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'''Biology''' is a [[natural science]] concerned with the study of [[life]] and [[organism|living organisms]], including their structure, function, growth, [[evolution]], distribution, and [[Taxonomy (biology)|taxonomy]].<ref name=aquarenagloss>Based on definition from: {{cite web |url=http://www.bio.txstate.edu/~wetlands/Glossary/glossary.html |archiveurl=https://web.archive.org/web/20040608113114/http://www.bio.txstate.edu/~wetlands/Glossary/glossary.html |archivedate=2004-06-08 |title=Aquarena Wetlands Project glossary of terms |author=<!--Staff writer(s); no by-line.--> |publisher=Texas State University at San Marcos }}</ref> Modern biology is a vast |
'''Biology''' is a [[natural science]] concerned with the study of [[life]] and [[organism|living organisms]], including their structure, function, growth, [[evolution]], distribution, and [[Taxonomy (biology)|taxonomy]].<ref name=aquarenagloss>Based on definition from: {{cite web |url=http://www.bio.txstate.edu/~wetlands/Glossary/glossary.html |archiveurl=https://web.archive.org/web/20040608113114/http://www.bio.txstate.edu/~wetlands/Glossary/glossary.html |archivedate=2004-06-08 |title=Aquarena Wetlands Project glossary of terms |author=<!--Staff writer(s); no by-line.--> |publisher=Texas State University at San Marcos }}</ref> Modern biology is a vast field, composed of many [[List of biology disciplines#Branches of biology|branches and subdisciplines]]. However, despite the broad scope of biology, there are certain general and unifying concepts within it that govern all study and research, consolidating it into single, coherent field. In general, biology recognizes the [[Cell (biology)|cell]] as the basic unit of life, [[genes]] as the basic unit of [[heredity]], and [[evolution]] as the engine that propels the synthesis and creation of new [[species]]. It is also understood today that all organisms survive by consuming and transforming [[energy]] and by [[homeostasis|regulating]] their internal environment to maintain a stable and vital condition. |
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Subdisciplines of biology are defined by the scale at which organisms are studied, the kinds of organisms studied, and the methods used to study them: [[Biochemistry]] examines the rudimentary chemistry of life; [[molecular biology]] studies the complex interactions among biological [[molecule]]s; [[botany]] studies the biology of plants; [[cellular biology]] examines the basic building-block of all life, the [[cell (biology)|cell]]; [[physiology]] examines the physical and chemical functions of [[tissue (biology)|tissues]], [[Organ (anatomy)|organs]], and [[organ system]]s of an organism; [[evolutionary biology]] examines the [[evolution|processes]] that produced the diversity of life; and [[ecology]] examines how organisms interact in their [[environment (biophysical)|environment]].<ref>{{cite web|url=http://community.weber.edu/sciencemuseum/pages/life_main.asp |title=Life Science, Weber State Museum of Natural Science |publisher=Community.weber.edu |accessdate=2013-10-02}}</ref> |
Subdisciplines of biology are defined by the scale at which organisms are studied, the kinds of organisms studied, and the methods used to study them: [[Biochemistry]] examines the rudimentary chemistry of life; [[molecular biology]] studies the complex interactions among biological [[molecule]]s; [[botany]] studies the biology of plants; [[cellular biology]] examines the basic building-block of all life, the [[cell (biology)|cell]]; [[physiology]] examines the physical and chemical functions of [[tissue (biology)|tissues]], [[Organ (anatomy)|organs]], and [[organ system]]s of an organism; [[evolutionary biology]] examines the [[evolution|processes]] that produced the diversity of life; and [[ecology]] examines how organisms interact in their [[environment (biophysical)|environment]].<ref>{{cite web|url=http://community.weber.edu/sciencemuseum/pages/life_main.asp |title=Life Science, Weber State Museum of Natural Science |publisher=Community.weber.edu |accessdate=2013-10-02}}</ref> |
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{{Main|History of biology}} |
{{Main|History of biology}} |
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[[File:Tree of life by Haeckel.jpg|thumb|[[Ernst Haeckel]]'s Tree of Life (1879)]] |
[[File:Tree of life by Haeckel.jpg|thumb|[[Ernst Haeckel]]'s Tree of Life (1879)]] |
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The term ''[[wikt:biology|biology]]'' is derived from the [[Greek Language|Greek]] word {{lang|grc|[[wikt:βίος|βίος]]}}, ''bios'', "[[life]]" and the suffix {{lang|grc|[[wikt:-λογία|-λογία]]}}, ''-logia'', "study of."<ref>{{cite web |url=http://topics.info.com/Who-coined-the-term-biology_716 |title=Who coined the term biology? |work=Info.com|accessdate=2012-06-03}}</ref><ref name=OnlineEtDict>{{cite web|title=biology|url=http://www.etymonline.com/index.php?term=biology&allowed_in_frame=0|publisher=[[Online Etymology Dictionary]]}}</ref> The Latin form of the term first appeared in 1736 when [[Carl Linnaeus|Linnaeus]] (Carl von Linné) used ''biologi'' in his ''Bibliotheca botanica''. It was used again in 1766 in a work entitled ''Philosophiae naturalis sive physicae: tomus III, continens geologian, biologian, |
The term ''[[wikt:biology|biology]]'' is derived from the [[Greek Language|Greek]] word {{lang|grc|[[wikt:βίος|βίος]]}}, ''bios'', "[[life]]" and the suffix {{lang|grc|[[wikt:-λογία|-λογία]]}}, ''-logia'', "study of."<ref>{{cite web |url=http://topics.info.com/Who-coined-the-term-biology_716 |title=Who coined the term biology? |work=Info.com|accessdate=2012-06-03}}</ref><ref name=OnlineEtDict>{{cite web|title=biology|url=http://www.etymonline.com/index.php?term=biology&allowed_in_frame=0|publisher=[[Online Etymology Dictionary]]}}</ref> The Latin form of the term first appeared in 1736 when [[Carl Linnaeus|Linnaeus]] (Carl von Linné) used ''biologi'' in his ''Bibliotheca botanica''. It was used again in 1766 in a work entitled ''Philosophiae naturalis sive physicae: tomus III, continens geologian, biologian, |
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:The objects of our research will be the different forms and manifestations of life, the conditions and laws under which these phenomena occur, and the causes through which they have been effected. The science that concerns itself with these objects we will indicate by the name biology [Biologie] or the doctrine of life [Lebenslehre]. |
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Although modern biology is a relatively 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]], [[Egypt]], the [[Indian subcontinent]], and [[China]]. However, the origins of modern biology and its approach to the study of nature are most often traced back to [[ancient Greece]].<ref>{{cite book|author=Magner, Lois N. |title=A History of the Life Sciences, Revised and Expanded|url=http://books.google.com/books?id=YKJ6gVYbrGwC|year=2002|publisher=CRC Press|isbn=978-0-203-91100-6}}</ref> While the formal study of [[medicine]] dates back to [[Hippocrates]] (ca. 460 BC – ca. 370 BC), it was [[Aristotle]] (384 BC – 322 BC) who contributed most extensively to the development of biology. Especially important are his [[History of Animals]] and other works where he showed naturalist leanings, and later more empirical works that focused on biological causation and the diversity of life. Aristotle's successor at the [[Lyceum]], [[Theophrastus]], wrote a series of books on [[botany]] that survived as the most important contribution of antiquity to the plant sciences, even into the [[Middle Ages]].<ref name="eb1911">{{EB1911|title=Theophrastus|url=http://www.1911encyclopedia.org/Theophrastus |inline=1}}</ref> |
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Scholars of the medieval Islamic world who wrote on biology included [[al-Jahiz]] (781–869), [[Al-Dinawari]] (828–896), who wrote on botany,<ref name=Fahd-815>{{Cite journal|last=Fahd|first=Toufic|contribution=Botany and agriculture|page=815|ref=harv}}, in {{Cite book |last1=Morelon |first1=Régis |last2=Rashed |first2=Roshdi |year=1996 |title=[[Encyclopedia of the History of Arabic Science]] |volume=3 |publisher=[[Routledge]] |isbn=0-415-12410-7}}</ref> and [[Muhammad ibn Zakarīya Rāzi|Rhazes]] (865–925) who wrote on [[anatomy]] and [[physiology]]. [[Medicine]] was especially well studied by Islamic scholars working in Greek philosopher traditions, while natural history drew heavily on Aristotelian thought, especially in upholding a fixed hierarchy of life. |
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Biology began to quickly develop and grow with [[Anton van Leeuwenhoek]]'s dramatic improvement of the [[microscope]]. It was then that scholars discovered [[spermatozoa]], [[bacteria]], [[infusoria]] 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]].<ref>{{cite book|author=Magner, Lois N. |title=A History of the Life Sciences, Revised and Expanded|url=http://books.google.com/books?id=YKJ6gVYbrGwC|year=2002|publisher=CRC Press|isbn=978-0-203-91100-6|pages= 133–144}}</ref> |
