V roce 2016 narazil geolog Allan Krill p\u0159i pr\u016fzkumu stezky Bright Angel Trail v N\u00e1rodn\u00edm parku Grand Canyon na zaj\u00edmav\u00fd objev. Do velk\u00e9ho p\u00edskovcov\u00e9ho balvanu byla vytes\u00e1na \u0159ada prohlubn\u00ed p\u0159ipom\u00ednaj\u00edc\u00edch prastar\u00e9 stopy. Tyto otisky se uk\u00e1zaly b\u00fdt zkamen\u011bl\u00fdmi stopami \u2013 nejstar\u0161\u00edmi stopami obratlovc\u016f, kter\u00e9 byly kdy v parku nalezeny.<\/p>\n\n
Paleontolog Stephen Rowland, kter\u00fd stopy prozkoumal, odhadl jejich st\u00e1\u0159\u00ed na p\u0159ibli\u017en\u011b 313 milion\u016f let. Tento pozoruhodn\u00fd n\u00e1lez nejen p\u0159in\u00e1\u0161\u00ed sv\u011btlo do v\u00fdvoje ran\u00fdch obratlovc\u016f, ale tak\u00e9 poskytuje nejstar\u0161\u00ed d\u016fkaz amniot \u2013 tvor\u016f, kte\u0159\u00ed kladou vejce s tvrd\u00fdm obalem \u2013 na sv\u011bt\u011b.<\/p>\n\n
Balvan nesouc\u00ed stopy, v\u00e1\u017e\u00edc\u00ed stovky kilogram\u016f, spadl z Manakacha Formation, p\u00edskovcov\u00e9ho \u00fatvaru, kter\u00fd se vytvo\u0159il p\u0159ed p\u0159ibli\u017en\u011b 314 miliony let. Stopy vznikly tak, \u017ee se p\u00eds\u010dit\u00fd povrch zvlh\u010dil a pot\u00e9 vyschl, \u010d\u00edm\u017e se otisky na miliony let zachovaly.<\/p>\n\n
Na povrchu balvanu jsou patrn\u00e9 dva odli\u0161n\u00e9 soubory stop. Prvn\u00ed soubor pat\u0159\u00ed zv\u00ed\u0159eti, kter\u00e9 pomalu kr\u00e1\u010delo pomoc\u00ed \u201epostrann\u00ed sekven\u010dn\u00ed ch\u016fze\u201c, kdy se kon\u010detiny pohybuj\u00ed v ur\u010dit\u00e9m vzoru kv\u016fli stabilit\u011b. Druh\u00fd soubor stop nazna\u010duje o n\u011bco rychlej\u0161\u00ed tempo.<\/p>\n\n
Studium stop p\u0159ineslo cenn\u00e9 poznatky o chov\u00e1n\u00ed a prost\u0159ed\u00ed ran\u00fdch obratlovc\u016f. Postrann\u00ed sekven\u010dn\u00ed ch\u016fze pozorovan\u00e1 u jednoho ze zv\u00ed\u0159at je zp\u016fsob pohybu b\u011b\u017en\u011b pou\u017e\u00edvan\u00fd \u017eij\u00edc\u00edmi \u010dty\u0159no\u017eci, jako jsou psi a ko\u010dky, p\u0159i pomal\u00e9m pohybu. Tento objev nazna\u010duje, \u017ee tento zp\u016fsob ch\u016fze se vyvinul ji\u017e brzy v historii obratlovc\u016f.<\/p>\n\n
Nav\u00edc p\u0159\u00edtomnost stop amniot\u016f v p\u00edse\u010dn\u00fdch dun\u00e1ch posouv\u00e1 zn\u00e1mou \u010dasovou osu v\u00fdskytu amniot\u016f v takov\u00fdch stanovi\u0161t\u00edch zp\u011bt o nejm\u00e9n\u011b 8 milion\u016f let. Tento n\u00e1klad roz\u0161i\u0159uje na\u0161e ch\u00e1p\u00e1n\u00ed diverzifikace a adaptace ran\u00fdch obratlovc\u016f.<\/p>\n\n
Mark Nebel, vedouc\u00ed paleontologick\u00e9ho programu v Grand Canyonu, poznamen\u00e1v\u00e1, \u017ee n\u011bkter\u00e9 aspekty z\u00e1v\u011br\u016f studie mohou b\u00fdt p\u0159edm\u011btem v\u011bdeck\u00e9 debaty, zejm\u00e9na pokud jde o interpretaci stop a st\u00e1\u0159\u00ed hornin. Zd\u016fraz\u0148uje v\u0161ak vzru\u0161en\u00ed, kter\u00e9 objev vyvol\u00e1v\u00e1, proto\u017ee odhaluje nov\u00e9 informace o prehistorick\u00e9m sv\u011bt\u011b a vyz\u00fdv\u00e1 k p\u0159ehodnocen\u00ed na\u0161eho ch\u00e1p\u00e1n\u00ed ran\u00e9 evoluce obratlovc\u016f.<\/p>\n\n
Objev prastar\u00fdch stop plaz\u016f v Grand Canyonu otev\u0159el okno do vzd\u00e1len\u00e9 minulosti a poskytl cenn\u00e9 poznatky o p\u016fvodu a chov\u00e1n\u00ed ran\u00fdch obratlovc\u016f. Studie nad\u00e1le vyvol\u00e1v\u00e1 diskusi a v\u00fdzkum, \u010d\u00edm\u017e d\u00e1le obohacuje na\u0161e znalosti o t\u011bchto fascinuj\u00edc\u00edch tvorech.<\/p>","protected":false},"excerpt":{"rendered":"
Prehistorick\u00e9 stopy plaz\u016f odkryty v Grand Canyonu Objev a jeho v\u00fdznam V roce 2016 narazil geolog Allan Krill p\u0159i pr\u016fzkumu stezky Bright Angel Trail v N\u00e1rodn\u00edm parku Grand Canyon na…<\/p>\n","protected":false},"author":2,"featured_media":25195,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[244],"tags":[23635,22340,137,23636,1561,19362],"class_list":["post-18056","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-natural-history","tag-ancient-reptiles","tag-grand-canyon","tag-paleontology","tag-prehistoric-discovery","tag-vertebrate-evolution","tag-fossil-footprints"],"_links":{"self":[{"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/posts\/18056","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\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/comments?post=18056"}],"version-history":[{"count":2,"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/posts\/18056\/revisions"}],"predecessor-version":[{"id":25196,"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/posts\/18056\/revisions\/25196"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/media\/25195"}],"wp:attachment":[{"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/media?parent=18056"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/categories?post=18056"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.lifescienceart.com\/cs\/wp-json\/wp\/v2\/tags?post=18056"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}