{"id":12865,"date":"2017-09-01T15:20:46","date_gmt":"2017-09-01T12:20:46","guid":{"rendered":"http:\/\/109.232.216.219\/~bilimvegelecek\/?p=12865"},"modified":"2018-02-07T19:12:45","modified_gmt":"2018-02-07T16:12:45","slug":"ilk-hayvanlarin-nasil-ortaya-ciktigiyla-ilgili-kadim-problem-cozuldu","status":"publish","type":"post","link":"https:\/\/bilimvegelecek.com.tr\/index.php\/2017\/09\/01\/ilk-hayvanlarin-nasil-ortaya-ciktigiyla-ilgili-kadim-problem-cozuldu","title":{"rendered":"\u0130lk hayvanlar\u0131n nas\u0131l ortaya \u00e7\u0131kt\u0131\u011f\u0131yla ilgili kadim problem \u00e7\u00f6z\u00fcld\u00fc"},"content":{"rendered":"

Kompleks ya\u015fam\u0131n ortaya \u00e7\u0131k\u0131\u015f hik\u00e2yesi, D\u00fcnya\u2019n\u0131n buzullarla kapl\u0131 oldu\u011fu d\u00f6nemden k\u00fcresel iklim de\u011fi\u015fikli\u011fiyle birlikte yeni bir biyolojik \u00e7a\u011f\u0131n ba\u011flad\u0131\u011f\u0131 d\u00f6neme kadar y\u00fcz milyonlarca y\u0131ll\u0131k bir zaman dilimini i\u00e7ine al\u0131yor. D\u00fcnya \u00fczerindeki ya\u015fam uzun zaman boyunca bakterilerin h\u00e2kimiyetindeydi. Taa ki g\u00fcn\u00fcm\u00fczden yakla\u015f\u0131k 650 milyon y\u0131l \u00f6nce daha kompleks canl\u0131lar ortaya \u00e7\u0131kana kadar. Bu ge\u00e7i\u015fin nas\u0131l ger\u00e7ekle\u015fti\u011fi b\u00fcy\u00fck bir s\u0131rd\u0131. Avustralya ve Almanya\u2019dan ara\u015ft\u0131rmac\u0131lar tam da bu s\u0131rr\u0131n \u00fczerine e\u011fildiler ve\u00a0Nature\u00a0<\/em>dergisinde yay\u0131mlad\u0131klar\u0131 makalede b\u00f6ceklerden dinozorlara -ve tabii insanlara- bilinen t\u00fcm hayvanlar\u0131n evrimine a\u00e7\u0131lan d\u00f6n\u00fcm noktas\u0131n\u0131 ke\u015ffettiklerini duyurdular.<\/p>\n

Ara\u015ft\u0131rmac\u0131lara g\u00f6re bu \u201cekosistem devrimi\u201d, g\u00fcn\u00fcm\u00fczden yakla\u015f\u0131k 700 milyon y\u0131l \u00f6nce, gezegenimizin y\u00fczeyi tamamen buzlarla kapl\u0131 oldu\u011fu zamanlarda ba\u015flad\u0131 (D\u00fcnya\u2019n\u0131n 50 milyon y\u0131l\u0131 a\u015fk\u0131n s\u00fcre buzlar alt\u0131nda kald\u0131\u011f\u0131 bu d\u00f6nem \u201cKartopu D\u00fcnya\u201d olarak adland\u0131r\u0131l\u0131yor). Dev buzullar\u0131n s\u0131rada\u011flar\u0131 ezip toza \u00e7evirmesiyle, ya\u015fam kayna\u011f\u0131 olan fosfat gibi besinler serbest kald\u0131. Daha sonra iklim de\u011fi\u015fikli\u011fiyle beraber havan\u0131n \u0131s\u0131nmas\u0131yla birlikte buzullar eridi ve nehirler bu besin maddelerini okyanuslara ta\u015f\u0131d\u0131. Yeni \u0131l\u0131man iklim ve ani besin ak\u0131n\u0131 hepimizin atas\u0131 ve ilk kompleks ya\u015fam formu olan algler i\u00e7in m\u00fckemmel ya\u015fam ko\u015fullar\u0131n\u0131 meydana getirdi.<\/p>\n

Avustralya Ulusal \u00dcniversitesi\u2019nden Dr. Jochen Brocks o d\u00f6nemden kalma kayalarla yapt\u0131klar\u0131 \u00e7al\u0131\u015fmalarla ilgili olarak, \u201cKayalar\u0131 toz haline getirdik ve i\u00e7lerinde bar\u0131nd\u0131rd\u0131klar\u0131 eski\u00e7a\u011flara ait organizmalar\u0131n molek\u00fcllerini ortaya \u00e7\u0131kard\u0131k. Bu molek\u00fcller g\u00fcn\u00fcm\u00fczden 650 milyon y\u0131l \u00f6nce i\u015flerin ger\u00e7ekten ilgin\u00e7le\u015fti\u011fini s\u00f6yl\u00fcyor. Bu bir ekosistem devrimiydi; alglerin y\u00fckseli\u015fiydi\u201d diyor.<\/p>\n

