{"id":44215,"date":"2020-05-18T17:02:50","date_gmt":"2020-05-18T14:02:50","guid":{"rendered":"https:\/\/bilimvegelecek.com.tr\/?p=44215"},"modified":"2020-05-18T17:02:50","modified_gmt":"2020-05-18T14:02:50","slug":"beslenme-ve-enerji-tuketimine-paleoantropolojik-bakis","status":"publish","type":"post","link":"https:\/\/bilimvegelecek.com.tr\/index.php\/2020\/05\/18\/beslenme-ve-enerji-tuketimine-paleoantropolojik-bakis","title":{"rendered":"Beslenme ve enerji t\u00fcketimine paleoantropolojik bak\u0131\u015f"},"content":{"rendered":"

\u201cBilim, sahip oldu\u011fumuzdan daha geni\u015f d\u00fcnyalar\u0131, i\u00e7inde ya\u015fad\u0131\u011f\u0131m\u0131z formuna nas\u0131l geldi\u011fiyle alakal\u0131 yeni soru ve bak\u0131\u015f a\u00e7\u0131lar\u0131 \u00fcreterek ke\u015ffetmemizi sa\u011flar\u201d Fran\u00e7ois Jacob (1994)<\/em><\/p>\n

Canl\u0131lar\u0131n enerji tedarik ve kullan\u0131m stratejileri ya\u015fad\u0131\u011f\u0131 \u00e7evre ve biyolojisi hakk\u0131nda bizlere g\u00f6z ard\u0131 edemeyece\u011fimiz bilgiler sa\u011flar. \u00c7evreden enerjinin nas\u0131l elde edildi\u011fi ve enerjinin v\u00fccudun temel ya\u015famsal olaylar\u0131 i\u00e7in ne \u015fekilde harcand\u0131\u011f\u0131, o canl\u0131n\u0131n hayatta kalma, \u00fcreme ve sa\u011fl\u0131k durumu \u00fczerinde \u00f6nemli etkilere sahiptir. Bu durum ya\u015fam boyu tedarik edilen enerjinin ba\u011f\u0131\u015f\u0131kl\u0131k sistemi, fiziksel aktivite, termoreg\u00fclasyon gibi bazal metabolizma ve b\u00fcy\u00fcme, \u00fcreme, depolama fonksiyonlar\u0131n\u0131 i\u00e7eren \u00fcretim temelli olan, bir canl\u0131n\u0131n ya\u015fam boyu ge\u00e7irdi\u011fi t\u00fcm biyolojik ve fizyolojik fonksiyonlar\u0131n devam\u0131 i\u00e7in kullan\u0131lmas\u0131ndan kaynaklanmaktad\u0131r (Leonard vd., 2006). Dolay\u0131s\u0131yla, insan\u0131n 6-7 milyon y\u0131ll\u0131k hik\u00e2yesinde enerji tedari\u011fi, metabolizma ve enerji t\u00fcketim temellerinden biyok\u00fclt\u00fcrel yakla\u015f\u0131m ile bahsetmek insan biyolojisinin adaptif de\u011fi\u015fimlerinin anla\u015f\u0131lmas\u0131nda farkl\u0131 fikirler geli\u015ftirilmesini sa\u011flayacakt\u0131r.<\/p>\n

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Beslenme ve enerji aras\u0131ndaki ili\u015fkiyi ele almadan \u00f6nce k\u0131saca enerji d\u00f6n\u00fc\u015f\u00fcm prensiplerinden bahsetmek yararl\u0131 olabilir. Herkes hayat\u0131nda enerji kavram\u0131n\u0131 bir \u015fekilde kullanmaktad\u0131r. Kim \u201cbug\u00fcn enerjim d\u00fc\u015f\u00fck\u201d ya da \u201cburan\u0131n enerjisi \u00e7ok g\u00fczel\u201d, \u201c\u00e7ocuklar enerji dolu\u201d c\u00fcmlelerini kurmam\u0131\u015ft\u0131r ki. \u00d6rnekleri daha da artt\u0131rabilece\u011fimiz gibi bu kavram\u0131n bilimsel tan\u0131m\u0131 literat\u00fcrde \u201ci\u015f yapma kapasitesinin \u00f6l\u00e7\u00fcs\u00fc\u201d olarak ge\u00e7mektedir (Cheetham, 2010). Bu tan\u0131ma dayanarak i\u015f yapma dedi\u011fimiz eylemi (bir \u015feyi ortaya \u00e7\u0131karmak ya da olu\u015fturmak i\u00e7in emek harcama durumu) bir formdan di\u011ferine d\u00f6n\u00fc\u015fen belli bir enerji miktar\u0131 olarak kabul edebiliriz. Peki, temelde fizi\u011fin ba\u015fl\u0131ca ara\u015ft\u0131rma konusu olup di\u011fer bilim dallar\u0131nca da incelenen enerji tam olarak nedir? Nas\u0131l \u00fcretilir ya da \u00fcretilebilir mi?<\/p>\n

