a "tassel" or a "bragger" in England. The technique of corbelling, where rows of corbels deeply keyed inside a wall support a projecting wall or parapet, has been used since Neolithic (New Stone Age) times. It is common in medieval architecture and in the Scottish baronial style as well as in the vocabulary of classical architecture, such as the modillions of a Corinthian cornice. The corbel arch and corbel vault use the technique systematically to make openings in walls and to form ceilings. These are found in the early architecture of most cultures, from Eurasia to Pre-Columbian architecture. A console is more specifically an "S"-shaped scroll bracket in the classica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Darwin's Dangerous Idea
''Darwin's Dangerous Idea: Evolution and the Meanings of Life'' is a 1995 book by the philosopher Daniel Dennett, in which the author looks at some of the repercussions of Darwinian theory. The crux of the argument is that, whether or not Darwin's theories are overturned, there is no going back from the dangerous idea that design (purpose or what something is for) might not need a designer. Dennett makes this case on the basis that natural selection is a blind process, which is nevertheless sufficiently powerful to explain the evolution of life. Darwin's discovery was that the generation of life worked algorithmically, that processes behind it work in such a way that given these processes the results that they tend toward must be so. Dennett says, for example, that by claiming that minds cannot be reduced to purely algorithmic processes, many of his eminent contemporaries are claiming that miracles can occur. These assertions have generated a great deal of debate and discussion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Daniel Dennett
Daniel Clement Dennett III (born March 28, 1942) is an American philosopher, writer, and cognitive scientist whose research centers on the philosophy of mind, philosophy of science, and philosophy of biology, particularly as those fields relate to evolutionary biology and cognitive science. , he is the co-director of the Center for Cognitive Studies and the Austin B. Fletcher Professor of Philosophy at Tufts University in Massachusetts. Dennett is a member of the editorial board for '' The Rutherford Journal'' and a co-founder of The Clergy Project. A vocal atheist and secularist, Dennett is referred to as one of the " Four Horsemen of New Atheism", along with Richard Dawkins, Sam Harris, and the late Christopher Hitchens. Early life, education, and career Daniel Clement Dennett III was born on March 28, 1942, in Boston, Massachusetts, the son of Ruth Marjorie (née Leck; 1903–1971) and Daniel Clement Dennett Jr. (1910–1947). Dennett spent part of his childhood ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pendentive
In architecture, a pendentive is a constructional device permitting the placing of a circular dome over a square room or of an elliptical dome over a rectangular room. The pendentives, which are triangular segments of a sphere, taper to points at the bottom and spread at the top to establish the continuous circular or elliptical base needed for a dome. In masonry the pendentives thus receive the weight of the dome, concentrating it at the four corners where it can be received by the piers beneath. Prior to the pendentive's development, builders used the device of corbelling or squinches in the corners of a room. Pendentives commonly occurred in Orthodox, Renaissance, and Baroque churches, with a drum with windows often inserted between the pendentives and the dome. The first experimentation with pendentives began with Roman dome construction in the 2nd–3rd century AD, while full development of the form came in the 6th-century Eastern Roman Hagia Sophia at Constantinople ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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