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how did the dinosaurs become extinct?what caused their extinction?

Asked by Elna Ann Shany(student) , on 20/9/14


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How did the dinosaurs become extinct

How did the dinosaurs become extinct? This is a question that has stumped scientists ever since dinosaur fossils were first discovered. There are many theories as to how the dinosaurs became extinct. This page presents some of the most popular thoeries. Keep in mind that there is no absolutely proven theory. Noone knows for certain exactly why and how the dinosaurs became extinct.
Probably the most popular theory right now is the Asteroid Theory. According to this theory a large asteroid or comet collided with Earth about 65 million years ago. Scientists think that such a large collision would throw so much dust into the air that sunlight would not be able to shine and plants and animals would die. The dramatic changes in climate that resulted from this huge collision were too much for the dinosaurs. They were not able to survive.
Another theory that could explain how the dinosaurs became extinct is volcanic activity. A huge increase in volcanic activity at around 65 millions years ago could have pumped so much ash into the air that it blocked out the sun killing the dinosaurs.
Some scientists believe that there was a severe ice age. Throughout Earth 's history there have been many ice ages. The last one ended about 10,000 years ago. A very severe ice age could have changed temperatures and frozen a lot of Earth 's water. The dinosaurs would not be able live under such conditions and that is how the dinosaurs became extinct.
It has also been suggested that desease killed off the dinosaurs. A very deadly and contagious desease may have circulated among the dinosaurs forcing them to become extinct.
Still yet another theory is that the Earth just gradually changed in climate over a long time period and the dinosaurs were not able to adapt to the cooler, dryer climate.
There are probably other theories as to how the dinosaurs became extinct. One thing is for certain. All dinosaurs that we know of are extinct. How did all the dinosaurs become extinct? Maybe one of these theories is the right answer. However, it is difficult to explain why all the dinosaurs died out but many other animals survived. Perhaps one day we will know for certain how the dinosaurs became extinct. Until then we must speculate and continue the search for the answer to this great mystery of nature.
 

Posted by Kishore(parent)on 28/4/13

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How did the dinosaurs become extinct

How did the dinosaurs become extinct? This is a question that has stumped scientists ever since dinosaur fossils were first discovered. There are many theories as to how the dinosaurs became extinct. This page presents some of the most popular thoeries. Keep in mind that there is no absolutely proven theory. Noone knows for certain exactly why and how the dinosaurs became extinct.
Probably the most popular theory right now is the Asteroid Theory. According to this theory a large asteroid or comet collided with Earth about 65 million years ago. Scientists think that such a large collision would throw so much dust into the air that sunlight would not be able to shine and plants and animals would die. The dramatic changes in climate that resulted from this huge collision were too much for the dinosaurs. They were not able to survive.
Another theory that could explain how the dinosaurs became extinct is volcanic activity. A huge increase in volcanic activity at around 65 millions years ago could have pumped so much ash into the air that it blocked out the sun killing the dinosaurs.
Some scientists believe that there was a severe ice age. Throughout Earth 's history there have been many ice ages. The last one ended about 10,000 years ago. A very severe ice age could have changed temperatures and frozen a lot of Earth 's water. The dinosaurs would not be able live under such conditions and that is how the dinosaurs became extinct.
It has also been suggested that desease killed off the dinosaurs. A very deadly and contagious desease may have circulated among the dinosaurs forcing them to become extinct.
Still yet another theory is that the Earth just gradually changed in climate over a long time period and the dinosaurs were not able to adapt to the cooler, dryer climate.
There are probably other theories as to how the dinosaurs became extinct. One thing is for certain. All dinosaurs that we know of are extinct. How did all the dinosaurs become extinct? Maybe one of these theories is the right answer. However, it is difficult to explain why all the dinosaurs died out but many other animals survived. Perhaps one day we will know for certain how the dinosaurs became extinct. Until then we must speculate and continue the search for the answer to this great mystery of nature.
 

Posted by Kishore(parent)on 28/4/13

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Dinosaur Extinction

Dinosaurs first appeared on Earth about 215 million years ago. They were the most important land animals for about 150 million years. By 65 million years ago, however, most of them had died out.

Many scientists believe that a large asteroid, or rock from space, caused this mass extinction. When the asteroid hit Earth, the impact caused drastic changes. Thick dust and other materials blocked the sun. Temperatures dropped, and plants could not grow. The dinosaurs could not survive the cold temperatures and lack of food. But early species of birds and mammals did survive.

One of the possible reasons is that a massive meteorite, asteroid or comet may have collided with Earth. The dust thrown up in such a collision could have blocked the light from the sun. This would have resulted in a cold and dark period. The loss of sunlight would have caused plants to die. The herbivores would have then died because they had nothing to eat. Their predators, the carnivores, would also have died as a result. An interesting fact that has puzzled scientists is that some animals survived beyond the period when the dinosaurs disappeared. If a disastrous collision did take place it is not clear why some animals were not hurt by it. The ancestors of such modern animals as frogs, turtles, lizards and snakes found a way to survive. Birds, which are said to be descendants of dinosaurs, also survived. Perhaps these survivors will give scientists the clues they need to find out what exactly happened to the dinosaurs.

Posted by Shivani(student)on 2/6/14

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Dinosaur's extint because of the climet change shortage of food.

