{{Short description|Scientific study of life}}
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'''Biology''' is the [[scientific study]] of [[life]] and living [[organism]]s. It is a broad [[natural science]] that encompasses a wide range of fields and unifying principles that explain the structure, function, growth, [[History of life|origin]], [[evolution]], and distribution of life. Central to biology are five fundamental themes: the [[cell (biology)|cell]] as the basic unit of life, [[gene]]s and [[heredity]] as the basis of inheritance, evolution as the driver of [[biological diversity]], [[energy]] transformation for sustaining life processes, and [[homeostasis]], the maintenance of internal stability.<ref name="modell2015">{{Cite journal |last1=Modell |first1=Harold |last2=Cliff |first2=William |last3=Michael |first3=Joel |last4=McFarland |first4=Jenny |last5=Wenderoth |first5=Mary Pat |last6=Wright |first6=Ann |date=December 2015 |title=A physiologist's view of homeostasis |journal=Advances in Physiology Education |volume=39 |issue=4 |pages=259–266 |doi=10.1152/advan.00107.2015 |pmc=4669363 |pmid=26628646 }}</ref><ref name="davies2013">{{cite journal |last1=Davies |first1=P. C. |author2=Rieper, E. |author3=Tuszynski, J. A. |title=Self-organization and entropy reduction in a living cell |journal=Bio Systems |volume=111 |issue=1 |pages=1–10 |date=January 2013 |pmid=23159919 |pmc=3712629 |doi=10.1016/j.biosystems.2012.10.005 |bibcode=2013BiSys.111....1D }}</ref>

Biology examines life across multiple [[biological organisation|levels of organization]], from [[molecule]]s and cells to organisms, [[Population_(biology)|population]], and [[ecosystem]]s. Subdisciplines include [[molecular biology]], [[physiology]], [[ecology]], [[evolutionary biology]], [[developmental biology]], and [[systematics]], among others. Each of these fields applies a range of methods to investigate biological phenomena, including [[scientific method|observation, experimentation]], and [[mathematical modeling]]. Modern biology is grounded in the theory of evolution by [[natural selection]], first articulated by [[Charles Darwin]], and in the molecular understanding of genes encoded in [[DNA]]. The discovery of the [[structure of DNA]] and advances in [[molecular genetics]] have transformed many areas of biology, leading to applications in [[medicine]], [[agriculture]], [[biotechnology]], and [[environmental science]].

Biologists classify [[organism]]s—from single-celled [[archaea]] and [[bacteria]] to multicellular [[plant]]s, [[fungi]], and [[animal]]s—based on shared characteristics and evolutionary relationships, using [[taxonomy (biology)|taxonomic]] and [[phylogenetic]]s.

==Etymology==

From [[Greek language|Greek]] [[wikt:βίος|βίος]] (''bíos'') 'life', (from [[Proto-Indo-European language|Proto-Indo-European]] root *gwei-, to live) and [[wikt:λογία|λογία]] (''logia'') 'study of'. The compound appears in the title of Volume 3 of [[Michael Christoph Hanow]]'s ''Philosophiae naturalis sive physicae dogmaticae: Geologia, biologia, phytologia generalis et dendrologia'', published in 1766. The term ''biology'' in its modern sense appears to have been introduced independently by [[Thomas Beddoes]] (in 1799),<ref>{{Cite OED|biology|19228}}</ref> [[Karl Friedrich Burdach]] (in 1800), [[Gottfried Reinhold Treviranus]] (''Biologie oder Philosophie der lebenden Natur'', 1802) and [[Jean-Baptiste Lamarck]] (''Hydrogéologie'', 1802).<ref>{{cite book |last1=Mayr |first1=Ernst |title=The Growth of Biological Thought: Diversity, Evolution, and Inheritance |date=1982 |publisher=Harvard University Press |isbn=978-0-674-36446-2 |page=108 |url=https://books.google.com/books?id=pHThtE2R0UQC&pg=PA1165 |access-date=29 May 2025}}</ref><ref>Junker ''Geschichte der Biologie'', p8.</ref><ref>Coleman, ''Biology in the Nineteenth Century'', pp 1–2.</ref>

