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Ana içerik
Güncel saat:0:00Toplam süre:1:55

Neden Kuşlar Dışındaki Bütün Dinozorların Nesli Tükendi?

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the question of non bird dinosaur extinction is really an open one I mean certainly that there's tremendous amount of evidence in fact that there's no doubt that at the time the dinosaurs went extinct a large meteorite or asteroid hit the planet somewhere off that the Yucatan Peninsula in Mexico however directly tying this event to the disappearance of the terrestrial fauna is very difficult and that's just because our sample is so small there's only a couple of places in the world where that both dinosaur fossils as well as evidence of the impact are preserved both of those are in Western North America so we don't know that whether it was an instantaneous event we don't know whether the dinosaurs in the southern hemisphere like held on for millions of years afterwards we just don't have the record to be able to determine that one thing we do know though is that certainly that the dinosaurs non bird dinosaurs appear to be coming more and more rare less common as you approach the time when the meteorite hit about sixty five point four million years ago so that it's not like everything was going great and then you just had this massive cataclysmic event and everything disappeared we know that you know stuff was changing stuff was changing quickly at the same time there was a huge amount of volcanic activity especially from places in western India and interestingly enough this coincides with around the time of the asteroid impact so many paleontologists feel that it was a combination of factors maybe both asteroids and volcanoes that did the non bird dinosaurs in and I should emphasize not just a non avian or non bird dinosaurs but many many other animals and plants in fact we estimate that maybe as much as 75 percent of all the species that lived on the earth at that time went extinct during this very dramatic event
Biyoloji bölümünün hazırlanmasına destek olan kurum: Amgen Foundation