D\u00fcnyan\u0131n temel enerji kayna\u011f\u0131 hepimizin bildi\u011fi gibi g\u00fcne\u015f kaynakl\u0131 foton enerjisidir ve fotosentez yoluyla kimyasal enerjiye d\u00f6n\u00fc\u015ft\u00fcr\u00fclerek canl\u0131lar taraf\u0131ndan kullan\u0131lmaktad\u0131r. Termodinami\u011fin birinci yasas\u0131na bakt\u0131\u011f\u0131m\u0131zda enerjinin yarat\u0131l\u0131p yok edilmedi\u011fi aksine bir formdan di\u011ferine d\u00f6n\u00fc\u015ft\u00fcr\u00fclme suretiyle kullan\u0131ld\u0131\u011f\u0131n\u0131 g\u00f6rmekteyiz (Cheetham, 2010). Buna en g\u00fczel \u00f6rnek akan suyun sahip oldu\u011fu kinetik enerjinin hidroelektrik jenerat\u00f6rlerinde elektrik enerjisine ve hatta kinetik enerjinin havadaki molek\u00fclleri hareket ettirme suretiyle bir di\u011fer enerji \u00e7e\u015fidi olan sese d\u00f6n\u00fc\u015fmesidir. Yine suyun, trib\u00fcn ve borulara \u00e7arpmas\u0131 bir di\u011fer enerji \u00e7e\u015fidi olan \u0131s\u0131 enerjisinin a\u00e7\u0131\u011fa \u00e7\u0131kmas\u0131na katk\u0131 sa\u011flamaktad\u0131r (Cheetham, 2010). Biyoloji s\u00f6z konusu oldu\u011funda ise bahsi ge\u00e7en enerji formlar\u0131 d\u0131\u015f\u0131nda kimyasal enerji \u00e7ok b\u00fcy\u00fck bir \u00f6nem kazanmaktad\u0131r. Nitekim ya\u015fayan t\u00fcm canl\u0131larda enerji, kimyasal ba\u011flar yard\u0131m\u0131yla depo edilip reaksiyonlar yard\u0131m\u0131yla a\u00e7\u0131\u011fa \u00e7\u0131kart\u0131larak kullan\u0131lmaktad\u0131r. Bu da t\u00fcm canl\u0131lar\u0131n hayatlar\u0131n\u0131 devam ettirebilmeleri i\u00e7in gereken kimyasal enerjiyi edinmeleri ve d\u00f6n\u00fc\u015ft\u00fcrmeleri gerekti\u011fi anlam\u0131na gelir. Bunun kayna\u011f\u0131 da besinlerdir. Enerji ak\u0131\u015f\u0131 bu anlamda canl\u0131lar i\u00e7in besin t\u00fcketimiyle ba\u015flayarak sindirimle devam eden ve su, karbondioksit \u00fcretimiyle sonlanan bir s\u00fcreci kapsamaktad\u0131r. T\u00fcm bu d\u00f6ng\u00fc hayati biyokimyasal olaylar\u0131n temelini de olu\u015fturmaktad\u0131r. H\u00fccre yenileme, b\u00fcy\u00fcme, hareket, \u00fcreme ve s\u0131cakl\u0131k de\u011fi\u015fimi bunlara \u00f6rnek g\u00f6sterilebilir. Dolay\u0131s\u0131yla hayati t\u00fcm i\u015flevlerin ard\u0131nda v\u00fccudun dinamik enerji dengesinin devaml\u0131l\u0131\u011f\u0131n\u0131 sa\u011flama stratejileri oldu\u011fu s\u00f6ylenebilir (Grafik 1) (Snodgrass, 2012). Bu sebeple biyolojik antropoloji alan\u0131nda \u00e7al\u0131\u015fan biliminsanlar\u0131 Hominin evrimini son y\u0131llarda enerji modelleri \u00fczerinden ara\u015ft\u0131rmaya ba\u015flam\u0131\u015flard\u0131r. Bu yakla\u015f\u0131m\u0131n evrimsel s\u00fcre\u00e7leri anlama yolunda \u00e7e\u015fitli avantajlar\u0131 bulunmaktad\u0131r. Birincisi, temel enerji kayna\u011f\u0131m\u0131z\u0131n besin olmas\u0131 ve besinin edinme ve t\u00fcketme a\u015famalar\u0131n\u0131n y\u00fcksek oranda organizma ile ya\u015fad\u0131\u011f\u0131 \u00e7evreye ba\u011fl\u0131 olmas\u0131, canl\u0131 ekolojileri hakk\u0131nda da fikir sahibi olmam\u0131z\u0131 sa\u011flamas\u0131d\u0131r. \u0130kinci avantaj ise enerji modelinin canl\u0131n\u0131n enerji dengesini sa\u011flama, hayatta kalma ve \u00fcreme a\u00e7\u0131s\u0131ndan \u00f6nemli adaptif sonu\u00e7lar do\u011furmas\u0131d\u0131r. K\u0131sacas\u0131 canl\u0131lar\u0131n besin edinme ve t\u00fcketme yollar\u0131 \u00fczerinde duruldu\u011funda do\u011fal se\u00e7ilimin evrimsel de\u011fi\u015fim \u00f6r\u00fcnt\u00fclerine nas\u0131l etki etti\u011fi hakk\u0131nda daha fazla s\u00f6z sahibi olabiliriz.<\/p>\n