==History==

{{Main|History of biology}}

The earliest of roots of science, which included medicine, can be traced to [[ancient Egypt]] and [[Mesopotamia]] in around 3000 to 1200 [[Common Era|BCE]].<ref name="Lindberg1">{{cite book |last=Lindberg |first=David C. |year=2007 |chapter=Science before the Greeks |title=The beginnings of Western science: the European Scientific tradition in philosophical, religious, and institutional context |pages=1–20 |edition=2nd |location=Chicago, Illinois |publisher=University of Chicago Press |isbn=978-0-226-48205-7}}</ref><ref name="Grant2007a">{{cite book |last=Grant|first=Edward |year=2007 |chapter=Ancient Egypt to Plato |title=A History of Natural Philosophy: From the Ancient World to the Nineteenth Century |url=https://archive.org/details/historynaturalph00gran|url-access=limited|pages=[https://archive.org/details/historynaturalph00gran/page/n16 1]–26 |location=New York|publisher=Cambridge University Press |isbn=978-052-1-68957-1}}</ref> Their contributions shaped ancient Greek [[natural philosophy]].<ref>{{Cite book |url=https://link.springer.com/book/10.1007/978-3-319-90119-0 |title=Handbook of the Historiography of Biology |series=Historiographies of Science |date=2021 |language=en |doi=10.1007/978-3-319-90119-0|isbn=978-3-319-90118-3 }}</ref><ref name="Lindberg1"/><ref name="Grant2007a"/><ref>{{cite book|last=Magner|first=Lois N.|title=A History of the Life Sciences, Revised and Expanded|url=https://books.google.com/books?id=YKJ6gVYbrGwC|year=2002|publisher=CRC Press|isbn=978-0-203-91100-6|url-status=live|archive-url=https://web.archive.org/web/20150324125937/http://books.google.com/books?id=YKJ6gVYbrGwC|archive-date=2015-03-24}}</ref><ref>{{cite book |first=Anthony |last=Serafini |title=The Epic History of Biology |date=2013 |publisher=Springer |url=https://books.google.com/books?id=Z3oECAAAQBAJ&q=biology%20egypt&pg=PA2 |access-date=14 July 2015 |isbn=978-1-4899-6327-7 |archive-date=15 April 2021 |archive-url=https://web.archive.org/web/20210415122005/https://books.google.com/books?id=Z3oECAAAQBAJ&q=biology%20egypt&pg=PA2 |url-status=live }}</ref> [[ancient Greece|Ancient Greek]] philosophers such as [[Aristotle]] (384–322 BCE) contributed extensively to the development of biological knowledge.<ref>Morange, Michel. 2021. ''A History of Biology''. Princeton, NJ: Princeton University Press. Translated by Teresa Lavender Fagan and Joseph Muise.</ref> He explored biological causation and the diversity of life. His successor, [[Theophrastus]], began the scientific study of plants.<ref name="eb1911">{{EB1911|wstitle=Theophrastus|inline=1}}</ref> Scholars of the [[Science in the medieval Islamic world|medieval Islamic world]] who wrote on biology included [[al-Jahiz]] (781–869), [[Al-Dīnawarī]] (828–896), who wrote on botany.<ref name="Fahd-815">{{cite book |last=Fahd |first=Toufic |contribution=Botany and agriculture |page=815 |editor-last1=Morelon |editor-first1=Régis |editor-last2=Rashed |editor-first2=Roshdi |year=1996 |title=Encyclopedia of the History of Arabic Science |volume=3 |publisher=[[Routledge]] |isbn=978-0-415-12410-2 |title-link=Encyclopedia of the History of Arabic Science}}</ref>

Biology began to develop quickly 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 techniques of microscopic [[dissection]] and [[staining]].<ref>{{cite book |last=Magner |first=Lois N. |title=A History of the Life Sciences, Revised and Expanded |url=https://books.google.com/books?id=YKJ6gVYbrGwC |year=2002 |publisher=CRC Press |isbn=978-0-203-91100-6 |pages=133–44 |url-status=live |archive-url=https://web.archive.org/web/20150324125937/http://books.google.com/books?id=YKJ6gVYbrGwC |archive-date=2015-03-24 }}</ref> Advances in microscopy had a profound impact on biological thinking. In the early 19th century, biologists pointed to the central importance of the [[cell (biology)|cell]]. 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, continuing to support [[spontaneous generation]]. However, [[Robert Remak]] and [[Rudolf Virchow]] were able to reify the third tenet, and by the 1860s most biologists accepted all three tenets which consolidated into [[cell theory]].<ref>{{cite book |first=Jan |last=Sapp |author-link=Jan Sapp |year=2003 |title=Genesis: The Evolution of Biology |chapter=7 |publisher=Oxford University Press |location=New York |isbn=978-0-19-515618-8 }}</ref><ref>{{cite book |last=Coleman |first=William |year=1977 |title=Biology in the Nineteenth Century: Problems of Form, Function, and Transformation |publisher=Cambridge University Press |location=New York |isbn=978-0-521-29293-1 }}</ref>

