{"id":14406,"date":"2016-11-01T17:43:37","date_gmt":"2016-11-01T14:43:37","guid":{"rendered":"http:\/\/109.232.216.219\/~bilimvegelecek\/?p=14406"},"modified":"2017-12-22T12:51:58","modified_gmt":"2017-12-22T09:51:58","slug":"kelebek-etkisi-isbasindaki-dogal-secilimin-anlattiklari","status":"publish","type":"post","link":"https:\/\/bilimvegelecek.com.tr\/index.php\/2016\/11\/01\/kelebek-etkisi-isbasindaki-dogal-secilimin-anlattiklari","title":{"rendered":"Kelebek etkisi:\u00a0\u0130\u015fba\u015f\u0131ndaki do\u011fal se\u00e7ilimin anlatt\u0131klar\u0131"},"content":{"rendered":"

Sanayi devriminin b\u00fct\u00fcn h\u0131z\u0131yla s\u00fcrd\u00fc\u011f\u00fc 19. y\u00fczy\u0131l \u0130ngiltere\u2019sinde, o d\u00f6neme dek esas olarak beyaz\u0131ms\u0131 renge sahip olan bir g\u00fcve t\u00fcr\u00fcnde siyah renkli bireylerin art\u0131\u015f g\u00f6stermesi, do\u011fal se\u00e7ilimin i\u015fleyi\u015fine ili\u015fkin en yal\u0131n ve tart\u0131\u015fmas\u0131z \u00f6rneklerden birini olu\u015fturuyor. <\/em><\/p>\n

Do\u011fal se\u00e7ilimin en genel tarifi, bir biyolojik \u00f6zellikte zaten var olan ve genetik temeli bulunan \u00e7e\u015fitlili\u011fin bir b\u00f6l\u00fcm\u00fcn\u00fcn, \u00e7evre ko\u015fullar\u0131 \u00f6ncekine g\u00f6re net bi\u00e7imde de\u011fi\u015fti\u011finde, organizman\u0131n hayatta kalma ve devaml\u0131l\u0131\u011f\u0131n\u0131 sa\u011flamas\u0131d\u0131r. \u00c7e\u015fitlili\u011fin bu \u015fekilde \u00e7evreye olumlu yan\u0131t veren k\u0131sm\u0131, dolay\u0131s\u0131yla, ilgili yeni \u00e7evresel ko\u015ful g\u00f6rece sabit kald\u0131\u011f\u0131 s\u00fcrece, ge\u00e7en her ku\u015fakta daha y\u00fcksek bir s\u0131kl\u0131kta temsil edilecek ve nihayetinde pop\u00fclasyonun -ya da t\u00fcr\u00fcn- tamam\u0131nda bask\u0131n \u00e7e\u015fitlilik durumu haline ge\u00e7ecektir. Do\u011fal se\u00e7ilimin \u00f6z itibar\u0131yla \u201ckanl\u0131 b\u0131\u00e7akl\u0131 bir kavga\u201d ya da \u201cvah\u015fi bir hayatta kalma m\u00fccadelesi\u201d olmay\u0131p, ku\u015faklar \u015feklindeki ge\u00e7en zaman\u0131n bir fonksiyonu olan bir yer de\u011fi\u015ftirme s\u00fcreci oldu\u011funa dikkati \u00e7eken bu tan\u0131m\u0131 do\u011frulayan \u00e7ok say\u0131daki do\u011fal ve laboratuvar \u00f6rne\u011fi de elbette mevcuttur.<\/p>\n

