{"id":37096,"date":"2019-09-30T03:38:23","date_gmt":"2019-09-30T00:38:23","guid":{"rendered":"https:\/\/bilimvegelecek.com.tr\/?p=37096"},"modified":"2019-09-27T13:41:26","modified_gmt":"2019-09-27T10:41:26","slug":"beyin-insandaki-tipik-yapisini-ne-zaman-kazandi","status":"publish","type":"post","link":"https:\/\/bilimvegelecek.com.tr\/index.php\/2019\/09\/30\/beyin-insandaki-tipik-yapisini-ne-zaman-kazandi","title":{"rendered":"Beyin insandaki tipik yap\u0131s\u0131n\u0131 ne zaman kazand\u0131?"},"content":{"rendered":"

\u0130nsanla\u015fma s\u00fcrecinde ikinci \u00f6nemli a\u015fama beyin kabu\u011fundaki \u00f6zg\u00fcn geli\u015fmedir. \u00a0Ailemizin ilk temsilcilerinde, bu de\u011ferli organ\u0131n iri primatlar\u0131nkinden pek farkl\u0131 oldu\u011fu s\u00f6ylenemez. Ancak k\u00fc\u00e7\u00fcc\u00fck bedenleriyle orant\u0131land\u0131\u011f\u0131nda yine de b\u00fcy\u00fck say\u0131l\u0131r. Eri\u015fkin insans\u0131larda (Australopitekus<\/em>) tespit edilen en k\u00fc\u00e7\u00fck beyin hacmi 400 cm3\u2019t\u00fcr. Dik duru\u015fla beraber, ba\u015f\u0131n g\u00f6vdeyle olan ili\u015fkisi yeni bir konuma ge\u00e7mi\u015f olmaktad\u0131r. Dolay\u0131s\u0131yla, kan dola\u015f\u0131m\u0131 sistemi de, iskeletin di\u011fer b\u00f6lgelerinde oldu\u011fu gibi, ortaya \u00e7\u0131kan yeni d\u00fczene uyum sa\u011flam\u0131\u015ft\u0131r. Baz\u0131 insans\u0131lar yeni davran\u0131\u015f \u00f6r\u00fcnt\u00fcleri geli\u015ftirdik\u00e7e, g\u00fcnl\u00fck ya\u015famlar\u0131nda do\u011fal organlar\u0131n yerini giderek aletler ald\u0131 ve v\u00fccudun y\u00fck\u00fcn\u00fc hafifleten bu aletler daha iri ve karma\u015f\u0131k bir beynin, do\u011fal ay\u0131klanma s\u00fcrecinde ister istemez avantajl\u0131 konuma ge\u00e7mesinin yolunu a\u00e7t\u0131. Geli\u015fen beyin de, s\u0131ras\u0131 geldi\u011finde, yeni ya\u015fam bi\u00e7imlerine kap\u0131 a\u00e7\u0131yordu. B\u00f6ylece bir t\u00fcr etki-tepki ili\u015fkisi ortaya \u00e7\u0131km\u0131\u015ft\u0131. Beyin kabu\u011funun farkl\u0131 i\u015flevlerine y\u00f6nelik loblar\u0131 hakk\u0131nda yeterince bilgiye sahibiz. \u00d6rne\u011fin Holloway\u2019e g\u00f6re, narin yap\u0131l\u0131lar\u0131n beyni temelde organizasyon a\u00e7\u0131s\u0131ndan insan\u0131nkine benzer. \u0130nsans\u0131lar\u0131n zihinsel kapasiteleri ku\u015fkusuz goril, \u015fempanze ve orangutan gibi iri primatlar\u0131nkinden fazlayd\u0131. Beyin, insans\u0131larda ba\u015flang\u0131\u00e7ta daha k\u00fc\u00e7\u00fck, sonralar\u0131 ise daha irile\u015fmi\u015f olarak kar\u015f\u0131m\u0131za \u00e7\u0131kar. Ancak yine de insana \u00f6zg\u00fc tipik geli\u015fmeyi bu insans\u0131larda de\u011fil de insan cinsi i\u00e7inde g\u00f6rmekteyiz. \u0130nsans\u0131larda beyin kabu\u011fu her ne kadar iri primatlar\u0131nkinden daha karma\u015f\u0131k ve geli\u015fmi\u015f bir yap\u0131da olsa da, \u00f6zellikle al\u0131n ve \u015fakak b\u00f6lgesinde insana g\u00f6re son derece yetersiz bir geli\u015fme s\u00f6z konusuydu.<\/p>\n