Meanwhile, taxonomy and classification became the focus of natural historians. [[Carl Linnaeus]] published a basic [[Taxonomy (biology)|taxonomy]] for the natural world in 1735, and in the 1750s introduced [[Binomial nomenclature|scientific names]] for all his species.<ref>Mayr, Ernst. ''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]].<ref>Mayr, Ernst. ''The Growth of Biological Thought'', chapter 7</ref>

[[File:Charles Darwin aged 51.jpg|thumb|upright|In 1842, [[Charles Darwin]] penned his first sketch of ''[[On the Origin of Species]]''.<ref>{{cite book |editor-last=Darwin |editor-first=Francis |editor-link=Francis Darwin |year=1909 |title=The foundations of The origin of species, a sketch written in 1842 |url=http://darwin-online.org.uk/converted/pdf/1909_Foundations_F1555.pdf |location=Cambridge |publisher=Printed at the University Press |lccn=61057537 |oclc=871844563 |access-date=27 November 2014 |archive-date=4 March 2016 |archive-url=https://web.archive.org/web/20160304111606/http://darwin-online.org.uk/converted/pdf/1909_Foundations_F1555.pdf |url-status=live |page=53 |doi=10.5962/bhl.title.168964 }}</ref>]]

Serious evolutionary thinking originated with the works of [[Jean-Baptiste Lamarck]], who presented 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> The British [[Natural history|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, 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, Ernst. ''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 |last=Larson |first=Edward J. |title=Evolution: The Remarkable History of a Scientific Theory |chapter-url=https://books.google.com/books?id=xzLRvxlJhzkC |year=2006 |publisher=Random House Publishing Group |isbn=978-1-58836-538-5 |chapter=Ch. 3 |archive-url=https://web.archive.org/web/20150324124009/http://books.google.com/books?id=xzLRvxlJhzkC |archive-date=2015-03-24 }}</ref>

The basis for modern genetics began with the work of [[Gregor Mendel]] in 1865.<ref>{{Cite book|last=Henig|url=http://archive.org/details/monkingardenlost00heni|title=Op. cit|date=2000|pages=134–138}}</ref> This outlined the principles of biological inheritance.<ref name="miko2008a">{{cite journal |last=Miko |first=Ilona |title=Gregor Mendel's principles of inheritance form the cornerstone of modern genetics. So just what are they? |journal=Nature Education |volume=1 |issue=1 |page=134 |date=2008 |url=https://www.nature.com/scitable/topicpage/gregor-mendel-and-the-principles-of-inheritance-593/ |access-date=2021-05-13 |archive-date=2019-07-19 |archive-url=https://web.archive.org/web/20190719224056/http://www.nature.com/scitable/topicpage/gregor-mendel-and-the-principles-of-inheritance-593 |url-status=live }}</ref> However, the significance of his work was not realized until the early 20th century when evolution became a unified theory as the [[Modern synthesis (20th century)|modern synthesis]] reconciled Darwinian evolution with [[classical genetics]].<ref name="Futuyma2017a">{{cite book |last1=Futuyma |first1=Douglas J. |last2=Kirkpatrick |first2=Mark |date=2017|pages=3–26 |chapter=Evolutionary Biology |title=Evolution |edition=4th |publisher=Sinauer Associates |location=Sunderland, Mass.}}</ref> In the 1940s and early 1950s, a [[Hershey–Chase experiment|series of experiments]] by [[Alfred Hershey]] and [[Martha Chase]] pointed to [[DNA]] as the component of [[chromosome]]s that held the trait-carrying units that had become known as [[gene]]s. A focus on new kinds of model organisms such as [[virus]]es and bacteria, along with the discovery of the double-helical structure of DNA by [[James Watson]] and [[Francis Crick]] in 1953, marked the transition to the era of [[molecular genetics]]. From the 1950s onwards, 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 [[codon]]s. The [[Human Genome Project]] was launched in 1990 to map the human [[genome]].<ref>{{cite news |url=https://news.bbc.co.uk/2/hi/science/nature/2940601.stm |title=Human genome finally complete |access-date=2006-07-22 |date=2003-04-14 |work=BBC News |first=Ivan |last=Noble |url-status=live |archive-url=https://web.archive.org/web/20060614141605/http://news.bbc.co.uk/2/hi/science/nature/2940601.stm |archive-date=2006-06-14 }}</ref>