Bu ve gelecek ayki ve yaz\u0131lar\u0131m\u0131zda ise, do\u011fal se\u00e7ilimin bilimsel cepheleriyle en a\u00e7\u0131k ve yine ayn\u0131 cephelerden g\u00f6rece en tart\u0131\u015fmal\u0131 \u00f6rneklerinden birine, 19. y\u00fczy\u0131l sanayi devrimi \u0130ngiltere\u2019sinin insanl\u0131\u011f\u0131n hali itibar\u0131yla karanl\u0131k atmosferinde y\u00fckselen \u201csanayi melanizmine\u201d, bir g\u00fcve t\u00fcr\u00fc olan Biston betularia<\/em>\u2019n\u0131n t\u00fcr i\u00e7i evrimine odaklanaca\u011f\u0131z. Yaz\u0131m\u0131n bu ayki k\u0131sm\u0131 sanayi melanizminin Biston betularia<\/em> \u00f6rne\u011findeki evrimine ve bu evrimle\u015fmeye ili\u015fkin bilimsel tart\u0131\u015fmalar\u0131n ana eksenine odaklanacak ve gelecek ay ise bu evrimle\u015feme \u0131\u015f\u0131k tutacak genetik ve genomik bulgulara de\u011finece\u011fiz.<\/p>\n

\"\"
Manchester g\u00fcvelerinin beyaz\u0131ms\u0131 renkli bireyi.<\/figcaption><\/figure>\n

Manchester g\u00fcveleri neden karar\u0131yor?<\/strong><\/p>\n

Biston betularia<\/em>, 1850 civar\u0131ndan ba\u015flayarak, \u0130ngiliz sanayile\u015fmesinin t\u00fcm h\u0131z\u0131yla i\u015fledi\u011fi Manchester\u2019da, sergiledi\u011fi dikkat \u00e7ekici morfolojik \u00e7e\u015fitlilikle dikkati \u00e7ekmi\u015f olan bir g\u00fcve t\u00fcr\u00fcd\u00fcr. Bu t\u00fcr\u00fcn \u00fcyeleri, o g\u00fcne de\u011fin yayg\u0131n olarak g\u00f6zlenen formuyla beyaz\u0131ms\u0131 bir ton \u00fczerine siyah pigment zerreciklerinin serpildi\u011fi bir v\u00fccut rengi sergilemekteyken, ilk kez ortaya \u00e7\u0131kan siyah renkli, \u201cmelanik\u201d bir di\u011fer forma sahip bireyler de g\u00f6r\u00fclmeye ba\u015flanm\u0131\u015ft\u0131. \u0130ngiltere\u2019nin y\u00fcksek sanayile\u015fme g\u00f6steren merkezlerinde s\u0131kl\u0131\u011f\u0131 19. y\u00fczy\u0131l boyunca giderek y\u00fckselen siyah renkli formun \u201ctipik\u201d beyaz\u0131ms\u0131 formun yerini almas\u0131 yine ayn\u0131 y\u00fczy\u0131lda hemen dikkati \u00e7ekmi\u015f, B.betularia<\/em> ile birlikte 70 kadar g\u00fcve t\u00fcr\u00fcnde benzer de\u011fi\u015fimler g\u00f6r\u00fclmekle birlikte, B.betularia<\/em> 20. y\u00fczy\u0131l\u0131n ilk on y\u0131llar\u0131ndan itibaren do\u011fal se\u00e7ilimin \u00e7arp\u0131c\u0131 \u00f6rneklerinden biri olarak \u00f6ncelikli bi\u00e7imde ara\u015ft\u0131rma konusu olmu\u015ftur. (1)<\/p>\n