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Advances in [[microscopy]] also had a profound impact on biological thinking. In the early 19th century, a number of biologists pointed to the central importance of the [[cell (biology)|cell]]. Then, in 1838, [[Matthias Jakob Schleiden|Schleiden]] and [[Theodor Schwann|Schwann]] began promoting the now universal ideas that (1) the basic unit of organisms is the cell and (2) that individual cells have all the characteristics of [[life]], although they opposed the idea that (3) 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]].<ref>[[Jan Sapp|Sapp, Jan]] (2003) ''Genesis: The Evolution of Biology'', Ch. 7. Oxford University Press: New York. ISBN 0-19-515618-8</ref><ref>Coleman, William (1977) ''Biology in the Nineteenth Century: Problems of Form, Function, and Transformation'', Ch. 2. Cambridge University Press: New York. ISBN 0-521-29293-X</ref> |
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Meanwhile, taxonomy and classification became the focus of natural historians. [[Carl Linnaeus]] published a basic [[Taxonomy (biology)|taxonomy]] for the natural world in 1735 (variations of which have been in use ever since), and in the 1750s introduced [[Binomial nomenclature|scientific names]] for all his species.<ref>Mayr, ''The Growth of Biological Thought'', chapter 4</ref> [[Georges-Louis Leclerc, Comte de Buffon]], treated species as artificial categories and living forms as malleable—even suggesting the possibility of [[common descent]]. Though he was opposed to evolution, Buffon is a key figure in the [[history of evolutionary thought]]; his work influenced the evolutionary theories of both [[Lamarck]] and [[Charles Darwin|Darwin]].<ref>Mayr, ''The Growth of Biological Thought'', chapter 7</ref> |
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Serious evolutionary thinking originated with the works of [[Jean-Baptiste Lamarck]], who was the first to present a coherent theory of evolution.<ref name="Gould 2002 187">[[Stephen Jay Gould|Gould, Stephen Jay]]. ''The Structure of Evolutionary Theory''. The Belknap Press of Harvard University Press: Cambridge, 2002. ISBN 0-674-00613-5. p. 187.</ref> He posited that evolution was the result of environmental stress on properties of animals, meaning that the more frequently 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 then be passed on to the animal's offspring, who would further develop and perfect them.<ref name=Lam1914>[[#Lamarck1914|Lamarck (1914)]]</ref> However, it was the British naturalist [[Charles Darwin]], combining the biogeographical approach of [[Alexander von Humboldt|Humboldt]], the uniformitarian geology of [[Charles Lyell|Lyell]], [[Thomas Malthus|Malthus's]] writings on population growth, and his own morphological expertise and extensive natural observations, who forged a more successful evolutionary theory based on [[natural selection]]; similar reasoning and evidence led [[Alfred Russel Wallace]] to independently reach the same conclusions.<ref>Mayr, ''The Growth of Biological Thought'', chapter 10: "Darwin's evidence for evolution and common descent"; and chapter 11: "The causation of evolution: natural selection"</ref><ref>{{cite book|author=Larson, Edward J. |title=Evolution: The Remarkable History of a Scientific Theory|url=http://books.google.com/books?id=xzLRvxlJhzkC|year=2006|publisher=Random House Publishing Group|isbn=978-1-58836-538-5|chapter=Ch. 3}}</ref> Although it was the subject of [[Creation–evolution controversy|controversy]] (which continues to this day), Darwin's theory quickly spread through the scientific community and soon became a central axiom of the rapidly developing science of biology. |
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The discovery of the physical representation of heredity came along with evolutionary principles and [[population genetics]]. In the 1940s and early 1950s, experiments pointed to [[DNA]] as the component of [[chromosomes]] that held the trait-carrying units that had become known as [[genes]]. A focus on new kinds of model organisms such as [[viruses]] and [[bacteria]], along with the discovery of the double helical structure of DNA in 1953, marked the transition to the era of [[molecular genetics]]. From the 1950s to present times, biology has been vastly extended in the [[Molecular Biology|molecular]] domain. The [[genetic code]] was cracked by [[Har Gobind Khorana]], [[Robert W. Holley]] and [[Marshall Warren Nirenberg]] after DNA was understood to contain [[codons]]. Finally, the [[Human Genome Project]] was launched in 1990 with the goal of mapping the general human [[genome]]. This project was essentially completed in 2003,<ref>{{cite news | url=http://news.bbc.co.uk/2/hi/science/nature/2940601.stm | title=BBC NEWS | Science/Nature | Human genome finally complete | accessdate=2006-07-22 | date=2003-04-14 | work=BBC News | first=Ivan | last=Noble}}</ref> with further analysis still being published. The Human Genome Project was the first step in a globalized effort to incorporate accumulated knowledge of biology into a functional, molecular definition of the human body and the bodies of other organisms. |
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==Foundations of modern biology== |
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===Cell theory=== |
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{{Main|Cell theory}} |
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Cell theory states that the [[cell biology|cell]] is the fundamental unit of [[life]], and that all living things are composed of one or more cells or the [[secretion|secreted]] products of those cells (e.g. [[animal shell|shells]]). All cells arise from other cells through [[cell division]]. In [[multicellular organisms]], every cell in the organism's body derives ultimately from a single cell in a fertilized [[egg (biology)|egg]]. The cell is also considered to be the basic unit in many pathological processes.<ref>{{cite journal|author=Mazzarello, P|title=A unifying concept: the history of cell theory|journal=Nature Cell Biology|volume=1|pages=E13–E15|year=1999|doi=10.1038/8964|pmid=10559875|issue=1|ref=harv}}</ref> In addition, the phenomenon of [[energy transfer|energy flow]] occurs in cells in processes that are part of the function known as [[metabolism]]. Finally, cells contain hereditary information ([[DNA]]), which is passed from cell to cell during cell division. |
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===Evolution=== |
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[[File:Mutation and selection diagram.svg|thumb|right|300px|[[Natural selection]] of a population for dark coloration.]] |
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{{Main|Evolution}} |
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A central organizing concept in biology is that life changes and develops through evolution, and that all life-forms known have a [[Common descent|common origin]]. The theory of evolution postulates that all [[organism]]s on the [[Earth]], both living and extinct, have descended from a common ancestor or an ancestral [[gene pool]]. This last universal common ancestor of all organisms is believed to have appeared about [[Timeline of evolution|3.5 billion years ago]].<ref>{{cite book | title = Life Evolving: Molecules, Mind, and Meaning | author = De Duve, Christian | location = New York | publisher = Oxford University Press | year = 2002| page = 44 | isbn = 0-19-515605-6}}</ref> Biologists generally regard the universality and ubiquity of the [[genetic code]] as definitive evidence in favor of the theory of universal common descent for all [[bacterium|bacteria]], [[archaea]], and [[eukaryote]]s (see: [[origin of life]]).<ref name="Futuyma">{{cite book|author=Futuyma, DJ|title=Evolution|year=2005|publisher=Sinauer Associates|isbn=978-0-87893-187-3|oclc=57311264 57638368 62621622}}</ref> |
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Introduced into the scientific lexicon by [[Jean-Baptiste de Lamarck]] in 1809,<ref name="p15">{{cite book |last=Packard |first=Alpheus Spring |title= Lamarck, the founder of Evolution: his life and work with translations of his writings on organic evolution|year= 1901 |publisher= Longmans, Green. |location=New York |isbn=0-405-12562-3}}</ref> evolution was established by [[Charles Darwin]] fifty years later as a viable scientific model when he articulated its driving force: [[natural selection]].<ref>[http://darwin-online.org.uk/biography.html The Complete Works of Darwin Online – Biography.] ''darwin-online.org.uk''. Retrieved on 2006-12-15</ref><ref>{{cite journal|url=http://www.phil.vt.edu/Burian/NothingInBiolChFina.pdf |last1 = Dobzhansky |first1 = T. |year = 1973 |title = Nothing in biology makes sense except in the light of evolution |journal = The American Biology Teacher |volume = 35 |issue = 3 |pages = 125–129}}</ref><ref>As Darwinian scholar Joseph Carroll of the University of Missouri–St. Louis puts it in his introduction to a modern reprint of Darwin's work: "''The Origin of Species'' has special claims on our attention. It is one of the two or three most significant works of all time—one of those works that fundamentally and permanently alter our vision of the world ... It is argued with a singularly rigorous consistency but it is also eloquent, imaginatively evocative, and rhetorically compelling." {{cite book |title=On the origin of species by means of natural selection |editor=Carroll, Joseph |year=2003 |publisher=Broadview |location= Peterborough, Ontario|isbn= 1-55111-337-6|page=15 }}</ref> ([[Alfred Russel Wallace]] is recognized as the co-discoverer of this concept as he helped research and experiment with the concept of evolution.)<ref>Shermer p. 149.</ref> Evolution is now used to explain the great variations of life found on Earth. |
