„Maður“: Munur á milli breytinga

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9.019 bætum bætt við ,  fyrir 7 mánuðum
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Þróun mannsins fólst í mörgum [[formfræði]]legum, [[atferli]]slegum, [[þróunarfræði]]legum og [[lífeðlisfræði]]legum breytingum sem hafa átt sér stað frá því þróunarlínan greindist frá þróunarlínu simpansa. Einna stærstu breytingarnar fólust í þróun tvífætlingsstöðu, stærri heila og minni [[tvíbreytni]] ([[síbernska|síbernsku]]). Innbyrðis tengsl þessara breytinga eru umdeild.<ref name="Boyd2003">{{cite book| vauthors = Boyd R, Silk JB |author1-link=Robert Boyd (anthropologist)|author2-link=Joan Silk|url=https://archive.org/details/howhumansevolved03edboyd|title=How Humans Evolved|publisher=Norton|year=2003|isbn=978-0-393-97854-4|location=New York City|url-access=registration}}</ref>
 
==Líffræði==
===Líkamsbygging og líffærafræði===
{{aðalgrein|Mannslíkaminn}}
Í meginatriðum [[samsvörun|samsvarar]] líkamsbygging manna líkamsbyggingu annarra dýra. Mannslíkaminn er samsettur úr [[fótur|fótum]], [[búkur|búk]], [[hendi|höndum]], [[háls]]i og [[höfuð|höfði]]. Í líkama fullorðins meðalkarlmanns eru um 30 billjón (30×10<sup>12</sup>) mennskar [[fruma|frumur]], meðan [[örverumengi mannsins]] er talið innihalda að minnsta kosti jafnmargar frumur.<ref>{{cite journal|author1=Sender R|author2=Fuchs S|author3=Milo R|title=Revised Estimates for the Number of Human and Bacteria Cells in the Body|publisher=PLoS Biology|year=2016|volume=14|issue=8|date=2016|doi=10.1371/journal.pbio.1002533|url=https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4991899/}}</ref> Helstu [[líffærakerfi]]n í mannslíkamanum eru [[taugakerfi]]ð, [[blóðrásarkerfi]]ð, [[meltingarkerfi]]ð, [[innkirtlakerfi]]ð, [[ónæmiskerfi]]ð, [[hörundskerfi]]ð, [[sogæðakerfi]]ð, [[vöðva- og beinakerfi]]ð, [[æxlunarkerfi]]ð, [[öndunarkerfi]]ð og [[þvagkerfi]]ð.<ref>{{cite book | vauthors = Roza G |title=Inside the human body : using scientific and exponential notation |date=2007 |publisher=Rosen Pub. Group's PowerKids Press |location=New York |isbn=978-1-4042-3362-1 | url = https://books.google.com/books?id=vhO8Ia2ik7oC | page = 21 }}</ref><ref>{{cite web |title=Human Anatomy |url=http://www.innerbody.com/htm/body.html |publisher=Inner Body |access-date=6 January 2013 |url-status=live |archive-url=https://web.archive.org/web/20130105065620/http://www.innerbody.com/htm/body.html |archive-date=5 January 2013 }}</ref> Menn hafa hlutfallslega minni [[gómur|góm]] og miklu minni [[tönn|tennur]] en önnur fremdardýr. Menn eru einu fremdardýrin sem hafa stuttar og tiltölulega flatar [[vígtönn|vígtennur]]. Tennur í mönnum sitja þétt og hjá ungum einstaklingum lokast bil vegna tannmissis fljótt. Menn eru smám saman að missa innstu [[endajaxl]]ana og sumir einstaklingar fá þá aldrei.<ref name="Revolution">{{cite book| vauthors = Collins D |url=https://archive.org/details/humanrevolutionf0000coll|title=The Human Revolution: From Ape to Artist|year=1976|isbn=978-0714816760|page=[https://archive.org/details/humanrevolutionf0000coll/page/208 208]|url-access=registration}}</ref>
 
