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How do you know the dinosaurs were extinct 64 to 65 million years ago?
Wiki User
∙ 14y ago
When plants fix atmospheric carbon dioxide (CO2) into organic material during photosynthesis they incorporate a quantity of 14C.After plants die or they are consumed by other organisms the 14C fraction of this organic material declines at a fixed exponential rate due to the radioactive decay of 14C. Comparing the remaining 14C fraction of a sample to that expected from atmospheric 14C allows the age of the sample to be estimated.Riki
Wiki User
∙ 14y ago
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How many millian years ago when the dinosaurs extinct from the asteroid?
scientists don't know if an asteroid killed the dinosaurs it is just a guess the dinosaurs died 65 million years ago
How do you know when the dinosaurs became extinct?
you don't because you weren't born yet but scientists say over a million years ago
Were dinosaurs alive 100 years ago?
No. As far as we know, nothing existed 75 billion years ago. The universe is about 13.7 billion years old and Earth about 4.55 billion. Dinosaurs appeared about 230 million years ago and died out 65.5 million years ago. So dinosaurs were around 75 million years ago, not 75 billion.
How many year passed the time the dinosaurs were dominant and when the dinosaurs became extinct?
The first date has to be an estimate, but since the dinosaurs effectively dominated the mammals by the start of the Jurassic (201 mya) we could reasonably credit them with 136 million years "in charge" using 65 mya (the end of the Cretaceous and a spectacular change in the fossil record) as the second.
Were ducks alive with dinosaurs?
Interestingly, ducks actually are dinosaurs. Based on fossil evidence, scientists now know that birds are the only surviving branch of dinosaurs. However, in terms of the classic view of dinosaurs, no. The first ducks appeared less than 25 million years ago, more than 40 million years after non-avian dinosaurs went extinct.
Where dinosaurs and cavemen living in the same time period?
No. Dinosaurs first emerged about 230 million years ago and, with the exception of birds, went extinct about 65 million years ago. The first human-like creatures appeared about 5 million years ago.
How many years were dinasours on earth?
Around 150 million years. 250 million is way off. I know its right because it was on `Who wants to be a millionaire`. I disagree the earth is only 6'000 years old so that is not possoble. P.S. you watch to much TV
What kind of dinosaurs roamed the earth in 248 to 206 million years ago?
The earliest dinosaurs evolved 231.4 million years ago, and only primitive dinosaurs had evolved by 206 million years ago. Dinosaurs we know of from that time range include Eoraptor, Eocursor, Herrerasaurus, and Plateosaurus.
Why did the thylacoleo become extinct?
the thylacoleo became extinct because of whop whop whop!!! lol lol lol
What are some elephants that were alive when dinosaurs where still alive?
Elephants and their relatives first appeared in the past 30 million years or so. Dinosaurs apart from birds went extinct 65.5 million years ago. So no elephants were around at the same time as non-avian dinosaurs.
When did water formed the Yosemite valley?
About a 100 million years ago. You know when there were dinosaurs.
Did people exist during the time of dinosaurs?
Yes and know. Most dinosaurs died of in a massextinction about 65 and a half million years ago. The oldest human ancestor or hominids found is about 3 to 4 millions years old. Some may have survived the mass extinction and others may have evolved into birds, fish and reptiles.