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Enerji dengesi<\/strong>
\nEnerjinin ak\u0131\u015f\u0131 ve antropolojik \u00e7al\u0131\u015fmalarda yakla\u015f\u0131m olarak benimsenmesinin \u00f6neminden biyolojik kullan\u0131m \u015fekillerine ge\u00e7i\u015f yapmak gerekirse, bilinmesi gereken en temel bilgi, tedarik edilen enerji ile harcanan enerji miktar\u0131n\u0131n birbirine e\u015fit oldu\u011fu takdirde beden dengesinin sabit kald\u0131\u011f\u0131d\u0131r. Sabitlik iki \u015fekilde bozulmaktad\u0131r: \u0130lki enerji harcamas\u0131n\u0131n t\u00fcketimden fazla oldu\u011fu durumlarda dokularda yer alan ya\u011f oran\u0131n\u0131n azalmas\u0131, di\u011fer durumda ise dokulardaki ya\u011f ve glikojen oran\u0131n\u0131n art\u0131\u015f g\u00f6stermesi ile. Ak\u015fam \u00e7ay\u0131na att\u0131\u011f\u0131m\u0131z \u015feker, kahvemizin yan\u0131nda t\u00fcketti\u011fimiz bir tatl\u0131 g\u00fcnl\u00fck ortalama enerji ihtiyac\u0131m\u0131z\u0131n \u00fczerine tekab\u00fcl etti\u011fi takdirde sindirilmeye devam ederek depo edilmektedir. Depolanma, g\u00fcnl\u00fck enerji ihtiyac\u0131n\u0131n y\u00fczde 85\u2019inin kar\u015f\u0131lanmas\u0131ndan sonra t\u00fcketilen t\u00fcm besinlerin d\u00e2hil oldu\u011fu bir s\u00fcre\u00e7tir (Cheetham, 2010). Bu bilginin kilit rol oynad\u0131\u011f\u0131 durum; uzun vadede bedenin, ya\u011f\u0131 y\u00fcksek enerji sa\u011flayan birincil depo kayna\u011f\u0131 olarak kullanmas\u0131ndan ileri gelmektedir. Tropik kara memelilerinin biyolojileri d\u00fc\u015f\u00fck ya\u011f depolama e\u011filimi g\u00f6sterirken (y\u00fczde 1-2) g\u00fcn\u00fcm\u00fczde \u00f6zellikle bat\u0131 toplumlar\u0131nda obezitenin y\u00fcksek prevelans (tekrarlanma s\u0131kl\u0131\u011f\u0131) g\u00f6stermesi bu anlamda fetal (do\u011fum \u00f6ncesi) ve postnatal (do\u011fum sonras\u0131) d\u00f6nemde zorlu ko\u015fullara kar\u015f\u0131 geli\u015ftirilen bir adaptasyonun ko\u015fullar de\u011fi\u015fince (y\u00fcksek kalorili yiyeceklere \u00e7evrelendi\u011fimiz durumda) nas\u0131l uyumsuz sonu\u00e7lara sebebiyet verebilece\u011finin \u00f6rne\u011fi olarak g\u00f6r\u00fclebilir. Dolay\u0131s\u0131yla uzun y\u0131llar boyunca uyum sa\u011flad\u0131\u011f\u0131m\u0131z \u00e7evresel ko\u015fullar\u0131n ve beslenme al\u0131\u015fkanl\u0131klar\u0131m\u0131z\u0131n de\u011fi\u015fiklik g\u00f6stermesi, g\u00fcn\u00fcm\u00fczde en s\u0131k rastlanan hastal\u0131klardan olan y\u00fcksek kilo ve obezite riskinin art\u0131\u015f g\u00f6stermesinde kilit rol oynamaktad\u0131r. Sonu\u00e7 olarak tarihsel s\u00fcre\u00e7 i\u00e7erisinde yaln\u0131zca ya\u011f dokunun oransal art\u0131\u015f\u0131na bakmak yerine, b\u00f6ylesi bir art\u0131\u015f\u0131n metabolik ve davran\u0131\u015fsal i\u00e7eriklerini yorumlamaya \u00e7al\u0131\u015fmak, b\u00fct\u00fcnc\u00fcl ve kapsay\u0131c\u0131 yakla\u015f\u0131mlar ileri s\u00fcrmemizi sa\u011flayacakt\u0131r.<\/p>\n