Menn eiga það sameiginlegt með simpönsum að vera með [[líffærisleif|leifar]] af hala, [[botnlangi|botnlanga]], sveigjanlega axlarliði, fingur sem grípa og [[andstæður þumall|andstæða þumla]].<ref>{{cite book|first1 = Marks|last1=J.M. |title=Human Biodiversity: Genes, Race, and History|date=2001|publisher=Transaction Publishers|isbn=978-0-202-36656-2|page=16|language=en}}</ref> Ef undan eru skilin tvífætlingsstaðan og heilastærðin felst aðalmunurinn á mönnum og simpönsum í [[lyktarskyn]]i, [[heyrn]] og [[melting]]u [[prótín]]a.<ref name="O'Neil" /> Þéttleiki [[hársekkur|hársekkja]] er svipaður hjá mönnum og öðrum öpum, en það eru mest [[líkhár]] sem eru svo þunn að þau eru næstum ósýnileg.<ref>{{cite news|date=2017|title=How to be Human: The reason we are so scarily hairy|work=New Scientist|url=https://www.newscientist.com/article/mg23631460-700-why-are-humans-so-hairy/|access-date=29 April 2020}}</ref><ref>{{cite journal | vauthors = Sandel AA | title = Brief communication: Hair density and body mass in mammals and the evolution of human hairlessness | journal = American Journal of Physical Anthropology | volume = 152 | issue = 1 | pages = 145–50 | date = September 2013 | pmid = 23900811 | doi = 10.1002/ajpa.22333 | hdl-access = free | hdl = 2027.42/99654 }}</ref> Menn eru með um það bil 2 milljón [[svitakirtill|svitakirtla]] á öllum líkamanum, miklu fleiri en simpansar sem eru aðallega með svitakirtla í lófum og á iljum.<ref>{{cite web| vauthors = Kirchweger G |title=The Biology of Skin Color: Black and White|url=https://www.pbs.org/wgbh/evolution/library/07/3/text_pop/l_073_04.html|url-status=live|archive-url=https://web.archive.org/web/20130216070146/http://www.pbs.org/wgbh/evolution/library/07/3/text_pop/l_073_04.html|archive-date=16 February 2013|access-date=6 January 2013|date=February 2, 2001|work=Evolution: Library|publisher=PBS}}</ref>
 