\"\"
Manchester siyah renkli bireyi.<\/figcaption><\/figure>\n

Sanayile\u015fmenin yaratt\u0131\u011f\u0131 \u00e7evresel d\u00f6n\u00fc\u015f\u00fcm\u00fcn adeta bir haritas\u0131 gibi okunabilecek bu hadise, ger\u00e7ekten de, do\u011fal se\u00e7ilimin i\u015fleyi\u015fine ili\u015fkin en yal\u0131n ve tart\u0131\u015fmas\u0131z \u00f6rneklerden birini olu\u015fturur ve sanayile\u015fmenin yaratt\u0131\u011f\u0131 \u00e7evre kirlenmesiyle temeli genetik olan biyolojik \u00e7e\u015fitlilik aras\u0131ndaki bariz bir ili\u015fkilenmeyi ifade eder. Bu \u00e7arp\u0131c\u0131 \u00f6yk\u00fcn\u00fcn ana hatlar\u0131 \u015f\u00f6yledir: Sanayile\u015fme ile ba\u015flayan hava kirlili\u011fi sonucunda, sanayi merkezleri civar\u0131ndaki a\u011fa\u00e7l\u0131k alanlarda ve ormanlardaki a\u011fa\u00e7lar\u0131n g\u00f6vdelerini kaplayan likenler \u00f6l\u00fcrler ve karar\u0131rlar. Biston betularia<\/em>\u2019n\u0131n a\u00e7\u0131k renkli formlar\u0131n\u0131n t\u00fcnedi\u011fi a\u011fa\u00e7lar\u0131n a\u00e7\u0131k g\u00f6vde renklerinin kararmas\u0131, a\u00e7\u0131k renkli formlar\u0131n avc\u0131 ku\u015flarca kolayca fark edilmesine yol a\u00e7arken, siyah renkli formlar art\u0131k koyula\u015fm\u0131\u015f g\u00f6vdelerde kolayl\u0131kla kamufle olacaklar ve b\u00f6ylece avc\u0131lardan korunacaklard\u0131r. Bu durum, yayg\u0131n form olan beyaz\u0131ms\u0131lar\u0131n sanayi merkezlerinde t\u00fckenmelerine yol a\u00e7arken siyah formlar\u0131n ku\u015faklar boyu art\u0131\u015f\u0131n\u0131 sa\u011flayacakt\u0131r. Nitekim hadise de bu \u015fekilde cereyan etmi\u015ftir; B.betularia<\/em>\u2019n\u0131n 19. y\u00fczy\u0131l ortalar\u0131ndan itibaren tutulan m\u00fcze \u00f6rneklerinin incelenmesi ve uzun s\u00fcreli ger\u00e7ekle\u015ftirilen saha g\u00f6zlemleri ve \u00f6rneklemeler, \u201ccarbonaria\u201d ad\u0131 verilen siyah formun s\u0131kl\u0131\u011f\u0131n\u0131n sanayile\u015fen b\u00f6lgelerde 19. y\u00fczy\u0131l\u0131n ortalar\u0131ndan itibaren h\u0131zla artt\u0131\u011f\u0131n\u0131 g\u00f6stermi\u015ftir. (2)<\/p>\n

Siyah renkli carbonaria formu ve a\u00e7\u0131k renkli tipik formla birlikte \u201cinsularia\u201d ad\u0131 verilen ve her iki u\u00e7 renk durumu aras\u0131nda bir rengi bulunan bir di\u011fer formla tan\u0131mlanan bu renk \u00e7e\u015fitlili\u011finin temeli genetiktir ve tek bir gendeki \u00fc\u00e7 ayr\u0131 genetik varyant\u0131n (alelin) yans\u0131mas\u0131 olduklar\u0131 \u015feklinde form\u00fcllendirilmi\u015ftir. Bu formlar\u0131n genetik bask\u0131nl\u0131k s\u0131ras\u0131 ise carbonaria (siyah) > insularia > tipik form (a\u00e7\u0131k renkli)\u00a0 \u015feklindedir ve bask\u0131n genetik varyant olan carbonaria\u2019n\u0131n s\u0131kl\u0131k de\u011fi\u015fimini, b\u00fcy\u00fck pop\u00fclasyon ve evrimsel genetik\u00e7i J. B. S. Haldane ger\u00e7ekle\u015ftirdi\u011fi ilk do\u011fal se\u00e7ilim \u015fiddeti hesaplamalar\u0131nda da kullanm\u0131\u015ft\u0131r. (3)<\/p>\n

