V obdob\u00ed triasu, p\u0159ibli\u017en\u011b p\u0159ed 225 a\u017e 250 miliony let, po Zemi putovala skupina b\u00fdlo\u017erav\u00fdch plaz\u016f zn\u00e1m\u00fdch jako rhynchosau\u0159i. Tito tvorov\u00e9 o velikosti ovce m\u011bli v\u00fdraznou adaptaci \u017ev\u00fdk\u00e1n\u00ed, kter\u00e1 je odli\u0161ovala od ostatn\u00edch plaz\u016f. M\u00edsto cvak\u00e1n\u00ed \u010delistmi nahoru a dol\u016f zam\u011bstn\u00e1vali rhynchosau\u0159i pohyb podobn\u00fd n\u016f\u017ek\u00e1m, aby drtili rostliny mezi sv\u00fdmi zuby a vystaven\u00fdmi \u010delistn\u00edmi kostmi.<\/p>\n\n
Tato neobvykl\u00e1 technika \u017ev\u00fdk\u00e1n\u00ed umo\u017enila rhynchosaur\u016fm rozkl\u00e1dat tuhou vegetaci a da\u0159it se v prost\u0159ed\u00ed triasu. Av\u0161ak jak ned\u00e1vno zjistili v\u011bdci, tato adaptace mohla tak\u00e9 p\u0159isp\u011bt k jejich kone\u010dn\u00e9 z\u00e1hub\u011b.<\/p>\n\n
V pr\u016fb\u011bhu \u010dasu neust\u00e1l\u00e9 drcen\u00ed rostlin opot\u0159ebov\u00e1valo zuby rhynchosaur\u016f. Aby to vykompenzovali, tito plazi vyvinuli pozoruhodnou schopnost vyp\u011bstovat nov\u00e9 \u00faseky \u010delisti s nov\u00fdmi zuby v zadn\u00ed \u010d\u00e1sti tlamy. Jak st\u00e1rli, nov\u00e9 \u00faseky se posouvaly dop\u0159edu a nahrazovaly opot\u0159ebovan\u00e9 zuby.<\/p>\n\n
Tento mechanismus v\u00fdm\u011bny \u010delisti dovolil rhynchosaur\u016fm udr\u017eet si schopnost \u017ev\u00fdkat a p\u0159ij\u00edmat potravu. Av\u0161ak p\u0159edstavoval tak\u00e9 potenci\u00e1ln\u00ed probl\u00e9m. Kdy\u017e rhynchosau\u0159i dos\u00e1hli vysok\u00e9ho v\u011bku, jejich t\u011bla u\u017e nedok\u00e1zala dr\u017eet krok s popt\u00e1vkou po nov\u00fdch \u00fasec\u00edch \u010delisti. Nakonec jim do\u0161ly zuby a stali se neschopn\u00fdmi \u017er\u00e1t, co\u017e vedlo k vyhladov\u011bn\u00ed.<\/p>\n\n
V\u011bdci zkoumali fosilizovan\u00e9 \u010delistn\u00ed kosti rhynchosaur\u016f pomoc\u00ed v\u00fdpo\u010detn\u00ed tomografie (CT), aby l\u00e9pe porozum\u011bli t\u00e9to jedine\u010dn\u00e9 adaptaci \u017ev\u00fdk\u00e1n\u00ed. Tyto skeny odhalily, \u017ee star\u0161\u00ed rhynchosau\u0159i m\u011bli v\u00fdrazn\u011b del\u0161\u00ed \u010delisti se za\u0161l\u00fdmi zuby a kostmi, kter\u00e9 z\u016fstaly v p\u0159edn\u00ed \u010d\u00e1sti jejich tlam. To nazna\u010duje, \u017ee tato zv\u00ed\u0159ata nebyla schopn\u00e1 vyp\u011bstovat nov\u00e9 \u00faseky \u010delisti, aby nahradila ty opot\u0159ebovan\u00e9.<\/p>\n\n
Krom\u011b individu\u00e1ln\u00edch d\u016fsledk\u016f pro rhynchosaury mohla jejich neobvykl\u00e1 technika \u017ev\u00fdk\u00e1n\u00ed hr\u00e1t roli tak\u00e9 v z\u00e1niku jejich druhu. V ran\u00e9m obdob\u00ed triasu byla planeta pokryt\u00e1 m\u011bkk\u00fdmi kapradinami, kter\u00e9 se rhynchosaur\u016fm snadno drtily. Nicm\u00e9n\u011b p\u0159ibli\u017en\u011b p\u0159ed 225 miliony let se klima na sv\u011bt\u011b zm\u011bnilo, co\u017e vedlo k rozmno\u017een\u00ed tvrd\u0161\u00edch jehli\u010dnan\u016f porostl\u00fdch jehli\u010d\u00edm.<\/p>\n\n
