Yanayin sanyi da zafi a cikin mutane

Sauye-sauyen sanyi da zafi a cikin mutane wani bangare ne na sauƙin daidaitawa na Homo sapiens. Daidaitawa a cikin mutane na iya zama na jiki, kwayar halitta, ko al'adu, wanda ke ba mutane damar rayuwa a cikin yanayi daban-daban. An yi bincike mai yawa game da daidaitawar ci gaba, daidaitawa, da ayyukan al'adu, amma ƙananan bincike game da daidaitawa na kwayoyin halitta zuwa yanayin yanayi da zafi.

 Asalin sanyi da daidaitawar zafi 
Mutanen zamani sun fito ne daga Afirka kimanin shekaru 70,000 da suka gabata a lokacin yanayi mara daidaituwa, wanda ya haifar da sababbin halaye daban-daban tsakanin jama'a. Lokacin da mutane na zamani suka bazu zuwa Turai, sun fi Neanderthals. Masu bincike sun yi la'akari da cewa wannan yana nuna cewa mutane na zamani na farko sun fi dacewa da juyin halitta don rayuwa a yanayi daban-daban. Wannan yana goyan bayan ra'ayi na zaɓin bambancin da Richard Potts ya gabatar, wanda ya ce sauƙin ɗan adam ya fito ne daga canjin muhalli na dogon lokaci.

 Dokokin yanayin muhalli 
Dokar Bergmann ta bayyana cewa nau'ikan dabbobi masu zafi da ke zaune a yanayin sanyi suna da jiki mafi girma fiye da na nau'ikan da ke zaune cikin yanayin zafi. Mutanen da ke da manyan jikuna sun fi dacewa da yanayin sanyi saboda manyan jikuna suna samar da karin zafi saboda samun ƙarin sel, kuma suna da karamin yanki zuwa girman rabo idan aka kwatanta da ƙananan mutane, wanda ke rage asarar zafi. Binciken da Frederick Foster da Mark Collard suka yi ya gano cewa ana iya amfani da mulkin Bergmann ga mutane lokacin da latitude da zafin jiki tsakanin kungiyoyi suka bambanta sosai.

 Rashin sanyi 
Jikin mutum yana da hanyoyi biyu na thermogenesis, wanda ke samar da zafi don kula da yanayin zafi na jiki. Na farko yana girgiza, wanda ke faruwa a cikin mutumin da ba shi da tufafi lokacin da yanayin iska ke ƙasa da  ° C (77 ° F) [dubious - tattauna] . Yana iya iyakance ta yawan glycogen da ke cikin jiki. Na biyu ba shi da girgizar ƙasa, wanda ke faruwa a cikin ƙwayoyin ƙwayoyin launin ruwan kasa  da tsokoki na kwarangwal.

 Manazarta