B\u00fcy\u00fcme ve geli\u015fme<\/strong>: \u0130nsans\u0131lar bizler gibi ayn\u0131 h\u0131zda ya\u015flanm\u0131yor muydu? Modern insan \u00e7ocuklar\u0131 ve eri\u015fkinle ri i\u00e7in \u00f6ng\u00f6r\u00fclen ya\u015f belirleme \u00f6l\u00e7\u00fctlerini bu uzak atalar\u0131m\u0131za aynen uygulamak ne \u00f6l\u00e7\u00fcde ge\u00e7erli olabilir? Bogin\u2019e g\u00f6re, insans\u0131lar bizler gibi b\u00fcy\u00fcme ve geli\u015fme temposuna sahip de\u011fildi; b\u00fcy\u00fck bir olas\u0131l\u0131kla \u00e7ocukluk evresini ya\u015famadan bebeklikten hemen gen\u00e7lik evresine ge\u00e7iyordu. Bu y\u00f6nleriyle de \u015fempanze ve gorile benzemekteydi.<\/p>\n

\u0130nsans\u0131lar\u0131n fiziksel b\u00fcy\u00fcme ve geli\u015fme ritimleri \u00fczerinde son y\u0131llarda ilgin\u00e7 bulgular elde edildi. \u0130ri primat, insans\u0131 ve insan di\u015f sistemlerinin bilgisayarl\u0131 tomografik analizleri yap\u0131ld\u0131. \u0130lk insans\u0131 t\u00fcrlerinde genelde modern insandan daha h\u0131zl\u0131 bir b\u00fcy\u00fcme ve geli\u015fmenin s\u00f6z konusu oldu\u011fu, dolay\u0131s\u0131yla \u00e7ocukluk evrelerinin daha k\u0131sa oldu\u011fu anla\u015f\u0131ld\u0131. H\u0131zl\u0131 b\u00fcy\u00fcme ayn\u0131 zamanda erken cinsel olgunlu\u011fa erme demektir. Bireyin \u00e7ocukluk a\u015famas\u0131nda sergiledi\u011fi fiziksel b\u00fcy\u00fcme ve geli\u015fme ritmi, bir bak\u0131ma beynin geli\u015fmesiyle de do\u011fru orant\u0131l\u0131d\u0131r.<\/p>\n

Di\u015f minesinde ger\u00e7ekle\u015ftirilen bilgisayarl\u0131 tomografik analizlerin \u0131\u015f\u0131\u011f\u0131nda son y\u0131llarda insans\u0131lara ait \u00e7ocuk iskeletlerinde \u00f6l\u00fcm ya\u015flar\u0131 yeniden g\u00f6zden ge\u00e7irildi. \u00d6rne\u011fin 1924 y\u0131l\u0131nda G\u00fcney Afrika\u2019da Taung b\u00f6lgesinde bulunan \u00e7ocu\u011fun, eskiden san\u0131ld\u0131\u011f\u0131 gibi 6 de\u011fil de, 3-4 ya\u015flar\u0131nda \u00f6ld\u00fc\u011f\u00fc saptand\u0131. Son yap\u0131lan ara\u015ft\u0131rmalar \u00e7ocukluk evresindeki tipik uzunlu\u011fun, insan ailesinin biyok\u00fclt\u00fcrel evrim s\u00fcrecinde nispeten ge\u00e7 (Homo erektus<\/em>) ortaya \u00e7\u0131kan bir biyolojik de\u011fi\u015fme oldu\u011funu kan\u0131tlad\u0131.<\/p>\n