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Darwin theorized that species and breeds developed through the processes of [[natural selection]] and [[artificial selection]] or [[selective breeding]].<ref>Darwin, Charles (1859). ''On the Origin of Species'', John Murray.</ref> [[Genetic drift]] was embraced as an additional mechanism of evolutionary development in the [[modern synthesis]] of the theory.<ref name = GGS>{{Cite book | last = Simpson | first = George Gaylord | author-link = George Gaylord Simpson | year = 1967 | title = The Meaning of Evolution | publisher = Yale University Press | edition = Second | isbn = 0-300-00952-6 }}</ref> |
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The evolutionary history of the [[species]]—which describes the characteristics of the various species from which it descended—together with its genealogical relationship to every other species is known as its [[phylogeny]]. Widely varied approaches to biology generate information about phylogeny. These include the comparisons of [[DNA sequence]]s conducted within [[molecular biology]] or [[genomics]], and comparisons of [[fossil]]s or other records of ancient organisms in [[paleontology]].<ref>{{cite web|url=http://www.bio-medicine.org/q-more/biology-definition/phylogeny/ |title=Phylogeny|publisher=Bio-medicine.org |date=2007-11-11 |accessdate=2013-10-02}}</ref> Biologists organize and analyze evolutionary relationships through various methods, including [[phylogenetics]], [[phenetics]], and [[cladistics]]. (For a summary of major events in the evolution of life as currently understood by biologists, see [[evolutionary timeline]].) |
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{{clear right}} |
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[[File:Punnett square mendel flowers.svg|left|thumb|A [[Punnett square]] depicting a cross between two pea plants heterozygous for purple (B) and white (b) blossoms]] |
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===Genetics=== |
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{{Main|Genetics}} |
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[[Gene]]s are the primary units of inheritance in all organisms. A gene is a unit of [[heredity]] and corresponds to a region of [[DNA]] that influences the form or function of an organism in specific ways. All organisms, from bacteria to animals, share the same basic machinery that copies and translates DNA into [[protein]]s. Cells [[Transcription (genetics)|transcribe]] a DNA gene into an [[RNA]] version of the gene, and a [[ribosome]] then [[Translation (biology)|translates]] the RNA into a protein, a sequence of [[amino acid]]s. The [[genetic code|translation code]] from RNA codon to amino acid is the same for most organisms, but slightly different for some. For example, a sequence of DNA that codes for [[insulin]] in humans also codes for insulin when inserted into other organisms, such as plants.<ref>Marcial, Gene G. (August 13, 2007) [http://www.businessweek.com/stories/2007-08-12/from-sembiosys-a-new-kind-of-insulin From SemBiosys, A New Kind Of Insulin]. businessweek.com</ref> |
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DNA usually occurs as linear [[chromosome]]s in [[eukaryote]]s, and circular chromosomes in [[prokaryote]]s. A chromosome is an organized structure consisting of [[DNA]] and [[histone]]s. The set of chromosomes in a cell and any other hereditary information found in the [[mitochondria]], [[chloroplasts]], or other locations is collectively known as its [[genome]]. In eukaryotes, genomic DNA is located in the [[cell nucleus]], along with small amounts in [[mitochondrion|mitochondria]] and [[chloroplast]]s. In prokaryotes, the DNA is held within an irregularly shaped body in the cytoplasm called the [[nucleoid]].<ref>{{cite journal |author=Thanbichler M, Wang S, Shapiro L |title=The bacterial nucleoid: a highly organized and dynamic structure | journal=J Cell Biochem |volume=96 |issue=3 | pages=506–21 |year=2005 |pmid=15988757 | doi = 10.1002/jcb.20519}}</ref> The genetic information in a genome is held within genes, and the complete assemblage of this information in an organism is called its [[genotype]].<ref>{{cite web|url=http://www.medterms.com/script/main/art.asp?articlekey=8472 |title=Genotype definition – Medical Dictionary definitions |publisher=Medterms.com |date=2012-03-19 |accessdate=2013-10-02}}</ref> |
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===Homeostasis=== |
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{{Main|Homeostasis}} |
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[[File:ACTH Negative Feedback.svg|right|thumb|The [[hypothalamus]] secretes [[Corticotropin-releasing hormone|CRH]], which directs the [[pituitary gland]] to secrete [[ACTH]]. In turn, ACTH directs the adrenal cortex to secrete [[glucocorticoid]]s, such as [[cortisol]]. The GCs then reduce the rate of secretion by the hypothalamus and the pituitary gland once a sufficient amount of GCs has been released.<ref>Raven, PH; Johnson, GB. (1999) ''Biology'', Fifth Edition, Boston: Hill Companies, Inc. p. 1058. ISBN 0697353532.</ref>]] |
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Homeostasis is the ability of an [[Open system (systems theory)|open system]] to regulate its internal environment to maintain stable conditions by means of multiple [[dynamic equilibrium]] adjustments controlled by interrelated regulation mechanisms. All living [[organism]]s, whether [[Single celled|unicellular]] or [[multicellular]], exhibit homeostasis.<ref>Rodolfo, Kelvin (2000-01-03) [http://www.scientificamerican.com/article.cfm?id=what-is-homeostasis What is homeostasis?] Scientific American.</ref> |
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To maintain dynamic equilibrium and effectively carry out certain functions, a system must detect and respond to perturbations. After the detection of a perturbation, a biological system normally responds through [[negative feedback]]. This means stabilizing conditions by either reducing or increasing the activity of an organ or system. One example is the release of [[glucagon]] when sugar levels are too low. |
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[[File:Energy and life.svg|thumb|240px|left|Basic overview of [[Bioenergetics|energy and human life]].]] |
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===Energy=== |
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The survival of a living organism depends on the continuous input of [[energy]]. Chemical reactions that are responsible for its structure and function are tuned to extract [[Chemistry#Energy|energy]] from substances that act as its food and transform them to help form new cells and sustain them. In this process, [[molecule]]s of [[chemical substance]]s that constitute [[food]] play two roles; first, they contain energy that can be transformed for biological [[chemical reaction]]s; second, they develop new molecular structures made up of biomolecules. |
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The organisms responsible for the introduction of energy into an ecosystem are known as producers or [[autotroph]]s. Nearly all of these organisms originally draw energy from the sun.<ref name=bryantfrigaard>{{cite journal | author = Bryant, D.A. and Frigaard, N.-U. | year=2006 | title = Prokaryotic photosynthesis and phototrophy illuminated | journal = Trends Microbiol | volume = 14 | issue = 11 | pages=488–96 | doi = 10.1016/j.tim.2006.09.001 | pmid = 16997562 }}</ref> Plants and other [[phototroph]]s use solar energy via a process known as [[photosynthesis]] to convert raw materials into organic molecules, such as [[Adenosine triphosphate|ATP]], whose bonds can be broken to release energy.<ref>{{cite book |author=Smith, A. L. |title=Oxford dictionary of biochemistry and molecular biology |publisher=Oxford University Press |location=Oxford [Oxfordshire] |year=1997 |page=508 |isbn=0-19-854768-4 |quote=Photosynthesis – the synthesis by organisms of organic chemical compounds, esp. carbohydrates, from carbon dioxide using energy obtained from light rather than the oxidation of chemical compounds.}}</ref> A few [[ecosystems]], however, depend entirely on energy extracted by [[chemotroph]]s from [[methane]], [[sulfides]], or other non-[[Solar energy|luminal]] energy sources.<ref>Edwards, Katrina. ''Microbiology of a Sediment Pond and the Underlying Young, Cold, |