Tarih\u00f6ncesi d\u00f6neme geri d\u00f6necek olursak Homo sapiens<\/em> ile kar\u015f\u0131la\u015ft\u0131rd\u0131\u011f\u0131m\u0131zda Australopithecus ve Paranthropuslar\u0131n beslenme evrimi hakk\u0131nda \u00e7ok az bilgi sahibi oldu\u011fumuzu s\u00f6yleyebiliriz. Homo habilis<\/em>ten H.erectus<\/em>a yiyecek yelpazesinin hayvansal besinler ile y\u00fcksek enerjili bitki kaynaklar\u0131n\u0131 i\u00e7eren, \u00e7e\u015fitli ve \u201ckalite odakl\u0131\u201d diyete sahip olduklar\u0131n\u0131 g\u00f6rmekteyiz. Bunu fosil kal\u0131nt\u0131lar\u0131n\u0131n di\u015f ve \u00e7ene mofolojisi, di\u015f kimyas\u0131, a\u015f\u0131nma analizleri ve besin kal\u0131nt\u0131lar\u0131ndan (arkeobotanik, zooarkeolojik) elde edilen sonu\u00e7lar \u0131\u015f\u0131\u011f\u0131nda s\u00f6yleyebiliriz. \u00d6rne\u011fin di\u015f morfolojilerine bak\u0131ld\u0131\u011f\u0131nda H.erectus ile Australopithecuslar\u0131n farkl\u0131 besinleri t\u00fcketti\u011fi anla\u015f\u0131lmaktad\u0131r (Robinson, 1954). Molar (b\u00fcy\u00fck az\u0131 di\u015fi) ve premolar (k\u00fc\u00e7\u00fck az\u0131) geni\u015flikleri Australopithecus afarensis<\/em>ten, A. boisei<\/em>\u2019ye geni\u015fleme g\u00f6sterirken, yakla\u015f\u0131k 2 milyon y\u0131l \u00f6nce tarih sahnesine \u00e7\u0131kan Homo cinslerinden olan habilis<\/em>ten erectus<\/em>a k\u00fc\u00e7\u00fclme e\u011filimi g\u00f6stermektedir. Sadece di\u015f boyutlar\u0131 de\u011fil di\u015f mine morfolojileri de canl\u0131lar\u0131n beslenme rejimleri hakk\u0131nda bilgi sahibi olmam\u0131za yard\u0131mc\u0131 olmaktad\u0131r. Ungar\u2019\u0131n (2004) \u00e7al\u0131\u015fmalar\u0131 Homo<\/em> cinsine ait di\u015flerin mine y\u00fczeylerinin Australopithecus afarensis<\/em> \u00f6rneklerine g\u00f6re daha girintili, Homo<\/em> cinslerinin baz\u0131 meyve, dal ve etleri \u00e7a\u011fda\u015flar\u0131ndan daha verimli bir \u015fekilde s\u0131y\u0131r\u0131p kesti\u011fi izlenimi de vermektedir. Yine mine morfolojisine dayanarak P. robustus<\/em>lar\u0131n tohum, yemi\u015f gibi daha sert yiyecekleri A. africanus<\/em>lardan daha etkili bir bi\u00e7imde par\u00e7alad\u0131\u011f\u0131 anla\u015f\u0131lmaktad\u0131r (Grine, 1986). T\u00fcm bu bilgiler bizlere Homo erectus<\/em>lar\u0131n di\u011fer t\u00fcrlere g\u00f6re besin de\u011feri y\u00fcksek, kalorili ve d\u00fc\u015f\u00fck lif oranl\u0131 bir beslenme rejimine sahip oldu\u011funu i\u015faret etmektedir. Bu anlat\u0131m 2-1,8 milyon y\u0131l \u00f6nce var olan \u00e7evreyle uyumlu bir tablo \u00e7izmektedir. Keza Pleistosen d\u00f6nemin bu zaman aral\u0131\u011f\u0131n\u0131 \u00e7al\u0131\u015fan arkeolog ve antropologlar bizlere kurak ve kuru otlak alanlar\u0131 artm\u0131\u015f bir Afrika tasvir etmektedir.<\/p>\n

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Grafik 1: \u0130nsanlarda enerji ak\u0131\u015f\u0131 (Snodgrass 2012\u2019den uyarlanm\u0131\u015ft\u0131r.)<\/figcaption><\/figure>\n