Bilimsel ve bilim d\u0131\u015f\u0131 tart\u0131\u015fmalar<\/strong><\/p>\n

Biston betularia<\/em> pop\u00fclasyonlar\u0131nda 19. y\u00fczy\u0131l ortalar\u0131nda ba\u015flayan bu do\u011fal se\u00e7ilim 20. y\u00fczy\u0131l boyunca b\u00fcy\u00fck ilgi oda\u011f\u0131 olmu\u015ftur ve do\u011fal ortamda insan\u0131n eliyle yarat\u0131lan bir \u00e7evresel de\u011fi\u015fim sonucunda g\u00f6rece k\u0131sa s\u00fcrede ger\u00e7ekle\u015fen evrimle\u015fmenin en belirgin \u00f6rneklerinden birini sunmaya h\u00e2l\u00e2 devam etmektedir. \u00d6zellikle, \u0130ngiliz entomolog B. D. Kettlewell\u2019in y\u00fcr\u00fctt\u00fc\u011f\u00fc on y\u0131llara yay\u0131lan ve \u0130ngiltere\u2019nin tamam\u0131nda ger\u00e7ekle\u015ftirilen y\u00fczlerce g\u00f6zlem ve \u00f6rneklemenin, sanayi melanizminin se\u00e7ilimi g\u00f6stermek i\u00e7in ba\u015fvurulan klasik bir \u00f6rnek olmas\u0131nda pay\u0131 son derece b\u00fcy\u00fckt\u00fcr. (4)<\/p>\n

Bununla birlikte, ba\u015fta Kettlewell olmak \u00fczere, B.betularia<\/em> ve di\u011fer kelebek ve g\u00fcve t\u00fcrlerindeki koyu renkli formlar\u0131n sanayile\u015fme ile birlikte avantajl\u0131 k\u0131l\u0131nmas\u0131na odaklanan \u00e7o\u011fu \u00e7al\u0131\u015fmada, canl\u0131 ya da \u00f6l\u00fc kelebek-g\u00fcve \u00f6rneklerinin a\u011fa\u00e7 g\u00f6vdelerine tutturulmu\u015f olmas\u0131, kirlilik d\u00fczeyi a\u00e7\u0131s\u0131ndan farkl\u0131la\u015fma b\u00f6lgeleri aras\u0131ndaki siyah ya da a\u00e7\u0131k renkli formlar\u0131n g\u00f6\u00e7leri meselesinin ba\u015flarda ihmal edilmesi, sanayi melanizmi \/ do\u011fal se\u00e7ilim olgusuna giderek \u015f\u00fcpheyle bak\u0131lmas\u0131na yol a\u00e7m\u0131\u015f ve hatta evrim kar\u015f\u0131tl\u0131\u011f\u0131n\u0131n malzemesi haline bile gelmi\u015fti. (5) Evrim kar\u015f\u0131tl\u0131\u011f\u0131n\u0131n, her zamanki f\u0131rsat\u00e7\u0131l\u0131\u011f\u0131n\u0131n g\u00f6stergesi olan, bilimsel bir \u00e7al\u0131\u015fmadaki bo\u015flu\u011fu yeri doldurulmas\u0131 m\u00fcmk\u00fcn olmayan kuramsal bir zaaf\u0131n i\u015fareti olarak damgalamas\u0131 t\u00fcr\u00fcnden bildik itirazlar\u0131n\u0131n ciddiye al\u0131nacak taraf\u0131 bulunmasa da, sanayile\u015fmenin bulunmad\u0131\u011f\u0131 yerlerde, kirlenmeye dayal\u0131 se\u00e7ilimsel \u015fiddet b\u00fcy\u00fckl\u00fc\u011f\u00fcn\u00fcn teorik hesaplamalar\u0131ndan beklenilmeyecek oranda siyah renkli formun yer almas\u0131 ya da herhangi bir \u00e7evresel manip\u00fclasyon i\u00e7ermeyen laboratuvar deneylerinde siyah formun a\u00e7\u0131k renkli olanlara g\u00f6re uyum ba\u015far\u0131s\u0131n\u0131n daha y\u00fcksek \u00e7\u0131kmas\u0131, sanayiye dayal\u0131 kirlenme \/ melanizmin se\u00e7ilimsel y\u00fckseli\u015fi t\u00fcr\u00fcnden bir do\u011frusal ili\u015fkinin kurulmas\u0131n\u0131n en az\u0131ndan acele bir tav\u0131r olaca\u011f\u0131n\u0131 ima etmekteydi.<\/p>\n

