D\u00fcnya\u2019daki ya\u015fam, uzun tarihi boyunca biyo\u00e7e\u015fitlilik kayb\u0131na neden olan kitlesel yokolu\u015flar ya\u015fad\u0131. Bunlardan en y\u0131k\u0131c\u0131 olan\u0131 252 milyon y\u0131l \u00f6nce Permiyen d\u00f6neminin son evrelerinde meydana gelen kitlesel yokolu\u015ftu. Buna “B\u00fcy\u00fck Kitlesel Yokolu\u015f” (The Great Dying\/B\u00fcy\u00fck \u00d6l\u00fcm) ad\u0131 verilmektedir.<\/p>\n
Proceedings of the Royal Society B<\/em> portal\u0131nda yay\u0131nlanan \u00e7al\u0131\u015fmada, B\u00fcy\u00fck Kitlesel Yokolu\u015f\u2019un ard\u0131ndan ya\u015fam\u0131n nas\u0131l yeniden \u00e7e\u015fitlendi\u011fine odaklan\u0131ld\u0131. Ayr\u0131ca k\u00fc\u00e7\u00fck \u00e7apl\u0131 iki kitlesel yokolu\u015f ile de kar\u015f\u0131la\u015ft\u0131rmal\u0131 analizler yap\u0131ld\u0131. Bunlar 273 milyon y\u0131l \u00f6nceki Guadalupiyen-Lopingiyen kitlesel yokolu\u015fu ile 201.3 milyon y\u0131l \u00f6nceki Triyas-Jura kitlesel yokolu\u015fuydu.<\/p>\n Ara\u015ft\u0131rmac\u0131lar B\u00fcy\u00fck Kitlesel Yokolu\u015f\u2019un d\u00fcnyadaki ya\u015fam i\u00e7in daha sert bir etkisi oldu\u011funu g\u00f6sterdi. Her 20 t\u00fcrden 19\u2019unun kaybedildi\u011fi bu kitlesel yokolu\u015ftan sonra \u00e7e\u015fitlili\u011fin eski seviyelere gelmesi olduk\u00e7a uzun zaman alm\u0131\u015ft\u0131. Ara\u015ft\u0131rmac\u0131lar bunun neden bu kadar uzun zamanda ger\u00e7ekle\u015fti\u011fini a\u00e7\u0131klamaya \u00e7al\u0131\u015ft\u0131.<\/p>\n Ara\u015ft\u0131rmac\u0131lara g\u00f6re permiyen sonunda g\u00f6r\u00fclen B\u00fcy\u00fck Kitlesel Yokolu\u015f iki y\u00f6n\u00fc nedeniyle ola\u011fan\u00fcst\u00fcyd\u00fc. \u0130lk olarak \u00e7e\u015fitlilikteki azalma \u00e7ok \u015fiddetliydi. Di\u011fer iki k\u00fc\u00e7\u00fck \u00e7apl\u0131 kitlesel yokolu\u015fta ise yap\u0131 itibariyle kararl\u0131 ekosistemler bulunuyordu. \u0130kinci olarak, B\u00fcy\u00fck Kitlesel Yokolu\u015f sonras\u0131nda ekosistemlerin toparlanmas\u0131 \u00e7ok uzun bir zaman alm\u0131\u015ft\u0131. Bu s\u00fcre 10 milyon y\u0131l ve \u00fczerindeydi. Ancak di\u011fer iki kitlesel yokolu\u015ftan sonra toparlanma daha h\u0131zl\u0131yd\u0131.<\/p>\n Biliminsanlar\u0131, B\u00fcy\u00fck Kitlesel Yokolu\u015f\u2019un biyolojik \u00e7e\u015fitlili\u011fe neden bu kadar y\u00fcksek bir zarar verdi\u011fini ke\u015ffetmek i\u00e7in 14 canl\u0131 grubunun g\u0131da a\u011flar\u0131n\u0131 yeniden tasarlad\u0131. Bu tasar\u0131mda fosillerden elde edilen mide i\u00e7eri\u011fi ve d\u0131\u015fk\u0131 \u00f6rnekleri temel al\u0131nd\u0131. Canl\u0131lar\u0131n t\u00fcketti\u011fi besinler g\u00f6letlerde ve nehirlerde ya\u015fayan bitkiler, yumu\u015fak\u00e7alar ve b\u00f6ceklerden baz\u0131 ot\u00e7ullara kadar y\u00fcksek bir \u00e7e\u015fitlili\u011fe sahipti. Besin a\u011flar\u0131n\u0131n detayl\u0131 olarak yeniden canland\u0131r\u0131lmas\u0131, B\u00fcy\u00fck Kitlesel Yokolu\u015f\u2019un ana nedeni olan olay ger\u00e7ekle\u015ftikten sonra besin zincirinin bozulmas\u0131yla birlikte geride kalan t\u00fcrlerin de yokolu\u015fa s\u00fcr\u00fcklendi\u011fini g\u00f6sterdi. B\u00f6ylelikle B\u00fcy\u00fck Kitlesel Yokolu\u015f\u2019un y\u0131k\u0131c\u0131l\u0131\u011f\u0131na \u0131\u015f\u0131k tutuldu.<\/p>\n