Peki, tarih\u00f6ncesi d\u00f6nemlerde atalar\u0131m\u0131z\u0131n i\u00e7erisinde bulundu\u011fu \u00e7evresel yap\u0131lanmaya bakarak ne yediklerini ve ne yemeye e\u011filimli olduklar\u0131n\u0131 tahmin edebilir miyiz? Bu sorunun muhtemel cevaplardan birine homininlerin ya\u015fad\u0131\u011f\u0131 d\u00fc\u015f\u00fcn\u00fclen yerlerde benzer besin ihtiyac\u0131na sahip (Paranthropus<\/em>, hominoid, primat vb.), ya\u015fam\u0131n\u0131 halen s\u00fcrd\u00fcren hayvanlar\u0131n beslenme \u015fekilleri ile kar\u015f\u0131la\u015ft\u0131rma yaparak ula\u015fabiliriz (Charles, 2006). Bu anlamda Do\u011fu ve G\u00fcney Afrika\u2019da primatlar taraf\u0131ndan t\u00fcketilen 461 yabani bitki (meyve, yaprak\/filiz, tohum\/kabuklu bitkiler, yumrular) ve k\u00fc\u00e7\u00fck hayvan incelendi\u011finde, homininlerin homidlerle beraber iri bedenli maymunlarla benzer habitatlarda hep\u00e7il olarak beslendi\u011fi s\u00f6ylenebilir (Peters ve O\u2019Brien, 1981; 1982). Ara\u015ft\u0131rmac\u0131lar bu \u00e7al\u0131\u015fma kapsam\u0131nda atalar\u0131m\u0131z\u0131n tahmini t\u00fcketmi\u015f olabilece\u011fi Afrika\u2019n\u0131n \u00e7e\u015fitli bitki t\u00fcrlerini, ta\u015f\u0131d\u0131klar\u0131 besin de\u011ferlerini de g\u00f6z \u00f6n\u00fcnde bulundurarak listelemi\u015ftir (Peters ve O\u2019Brien, 1981; Stahl, 1984). Buna g\u00f6re; homininlerin olas\u0131l\u0131kla t\u00fckettikleri besinlerden f\u0131nd\u0131k benzeri ya\u011fl\u0131 yemi\u015fler ya\u011f ve protein a\u00e7\u0131s\u0131ndan zengin bulunurken, olgunla\u015fm\u0131\u015f meyveler, kuru meyveler, baklagiller, \u00e7im tohumlar\u0131, s\u0131\u011f yumrular (so\u011fanl\u0131, k\u00f6ksap, etli k\u00f6kler) ve nektarlar karbonhidrat a\u00e7\u0131s\u0131ndan zengin; olgunla\u015fmam\u0131\u015f k\u00f6k ve yapraklar ile baklagiller ise protein a\u00e7\u0131s\u0131ndan ortalama de\u011fer ta\u015f\u0131yan besin kaynaklar\u0131d\u0131r. Charles (2006)\u2019\u0131n ortaya koydu\u011fu bir di\u011fer analizde ise Kalahari\u2019den Do\u011fu Zimbabve\u2019ye uzanan b\u00f6lge i\u00e7erisinde 1 ile 194 aras\u0131nda de\u011fi\u015fen say\u0131da yenebilen meyve t\u00fcr\u00fc bulundu\u011funu, t\u00fcm b\u00f6lge b\u00fct\u00fcn kabul edildi\u011finde ise 301\u2019e yak\u0131n yenebilir bitki t\u00fcr\u00fcn\u00fcn mevcut oldu\u011funu iletmektedir. Bahsedilen bitki t\u00fcrlerinden baz\u0131 f\u0131nd\u0131k benzeri a\u011fa\u00e7lar, kuru meyve t\u00fcrleri y\u0131l\u0131n kurak zamanlar\u0131nda iyi \u00fcr\u00fcn vermesi a\u00e7\u0131s\u0131ndan da avantaj sa\u011flamaktad\u0131r. Bu anlamda Afrika\u2019n\u0131n a\u011fa\u00e7l\u0131k alanlar\u0131n\u0131n iklim ve t\u00fcr \u00e7e\u015fitlili\u011fi a\u00e7\u0131s\u0131ndan yeterli zenginlikte oldu\u011fu a\u015fik\u00e2rd\u0131r.<\/p>\n

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Uzun y\u0131llar boyunca uyum sa\u011flad\u0131\u011f\u0131m\u0131z \u00e7evresel ko\u015fullar\u0131n ve beslenme al\u0131\u015fkanl\u0131klar\u0131m\u0131z\u0131n de\u011fi\u015fiklik g\u00f6stermesi, g\u00fcn\u00fcm\u00fczde en s\u0131k rastlanan hastal\u0131klardan olan y\u00fcksek kilo ve obezite riskinin art\u0131\u015f g\u00f6stermesinde kilit rol oynamaktad\u0131r.<\/figcaption><\/figure>\n