==Fields==

{{see also|List of biology disciplines}}

===Biochemistry===

[[Biochemistry]] is the study of [[chemical process]]es within and relating to living [[organism]]s.<ref>{{cite web |url=http://www.acs.org/content/acs/en/careers/college-to-career/areas-of-chemistry/biological-biochemistry.html.html |title=Biological/Biochemistry |work=acs.org |access-date=2016-01-04 |archive-date=2019-08-21 |archive-url=https://web.archive.org/web/20190821192332/https://www.acs.org/content/acs/en/careers/college-to-career/areas-of-chemistry/biological-biochemistry.html.html |url-status=live}}</ref>
 
===Molecular biology===

[[Molecular biology]] is the branch of biology that seeks to understand the molecular basis of biological activity in and between cells. It is centered largely on the study of [[Nucleic acid |nucleic acids]] (such as [[DNA]] and [[RNA]]) and [[Protein |proteins]]. It examines the structure, function, and interactions of these [[Macromolecule |macromolecules]] as they orchestrate processes such as [[DNA replication |replication]], [[Transcription (biology) |transcription]], [[Translation (biology) |translation]], [[Protein biosynthesis |protein synthesis]], and complex [[biomolecule |biomolecular]] interactions.<ref name="cell2">{{cite book |last1=Alberts |first1=Bruce |url=https://books.google.com/books?id=jK6UBQAAQBAJ |title=Molecular Biology of the Cell, Sixth Edition |last2=Johnson |first2=Alexander |last3=Lewis |first3=Julian |last4=Morgan |first4=David |last5=Raff |first5=Martin |last6=Roberts |first6=Keith |last7=Walter |first7=Peter |date=2014 |publisher=Garland Science |isbn=978-1-317-56375-4 |pages=1–10}}</ref><ref name="Gannon-2002">{{cite journal |last=Gannon |first=F. |title=Molecular biology--what's in a name? |journal=EMBO Reports |volume=3 |issue=2 |page=101 |date=February 2002 |pmid=11839687 |pmc=1083977 |doi=10.1093/embo-reports/kvf039 }}</ref><ref>{{Cite web |title=Molecular biology |url=https://www.nature.com/subjects/molecular-biology |access-date=2021-11-07 |website=nature.com}}</ref>

In 1953, the [[Miller–Urey experiment]] showed that organic compounds could be synthesized abiotically within a closed system mimicking the conditions of [[early Earth]], thus suggesting that complex organic molecules could have arisen spontaneously in early Earth in the process of [[abiogenesis]].<ref name="hillisetal2014d">{{cite book |last1=Hillis |first1=David M. |last2=Sadava |first2=David |last3=Hill |first3=Richard W. |last4=Price |first4=Mary V. |chapter=Carbon and molecular diversity of life |title=Principles of Life |publisher=Sinauer Associates |edition=2nd |date=2014 |location=Sunderland, Massachusetts |pages=56–65 |isbn=978-1-4641-7512-1}}</ref><ref name="freeman2017b">{{cite book |last1=Freeman |first1=Scott |title=Biological Science |last2=Quillin |first2=Kim |last3=Allison |first3=Lizabeth |last4=Black |first4=Michael |last5=Podgorski |first5=Greg |last6=Taylor |first6=Emily |last7=Carmichael |first7=Jeff |date=2017 |publisher=Pearson |isbn=978-0-321-97649-9 |edition=6th |location=Hoboken, N.J. |pages=55–77 |chapter=Water and carbon: The chemical basis of life}}</ref>

===Cell biology===

{{main|Cell biology}}

[[Cell biology]] is the branch of biology that studies the structure, function, and behaviour of [[cell (biology)|cell]]s.<ref name="alberts2017a">{{cite book |last1=Alberts |first1=Bruce |last2=Johnson |first2=Alexander D. |last3=Morgan |first3=David |last4=Raff |first4=Martin |last5=Roberts |first5=Keith |last6=Walter |first6=Peter |chapter=Cells and genomes |title=Molecular Biology of the Cell |publisher=Garland Science |edition=6th |date=2015 |location=New York, NY |pages=1–42 |isbn=978-0815344322}}</ref><ref>{{cite web |last=Bisceglia |first=Nick |url=https://www.nature.com/scitable/topic/cell-biology-13906536 |title=Cell Biology |website=Scitable}}</ref>