Pokud by rhynchosau\u0159i pokra\u010dovali v \u017eran\u00ed stejn\u00fdm zp\u016fsobem, museli by \u010delit v\u00fdznamn\u00fdm v\u00fdzv\u00e1m p\u0159i z\u00edsk\u00e1v\u00e1n\u00ed dostate\u010dn\u00e9ho mno\u017estv\u00ed \u017eivin na p\u0159e\u017eit\u00ed. Kombinace opot\u0159eben\u00ed zub\u016f a neschopnosti p\u0159izp\u016fsobit se m\u011bn\u00edc\u00ed se vegetaci mohla p\u0159isp\u011bt k jejich kone\u010dn\u00e9mu vyhynut\u00ed.<\/p>\n\n
Je zaj\u00edmav\u00e9, \u017ee hrstka modern\u00edch zv\u00ed\u0159at, jako jsou n\u011bkte\u0159\u00ed chameleoni, st\u00e1le pou\u017e\u00edv\u00e1 podobnou techniku \u017ev\u00fdk\u00e1n\u00ed jako rhynchosau\u0159i. V\u011bdci tyto \u017eivo\u010dichy studuj\u00ed, aby z\u00edskali poznatky o potenci\u00e1ln\u00edch zdravotn\u00edch rizic\u00edch a evolu\u010dn\u00edch d\u016fsledc\u00edch t\u00e9to adaptace.<\/p>\n\n
Jedine\u010dn\u00e1 strategie \u017ev\u00fdk\u00e1n\u00ed rhynchosaur\u016f a jejich n\u00e1sledn\u00e9 vyhynut\u00ed poskytuj\u00ed cenn\u00e9 poznatky o evoluci zubn\u00edch struktur a v\u00fdzv\u00e1ch, kter\u00fdm b\u00fdlo\u017eravci \u010del\u00ed p\u0159i p\u0159izp\u016fsobov\u00e1n\u00ed se m\u011bn\u00edc\u00edmu se prost\u0159ed\u00ed. Studiem t\u011bchto d\u00e1vn\u00fdch plaz\u016f mohou v\u011bdci l\u00e9pe pochopit slo\u017eitosti zubn\u00edch adaptac\u00ed a jejich potenci\u00e1ln\u00ed vliv na p\u0159e\u017eit\u00ed druh\u016f.<\/p>","protected":false},"excerpt":{"rendered":"
Triasov\u00ed plazi: \u0160kleb\u00edc\u00ed se b\u00fdlo\u017eravci se smrtelnou vadou Unik\u00e1tn\u00ed adaptace \u017ev\u00fdk\u00e1n\u00ed a jej\u00ed d\u016fsledky V obdob\u00ed triasu, p\u0159ibli\u017en\u011b p\u0159ed 225 a\u017e 250 miliony let, po Zemi putovala skupina b\u00fdlo\u017erav\u00fdch plaz\u016f…<\/p>\n","protected":false},"author":6,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[138],"tags":[7110,7109,7112,7111,7108,4939,400],"class_list":["post-3802","post","type-post","status-publish","format-standard","hentry","category-paleontology","tag-chewing-adaptation","tag-herbivores","tag-jaw-replacement","tag-dental-wear","tag-rhynchosaurs","tag-triassic-period","tag-extinction"],"_links":{"self":[{"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/posts\/3802","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/users\/6"}],"replies":[{"embeddable":true,"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/comments?post=3802"}],"version-history":[{"count":1,"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/posts\/3802\/revisions"}],"predecessor-version":[{"id":3803,"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/posts\/3802\/revisions\/3803"}],"wp:attachment":[{"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/media?parent=3802"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/categories?post=3802"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/tags?post=3802"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}