G\u00fcn\u00fcm\u00fcze yakla\u015ft\u0131k\u00e7a yap\u0131lan etnografik ve retrospektif \u00e7al\u0131\u015fmalar bahsedilen rejim de\u011fi\u015fikli\u011finin, avc\u0131 toplay\u0131c\u0131 ge\u00e7im ekonomisine sahip insan topluluklar\u0131 \u00fczerinden evrimsel bak\u0131\u015fla yorumlanmas\u0131na imkan sa\u011flamaktad\u0131r. Bu \u00e7al\u0131\u015fmalar avc\u0131 toplay\u0131c\u0131 ge\u00e7im ekonomisine sahip insan topluluklar\u0131n g\u00fcnl\u00fck enerjisinin kuyruksuz b\u00fcy\u00fck maymunlar\u0131n aksine y\u00fczde 45-65 oran\u0131nda hayvansal besinlerden sa\u011flad\u0131\u011f\u0131n\u0131 ortaya koymaktad\u0131r. Goriller enerjilerinin y\u00fczde 80\u2019inini yaprak ve kabuk gibi lifli ve d\u00fc\u015f\u00fck besin de\u011feri olan ye\u015filliklerden tedarik ederken, kuyruksuz b\u00fcy\u00fck maymunlar i\u00e7erisinde y\u0131rt\u0131c\u0131 say\u0131labilecek olan \u015fempanzeler dahi enerjilerinin yaln\u0131zca y\u00fczde 5\u2019ini hayvansal besinlerden sa\u011flamaktad\u0131r (Snodgrass, 2012). Av eti gibi hayvansal kaynakl\u0131 besinler, iri bedenli kuyruksuz b\u00fcy\u00fck maymunlar taraf\u0131ndan tercih edilen bitkilerden daha y\u00fcksek enerji bar\u0131nd\u0131rmaktad\u0131r. \u0130nsanlar\u0131n y\u00fcksek enerji kaynakl\u0131 besinlere y\u00f6nelmesi ile daha az miktarlar t\u00fcketerek g\u00fcnl\u00fck enerji ihtiyac\u0131n\u0131 kar\u015f\u0131lad\u0131\u011f\u0131 s\u00f6ylenebilir. Bu durum yaln\u0131zca miktarla de\u011fil, beyin b\u00fcy\u00fckl\u00fc\u011f\u00fc ile de ili\u015fkilendirilmektedir. Antropologlar taraf\u0131ndan yap\u0131lan kar\u015f\u0131la\u015ft\u0131rmal\u0131 analizler besin kalitesi ve beyin b\u00fcy\u00fckl\u00fc\u011f\u00fc aras\u0131nda bir ili\u015fki oldu\u011funu ortaya koymaktad\u0131r. Leonard ve arkada\u015flar\u0131n\u0131n (2006) 31 farkl\u0131 primat t\u00fcr\u00fcyle yapt\u0131\u011f\u0131 ara\u015ft\u0131rmalar beyne ayr\u0131lan enerji miktar\u0131 ile kalori ve beslenmenin kalitesi aras\u0131nda pozitif bir ili\u015fki oldu\u011funu g\u00f6stermektedir (bkz. Aiello, 1997; Aiello ve Wheeler, 1995). Dahas\u0131 insanlarda depo edilen ya\u011f dokusunun, enerji k\u0131s\u0131tl\u0131l\u0131klar\u0131n\u0131n giderilmesinde ve metabolik g\u00f6revler aras\u0131nda enerji ak\u0131\u015f\u0131n\u0131n devam etmesinde \u00f6nemli rol oynad\u0131\u011f\u0131 bilinmektedir (Blackwell vd., 2010). Yeni do\u011fmu\u015f bir bebe\u011fin y\u00fczde 15-16 civar\u0131nda olan ya\u011f oran\u0131 ilerleyen 12-18 ay i\u00e7erisinde y\u00fczde 25-26\u2019e y\u00fckselmekte ve erken \u00e7ocukluk evresinde y\u00fczde 15\u2019e tekrar gerilemektedir (Dewey vd., 1993). \u0130nsan bebekleri bu anlamda di\u011fer memeli t\u00fcrlerin bebeklerine g\u00f6re daha fazla ya\u011f dokusuna sahiptir (Leonard vd., 2006). Ungar (2006), ya\u011fl\u0131l\u0131k oran\u0131n\u0131n en y\u00fcksek oldu\u011fu d\u00f6nem ile beynin metabolik talebinin en fazla oldu\u011fu d\u00f6nemlerin benzer olmas\u0131n\u0131, yine beyin b\u00fcy\u00fckl\u00fc\u011f\u00fcn\u00fcn arkas\u0131nda yatan sebeplerden biri olarak g\u00f6rmektedir.<\/p>\n

