![\"Virtu\u00e1ln\u00ed](\"https:\/\/www.osel.cz\/popisek.php?popisek=45020&img=reliance-on-vision-dro.jpeg\" "\\"Virtu\u00e1ln\u00ed")
<\/a><\/p>\nVirtu\u00e1ln\u00ed odlitek mozkovny vyhynul\u00e9ho parapit\u00e9ka Simonsius grangeri. Kredit: Kay et al.\/MorphoSource.<\/p>\n
Je \u00fasm\u011bvn\u00e9, jak lid\u00e9 r\u00e1di mudruj\u00ed o velikosti sv\u00e9ho mozku, zat\u00edmco mnoh\u00e9 dal\u0161\u00ed org\u00e1ny, kter\u00e9 m\u00e1me v\u00a0t\u011ble, n\u00e1s nech\u00e1vaj\u00ed zcela chladn\u00fdmi. Pr\u00e1v\u011b tato zamilovanost do mozku je z\u0159ejm\u011b zodpov\u011bdn\u00e1 za dojem, \u017ee lidsk\u00fd mozek, kter\u00fd p\u0159ece mus\u00ed b\u00fdt k\u00a0my\u0161len\u00ed, se p\u0159ece musel zv\u011bt\u0161it pr\u00e1v\u011b kv\u016fli my\u0161len\u00ed. Pot\u00ed\u017e je v\u00a0tom, \u017ee to nejsp\u00ed\u0161 v\u016fbec nen\u00ed pravda.<\/p>\n
\u00a0<\/p>\n
Potvrzuje to i ned\u00e1vn\u00fd v\u00fdzkum, kter\u00fd vedl Richard Kay z\u00a0Duke University. Zam\u011b\u0159ili se na dramatick\u00e9 zv\u011bt\u0161en\u00ed mozkov\u00e9 k\u016fry \u010dili neokortexu, kter\u00e9 se prol\u00edn\u00e1 celou evoluc\u00ed prim\u00e1t\u016f. Mozkov\u00e1 k\u016fra je rozs\u00e1hl\u00e1 vn\u011bj\u0161\u00ed zvr\u00e1sn\u011bn\u00e1 vrstva mozku, kter\u00e1 je zodpov\u011bdn\u00e1 za smyslov\u00e9 vn\u00edm\u00e1n\u00ed, kognitivn\u00ed schopnosti a dal\u0161\u00ed komplexn\u00ed funkce. Nelze p\u0159ehl\u00e9dnout, \u017ee u prim\u00e1t\u016f je ve srovn\u00e1n\u00ed s ostatn\u00edmi savci v\u00fdrazn\u011b v\u011bt\u0161\u00ed.<\/p>\n
\u00a0<\/p>\n
Richard Kay. Kredit: Duke University.<\/p>\n Sou\u010dasn\u011b ale nen\u00ed snadn\u00e9 ur\u010dit, kdy\u017e se oprost\u00edme od p\u0159edsudk\u016f, jak a pro\u010d se b\u011bhem evoluce prim\u00e1t\u016f mozkov\u00e1 k\u016fra tolik zv\u011bt\u0161ila. Je to mozkov\u00e1 tk\u00e1\u0148 a ta se a\u017e na naprost\u00e9 a velmi mlad\u00e9 v\u00fdjimky ve fosiln\u00edm z\u00e1znamu nezachov\u00e1v\u00e1.<\/p>\n \u00a0<\/p>\n Kay s\u00a0kolegy to \u0159e\u0161ili s\u00a0vyu\u017eit\u00edm unik\u00e1tn\u00ed sb\u00edrky lebek, z nich\u017e mnoh\u00e9 poch\u00e1zej\u00ed z Duke Lemur Center. Pomoc\u00ed mikro-CT sken\u016f s\u00a0vysok\u00fdm rozli\u0161en\u00edm vytvo\u0159ili virtu\u00e1ln\u00ed vnit\u0159n\u00ed \u201eodlitky\u201c mozkovny rozmanit\u00fdch prim\u00e1t\u016f. Porovn\u00e1n\u00edm t\u011bchto odlitk\u016f zji\u0161\u0165ovali, jak se jednotliv\u00e9 \u010d\u00e1sti mozkov\u00e9 k\u016fry vyv\u00edjely v\u00a0r\u016fzn\u00fdch lini\u00edch prim\u00e1t\u016f.<\/p>\n \u00a0<\/p>\n V\u00fdsledky zcela zpochyb\u0148uj\u00ed dosavadn\u00ed p\u0159edstavy o v\u00fdvoji mozkov\u00e9 k\u016fry prim\u00e1t\u016f. Dlouho se p\u0159edpokl\u00e1dalo, \u017ee se \u010deln\u00ed lalok \u010dili velmi stru\u010dn\u011b a povrchn\u011b \u0159e\u010deno \u201ecentrum my\u0161len\u00ed,\u201c v r\u016fzn\u00fdch lini\u00edch prim\u00e1t\u016f nez\u00e1visle v\u00fdrazn\u011b zv\u011bt\u0161oval. Nov\u00fd v\u00fdzkum ale uk\u00e1zal, \u017ee velikost \u010deln\u00edho laloku rostla velmi postupn\u011b a spo\u0159\u00e1dan\u011b spolu s celkovou velikost\u00ed mozku. Ne\u0161lo o \u017e\u00e1dn\u00e9 dramatick\u00e9, nez\u00e1visl\u00e9 zv\u011bt\u0161ov\u00e1n\u00ed \u010deln\u00edho laloku, kter\u00e9 d\u0159\u00edv v\u011bdci vid\u011bli na z\u00e1klad\u011b pouh\u00e9ho vizu\u00e1ln\u00edho hodnocen\u00ed fosili\u00ed.