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Hydrologically Active Ridge Flank''. Woods Hole Oceanographic Institution.</ref> |
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Some of the captured energy is used to produce [[biomass]] to sustain [[life]] and provide energy for growth and development. The majority of the rest of this energy is lost as heat and waste molecules. The most important processes for converting the energy trapped in chemical substances into energy useful to sustain life are [[metabolism]]<ref>{{cite book |author=Campbell, Neil A. and Reece, Jane B|title=Biology |publisher=Benjamin Cummings |year=2001 |chapter=6|isbn=978-0-8053-6624-2 |oclc=47521441 48195194 53439122 55707478 64759228 79136407}}</ref> and [[cellular respiration]].<ref name="Colvard, 2009">Bartsch, John and Colvard, Mary P. (2009) ''The Living Environment''. New York State Prentice Hall. ISBN 0133612023.</ref> |
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==Study and research== |
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===Structural=== |
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{{Main|Molecular biology|Cell biology|Genetics|Developmental biology}} |
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[[File:biological cell.svg|thumb|300px|Schematic of typical animal [[cell (biology)|cell]] depicting the various [[organelle]]s and structures.]] |
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[[Molecular biology]] is the study of biology at a molecular level.<ref>{{cite web|url=http://www.biology-online.org/dictionary/Molecular_biology |title=Molecular Biology – Definition |publisher=biology-online.org|accessdate=2013-10-02}}</ref> This field overlaps with other areas of biology, particularly with [[genetics]] and [[biochemistry]]. Molecular biology chiefly concerns itself with understanding the interactions between the various systems of a cell, including the interrelationship of DNA, RNA, and protein synthesis and learning how these interactions are regulated. |
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[[Cell biology]] studies the structural and [[physiology|physiological]] properties of [[cell (biology)|cells]], including their [[behavior]]s, interactions, and [[natural environment|environment]]. This is done on both the [[microscope|microscopic]] and [[molecule|molecular]] levels, for unicellular organisms such as [[bacterium|bacteria]], as well as the specialized cells in multicellular organisms such as [[human]]s. Understanding the structure and function of cells is fundamental to all of the biological sciences. The similarities and differences between cell types are particularly relevant to molecular biology. |
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[[Anatomy]] considers the forms of macroscopic structures such as [[organ (biology)|organs]] and organ systems.<ref>Gray, Henry (1918) [http://www.bartleby.com/107/1.html "Anatomy of the Human Body".] 20th edition.</ref> |
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[[Genetics]] is the science of [[gene]]s, [[heredity]], and the variation of [[organism]]s.<ref name=griffiths2000sect60>{{cite book |editor1-first=Anthony J. F. |editor1-last=Griffiths |editor2-first=Jeffrey H. |editor2-last=Miller |editor3-first=David T. |editor3-last=Suzuki |editor4-first=Richard C. |editor4-last=Lewontin |editor5-first=William M.|editor5-last=Gelbart |title=An Introduction to Genetic Analysis |year=2000 |isbn=0-7167-3520-2 |edition=7th |publisher=W. H. Freeman |location=New York |chapterurl=http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=iga.section.60 |chapter=Genetics and the Organism: Introduction |author=Anthony J. F. Griffiths ... }}</ref><ref name=Hartl_and_Jones>{{Cite book |author=Hartl D, Jones E |title=Genetics: Analysis of Genes and Genomes |edition=6th |publisher=Jones & Bartlett |year=2005 |isbn=0-7637-1511-5}} |
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</ref> Genes encode the information necessary for synthesizing proteins, which in turn play a central role in influencing the final [[phenotype]] of the organism. In modern research, genetics provides important tools in the investigation of the function of a particular gene, or the analysis of [[genetic interaction]]s. Within organisms, genetic information generally is carried in [[chromosome]]s, where it is represented in the [[DNA sequence|chemical structure]] of particular [[DNA]] [[molecule]]s. |
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[[Developmental biology]] studies the process by which organisms grow and develop. Originating in [[embryology]], modern developmental biology studies the genetic control of [[cell growth]], [[cellular differentiation|differentiation]], and "[[morphogenesis]]," which is the process that progressively gives rise to [[biological tissue|tissues]], [[organ (anatomy)|organs]], and [[anatomy]]. |
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[[Model organism]]s for developmental biology include the round worm ''[[Caenorhabditis elegans]],''<ref>{{cite journal |author=Brenner, S. | year=1974 |url=http://www.wormbase.org/resources/paper/WBPaper00000031 |title=The genetics of ''Caenorhabditis elegans'' |journal=[[Genetics (journal)|Genetics]] |volume=77 |pages=71–94|pmid=4366476 |issue=1 |pmc=1213120}}</ref> the fruit fly ''[[Drosophila melanogaster]],''<ref name="Encyclopedia of genetics">{{cite encyclopedia|author=Sang, James H. |editor=Eric C. R. Reeve |encyclopedia=Encyclopedia of genetics |title=Drosophila melanogaster: The Fruit Fly |url=http://books.google.com/?id=JjLWYKqehRsC&pg=PA157|year=2001|publisher=Fitzroy Dearborn Publishers, I |location=USA |page=157 |isbn= 978-1-884964-34-3 }}</ref> the zebrafish ''[[Danio rerio]],''<ref>{{cite journal |title=Large scale genetics in a small vertebrate, the zebrafish |journal=Int. J. Dev. Biol. |volume=40 |pages=221–7 |year=1996 |pmid=8735932 |url=http://www.ijdb.ehu.es/web/paper.php?doi=8735932 |author1=Haffter P |author2=Nüsslein-Volhard C |issue=1 }}</ref> the mouse ''[[Mus musculus]]'',<ref>{{cite journal |author=Keller G |title=Embryonic stem cell differentiation: emergence of a new era in biology and medicine |journal=Genes Dev. |volume=19 |issue=10 |pages=1129–55 |year=2005 |pmid=15905405 |doi=10.1101/gad.1303605}}</ref> and the weed ''[[Arabidopsis thaliana]]''.<ref>{{cite journal |author=Rensink WA, Buell CR |title=Arabidopsis to Rice. Applying Knowledge from a Weed to Enhance Our Understanding of a Crop Species |journal=Plant Physiol. |volume=135 |issue=2 |pages=622–9 |year=2004 |pmid=15208410 |doi=10.1104/pp.104.040170 |pmc=514098}}</ref><ref>{{cite journal |author=Coelho SM, Peters AF, Charrier B, ''et al'' |title=Complex life cycles of multicellular eukaryotes: new approaches based on the use of model organisms |journal=Gene |volume=406 |issue=1–2 |pages=152–70 |year=2007 |pmid=17870254 |doi=10.1016/j.gene.2007.07.025}}</ref> (A model organism is a [[species]] that is extensively studied to understand particular biological [[phenomena]], with the expectation that discoveries made in that organism provide insight into the workings of other organisms.)<ref>{{cite journal |author=Fields S, Johnston M |title=Cell biology. Whither model organism research? |journal=Science |volume=307 |issue=5717 |pages=1885–6 | year=2005 |pmid=15790833 |doi=10.1126/science.1108872 }}</ref> |
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===Physiological=== |
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{{Main|Physiology}} |
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Physiology studies the mechanical, physical, and biochemical processes of living organisms by attempting to understand how all of the structures function as a whole. The theme of "structure to function" is central to biology. Physiological studies have traditionally been divided into [[plant physiology]] and [[animal physiology]], but some principles of physiology are universal, no matter what particular [[organism]] is being studied. For example, what is learned about the physiology of [[yeast]] cells can also apply to human cells. The field of animal physiology extends the tools and methods of [[human physiology]] to non-human species. Plant physiology borrows techniques from both research fields. |
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Physiology studies how for example [[nervous system|nervous]], [[immune system|immune]], [[endocrine system|endocrine]], [[respiratory system|respiratory]], and [[circulatory system|circulatory]] systems, function and interact. The study of these systems is shared with [[medicine|medically]] oriented disciplines such as [[neurology]] and [[immunology]]. |
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===Evolutionary=== |
