Christopher Joyce\u2019un haz\u0131rlad\u0131\u011f\u0131 habere g\u00f6re, son 125 biny\u0131lda, d\u00fcnyadaki memelilerin boyutlar\u0131 k\u00fc\u00e7\u00fcld\u00fc ve bunun sorumlulu\u011fu tek bir canl\u0131 t\u00fcr\u00fcne ait, yani insano\u011fluna. Bu \u00e7\u0131kar\u0131m, New-Mexico \u00dcniversitesi\u2019nde \u00e7al\u0131\u015fmalar\u0131n\u0131 s\u00fcrd\u00fcren paleobiyolog Felisa Smith\u2019in fosil kay\u0131tlar\u0131 \u00fczerine olan yeni \u00e7al\u0131\u015fmas\u0131n\u0131n sonucu.<\/p>\n
Smith, dinozorlar\u0131n \u00f6l\u00fcp memelilerin boy g\u00f6sterdi\u011fi 65 milyon y\u0131l geriye giden fosilleri ara\u015ft\u0131rd\u0131. Bir\u00e7ok memeli daha iri hale gelmeye devam etmi\u015fti. Smith, devasa yarat\u0131klar aras\u0131nda, lamalar, develer, tembel-hayvanlar, \u00e7atal-boynuzlu antiloplar\u0131n be\u015f t\u00fcr\u00fc ve elbette mamutlar ve hatta k\u00fc\u00e7\u00fck suratl\u0131 dev ay\u0131 Arctoudus<\/em> gibi ger\u00e7ekten haval\u0131 bir\u00e7ok y\u0131rt\u0131c\u0131n\u0131n bulundu\u011funu s\u00f6yl\u00fcyor. K\u00fc\u00e7\u00fck suratl\u0131 dev ay\u0131, baz\u0131 tarih\u00f6ncesi deve t\u00fcrlerinin omuz hizas\u0131na gelecek bi\u00e7imde, ayakta 3,5 m kadard\u0131. Bu ay\u0131ya sadece Kuzey Amerika\u2019da rastlan\u0131yordu.<\/p>\n B\u00fcy\u00fck olmak, en az k\u00fc\u00e7\u00fck olmak kadar avantajl\u0131yd\u0131 ve b\u00fcy\u00fck y\u0131rt\u0131c\u0131lardan kurtulma konusunda baz\u0131 yararl\u0131 yanlar\u0131 vard\u0131. Smith, \u201cBir b\u00fct\u00fcn olarak ele al\u0131nd\u0131\u011f\u0131nda, 65 milyon y\u0131l boyunca, b\u00fcy\u00fck olmak memelilerin yok olma riskini artt\u0131rmad\u0131. Fakat insanlar evrimle\u015fti\u011finde ise, art\u0131k b\u00fcy\u00fck olmak ciddi bir risk fakt\u00f6r\u00fc haline gelmi\u015fti\u201d diyor.<\/p>\n Son 125 bin y\u0131l\u0131n fosil kay\u0131tlar\u0131na bak\u0131ld\u0131\u011f\u0131nda, Smith, insanlar\u0131n herhangi bir yere geli\u015fiyle birlikte b\u00fcy\u00fck memelilerin yok olma oran\u0131n\u0131n artt\u0131\u011f\u0131n\u0131 buldu. Ara\u015ft\u0131rmac\u0131 bunun temelde a\u00e7l\u0131kla ilgili oldu\u011funu belirtiyor ve \u201c\u0130nsanlar, a\u00e7\u0131k\u00e7a av hayvanlar\u0131n\u0131 s\u00f6m\u00fcrd\u00fcler. \u00c7\u00fcnk\u00fc muhtemelen yedikleri di\u011fer besinlerden daha lezzetliydiler\u201d diyor. Ayr\u0131ca, daha b\u00fcy\u00fck hayvan daha \u00e7ok yemek demekti.<\/p>\n Fakat, insanlar b\u00fcy\u00fck memelilerin yok olu\u015funu h\u0131zland\u0131rmaktan ba\u015fka \u015feyler de yapt\u0131. B\u00fcy\u00fck memelilerin kulland\u0131\u011f\u0131 ormanlar\u0131 ve \u00e7ay\u0131rlar\u0131 yakt\u0131lar. Av hayvanlar\u0131 i\u00e7in b\u00fcy\u00fck et\u00e7illerle rekabete giri\u015ftiler. Kendilerini daha iyi avc\u0131lar yapan k\u00f6pekleri kuland\u0131lar.