[[Bioenergetics]] is a field in [[biochemistry]] and cell biology that concerns [[energy]] flow through living systems.<ref> Nelson, David L., Cox, Michael M. ''Lehninger: Principles of Biochemistry.'' New York: W.H. Freeman and Company, 2013. Sixth ed., p. 24.</ref> This is an active area of [[Biology|biological]] research that includes the study of the transformation of energy in living organisms and the study of thousands of different [[Cell (biology)|cellular]] processes such as [[cellular respiration]] and other [[metabolism|metabolic]] and [[Enzyme|enzymatic]] processes that enable the use of energy.<ref>{{cite journal |pmc=348741 |year=1981 |last1=Green|first1=D. E. |title=Universal energy principle of biological systems and the unity of bioenergetics |journal=[[PNAS]] |volume=78 |issue=9 |pages=5344–5347 |last2=Zande |first2=H. D. |pmid=6946475 |doi=10.1073/pnas.78.9.5344 |bibcode=1981PNAS...78.5344G |doi-access=free }}</ref>

===Genetics===

{{main|Genetics}}

[[File:Punnett square mendel flowers.svg|thumb|upright=0.6|[[Punnett square]] depicting a cross between two pea plants heterozygous for purple (B) and white (b) blossoms]]

[[Genetics]] is the scientific study of inheritance.<ref name="griffithsetal2014l">{{cite book |last1=Griffiths |first1=Anthony J. |last2=Wessler |first2=Susan R. |last3=Carroll |first3=Sean B. |last4=Doebley |first4=John |chapter=The genetics revolution |title=An Introduction to Genetic Analysis |publisher=W.H. Freeman & Company |edition=11th |date=2015 |location=Sunderland, Massachusetts |pages=1–30 |isbn=978-1-4641-0948-5}}</ref><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=978-0-7167-3520-5 |edition=7th |publisher=W. H. Freeman |location=New York |chapter-url=https://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=iga.section.60 |chapter=Genetics and the Organism: Introduction }}</ref><ref name=Hartl_and_Jones>{{Cite book |author1=Hartl, D. |author2=Jones, E |title=Genetics: Analysis of Genes and Genomes |edition=6th |publisher=Jones & Bartlett |year=2005 |isbn=978-0-7637-1511-3 |url=https://archive.org/details/genetics00dani }}</ref> [[Classical genetics]], specifically, is the study of how genes and traits are passed on from parents to offspring; its principles are called [[Mendelian inheritance]].<ref name="miko2008a"/> A [[Punnett square]] can be used to predict the results of a test cross. The [[Boveri–Sutton chromosome theory|chromosome theory of inheritance]], which states that genes are found on chromosomes, was supported by [[Thomas Hunt Morgan|Thomas Morgans]]'s experiments with [[Drosophila melanogaster|fruit flies]], which established the [[sex linkage]] between eye color and sex in these insects.<ref name="miko2008c">{{cite journal |last=Miko |first=Ilona |title=Thomas Hunt Morgan and sex linkage |journal=Nature Education |volume=1 |issue=1 |page=143 |date=2008 |url=https://www.nature.com/scitable/topicpage/thomas-hunt-morgan-and-sex-linkage-452/ |access-date=2021-05-28 |archive-date=2021-05-20 |archive-url=https://web.archive.org/web/20210520234008/https://www.nature.com/scitable/topicpage/thomas-hunt-morgan-and-sex-linkage-452/ |url-status=live }}</ref>

===Evolutionary developmental biology===

{{Main|Evolutionary developmental biology}}

Evolutionary developmental biology compares the [[developmental biology|developmental processes]] of different [[organism]]s to infer how developmental processes evolved. The field grew from 19th-century beginnings, where [[embryology]] faced a mystery: [[zoology|zoologists]] did not know how [[embryogenesis|embryonic development]] was controlled at the molecular level. [[Charles Darwin]] noted that having similar embryos implied common ancestry, but little progress was made until the 1970s. Then, [[recombinant DNA]] technology at last brought embryology together with [[molecular genetics]].<ref>{{cite journal |last1=Gilbert |first1=S.F. |last2=Opitz |first2=J.M. |last3=Raff |first3=R.A. |date=1996 |title=Resynthesizing Evolutionary and Developmental Biology |journal=Developmental Biology |volume=173 |issue=2 |pages=357–372 |doi=10.1006/dbio.1996.0032 |pmid=8605997 |doi-access=free}}</ref><ref>{{cite journal |last=Müller |first=G. B. |author-link=Gerd B. Müller |date=2007 |title=Evo–devo: extending the evolutionary synthesis |journal=Nature Reviews Genetics |volume=8 |issue=12 |pages=943–949 |doi=10.1038/nrg2219 |pmid=17984972 |s2cid=19264907}}</ref> A key early discovery was that of [[homeotic gene]]s that regulate development in a wide range of [[eukaryote]]s.<ref>{{Cite web |last=Bürglin |first=Thomas R. |title=The Homeobox Page |url=http://homeobox.biosci.ki.se/ |access-date=13 October 2016 |publisher=[[Karolinska Institutet]]}}</ref> The field explores [[deep homology]], the finding that dissimilar organs such as the eyes of [[insect]]s, [[vertebrate]]s and [[cephalopod]] molluscs, long thought to have evolved separately, are controlled by similar genes from the [[evo-devo gene toolkit]].<ref name="CarrollNatHist">{{Cite web |last=Carroll |first=Sean B. |author-link=Sean B. Carroll |title=The Origins of Form |url=http://www.naturalhistorymag.com/features/061488/the-origins-of-form |access-date=9 October 2016 |website=Natural History |quote=Biologists could say, with confidence, that forms change, and that natural selection is an important force for change. Yet they could say nothing about how that change is accomplished. How bodies or body parts change, or how new structures arise, remained complete mysteries.}}</ref>