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[[Current research in evolutionary biology|Evolutionary research]] is concerned with the origin and descent of [[species]], as well as their change over time, and includes scientists from many taxonomically oriented disciplines. For example, it generally involves scientists who have special training in particular [[organism]]s such as [[mammalogy]], [[ornithology]], [[botany]], or [[herpetology]], but use those organisms as systems to answer general questions about evolution. |
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Evolutionary biology is partly based on [[paleontology]], which uses the [[fossil]] record to answer questions about the mode and tempo of evolution,<ref name=Jablonski>{{cite journal |author=Jablonski D |title=The future of the fossil record |journal=Science |volume=284 |issue=5423 |pages=2114–16 |year=1999 |pmid=10381868 |doi=10.1126/science.284.5423.2114 }}</ref> and partly on the developments in areas such as [[population genetics]].<ref>[[John H. Gillespie|Gillespie, John H.]] (1998) ''Population Genetics: A Concise Guide'', Johns Hopkins Press. ISBN 0-8018-5755-4.</ref> In the 1980s, [[developmental biology]] re-entered evolutionary biology from its initial exclusion from the [[modern synthesis]] through the study of [[evolutionary developmental biology]].<ref>Vassiliki Betta Smocovitis (1996) ''Unifiying Biology: the evolutionary synthesis and evolutionary biology''. Princeton University Press. ISBN 0-691-03343-9.</ref> Related fields often considered part of evolutionary biology are [[phylogenetics]], [[systematics]], and [[alpha taxonomy|taxonomy]]. |
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===Systematic=== |
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{{PhylomapB|caption=A [[phylogenetic tree]] of all living things, based on [[rRNA]] [[gene]] data, showing the separation of the three domains [[bacterium|bacteria]], [[archaea]], and [[eukaryote]]s as described initially by [[Carl Woese]]. Trees constructed with other genes are generally similar, although they may place some early-branching groups very differently, presumably owing to rapid rRNA evolution. The exact relationships of the three domains are still being debated.}} |
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[[File:Biological classification L Pengo.svg|thumb|left|The hierarchy of [[biological classification]]'s eight major taxonomic ranks. Intermediate minor |
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rankings are not shown. This diagram uses a 3 [[Domain (biology)|Domain]]s / 6 [[Kingdom (biology)|Kingdom]]s format]] |
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{{Main|Systematics}} |
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Multiple [[speciation]] events create a tree structured system of relationships between species. The role of [[systematics]] is to study these relationships and thus the differences and similarities between species and groups of species.<ref>{{cite book |
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| last = Neill |
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| first = Campbell |
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| title = Biology; Fourth edition |
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| publisher = The Benjamin/Cummings Publishing Company |
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| year = 1996 |
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| isbn = 0-8053-1940-9 |
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| page = G-21 (Glossary)}}</ref> |
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However, systematics was an active field of research long before evolutionary thinking was common.<ref>{{cite book |
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| last = Douglas |
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| first = Futuyma |
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| title = Evolutionary Biology; Third edition |
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| publisher = [[Sinauer Associates]] |
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| year = 1998 |
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| isbn = 0-87893-189-9 |
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| page = 88}}</ref> |
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Traditionally, living things have been divided into five kingdoms: [[Monera]]; [[Protist]]a; [[Fungus|Fungi]]; [[Plant]]ae; [[Animal]]ia.<ref>{{cite book|last=Margulis|first=L|coauthors=Schwartz, KV|authorlink=Lynn Margulis|title=Five Kingdoms: An Illustrated Guide to the Phyla of Life on Earth|edition=3rd|publisher= WH Freeman & Co|year=1997|isbn=978-0-7167-3183-2|oclc=223623098 237138975}}</ref> However, many scientists now consider this five-kingdom system outdated. Modern alternative classification systems generally begin with the [[three-domain system]]: [[Archaea]] (originally Archaebacteria); [[Bacterium|Bacteria]] (originally Eubacteria) and [[Eukaryote|Eukaryota]] (including [[protist]]s, [[fungi]], [[plants]], and [[animal]]s)<ref name="domain">{{cite journal | author = Woese C, Kandler O, Wheelis M | title = Towards a natural system of organisms: proposal for the domains Archaea, Bacteria, and Eucarya | journal = Proc Natl Acad Sci USA | volume = 87 | issue = 12 | pages = 4576–9 | year = 1990 | pmid = 2112744 | doi = 10.1073/pnas.87.12.4576 | pmc = 54159 | bibcode=1990PNAS...87.4576W}}</ref> These domains reflect whether the cells have nuclei or not, as well as differences in the chemical composition of key biomolecules such as [[ribosome]]s.<ref name="domain"/> |
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Further, each kingdom is broken down recursively until each species is separately classified. The order is: |
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[[Domain (biology)|Domain]]; [[Kingdom (biology)|Kingdom]]; [[Phylum]]; [[Class (biology)|Class]]; [[Order (biology)|Order]]; [[Family (biology)|Family]]; [[Genus]]; [[Species]]. |
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Outside of these categories, there are obligate intracellular [[parasite]]s that are "on the edge of life"<ref>{{cite journal | author = Rybicki EP | year = 1990 | title = The classification of organisms at the edge of life, or problems with virus systematics | journal = S Aft J Sci | volume = 86 | url=http://www.researchgate.net/publication/230603479_The_classification_of_organisms_at_the_edge_of_life_or_Problems_with_virus_systematics| pages = 182–186 }}</ref> in terms of [[metabolism|metabolic]] activity, meaning that many scientists do not actually classify these structures as alive, due to their lack of at least one or more of the fundamental functions or characteristics that define life. They are classified as [[virus (biology)|viruses]], [[viroid]]s, [[prion]]s, or [[Satellite (biology)|satellites]]. |
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The scientific name of an organism is generated from its genus and species. For example, humans are listed as ''[[Homo sapiens]]''. ''Homo'' is the genus, and ''sapiens'' the species. When writing the scientific name of an organism, it is proper to capitalize the first letter in the genus and put all of the species in lowercase. Additionally, the entire term may be italicized or underlined.<ref>{{cite book | url = http://books.google.com/?id=hVUU7Gq8QskC&lpg=PA198| page = 198 | title = Writing for Science and Engineering: Papers, Presentation | author = Silyn-Roberts, Heather | year = 2000 | isbn = 0-7506-4636-5 | publisher = Butterworth-Heinemann | location = Oxford}}</ref><ref>{{cite web | url = http://ibot.sav.sk/icbn/frameset/0065Ch7OaGoNSec1a60.htm#recF | title = Recommendation 60F | work = [[International Code of Botanical Nomenclature]], Vienna Code | year = 2006 | pages = 60F.1}}</ref> |
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The dominant classification system is called the [[Linnaean taxonomy]]. It includes ranks and [[binomial nomenclature]]. How organisms are named is governed by international agreements such as the [[International Code of Botanical Nomenclature]] (ICBN), the [[International Code of Zoological Nomenclature]] (ICZN), and the [[International Code of Nomenclature of Bacteria]] (ICNB). The classification of [[viruses]], [[viroids]], [[prions]], and all other sub-viral agents that demonstrate biological characteristics is conducted by the [[International Committee on Taxonomy of Viruses]] (ICTV) and is known as the International Code of Viral Classification and Nomenclature (ICVCN).<ref>{{cite web|url=http://www.ictvonline.org/virusTaxonomy.asp |title=ICTV Virus Taxonomy 2009 |publisher=Ictvonline.org|accessdate=2013-10-02}}</ref><ref name=ictvdbpopsi><!--citation specified in source-->''[https://web.archive.org/web/20090813214826/http://www.ncbi.nlm.nih.gov/ICTVdb/Ictv/fs_pospi.htm Index of Viruses – Pospiviroidae]'' (2006). In: ICTVdB – The Universal Virus Database, version 4. Büchen-Osmond, C (Ed), Columbia University, New York, USA. |