<\/p>\n Smith\u2019e g\u00f6re, memelilerin zamanla k\u00fc\u00e7\u00fclmesi, erozyon gibi, \u00e7evre \u00fczerinde tahmin edemeyece\u011fimiz etkilere yol a\u00e7t\u0131. Smith \u015f\u00f6yle a\u00e7\u0131kl\u0131yor, \u201cB\u00fcy\u00fck bir memeli hayvan bir tepede y\u00fcr\u00fcd\u00fc\u011f\u00fc zaman, \u00e7o\u011funlukla zikzak yaparak y\u00fcr\u00fcr; oysaki k\u00fc\u00e7\u00fck hayvanlar \u00e7o\u011funlukla d\u00fcz y\u00fcr\u00fcr. Bunun bir etkisi vard\u0131r, \u00e7\u00fcnk\u00fc su, bu av hayvanlar\u0131n\u0131n izlerini takip eder. Dolay\u0131s\u0131yla erozyon, bitki \u00f6rt\u00fcs\u00fc vb. de bundan etkilenir.\u201d<\/p>\n Smith\u2019in \u00e7al\u0131\u015fmas\u0131 Science<\/em> dergisinde yay\u0131mland\u0131. Oregon Devlet \u00dcniversitesi\u2019nden meslekta\u015f\u0131 Rebecca Terryat, bu \u00e7al\u0131\u015fman\u0131n, insanlar\u0131n ilk evrimle\u015fti\u011fi Afrika\u2019da da, insanlar\u0131n, memelilerin \u00f6l\u00e7\u00fclerini nas\u0131l etkiledi\u011fini g\u00f6sterdi\u011fini s\u00f6yl\u00fcyor ve devam ediyor: \u201cMemeliler \u00fczerindeki bu etkiler, insanlar\u0131n yolculu\u011funu takip etti. Nihayetinde modern insan\u0131n yay\u0131l\u0131\u015f\u0131yla Homo sapiens<\/em>\u2019ler yenid\u00fcnyaya hareket etti. Bu noktada art\u0131k, olduk\u00e7a geli\u015fmi\u015f silahlar\u0131 vard\u0131. G\u00fcney ve Kuzey Amerika\u2019daki yok olu\u015flar\u0131n s\u0131ra d\u0131\u015f\u0131 sonu\u00e7lar\u0131 oldu.\u201d<\/p>\n Asl\u0131nda Amerika, b\u00fcy\u00fck memeliler i\u00e7in son dayanakt\u0131; taa ki, bu k\u0131ta insanlarca istila edilene kadar.<\/p>\n Gezegende h\u00e2l\u00e2 bir\u00e7ok k\u00fcrkl\u00fc k\u00fc\u00e7\u00fck memeli hayvan ya\u015f\u0131yor. Fakat ba\u011flant\u0131 ortada: 11 biny\u0131l \u00f6ncesinde, insan bar\u0131nd\u0131rmayan Kuzey Amerika\u2019daki bir memelinin ortalama a\u011f\u0131rl\u0131\u011f\u0131 100 kg\u2019d\u0131, \u015fimdi ise 7,5 kg kadar. Ara\u015ft\u0131rmac\u0131lar bu k\u00fctlenin gittik\u00e7e azald\u0131\u011f\u0131n\u0131 da belirtiyor.<\/p>\n","protected":false},"excerpt":{"rendered":" Christopher Joyce\u2019un haz\u0131rlad\u0131\u011f\u0131 habere g\u00f6re, son 125 biny\u0131lda, d\u00fcnyadaki memelilerin boyutlar\u0131 k\u00fc\u00e7\u00fcld\u00fc ve bunun sorumlulu\u011fu tek bir canl\u0131 t\u00fcr\u00fcne ait, yani insano\u011fluna. Bu \u00e7\u0131kar\u0131m, New-Mexico \u00dcniversitesi\u2019nde \u00e7al\u0131\u015fmalar\u0131n\u0131 s\u00fcrd\u00fcren paleobiyolog Felisa Smith\u2019in fosil kay\u0131tlar\u0131 \u00fczerine olan yeni \u00e7al\u0131\u015fmas\u0131n\u0131n sonucu. Smith, dinozorlar\u0131n \u00f6l\u00fcp memelilerin boy g\u00f6sterdi\u011fi 65 milyon y\u0131l geriye giden fosilleri ara\u015ft\u0131rd\u0131. Bir\u00e7ok memeli daha iri […]<\/p>\n","protected":false},"author":673,"featured_media":24387,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[211,19,21,217,32],"tags":[3080,3081,3078,3083,3079,3077,3076,3082],"class_list":["post-24386","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-antropoloji","category-bilim-gundemi","category-biyoloji","category-cevre-bilimleri","category-evrim","tag-arctoudus","tag-erozyon","tag-guney-amerika","tag-insanin-evrime-etkisi","tag-kucuk-suratli-dev-ayi","tag-kuzey-amerika","tag-memeli-evrimi","tag-memeli-kutlesi"],"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