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Homo habilisten H.erectusa yiyecek yelpazesinin hayvansal besinler ile y\u00fcksek enerjili bitki kaynaklar\u0131n\u0131 i\u00e7eren, \u00e7e\u015fitli ve \u201ckalite odakl\u0131\u201d diyete sahip olduklar\u0131n\u0131 g\u00f6rmekteyiz. Bunu fosil kal\u0131nt\u0131lar\u0131n\u0131n di\u015f ve \u00e7ene mofolojisi, di\u015f kimyas\u0131, a\u015f\u0131nma analizleri ve besin kal\u0131nt\u0131lar\u0131ndan (arkeobotanik, zooarkeolojik) elde edilen sonu\u00e7lar \u0131\u015f\u0131\u011f\u0131nda s\u00f6yleyebiliriz.
Foto: https:\/\/australianmuseum.net.au\/learn\/science\/human-evolution\/homo-habilis\/<\/figcaption><\/figure>\n

Beyin d\u0131\u015f\u0131nda iri primatlar\u0131n sahip olduklar\u0131 uzun kal\u0131n ba\u011f\u0131rsaklar\u0131n da beslenme rejimlerinde yer alan lifli yiyeceklere kar\u015f\u0131 geli\u015ftirilmi\u015f adaptif bir olu\u015fum olarak g\u00f6r\u00fclmektedir (Milton, 1987). Uzam\u0131\u015f kal\u0131n ba\u011f\u0131rsaklar bitki liflerinin fermantasyonunda bir enerji formu olan u\u00e7ucu ya\u011flar\u0131n da elde edilmesini sa\u011flamaktad\u0131r (Milton, 1993). Bu durum iri primatlar\u0131n ihtiyac\u0131 olan g\u00fcnl\u00fck enerji miktarlar\u0131n\u0131 elde etti\u011fi besinlerden daha verimli bir \u015fekilde teminine yorumlanmaktad\u0131r. \u0130ri primatlar\u0131n aksine insanlarda ise ince ba\u011f\u0131rsaklar kal\u0131n ba\u011f\u0131rsaklardan daha uzun olup b\u00f6ylesi bir olu\u015fumun zengin besin i\u00e7erikli, kolay sindirilebilen beslenme rejimlerine sahip y\u0131rt\u0131c\u0131larla benzerli\u011fi dikkat \u00e7ekmektedir (Sussman,1987; Martin, 1989). Afrika\u2019y\u0131 ya\u015fam alan\u0131 edinen Homo \u00fcyelerinin sahip oldu\u011fu beslenme rejiminin ne sadece et ne de sadece bitki odakl\u0131 olmad\u0131\u011f\u0131 aksine di\u011fer kaynaklarla beraber t\u00fcketebilecekleri kalorisi y\u00fcksek ve \u00e7e\u015fitli besinleri i\u00e7eren kar\u0131\u015f\u0131k bir diyete sahip oldu\u011fu g\u00f6sterilmektedir (Schoeninger vd., 2001; Leonard vd., 2012). Bu beslenme \u015fekli canl\u0131lar\u0131n enerji tedarikini y\u0131l boyu belli bir d\u00fczeyde stabil k\u0131larak v\u00fccudun metabolik fonksiyonlar\u0131n\u0131n devaml\u0131l\u0131\u011f\u0131na ve fonksiyonlar aras\u0131 \u00f6d\u00fcnle\u015fim mekanizmas\u0131na katk\u0131 sa\u011flamaktad\u0131r.<\/p>\n

KAYNAKLAR:<\/strong><\/p>\n

– Aiello LC. (1997) \u201cBrains and guts in human evolution: The expensive tissue hypothesis.\u201d Braz. J. Genet. Vol.20, 141\u2013148.<\/p>\n

– Aiello LC., Wheeler, P. (1995) \u201cThe expensive-tissue hypothesis: The brain and the digestive system in human and primate evolution.\u201d Curr Anthropol. Vol.36, pp.199\u2013221.<\/p>\n

– Blackwell AD, Snodgrass JJ, Madimenos FC, Sugiyama LS (2010) Life history, immune function, and intestinal helminths: Trade-offs among immunoglobulin E, C-reactive protein, and growth in an Amazonian population. Am J Hum Biol. Vol.22, pp.836\u2013848.<\/p>\n

– Charles P. (2006) \u201cTheoretical and Actualistic Ecobotanical Perspectives on Early Hominin Diets and Paleoecology.\u201d In: Unger P. (Ed.). Evolution of the Human Diet. Oxford University Press.<\/p>\n

– Dewey KG., Heinig MJ., Nommsen LA., Peerson JM., Lonnerdal B. (1993) \u201cBreastfed infants are leaner than formula-fed infants at 1 y of age: The Darling Study.\u201d Am J Clin Nutr. Vol.52, pp.140\u2013145.<\/p>\n