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Version 4 is based on [https://web.archive.org/web/20090813214826/http://www.ncbi.nlm.nih.gov/ICTVdb/report8.htm Virus Taxonomy], Classification and Nomenclature of Viruses, 8th ICTV Report of the International Committee on Taxonomy of Viruses. Fauquet, CM, Mayo, MA, Maniloff, J, Desselberger, U, and Ball, LA (EDS) (2005) Elsevier/Academic Press, pp. 1259.</ref><ref name=ictvdbprions>{{cite web |url=http://www.ncbi.nlm.nih.gov/ICTVdb/Ictv/fs_prion.htm |archiveurl=https://web.archive.org/web/20090827131816/http://www.ncbi.nlm.nih.gov/ICTVdb/Ictv/fs_prion.htm |archivedate=2009-08-27 |title=90. Prions – ICTVdB Index of Viruses |author=Prusiner SB |author2=Baldwin M |author3=Collinge J |author4=DeArmond SJ |author5=Marsh R |author6=Tateishi J |author7=Weissmann C |publisher=United States National Institutes of Health |accessdate=2009-10-28 }}</ref><ref name=ictvdbsatel>{{cite web |url=http://www.ncbi.nlm.nih.gov/ICTVdb/Ictv/fs_satel.htm |archiveurl=https://web.archive.org/web/20090501015827/http://www.ncbi.nlm.nih.gov/ICTVdb/Ictv/fs_satel.htm |archivedate=2009-05-01 |title=81. Satellites – ICTVdB Index of Viruses |author=Mayo MA |author2=Berns KI |author3=Fritsch C |author4=Jackson AO |author5=Leibowitz MJ |author6=Taylor JM |publisher=United States National Institutes of Health |accessdate=2009-10-28 }}</ref> However, several other viral classification systems do exist. |
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A merging draft, [[BioCode]], was published in 1997 in an attempt to standardize nomenclature in these three areas, but has yet to be formally adopted.<ref>{{cite conference | title=The BioCode: Integrated biological nomenclature for the 21st century? | booktitle=Proceedings of a Mini-Symposium on Biological Nomenclature in the 21st Century | author=McNeill, John | date=1996-11-04|url=http://www.plantsystematics.org/reveal/pbio/nomcl/mcne.html}}</ref> The BioCode draft has received little attention since 1997; its originally planned implementation date of January 1, 2000, has passed unnoticed. A revised BioCode that, instead of replacing the existing codes, would provide a unified context for them, was proposed in 2011.<ref>{{cite web|url=http://www.bionomenclature.net/index.html|title=The Draft BioCode (2011)|publisher=International Committee on Bionomenclature (ICB)}}</ref><ref>{{cite journal|url=http://www.ingentaconnect.com/content/iapt/tax/2011/00000060/00000001/art00019|author= Greuter, W.; Garrity, G.; Hawksworth, D.L.; Jahn, R.; Kirk, P.M.; Knapp, S.; McNeill, J.; Michel, E.; Patterson, D.J.; Pyle, R.; Tindall, B.J. |year=2011|title= Draft BioCode (2011): Principles and rules regulating the naming of organisms|journal=Taxon|volume= 60 |pages= 201–212}}</ref><ref>{{cite journal|url=http://www.ingentaconnect.com/content/iapt/tax/2011/00000060/00000001/art00018|year=2011|journal=Taxon|volume= 60 |pages= 199–200|title=Introducing the Draft BioCode (2011)|author= Hawksworth, David L.}}</ref> However, the [[International Botanical Congress]] of 2011 declined to consider the BioCode proposal. The [[International Committee on Taxonomy of Viruses|ICVCN]] remains outside the BioCode, which does not include viral classification. |
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===Ecological and environmental=== |
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[[File:Common clownfish.jpg|thumb|250px|right|Mutual [[symbiosis]] between [[clownfish]] of the genus [[Amphiprion]] that dwell among the tentacles of tropical [[sea anemone]]s. The territorial fish protects the anemone from anemone-eating fish, and in turn the stinging tentacles of the anemone protects the clown fish from its predators.]] |
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{{Main|Ecology|Ethology|Behavior|Biogeography}} |
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[[Ecology]] studies the distribution and abundance of [[life|living organisms]], and the interactions between organisms and their [[natural environment|environment]].<ref>{{cite book |last=Begon |first=M. |coauthors= Townsend, C. R., Harper, J. L. |title=Ecology: From individuals to ecosystems. (4th ed.) |year=2006 |publisher=Blackwell |isbn=1-4051-1117-8 }}</ref> The [[habitat]] of an organism can be described as the local [[abiotic factors]] such as [[climate]] and [[ecology]], in addition to the other organisms and [[biotic factors]] that share its environment.<ref name="habitats_of_the_world">{{Cite book | title = Habitats of the world | year = 2004 | url = http://books.google.com/?id=U-_mlcy8rGgC&pg=PA238 | publisher = Marshall Cavendish | location = New York | isbn = 978-0-7614-7523-1 | page = 238 }}</ref> One reason that biological systems can be difficult to study is that so many different interactions with other organisms and the environment are possible, even on small scales. A microscopic [[bacterium]] in a local sugar gradient is responding to its environment as much as a lion searching for food in the African [[savanna]]. For any species, [[behavior]]s can be [[co-operation|co-operative]], [[Competition (biology)|competitive]], [[parasite|parasitic]], or [[symbiosis|symbiotic]]. Matters become more complex when two or more species interact in an [[ecosystem]]. |
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Ecological systems are studied at several different levels, from individuals and [[population]]s to [[ecosystem]]s and the [[biosphere]]. The term [[population biology]] is often used interchangeably with [[population ecology]], although ''population biology'' is more frequently used when studying [[diseases]], [[viruses]], and [[microbes]], while population ecology is more commonly used when studying plants and animals. Ecology draws on many subdisciplines. |
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[[Ethology]] studies animal [[behavior]] (particularly that of social animals such as [[primate]]s and [[canidae|canids]]), and is sometimes considered a branch of zoology. Ethologists have been particularly concerned with the [[evolution]] of behavior and the understanding of behavior in terms of the theory of [[natural selection]]. In one sense, the first modern ethologist was [[Charles Darwin]], whose book, ''[[The Expression of the Emotions in Man and Animals]],'' influenced many ethologists to come.<ref name="black">{{Cite journal | pmc = 1279921 | pmid = 12042386 | year= 2002 | author = Black, J | title = Darwin in the world of emotions | volume = 95 | issue = 6 | pages = 311–3 | journal = Journal of the Royal Society of Medicine | doi = 10.1258/jrsm.95.6.311 }}</ref> |
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[[Biogeography]] studies the spatial distribution of organisms on the [[Earth]], focusing on topics like [[plate tectonics]], [[climate change]], [[Biological dispersal|dispersal]] and [[Animal migration|migration]], and [[cladistics]]. |
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==Basic unresolved problems in biology== |
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{{main|List of unsolved problems in biology}} |
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Despite the profound advances made over recent decades in our understanding of life’s fundamental processes, some basic problems have remained unresolved. For example, one of the major unresolved problems in biology is the primary adaptive function of sex, and particularly its key processes in eukaryotes, meiosis and homologous recombination. One view is that sex evolved primarily as an adaptation for increasing genetic diversity (see references e.g.<ref>{{cite pmid|16856849}}</ref><ref>{{cite pmid| 16950096}}</ref>). An alternative view is that sex is an adaptation for promoting accurate DNA repair in germ-line DNA, and that increased genetic diversity is primarily a byproduct that may be useful in the long run.<ref>Bernstein, Harris; Bernstein, Carol and Michod, Richard E. (2011). [http://www.intechopen.com/books/dna-repair/meiosis-as-an-evolutionary-adaptation-for-dna-repair "Meiosis as an Evolutionary Adaptation for DNA Repair"]. Chapter 19 in ''DNA Repair''. Inna Kruman editor. InTech Open Publisher. {{DOI|10.5772/25117}}</ref><ref>Hörandl, Elvira (2013). [http://www.intechopen.com/books/meiosis/meiosis-and-the-paradox-of-sex-in-nature Meiosis and the Paradox of Sex in Nature], Meiosis, Dr. Carol Bernstein (Ed.), ISBN 978-953-51-1197-9, InTech, {{DOI|10.5772/56542}}.</ref> (See also [[Evolution of sexual reproduction]]). |
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Another basic unresolved problem in biology is the biologic basis of aging. At present, there is no consensus view on the underlying cause of aging. Various competing theories are outlined in [[Ageing#Theories]]. |
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==Branches of biology== |
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These are the main branches of biology:<ref>{{cite web|url=http://www.biology-online.org/dictionary/Branches_of_biology |title=Branches of Biology|publisher=Biology-online.org|accessdate=2013-10-02}}</ref><ref>{{cite web|url=http://www.bellaonline.com/articles/art28786.asp |title=Biology on |publisher=Bellaonline.com |accessdate=2013-10-02}}</ref> |