===Evolutionary biology===

{{Main|Evolutionary biology}}

[[Evolutionary biology]] is a subfield of biology that analyzes the mechanisms of [[evolution]]. Evolution accounts for the unity and [[diversity of life]] on Earth; [[Theodosius Dobzhansky]] famously said "nothing in biology makes sense except in the light of evolution".<ref>{{cite journal |last=Dobzhansky |first=Theodosius |author-link=Theodosius Dobzhansky |title=Nothing in Biology Makes Sense Except in the Light of Evolution |date=March 1973 |journal=[[American Biology Teacher]] |volume=35 |issue=3 |pages=125–129 |doi=10.2307/4444260 |jstor=4444260 |s2cid=207358177}}</ref> [[Population genetics]] for example studies how genetic variation develops, how it is inherited, and how the evolutionary mechanisms shape a population's genetic composition.<ref>{{Cite journal |last=Olson |first=Mark E. |date=2024-06-01 |title=Is Population Genetics Really Relevant to Evolutionary Biology? |journal=Evolutionary Biology |language=en |volume=51 |issue=2 |pages=235–243 |doi=10.1007/s11692-024-09630-x |bibcode=2024EvBio..51..235O |issn=1934-2845|doi-access=free }}</ref> Research in evolutionary biology covers many topics and incorporates ideas from diverse areas, such as [[molecular genetics]] and [[mathematical and theoretical biology]]. Some fields of evolutionary research try to explain phenomena that were poorly accounted for in the modern evolutionary synthesis. These include [[speciation]],<ref>{{cite journal |date=2004 |title=What is speciation and how should we study it? |journal=American Naturalist |volume=163 |issue=6 |pages=914–923 |doi=10.1086/386552 |jstor=10.1086/386552 |author=Wiens, J.J. |pmid=15266388 |bibcode=2004ANat..163..914W |s2cid=15042207 }}</ref><ref>{{cite journal |last1=Bernstein |first1=Harris |last2=Byerly |first2=Henry C. |last3=Hopf |first3=Frederic A. |last4=Michod |first4=Richard E. |title=Sex and the emergence of species |journal=Journal of Theoretical Biology |date=1985 |volume=117 |issue=4 |pages=665–690 |doi=10.1016/s0022-5193(85)80246-0 |pmid=4094459 |bibcode=1985JThBi.117..665B }}</ref> the [[evolution of sexual reproduction]],<ref>{{cite journal |date=2009 |title=The evolutionary enigma of sex |journal=American Naturalist |volume=174 |issue=s1 |pages=S1–S14 |doi=10.1086/599084 |author=Otto SP |pmid=19441962 |bibcode=2009ANat..174S...1O |s2cid=9250680 }}</ref><ref>{{cite journal |last1=Bernstein |first1=Harris |last2=Byerly |first2=Henry C. |last3=Hopf |first3=Frederic A. |last4=Michod |first4=Richard E. |title=Genetic Damage, Mutation, and the Evolution of Sex |journal=Science |date=1985 |volume=229 |issue=4719 |pages=1277–1281 |doi=10.1126/science.3898363 |pmid=3898363 |bibcode=1985Sci...229.1277B }}</ref> the evolution of [[Co-operation (evolution) |cooperation]], the [[evolution of ageing]],<ref>{{cite journal |last1=Avise |first1=John C. |title=Perspective: The Evolutionary Biology of Aging, Sexual Reproduction, and DNA Repair |journal=Evolution |date=1993 |volume=47 |issue=5 |pages=1293–1301 |doi=10.1111/j.1558-5646.1993.tb02155.x |pmid=28564887 |bibcode=1993Evolu..47.1293A }}</ref> and [[evolvability]].<ref>{{cite journal |date=2007 |title=Evolvability as the proper focus of evolutionary developmental biology |journal=Evolution & Development |volume=9 |issue=4 |pages=393–401 |doi=10.1111/j.1525-142X.2007.00176.x |pmid=17651363 |author=Hendrikse, Jesse Love |author2=Parsons, Trish Elizabeth |author3=Hallgrímsson, Benedikt |s2cid=31540737 }}</ref>