Posted by Zeba(student)on 2/6/14

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Hi !

Dinosaur extinction was caused due to climate change, food shortage and the main reason disasters.

Thumbs up !

Posted by Arnab Paul(student)on 3/6/14

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what are the animals becoming extinction?

Posted by Stacy(student)on 22/8/14

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The dinosaurs' extinction was probably caused by a meteorite. This can be proven because a huge crater was found in the Yucatan Peninsula in Mexico. Many other theories about what killed the dinosaurs have been proposed, but a meteorite is the most likely one. It may be, though, that the dinosaurs were already slowly dying out because the world's climates were gradually becoming more extreme as the continents drifted farther apart.

Regards

Keep Posting!

Posted by Shlok N. Lokre(parent)on 20/9/14

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The dinosaurs' extinction was probably caused by a meteorite. This can be proven because a huge crater was found in the Yucatan Peninsula in Mexico. Many other theories about what killed the dinosaurs have been proposed, but a meteorite is the most likely one. It may be, though, that the dinosaurs were already slowly dying out because the world's climates were gradually becoming more extreme as the continents drifted farther apart.

Posted by Aatman(student)on 20/9/14

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The dinosaurs (except the birds) went extinct 65 million years ago, probably due to the after-effects of an asteroid impact off the Yucatan Peninsula. There are a lot of theories about why this K-T (Cretaceous-Tertiary) extinction occurred, but a widely accepted theory (proposed in 1980 by physicist Luis Alvarez and his son Walter Alvarez, a geologist), is that an asteroid 4-9 miles (6-15 km) in diameter hit the Earth about 65 million years ago. The impact would have penetrated the Earth's crust, scattering dust and debris into the atmosphere, and caused huge fires, volcanic activity , tsunamis, severe storms with high windsand highly acidic rain . The impact could have caused chemical changes in the Earth's atmosphere, increasing concentrations of sulfuric acid, nitric acid, and fluoride compounds. The heat from the impact's blast wave would have incinerated all the life forms in its path. The dust and debris thrust into the atmosphere would have blocked most of the sunlight for months, and lowered the temperature globally. Those organisms that could not adapt to the temperature and light changes would die out. Since plants' energy is derived from the sun, they would likely be the first to be affected by changes in climate. Many families of phytoplankton and plants would die out, and the Earth's oxygen levels may well have dramatically decreased, both on land and in the oceans, suffocating those organisms which were unable to cope with the lower oxygen levels. Major changes in the food web would result from all of these these environmental upheavals. The herbivores (plant eaters) who ate those plants would starve soon after the plants died. Then, at the top of the food chain, the carnivores (meat eaters), having lost their prey, would have to eat each other, and eventually die out. Their large carcasses must have provided smaller animals with food for quite a while. Although most dinosaurs went extinct about 65 million years ago, one branch of the dinosaurs (the dromaeosaurids) evolved into the birds.

Posted by Shivani(student)on 23/9/14

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Dinosaurs became extinct about 65 million years ago at the end of the cretaceous period (see what cretaceous dinosaurs were around at this time). About 70% of all animal life on earth died out. Scientists call it a mass extinction it wasnt the first mass extinction in earths history and it probably wont be the last! Having existed for 165 million years, why did dinosaurs die out? There are many different theories about why this happened. We will probably never know exactly what happened, which means that scientists will continue to disagree and come up with different dinosaur extinction theories. Here are some of them:

Asteroid Impact

A massive asteroid hit the earth at Chicxulub on the Yucatan Peninsula in Mexico about 65 million years. The meteor crater is 180 km from rim to rim and scientists have worked out that the asteroid must have been 10 km across. It is thought that the impact would have caused massive damage, including a giant dust cloud which lead to massive changes in the climate. This would have destroyed lots of the cretaceous plants, so herbivorous dinosaurs starved and the meat eating ones were left with nothing to eat either.

Ice Age Theory

Now and again, the earth cools into periods we call ice ages. As dinosaurs were thought to be cold blooded, it would have been hard for them to cope with such cold conditions. For example, if large parts of the planet were covered in ice, then there would have been little or no plants for herbivorous dinos to eat. However, there is no real evidence of an ice age at this time.

Volcano Theory

There was massive volcanic activity between 63 and 67 million years ago, particularly on the Deccan Plateau in western India. This, again, would have caused a massive change in climate, which dinosaurs would have found hard to adapt to.

Disease

It is possible that a disease spread through the dinosaur population causing their extinction.

Competition from Other Animals

Fossils of small mammals have been found from 65 million years ago. It is possible that these small cretaceous animals started to compete with dinosaurs, for example stealing and eating dinosaur eggs. However, no-one is sure whether mammals caused dinosaur extinction, or they thrived because dinosaurs were no longer around.

Gradual Extinction

The number of dinos declined throughout the cretaceous period. Maybe a number of factors contributed to their eventual extinction and they just died out. Dinosaur extinction is a big mystery, as although dinosaurs died out at this time, many species survived, including similar animal types like crocodiles.

New Discoveries

Scientist have come up with some strange ideas but none of the theories really explains everything, so we will probably never be sure what happened.

Posted by Shivani(student)on 23/9/14

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Because they were not able to adapt themselves in the environment

Posted by Lavanya Joshi(student)on 24/9/14

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