– Grine FE. (1986) \u201cDental evidence for dietary differences in Australopithecus and Paranthropus:
\nA quantitative analysis of permanent molar microwear.\u201d J Hum Evol. Vol.15, pp.783\u2013822.<\/p>\n

– Hill RW., Wyse GA., Anderson M. ( 2008 ) Animal Physiology , 2nd ed. Sunderland, UK.<\/p>\n

– Leonard WR., Robertson ML. (1994) \u201cEvolutionary perspectives on human nutrition: The influence of brain and body size on diet and metabolism.\u201d Am. J Hum Biol. Vol.6, pp.77\u201388.<\/p>\n

– Leonard WR., Robertson ML., Snodgrass JJ. (2006) \u201cEnergetic Models of Human Nutritional Evolution.\u201d In: Unger P. (Ed.). Evolution of the Human Diet. Oxford University Press. pp. 344-359.<\/p>\n

– Luisi PL. (2006) The Emergence of Life. Cambridge University Press, Cambridge.<\/p>\n

– Martin RD. (1989) Primate Origins and Evolution: A Phylogenetic Reconstruction. Princeton University Press. Princeton, NJ.<\/p>\n

– Milton K. (1987) \u201cPrimate diets and gut morphology: Implications for hominid evolution.\u201d In: Harris M., Ross EB. (Eds.). Food and Evolution: Toward a Theory of Human Food Habits. Temple University Press, Philadelphia, PA, pp. 93\u2013115.<\/p>\n

– Milton K. (1993) \u201cDiet and primate evolution.\u201d Sci Am. Vol.269(2), pp.86\u201393.<\/p>\n

– Peters CR., O\u2019Brien EM. (1981) \u201cThe early hominid plant-food niche: Insights from an analysis of plant exploitation by Homo, Pan, and Papio in eastern and southern Africa.\u201d Curr Anthropol. Vol.22, pp.127\u2013140.<\/p>\n

– Peters CR., O\u2019Brien EM. (1982) \u201cOn early hominid plant-food niches: Reply.\u201d Curr Anthropol. Vol.23, pp.214\u2013218.<\/p>\n

– Robinson JT. (1954) \u201cPrehominid dentition and hominid evolution.\u201d Evolution, Vol.8, pp.324\u2013334.<\/p>\n

– Schoeninger MJ., Bunn HT., Murray SS., Pickering T., Moore J. (2001) \u201cMeat-eating by the fourth African ape.\u201d In: Stanford CB., Bunn HT. (Eds.). Meat-Eating and Human Evolution. Oxford University Press, New York, pp.179\u2013195.<\/p>\n

– Snodgrass JJ. (2012). \u201cHuman Energetics.\u201d In: Stinson S., Bogin B., O\u2019Rourke D. (Ed.). Human Biology and Biocultural Perspective. Wiley Black. pp.325-384.<\/p>\n

– Sussman RW. (1987) \u201cSpecies-specific dietary patterns in primates and human dietary adaptations.\u201d
\nIn: Kinzey WG. (Ed.). The Evolution of Human Behavior: Primate Models. SUNY Press: Albany, NY, pp. 131\u2013179.<\/p>\n

– Stahl AB. (1984) \u201cHominid dietary selection before fire.\u201d Curr Anthropol. Vol.25, pp.151\u2013168.<\/p>\n

– Wells JCK. (2010) The Evolutionary Biology of Human Body Fatness Thrift and Control. Cambridge University Press.<\/p>\n","protected":false},"excerpt":{"rendered":"

\u201cBilim, sahip oldu\u011fumuzdan daha geni\u015f d\u00fcnyalar\u0131, i\u00e7inde ya\u015fad\u0131\u011f\u0131m\u0131z formuna nas\u0131l geldi\u011fiyle alakal\u0131 yeni soru ve bak\u0131\u015f a\u00e7\u0131lar\u0131 \u00fcreterek ke\u015ffetmemizi sa\u011flar\u201d Fran\u00e7ois Jacob (1994) Canl\u0131lar\u0131n enerji tedarik ve kullan\u0131m stratejileri ya\u015fad\u0131\u011f\u0131 \u00e7evre ve biyolojisi hakk\u0131nda bizlere g\u00f6z ard\u0131 edemeyece\u011fimiz bilgiler sa\u011flar. \u00c7evreden enerjinin nas\u0131l elde edildi\u011fi ve enerjinin v\u00fccudun temel ya\u015famsal olaylar\u0131 i\u00e7in ne \u015fekilde harcand\u0131\u011f\u0131, […]<\/p>\n","protected":false},"author":2501,"featured_media":44224,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[19],"tags":[253,1488,281,1712,4248,1037],"class_list":["post-44215","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-bilim-gundemi","tag-beslenme","tag-dis","tag-enerji","tag-fotosentez","tag-hominin","tag-obezite"],"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