27 replies to this topic

[nirmaldaniel]

okay, here i have a clarification, every one says dionosours got extinct , why is that when some one say the term "extinct species" immediately the thing that comes to our mind is Dianosours . Is Dianosour the only species which got extinct ?? or are there many other species but we forget them ?? Why is that every one remembers this animal alone ? just try asking a small kid , do you know extinct species, they will shoot out Dianosours . Is this because of its gigantic structure that every one remembers it or does it have some other reason too ??

But thanks to Jurassic park any way, else it would have been difficult to make kids understand what a dianosur is and what all it does

[kleong]

As such as the debates on the theories on how the dinosaurs got extinct, anyone interest to discuss how did mankind come along? And pls, as much as possible, try not to mention the bible in the debate.

[webishqiptar]

What killed the dinosaurs? What did disappear in a short time the large reptiles that had dominated the Planet? The researchers (and fans of lizards) are quarreling for decades over what is the real cause of their extinction. Peter Schulte and 41 other scholars around the globe are trying to put an end (at least for the moment) the age-old question in an article due out tomorrow in Science and is the result of a review of all studies and Evidence gathered over the past twenty years.

Schulte, geologist Geocenter delll'università of Ernlagen-Nürnberg and his large group of colleagues say that the great extinction occurred at the end of the Cretaceous period in which more than half of all species disappeared, including the dinosaurs, gaudy, is due to the single impact an asteroid.
A meteorite crashed 15 km in diameter that generated the Chicxulub crater in Mexico. With a sudden a billion times more powerful than the bomb that destroyed Hiroshima and devastating tsunami waves lifted instantly anywhere in the world. The earthquake broke the tenth on the Richter scale and raised so much dust and gas that the sun was darkened for a long time, the earth's surface cooled, the oceans acidify killing in a few days photosynthetic organisms and those who depended on them.
Disappeared in one fell swoop (it must be said) dinosaurs, pterosaurs (winged reptiles that looked like birds and were the first vertebrates that can fly), and large marine reptiles, paving the way for the domination of mammals.
Thirty years ago, Nobel laureate Luis Alvarez, Jan Smith and colleagues found in the late Cretaceous sediments Createsi (collected near Gubbio) an unusually high concentration of iridium, a chemical element rare on Earth but common in meteorites. Then hypothesized that a large asteroid hit the earth 65 million years ago causing the extinction of the dinosaurs and many other species. In 1991, an impact crater 200 km wide as it was discovered in Mexico, the Yucatan Peninsula.
Since then, the impact hypothesis to explain the great extinction of the Late Cretaceous, one of the three largest in the history of life on earth, has gathered more support. Other hypotheses, however, were taken into account, such as prolonged volcanism that lasted 1.5 million years and poured in Deccan Traps lava so than it would have been enough to fill the Black Sea twice. It is thought that the endless eruptions have caused a cooling of the atmosphere and acid rain over the entire planet.
According Shulte, however, this event caused - in 500 thousand years that separate him from the impact of meteorites - only small changes in the types of fossils have been found in sediments at the time. And the sulphurous fumes produced by volcanism, the researchers did not have enough life in the atmosphere to cause such a disaster on land and seas.
To convince the authors of the article to be published tomorrow in Science of the validity of the meteorite would especially the abundance of iridium, which has now been found in sediments of the time all over the planet, which is followed by plenty a sudden absence of fossils in successive layers, In addition, the presence, always in sediments of the time and always around the globe, a form of quartz that arises when it is hit by a strong shock wave. A form of quartz that is usually found only in the areas affected by nuclear explosions or meteorite impact.
The researchers also argue that the studies that concluded that the Chicxulub crater was generated del'estinzione 300 thousand years before the great reptiles had misinterpreted the geological data that you were served.