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* [[Aerobiology]] – the study of airborne organic particles |
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* [[Agriculture]] – the study of producing crops and raising livestock, with an emphasis on practical applications |
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* [[Anatomy]] – the study of form and function, in plants, animals, and other organisms, or specifically in humans |
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** [[Histology]] – the study of cells and tissues, a microscopic branch of anatomy |
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* [[Astrobiology]] (also known as exobiology, exopaleontology, and bioastronomy) – the study of evolution, distribution, and future of life in the universe |
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* [[Biochemistry]] – the study of the chemical reactions required for life to exist and function, usually a focus on the cellular level |
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* [[Bioengineering]] – the study of biology through the means of engineering with an emphasis on applied knowledge and especially related to biotechnology |
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* [[Biogeography]] – the study of the distribution of species spatially and temporally |
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* [[Bioinformatics]] – the use of information technology for the study, collection, and storage of genomic and other biological data |
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* [[Biomathematics]] (or Mathematical biology) – the quantitative or mathematical study of biological processes, with an emphasis on modeling |
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* [[Biomechanics]] – often considered a branch of medicine, the study of the mechanics of living beings, with an emphasis on applied use through [[prosthetics]] or [[orthotics]] |
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* [[Biomedical research]] – the study of health and disease |
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** [[Pharmacology]] – the study and practical application of preparation, use, and effects of drugs and synthetic medicines |
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* [[Biomusicology]] – the study of music from a biological point of view. |
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* [[Biophysics]] – the study of biological processes through physics, by applying the theories and methods traditionally used in the physical sciences |
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* [[Biotechnology]] – the study of the manipulation of living matter, including genetic modification and [[synthetic biology]] |
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** [[Synthetic Biology]] – research integrating biology and engineering; construction of biological functions not found in nature |
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* [[Building biology]] – the study of the indoor living environment |
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* [[Botany]] – the study of plants |
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* [[Cell biology]] – the study of the cell as a complete unit, and the molecular and chemical interactions that occur within a living cell |
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* [[Conservation biology]] – the study of the preservation, protection, or restoration of the natural environment, natural ecosystems, vegetation, and wildlife |
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* [[Cryobiology]] – the study of the effects of lower than normally preferred temperatures on living beings |
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* [[Developmental biology]] – the study of the processes through which an organism forms, from zygote to full structure |
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** [[Embryology]] – the study of the development of embryo (from fecundation to birth) |
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* [[Ecology]] – the study of the interactions of living organisms with one another and with the non-living elements of their environment |
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* [[Environmental biology]] – the study of the natural world, as a whole or in a particular area, especially as affected by human activity |
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* [[Epidemiology]] – a major component of public health research, studying factors affecting the health of populations |
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* [[Evolutionary biology]] – the study of the origin and descent of species over time |
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* [[Genetics]] – the study of genes and heredity. |
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**[[Epigenetics]] – the study of heritable changes in gene expression or cellular phenotype caused by mechanisms other than changes in the underlying DNA sequence |
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* [[Hematology]] (also known as Haematology) – the study of blood and blood-forming organs. |
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* [[Integrative biology]] – the study of whole organisms |
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* [[Limnology]] – the study of inland waters |
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* [[Marine biology]] (or Biological oceanography) – the study of ocean ecosystems, plants, animals, and other living beings |
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* [[Microbiology]] – the study of microscopic organisms (microorganisms) and their interactions with other living things |
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** [[Parasitology]] – the study of parasites and parasitism |
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** [[Virology]] – the study of viruses and some other virus-like agents |
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* [[Molecular biology]] – the study of biology and biological functions at the molecular level, some cross over with biochemistry |
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* [[Mycology]] – the study of fungi |
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* [[Neurobiology]] – the study of the nervous system, including anatomy, physiology and pathology |
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* [[Population biology]] – the study of groups of conspecific organisms, including |
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** [[Population ecology]] – the study of how population dynamics and extinction |
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** [[Population genetics]] – the study of changes in gene frequencies in populations of organisms |
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* [[Paleontology]] – the study of fossils and sometimes geographic evidence of prehistoric life |
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* [[Pathology|Pathobiology or pathology]] – the study of diseases, and the causes, processes, nature, and development of disease |
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* [[Physiology]] – the study of the functioning of living organisms and the organs and parts of living organisms |
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* [[Phytopathology]] – the study of plant diseases (also called Plant Pathology) |
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* [[Psychobiology]] – the study of the biological bases of [[psychology]] |
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* [[Sociobiology]] – the study of the biological bases of [[sociology]] |
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* [[Structural biology]] – a branch of [[molecular biology]], [[biochemistry]], and [[biophysics]] concerned with the molecular structure of biological macromolecules |
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* [[Zoology]] – the study of animals, including classification, physiology, development, and behavior. Subbranches include: [[Ethology]](animal behavior), [[Entomology]](insects), [[Herpetology]](reptiles and amphibians), [[Ichthyology]](fish), [[Mammalogy]](mammals), and [[Ornithology]](birds) |
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==See also== |
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{{Wikipedia books}} |
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{{Portal|Biology|Environment|Ecology|Earth sciences}} |
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* [[Glossary of biology]] |
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* [[List of biological websites]] |
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* [[List of biologists]] |
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* [[List of biology topics]] |
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* [[List of omics topics in biology]] |