===Ecology===

{{Main|Ecology}}

Ecology is the study of the distribution and abundance of life, the interaction between organisms and their [[natural environment|environment]].<ref>{{cite book |author1=Begon, M |title=Ecology: From individuals to ecosystems |author2=Townsend, CR |author3=Harper, JL |publisher=Blackwell |year=2006 |isbn=978-1-4051-1117-1 |edition=4th}}</ref>

===Systematics, phylogenetics, and taxonomy===

{{further|Systematics|Phylogenetics|Taxonomy}}

[[Systematics]] is the study of the diversification of living forms, both past and present, and the relationships among living things through time. Relationships are visualized as [[phylogenetic tree|evolutionary trees]], studied using [[phylogenetics]], and creating a unified [[Taxonomy (biology)|taxonomy]] of life.<ref>Michener, Charles D., John O. Corliss, Richard S. Cowan, Peter H. Raven, Curtis W. Sabrosky, Donald S. Squires, and G. W. Wharton (1970). ''Systematics In Support of Biological Research''. Division of Biology and Agriculture, National Research Council. Washington, D.C. 25 pp.</ref><ref>{{cite journal |last1=Zhang |first1=G. |last2=Feng |first2=Q. |year=2025 |title=Why we should not describe new taxa without using phylogenetics. Comment on Chen et al. (2025) |journal=Journal of Natural History |volume=59 |issue=37–40 |pages=2355–2359 |doi=10.1080/00222933.2025.2564347}}</ref>