Dahas\u0131, canl\u0131 ya da cans\u0131z \u00f6rneklerin a\u011fa\u00e7 g\u00f6vdelerine tutturulmas\u0131 esas\u0131na dayal\u0131, g\u00f6rsel ay\u0131rt edicili\u011fi temel alan ku\u015flarla avlanma modeli de ger\u00e7ek\u00e7i g\u00f6z\u00fckmemekteydi zira g\u00fcvelerin s\u0131kl\u0131kla a\u011fa\u00e7 g\u00f6vdelerine t\u00fcnedikleri ne malumdu? A\u011fa\u00e7lar\u0131n g\u00f6zden uzak di\u011fer k\u0131s\u0131mlar\u0131na ve i\u00e7 b\u00f6lgelerine yerle\u015fen g\u00fcvelerin durumu ne olmaktayd\u0131? Bu itirazlar\u0131n tamam\u0131 da bilimseldi ve evrimsel biyolojinin pop\u00fclasyon geneti\u011fi ve ekoloji birikimlerinden k\u0131l\u0131 k\u0131rk yararak olu\u015fturdu\u011fu makul sorular\u0131 i\u00e7ermekteydi. Evrimsel biyolojinin tamam\u0131 a\u00e7\u0131s\u0131ndan k\u00fc\u00e7\u00fck ancak sanayi melanizmini \u00e7al\u0131\u015fan pek \u00e7ok uzman i\u00e7in \u00f6nemi b\u00fcy\u00fck bu krizin \u00fcstesinden nas\u0131l gelindi\u011fini ise \u00f6n\u00fcm\u00fczdeki ay \u00f6zetleyece\u011fiz ve modern genetik biliminin sa\u011flad\u0131\u011f\u0131 olanaklar ile melanizmin evrimine daha yak\u0131ndan bakaca\u011f\u0131z.<\/p>\n

Kaynaklar<\/strong><\/p>\n

1) L. M. Cook ve I. J. Saccheri (2013), The peppered moth and industrial melanism: evolution of a natural selection case study, Heredity<\/em>, 110: 207-212.<\/p>\n

2) P. M. Sheppard (1959), Natural Selection and Heredity<\/em>, Hutchinson University Library, London.<\/p>\n

3) J. B. S. Haldane (1924), A mathematical theory of natural and artificial selection Part I. Transactions of the Cambridge Philosophical Society<\/em>, 23:19.<\/p>\n

4) B. D. Kettlewell (1973), The Evolution of Melanism: A Study Of Recurring Necessity; With Special Reference To Industrial Melanism In The Lepidoptera<\/em>, Clarendon Press, Oxford.<\/p>\n

5) Bruce S. Grant (1998), Fine tuning the peppered moth paradigm, Evolution<\/em>, 53:980-984.<\/p>\n

 <\/p>\n","protected":false},"excerpt":{"rendered":"

Sanayi devriminin b\u00fct\u00fcn h\u0131z\u0131yla s\u00fcrd\u00fc\u011f\u00fc 19. y\u00fczy\u0131l \u0130ngiltere\u2019sinde, o d\u00f6neme dek esas olarak beyaz\u0131ms\u0131 renge sahip olan bir g\u00fcve t\u00fcr\u00fcnde siyah renkli bireylerin art\u0131\u015f g\u00f6stermesi, do\u011fal se\u00e7ilimin i\u015fleyi\u015fine ili\u015fkin en yal\u0131n ve tart\u0131\u015fmas\u0131z \u00f6rneklerden birini olu\u015fturuyor. Do\u011fal se\u00e7ilimin en genel tarifi, bir biyolojik \u00f6zellikte zaten var olan ve genetik temeli bulunan \u00e7e\u015fitlili\u011fin bir b\u00f6l\u00fcm\u00fcn\u00fcn, \u00e7evre […]<\/p>\n","protected":false},"author":67,"featured_media":14407,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[190,1475,21],"tags":[1636,871,1610,1494],"class_list":["post-14406","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-153-sayi","category-bilim-ve-tarih","category-biyoloji","tag-biston-betularia","tag-dogalsecilim","tag-kelebek","tag-secilim"],"acf":[],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/posts\/14406","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/users\/67"}],"replies":[{"embeddable":true,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/comments?post=14406"}],"version-history":[{"count":0,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/posts\/14406\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/media\/14407"}],"wp:attachment":[{"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/media?parent=14406"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/categories?post=14406"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/bilimvegelecek.com.tr\/index.php\/wp-json\/wp\/v2\/tags?post=14406"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}