<\/p>\n \u00a0<\/p>\n Lidsk\u00fd \u010deln\u00ed lalok mod\u0159e. Kredit: Henry Vandyke Carter, Wikimedia Commons.<\/p>\n Jak Kay a spol. zjistili, skute\u010dn\u00fd evolu\u010dn\u00ed p\u0159\u00edb\u011bh se odehr\u00e1v\u00e1 jinde v mozku. Rychle a nepom\u011brn\u011b ke zbytku mozku se v\u00a0pr\u016fb\u011bhu evoluce zv\u011bt\u0161uj\u00ed t\u00fdln\u00ed, temenn\u00ed a sp\u00e1nkov\u00e9 oblasti, tedy \u010d\u00e1sti mozku intenzivn\u011b zapojen\u00e9 do zpracov\u00e1n\u00ed zrakov\u00fdch informac\u00ed. K\u00a0tomuto zv\u011bt\u0161ov\u00e1n\u00ed p\u0159itom doch\u00e1zelo na stejn\u00fdch v\u011btv\u00edch evolu\u010dn\u00edho stromu prim\u00e1t\u016f, na nich\u017e se zv\u011bt\u0161oval tak\u00e9 zrakov\u00fd nerv. To nazna\u010duje, \u017ee do mozku proudilo st\u00e1le v\u00edce zrakov\u00fdch informac\u00ed. Badatel\u00e9 rovn\u011b\u017e dosp\u011bli k\u00a0z\u00e1v\u011bru, \u017ee velk\u00e9 mozky prim\u00e1t\u016f v\u010detn\u011b linie vedouc\u00ed k\u00a0\u010dlov\u011bku, se objevily u\u017e velmi d\u00e1vno, zhruba p\u0159ed 33 miliony let, kdy se t\u011bm mal\u00fdm opi\u010d\u00e1k\u016fm je\u0161t\u011b ani nezd\u00e1lo o katedr\u00e1l\u00e1ch nebo symfoni\u00edch.<\/p>\n \u00a0<\/p>\n Tak\u017ee na\u0161e velk\u00e9 mozky vlastn\u011b p\u016fvodn\u011b nebyly o my\u0161len\u00ed, ale o zraku. Pro biologa je to docela vtipn\u00e9, proto\u017ee prim\u00e1ti, i kdy\u017e v\u00a0r\u00e1mci savc\u016f maj\u00ed zrak jak\u017etak\u017e uch\u00e1zej\u00edc\u00ed, proti pt\u00e1k\u016fm nebo t\u0159eba s\u00e9pi\u00edm jsou ve zraku u\u010din\u011bn\u00ed b\u0159\u00eddilov\u00e9. Pro\u010d je pro prim\u00e1ty zrak tak d\u016fle\u017eit\u00fd? Kay uv\u00e1d\u00ed dv\u011b hlavn\u00ed a navz\u00e1jem se nevylu\u010duj\u00edc\u00ed mo\u017enosti, z\u00a0nich\u017e ta lechtiv\u00e1 p\u0159ipisuje zraku d\u016fle\u017eitou roli v\u00a0soci\u00e1ln\u00edm \u017eivot\u011b. Opi\u010d\u00e1ci se r\u00e1di d\u00edvaj\u00ed.<\/p>\n Druhou mo\u017enost lze t\u011b\u017eko ozna\u010dit jinak ne\u017e trapnou, i kdy\u017e j\u00ed vd\u011b\u010d\u00edme za hodn\u011b, proto\u017ee se t\u00fdk\u00e1 pon\u011bkud trapn\u00e9 mutace, kter\u00e1 postihla d\u00e1vn\u00e9ho p\u0159edka dne\u0161n\u00edch prim\u00e1t\u016f. Na po\u010d\u00e1tku sv\u00e9 evoluce prim\u00e1ti p\u0159i\u0161li o schopnost syntetizovat vitam\u00edn C, nejsp\u00ed\u0161 \u010dist\u011b n\u00e1hodou, a od t\u00e9 doby ho mus\u00edme dopl\u0148ovat t\u00edm, co j\u00edme. To, \u017ee vitam\u00edn C \u010dasto obsahuj\u00ed \u010derven\u011b \u010di podobn\u011b zbarven\u00e9 plody, z\u0159ejm\u011b t\u011bsn\u011b souvis\u00ed s\u00a0t\u00edm, \u017ee se u prim\u00e1t\u016f objevilo barevn\u00e9 vid\u011bn\u00ed, a z\u0159ejm\u011b i s\u00a0celkov\u00fdm rozvojem zraku.<\/p>\n \u00a0<\/p>\n Video: Primate Evolution’s Tangled Tree | Fundamental Concepts with Jenny Tung<\/p>\n \n \u00a0<\/p>\n Literatura<\/p>\n<\/a><\/p>\n<\/a><\/p>\n