===Conservation biology===

{{Main|Conservation biology}}

Conservation biology is the study of the conservation of Earth's [[biodiversity]] with the aim of protecting [[species]], their [[habitats]], and [[ecosystems]] from excessive rates of [[extinction]] and the erosion of biotic interactions.<ref name="SahneyBenton2008RecoveryFromProfoundExtinction">{{cite journal |last1=Sahney |first1=S. |last2=Benton |first2=M. J |title=Recovery from the most profound mass extinction of all time |journal=Proceedings of the Royal Society B: Biological Sciences |volume=275 |issue=1636 |pages=759–65 |year=2008 |pmid=18198148 |pmc=2596898 |doi=10.1098/rspb.2007.1370 }}</ref><ref name="ConsBiol80">{{cite book |author1=Soulé, Michael E. |author2=Wilcox, Bruce A. |title=Conservation biology: an evolutionary-ecological perspective |publisher=Sinauer Associates |location=Sunderland, Mass. |year=1980 |isbn=978-0-87893-800-1 }}</ref><ref>{{cite journal |last1=Soulé |first1=Michael E. |title=What is Conservation Biology? |journal=BioScience |volume=35 |issue=11 |pages=727–34 |year=1986 |url=http://www.michaelsoule.com/resource_files/85/85_resource_file1.pdf |doi=10.2307/1310054 |jstor=1310054 |publisher=American Institute of Biological Sciences |access-date=2021-05-15 |archive-date=2019-04-12 |url-status=usurped |archive-url=https://web.archive.org/web/20190412085412/http://www.michaelsoule.com/resource_files/85/85_resource_file1.pdf }}</ref> It is concerned with factors that influence the maintenance, loss, and restoration of biodiversity and the science of sustaining evolutionary processes that engender [[genetics|genetic]], population, species, and ecosystem diversity.<ref name="Hunter96">{{cite book |author=Hunter, Malcolm L. |title=Fundamentals of conservation biology |publisher=Blackwell Science |location=Oxford |year=1996 |isbn=978-0-86542-371-8 |url=https://archive.org/details/fundamentalsofco00hunt }}</ref><ref name="Groom06">{{cite book |author1=Meffe, Gary K. |author2=Martha J. Groom |title=Principles of conservation biology |publisher=Sinauer Associates |location=Sunderland, Mass. |year=2006 |isbn=978-0-87893-518-5 |edition=3rd}}</ref><ref name="Dyke08">{{cite book |last=Van Dyke |first=Fred |date=2008 |title=Conservation biology: foundations, concepts, applications |location=New York |publisher=[[Springer-Verlag]] |edition=2nd |isbn=978-1-4020-6890-4 |oclc=232001738 |doi=10.1007/978-1-4020-6891-1 |hdl=11059/14777 |url=https://books.google.com/books?id=Evh1UD3ZYWcC |access-date=2021-05-15 |archive-date=2020-07-27 |archive-url=https://web.archive.org/web/20200727115147/https://books.google.com/books?id=Evh1UD3ZYWcC |url-status=live }}</ref><ref name="SahneyBentonFerry2010LinksDiversityVertebrates">{{cite journal |last1=Sahney |first1=S. |last2=Benton |first2=M. J. |last3=Ferry |first3=P. A. |title=Links between global taxonomic diversity, ecological diversity and the expansion of vertebrates on land |journal=Biology Letters |volume=6 |issue=4 |pages=544–7 |year=2010 |pmid=20106856 |pmc=2936204 |doi=10.1098/rsbl.2009.1024 }}</ref> The concern stems from estimates suggesting that up to 50% of all species on the planet will disappear within the next 50 years,<ref name="Koh">{{cite journal |last1=Koh |first1=Lian Pin |last2=Dunn |first2=Robert R. |last3=Sodhi |first3=Navjot S. |last4=Colwell |first4=Robert K. |last5=Proctor |first5=Heather C. |last6=Smith |first6=Vincent S. |title=Species coextinctions and the biodiversity crisis |journal=Science |volume=305 |issue=5690 |pages=1632–4 |year=2004 |pmid=15361627 |doi=10.1126/science.1101101 |bibcode=2004Sci...305.1632K |url=http://scholarbank.nus.edu.sg/handle/10635/101709 }}</ref> which has contributed to poverty, starvation, and will reset the course of evolution on this planet.<ref>Millennium Ecosystem Assessment (2005). ''Ecosystems and Human Well-being: Biodiversity Synthesis.'' World Resources Institute, Washington, D.C.[http://www.millenniumassessment.org/documents/document.354.aspx.pdf] {{Webarchive|url=https://web.archive.org/web/20191014033601/http://www.millenniumassessment.org/documents/document.354.aspx.pdf|date=2019-10-14}}</ref><ref name="Jackson">{{cite journal |last1=Jackson |first1=J. B. C. |title=Ecological extinction and evolution in the brave new ocean |journal=Proceedings of the National Academy of Sciences |volume=105 |issue=Suppl 1 |pages=11458–65 |year=2008 |pmid=18695220 |pmc=2556419 |doi=10.1073/pnas.0802812105 |bibcode=2008PNAS..10511458J |doi-access=free }}</ref> Conservation biologists research the trends of [[biodiversity loss]], species extinctions, and the negative effect these are having on our capabilities to [[Sustainability|sustain]] the well-being of human society.<ref name="Soule86">{{cite book|last=Soule|first=Michael E. |title=Conservation Biology: The Science of Scarcity and Diversity|year=1986 |publisher=Sinauer Associates|page=584 |isbn=978-0-87893-795-0}}</ref><ref name="Hunter96"/><ref name="Groom06"/><ref name="Dyke08"/>

==See also==
{{div col|colwidth=20em}}
* [[Biology in fiction]]
* [[Glossary of biology]]
* [[List of biological websites]]
* [[List of biologists]]
* [[List of biology journals]]
* [[List of biology topics]]
* [[List of life sciences]]
* [[Outline of biology]]
* Periodic table of life sciences in [[Tinbergen's four questions]]
* [[:Category:Biology terminology|Terminology of biology]]
{{div col end}}

==References==

{{reflist|30em}}

==Further reading==

{{further|Bibliography of biology}}

==External links==

{{Library resources box}}
{{Sister project links|auto=yes}}

* [http://phylonames.org/code/ OSU's Phylocode]
* [https://www.biologyonline.com/dictionary Biology Dictionary Online]

'''Journal links'''
* ''[[PLOS Biology]]'': A peer-reviewed, open-access journal published by the [[Public Library of Science]]
* ''[[Current Biology]]'': General journal publishing [[original research]] from all areas of biology
* ''[[Biology Letters]]'': A [[Impact factor|high-impact]] [[Royal Society]] journal publishing [[peer-review]]ed biology papers of general interest
* ''[[Science (journal)|Science]]'': Internationally renowned [[American Association for the Advancement of Science|AAAS]] science journal – see sections of the life sciences
* ''[[International Journal of Biological Sciences]]'': A biological journal publishing significant peer-reviewed scientific papers
* ''[[Perspectives in Biology and Medicine]]'': An [[interdisciplinary]] [[scholarly method|scholarly]] journal publishing essays of broad relevance

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