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* [[Lists of biology journals and magazines]] |
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* [[Outline of biology]] |
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* ''[[The Journal of Life Sciences]]'' |
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* Periodic Table of Life Sciences in [[Tinbergen's four questions]] |
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==Notes and references== |
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{{Reflist|30em}} |
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==Bibliography== |
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*{{cite book|author=Mayr, Ernst |title=The Growth of Biological Thought: Diversity, Evolution, and Inheritance|url=http://books.google.com/books?id=pHThtE2R0UQC|year=1982|publisher=Harvard University Press|isbn=978-0-674-36446-2}} |
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==Further reading== |
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* {{cite book|last =Alberts|first=Bruce|coauthors=Johnson, A, Lewis, J, Raff, M, Roberts, K & Walter, P|title=Molecular Biology of the Cell|edition=4th|publisher=Garland|year=2002|isbn=978-0-8153-3218-3|oclc =145080076 48122761 57023651 69932405}} |
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* {{cite book|last=Begon|first=Michael|coauthors= Townsend, CR & Harper, JL|title=[[Ecology: From Individuals to Ecosystems]]|edition=4th|publisher=Blackwell Publishing Limited|year=2005|isbn=978-1-4051-1117-1|oclc=57639896 57675855 62131207}} |
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* {{cite book|last=Campbell|first=Neil|authorlink=Neil Campbell (scientist)|title=Biology|edition=7th|publisher=Benjamin-Cummings Publishing Company|year=2004|isbn=0-8053-7146-X|oclc=71890442}} |
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* {{cite book|last=Colinvaux|first=Paul|authorlink=Paul Colinvaux |title=Why Big Fierce Animals are Rare: An Ecologist's Perspective|edition=reissue|publisher=Princeton University Press|year=1979|isbn=0-691-02364-6|oclc=10081738 24132192}} |
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* {{cite book|last=Hoagland|first=Mahlon|title=The Way Life Works|edition=reprint|publisher=Jones and Bartlett Publishers inc|year=2001|isbn=0-7637-1688-X|oclc=223090105 45487537}} |
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* {{cite book|last=Janovy|first=John Jr.|title=On Becoming a Biologist|edition=2nd|publisher=Bison Books|year=2004|isbn=0-8032-7620-6|oclc=55138571 56964280}} |
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* {{cite book|last=Johnson|first=George B.|authorlink=Johnson George B.|title=Biology, Visualizing Life|publisher=Holt, Rinehart, and Winston|year=2005|isbn=0-03-016723-X|oclc=36306648}} |
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* {{cite book|last =Tobin|first=Allan|coauthors=Dusheck, Jennie|title=Asking About Life|edition=3rd|publisher=Wadsworth|location=Belmont, CA|year=2005|isbn=0-534-40653-X}} |
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==External links== |
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{{Wikibooks}} |
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{{Wiktionary}} |
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{{wikiversity|Biology|at-link=School:Biology|at=The School of Biology}} |
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* {{dmoz|Science/Biology}} |
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* [http://www.ohio.edu/phylocode/index.html OSU's Phylocode] |
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* [http://www.biology-online.org/dictionary/Main_Page Biology Online – Wiki Dictionary] |
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* [http://ocw.mit.edu/courses/biology/7-012-introduction-to-biology-fall-2004/ MIT video lecture series on biology] |
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* [http://www.bioeticaunbosque.edu.co/english/ Biology and Bioethics]. |
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* [https://inlportal.inl.gov/portal/server.pt?open=514&objID=2622&parentname=CommunityPage&parentid=7&mode=2&in_hi_userid=200&cached=true Biological Systems] – Idaho National Laboratory |
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* [http://tolweb.org/tree/phylogeny.html ''The Tree of Life'']: A multi-authored, distributed Internet project containing information about phylogeny and biodiversity. |
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* [http://logic-law.com/index.php?title=The_Study_of_Biology The Study of Biology] |
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* [http://www.library.illinois.edu/bix/biologicalliterature/ Using the Biological Literature Web Resources] |
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;Journal links |
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* [http://biology.plosjournals.org/perlserv/?request=index-html&issn=1545-7885 PLos Biology] A peer-reviewed, open-access journal published by the [[Public Library of Science]] |
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* [http://www.cell.com/current-biology/ Current Biology] General journal publishing [[original research]] from all areas of biology |
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* [http://rsbl.royalsocietypublishing.org/ Biology Letters] A [[Impact factor|high-impact]] [[Royal Society]] journal publishing [[peer-review]]ed Biology papers of general interest |
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* [http://www.sciencemag.org/collections/subject/ Science Magazine] Internationally Renowned [[American Association for the Advancement of Science|AAAS]] Science Publication – See Sections of the Life Sciences |
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* [http://www.biolsci.org/ International Journal of Biological Sciences] A biological journal publishing significant peer-reviewed scientific papers |
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* [http://www.press.jhu.edu/journals/perspectives_in_biology_and_medicine/index.html Perspectives in Biology and Medicine] An [[interdisciplinarity|interdisciplinary]] [[scholarly method|scholarly]] journal publishing [[essay]]s of broad relevance |
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* [http://www.lifesciencelog.com/ Life Science Log] |
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{{Natural science}} |
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{{Nature}} |
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{{Biology nav}} |
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{{Biology topics}} |
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{{Good article}} |
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Revision as of 12:39, 24 January 2014
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Biology is a natural science concerned with the study of life and living organisms, including their structure, function, growth, evolution, distribution, and taxonomy.[1] Modern biology is a vast field, composed of many branches and subdisciplines. However, despite the broad scope of biology, there are certain general and unifying concepts within it that govern all study and research, consolidating it into single, coherent field. In general, biology recognizes the cell as the basic unit of life, genes as the basic unit of heredity, and evolution as the engine that propels the synthesis and creation of new species. It is also understood today that all organisms survive by consuming and transforming energy and by regulating their internal environment to maintain a stable and vital condition.
Subdisciplines of biology are defined by the scale at which organisms are studied, the kinds of organisms studied, and the methods used to study them: Biochemistry examines the rudimentary chemistry of life; molecular biology studies the complex interactions among biological molecules; botany studies the biology of plants; cellular biology examines the basic building-block of all life, the cell; physiology examines the physical and chemical functions of tissues, organs, and organ systems of an organism; evolutionary biology examines the processes that produced the diversity of life; and ecology examines how organisms interact in their environment.[2]
History
The term biology is derived from the Greek word βίος, bios, "life" and the suffix -λογία, -logia, "study of."[3][4] The Latin form of the term first appeared in 1736 when Linnaeus (Carl von Linné) used biologi in his Bibliotheca botanica. It was used again in 1766 in a work entitled Philosophiae naturalis sive physicae: tomus III, continens geologian, biologian,
- ^ Based on definition from: "Aquarena Wetlands Project glossary of terms". Texas State University at San Marcos. Archived from the original on 2004-06-08.
- ^ "Life Science, Weber State Museum of Natural Science". Community.weber.edu. Retrieved 2013-10-02.
- ^ "Who coined the term biology?". Info.com. Retrieved 2012-06-03.
- ^ "biology". Online Etymology Dictionary.