\u0130nsans\u0131lar\u0131n fizyolojik \u00f6zellikleri iskelet sisteminden anla\u015f\u0131lamad\u0131\u011f\u0131 i\u00e7in bu y\u00f6nleriyle onlar\u0131 pek tan\u0131yam\u0131yoruz. Ailemizin bu ilk temsilcilerinde \u00f6rne\u011fin ilk adet g\u00f6rme ya\u015f\u0131 ka\u00e7t\u0131? Kad\u0131nlar\u0131n hamilelik s\u00fcreleri ne kadard\u0131? Ka\u00e7 ya\u015f\u0131nda menopoza giriyorlard\u0131? Menopoza girme ya\u015f\u0131 e\u011fer g\u00fcn\u00fcm\u00fczdeki gibiyse, ortalama 18-20 ya\u015flar\u0131nda \u00f6len insans\u0131lar belki de menopoz olay\u0131n\u0131 ya\u015fama f\u0131rsat\u0131 bulam\u0131yordu. T\u00fcm insans\u0131 t\u00fcrlerinde g\u00f6r\u00fclen ortak bir \u00f6zellik de, di\u015fi ve erkek aras\u0131ndaki belirgin c\u00fcsse fark\u0131d\u0131r. Bu biyolojik \u00f6zelli\u011fe genelde -primat tak\u0131m\u0131n\u0131n baz\u0131 t\u00fcrlerinde g\u00f6zlendi\u011fi \u00fczerebir erke\u011fin birden fazla di\u015fiyle bir arada ya\u015fad\u0131\u011f\u0131 gruplarda rastlan\u0131r. Bu durumda, insans\u0131larda monogami (teke\u015flilik) b\u00fcy\u00fck bir olas\u0131l\u0131kla yoktu. Teke\u015fli evlili\u011fin insan evriminde daha ge\u00e7 d\u00f6nemlerde ortaya \u00e7\u0131kt\u0131\u011f\u0131n\u0131 d\u00fc\u015f\u00fcn\u00fcyoruz. Genelde a\u00e7\u0131k savanl\u0131k b\u00f6lgelerde kurduklar\u0131 ge\u00e7ici kamplarda ya\u015fayan insans\u0131larda, kalabal\u0131k aileler halinde ya\u015famak g\u00fcvenlikleri ve besinlerini sa\u011flamalar\u0131 a\u00e7\u0131s\u0131ndan ka\u00e7\u0131n\u0131lmazd\u0131.<\/p>\n

Kaynak: <\/strong>Metin \u00d6zbek, 50 Soruda \u0130nsan\u0131n Tarih \u00d6ncesi Evrimi, Bilim ve Gelecek Kitapl\u0131\u011f\u0131, Ocak 2010, s.70-72<\/p>\n","protected":false},"excerpt":{"rendered":"

\u0130nsanla\u015fma s\u00fcrecinde ikinci \u00f6nemli a\u015fama beyin kabu\u011fundaki \u00f6zg\u00fcn geli\u015fmedir. \u00a0Ailemizin ilk temsilcilerinde, bu de\u011ferli organ\u0131n iri primatlar\u0131nkinden pek farkl\u0131 oldu\u011fu s\u00f6ylenemez. Ancak k\u00fc\u00e7\u00fcc\u00fck bedenleriyle orant\u0131land\u0131\u011f\u0131nda yine de b\u00fcy\u00fck say\u0131l\u0131r. Eri\u015fkin insans\u0131larda (Australopitekus) tespit edilen en k\u00fc\u00e7\u00fck beyin hacmi 400 cm3\u2019t\u00fcr. Dik duru\u015fla beraber, ba\u015f\u0131n g\u00f6vdeyle olan ili\u015fkisi yeni bir konuma ge\u00e7mi\u015f olmaktad\u0131r. Dolay\u0131s\u0131yla, kan dola\u015f\u0131m\u0131 […]<\/p>\n","protected":false},"author":429,"featured_media":37097,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[19],"tags":[254,5347,3179,200,5348,5346,555],"class_list":["post-37096","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-bilim-gundemi","tag-beyin","tag-biyokulturel-evrim","tag-buyume","tag-evrim","tag-gelisme","tag-homoerectus","tag-insan"],"acf":[],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t