Meðalhæð kvenna á heimsvísu er talin vera um 159 cm, en meðalhæð karla um 171 cm.<ref>{{cite journal| vauthors = Roser M, Appel C, Ritchie H |date=8 October 2013|title=Human Height|url=https://ourworldindata.org/human-height|journal=Our World in Data}}</ref> Eftir miðjan aldur dregst hæð sumra einstaklinga örlítið saman, en hæðin helst nokkuð stöðug fram á [[öldrun|gamals aldur]].<ref>{{cite web|title=Senior Citizens Do Shrink – Just One of the Body Changes of Aging|url=http://seniorjournal.com/NEWS/Aging/5-11-28-SeniorsDoShrink.htm|url-status=dead|archive-url=https://web.archive.org/web/20130219004303/http://seniorjournal.com/NEWS/Aging/5-11-28-SeniorsDoShrink.htm|archive-date=19 February 2013|access-date=6 January 2013|work=News|publisher=Senior Journal}}</ref> Í gegnum söguna hafa hópar fólks orðið hærri, líklega vegna betri næringar, heilsugæslu og lífsskilyrða.<ref>{{cite journal | vauthors = Bogin B, Rios L | title = Rapid morphological change in living humans: implications for modern human origins | journal = Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology | volume = 136 | issue = 1 | pages = 71–84 | date = September 2003 | pmid = 14527631 | doi = 10.1016/S1095-6433(02)00294-5 }}</ref> Meðal[[líkamsþyngd]] fullorðinna kvenna er 59 kg, en 77 kg hjá körlum.<ref>{{cite web|title=Human weight|url=http://www.articleworld.org/index.php/Human_weight|url-status=live|archive-url=https://web.archive.org/web/20111208053451/http://articleworld.org/index.php/Human_weight|archive-date=8 December 2011|access-date=10 December 2011|publisher=Articleworld.org}}</ref><ref>{{cite web | vauthors = Schlessingerman A | date = 2003 |title=Mass Of An Adult|url=https://hypertextbook.com/facts/2003/AlexSchlessingerman.shtml|url-status=live|archive-url=https://web.archive.org/web/20180101030223/https://hypertextbook.com/facts/2003/AlexSchlessingerman.shtml|archive-date=1 January 2018|access-date=31 December 2017|publisher=The Physics Factbook: An Encyclopedia of Scientific Essays}}</ref> Líkt og margt annað í líkamsbyggingu manna eru bæði hæð og þyngd mjög breytileg milli einstaklinga og ráðast af bæði erfðum og umhverfisaðstæðum.<ref>{{cite book| vauthors = Kushner R |url=https://books.google.com/books?id=vWjK5etS7PMC&pg=PA121|title=Treatment of the Obese Patient (Contemporary Endocrinology)|publisher=Humana Press|year=2007|isbn=978-1-59745-400-1|location=Totowa, NJ|page=158|access-date=5 April 2009}}</ref><ref name="Anes2000">{{cite journal | vauthors = Adams JP, Murphy PG | title = Obesity in anaesthesia and intensive care | journal = British Journal of Anaesthesia | volume = 85 | issue = 1 | pages = 91–108 | date = July 2000 | pmid = 10927998 | doi = 10.1093/bja/85.1.91 | doi-access = free }}</ref>
 
Menn eru færir um að [[kast]]a hlutum miklu hraðar og nákvæmar en önnur dýr.<ref>{{cite journal| vauthors = Lombardo MP, Deaner RO |date=March 2018|title=Born to Throw: The Ecological Causes that Shaped the Evolution of Throwing In Humans |journal=The Quarterly Review of Biology|language=en|volume=93|issue=1|pages=1–16|doi=10.1086/696721|s2cid=90757192|issn=0033-5770}}</ref> Menn eru líka með hraðskreiðustu langhlaupurum dýraríkisins þótt mörg dýr slái þeim við á styttri vegalengdum.<ref>{{cite news |url=https://www.nytimes.com/2009/10/27/health/27well.html |work=The New York Times |title=The Human Body Is Built for Distance |last1 = Parker-Pope|first1=Tara|author-link1=Tara Parker-Pope |date=27 October 2009 |url-status=live |archive-url=https://web.archive.org/web/20151105211812/http://www.nytimes.com/2009/10/27/health/27well.html |archive-date=5 November 2015 }}</ref><ref name="O'Neil">{{cite web | vauthors = O'Neil D |title=Humans |url=http://anthro.palomar.edu/primate/prim_8.htm |work=Primates |publisher=Palomar College |access-date=6 January 2013 |url-status=live |archive-url=https://web.archive.org/web/20130111004211/http://anthro.palomar.edu/primate/prim_8.htm |archive-date=11 January 2013 }}</ref> Þynnri hár og virkari svitakirtlar draga úr hættu á [[hitaörmögnun]] í langhlaupum.<ref>{{cite web | vauthors = John B |title=What is the role of sweating glands in balancing body temperature when running a marathon? |url=http://www.livestrong.com/article/514545-what-is-the-role-of-sweat-glands-in-balancing-body-temperature-when-running-a-marathon/ |publisher=Livestrong.com |access-date=6 January 2013 |url-status=live |archive-url=https://web.archive.org/web/20130131184339/http://www.livestrong.com/article/514545-what-is-the-role-of-sweat-glands-in-balancing-body-temperature-when-running-a-marathon/ |archive-date=31 January 2013 }}</ref>
 
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