Bir zamanlar okyanuslara h\u00e2kim olan bakteriler daha komplike ya\u015fam formlar\u0131 taraf\u0131ndan tahtlar\u0131ndan indirildiler. \u201cBesin zincirinin en alt\u0131ndaki bu b\u00fcy\u00fck ve besleyici organizmalar daha b\u00fcy\u00fck ve kompleks hayvanlar\u0131 bar\u0131nd\u0131ran karma\u015f\u0131k ekosistemlerin evrimle\u015fmesi i\u00e7in gerekli olan enerji patlamas\u0131n\u0131 sa\u011flad\u0131lar\u201d diyor Dr. Brocks.<\/p>\n

Eski\u00e7a\u011f organizmalar\u0131na ait kal\u0131nt\u0131lar\u0131n \u00e7\u0131kart\u0131ld\u0131\u011f\u0131 orta Avustralya\u2019daki tortul kayalar\u0131, Kartopu D\u00fcnya\u2019n\u0131n erime s\u00fcrecinin hemen sonras\u0131ndaki d\u00f6neme tarihlendirildi. Ara\u015ft\u0131rma ekibinden Dr. Amber Jarrett\u2019in belirtti\u011fine g\u00f6re, bulgular Kartopu D\u00fcnya\u2019n\u0131n karma\u015f\u0131k ya\u015fam\u0131n evrimiyle ili\u015fkisini ortaya koymas\u0131 bak\u0131m\u0131nda \u00e7\u0131\u011f\u0131r a\u00e7\u0131c\u0131 bir niteli\u011fe sahip. Makalede belirtildi\u011fine g\u00f6re algler bilinenden \u00e7ok daha erken, g\u00fcn\u00fcm\u00fczden yakla\u015f\u0131k olarak 900 milyon-1,9 milyar y\u0131l \u00f6nce evrimle\u015ftiler. Fakat fosil steroit kay\u0131tlar\u0131n\u0131n g\u00f6sterdi\u011fi \u00fczere algler, g\u00fcn\u00fcm\u00fczden 659 ile 645 milyon y\u0131l \u00f6nceki D\u00fcnya\u2019n\u0131n sular\u0131nda ya\u015fayan ve ba\u015fl\u0131ca oksijen \u00fcreticileri olan fototrofik bakterileri tahtlar\u0131ndan indirmi\u015f. Bu yeni zaman \u00e7er\u00e7evesi atmosferdeki oksijen seviyesinin zamanla y\u00fckseli\u015fine, daha modern besin ve karbon d\u00f6ng\u00fcs\u00fcn\u00fcn olu\u015fumuna ve gittik\u00e7e karma\u015f\u0131kla\u015fan ya\u015fam\u0131n evrimine dair bir grup a\u00e7\u0131klama sunuyor.<\/p>\n","protected":false},"excerpt":{"rendered":"

Kompleks ya\u015fam\u0131n ortaya \u00e7\u0131k\u0131\u015f hik\u00e2yesi, D\u00fcnya\u2019n\u0131n buzullarla kapl\u0131 oldu\u011fu d\u00f6nemden k\u00fcresel iklim de\u011fi\u015fikli\u011fiyle birlikte yeni bir biyolojik \u00e7a\u011f\u0131n ba\u011flad\u0131\u011f\u0131 d\u00f6neme kadar y\u00fcz milyonlarca y\u0131ll\u0131k bir zaman dilimini i\u00e7ine al\u0131yor. D\u00fcnya \u00fczerindeki ya\u015fam uzun zaman boyunca bakterilerin h\u00e2kimiyetindeydi. Taa ki g\u00fcn\u00fcm\u00fczden yakla\u015f\u0131k 650 milyon y\u0131l \u00f6nce daha kompleks canl\u0131lar ortaya \u00e7\u0131kana kadar. Bu ge\u00e7i\u015fin nas\u0131l ger\u00e7ekle\u015fti\u011fi […]<\/p>\n","protected":false},"author":677,"featured_media":12866,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1128,19,21,32],"tags":[197,285,776,595],"class_list":["post-12865","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-163-sayi","category-bilim-gundemi","category-biyoloji","category-evrim","tag-biyoloji","tag-evrende-yasam","tag-hayvanlar","tag-yasam"],"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