What do scientists believe caused the extinction of the dinosaurs?

Answer 1

because back in the 1800's there was this huge asteroid that hit the earth. since it was so big all the dinosaurs in the world all died and now u can find dinosaur tracks on the ocean floor, rivers, lakes, and other bodies of water.so they died and became extinct because of the asteroid. that's how it happened

because back in the 1800's there was this huge asteroid that hit the earth. since it was so big all the dinosaurs in the world all died and now u can find dinosaur tracks on the ocean floor, rivers, lakes, and other bodies of water.so they died and became extinct because of the asteroid. that's how it happened

Answer 2

Scientists have many theories about what caused the extinction of dinosaurs. Below are thoughts on some of the most common theories:

• Since about 90% of dinosaurs were herbivores (plant eaters), it was thought that when an asteroid hit earth and many tons of dust was thrown into the atmosphere that the result was a "long night" due to the lack of sunlight that was able to reach earth, the plants died out and without a food source, so did the dinosaurs.

• It could also have been the combination of the Chicxulub asteroid impact event (causing worldwide fires and environmental catastrophe) in association with the Deccan Traps volcanic event, which occurred at around the same time, or possibly as a result of, the asteroid impact event.

• There are many theories that are written throughout history of why the dinosaurs exactly were driven into extinction. Most are meteor impact related. By looking at craters all over the world, scientists can estimate the meteors size, speed and its impacts effect on the local environment. See the related link for more information.

• Though the large meteorite impact (Chicxulub) figures prominently in a lot of the theories of how the dinosaurs became extinct, the idea of a gamma ray burst has also come up now that we are aware of them and the threat they pose. Additionally, there was an "outburst" of volcanic activity during this period. This extinction event is at the Cretaceous-Tertiary (K-T) boundary.

• It should also be added that several other large impact events occurred right about the time of Chicxulub, including Silverpit and Boltysh craters, among others. It seems the deck was "stacked against" the dinosaurs, regardless of how you look at it. It is possible that things are "found" to "corroborate" extinction by space rock, but the facts are pretty convincing, even for the skeptic.

• It was noted but is worth repeating: many of the ideas that represent credible ways that could have triggered the dinosaurs' extinction could have arisen separately and acted in concert to kill off all these creatures. One thing is certain - they're gone. And the demise of the terrible lizards was caused by something dramatic given the relatively narrow window in which they disappeared.

• The hypothesis that states an asteroid-impact was the sole cause of the extinction is just that - an hypothesis, not a fact. Most paleontologists feel that the asteroid impact was just one of a series of catastrophic events that ultimately wiped out the dinosaurs. There is evidence of a huge meteor strike just off the Yucatan Peninsula, true. And a meteor may well have put a final period to the extinction pulse. But there is also evidence that other factors may have been involved. For one thing, the dinosaurs didn't become extinct all at once. The pulse seems to have taken more than 10-thousand years to complete which makes the asteroid theory implausible as a complete explanation. There is evidence that there was massive volcanic activity also, and a drastic climatic change. The dinosaurs were in decline in number of species long before the K/T extinction was over. Furthermore, some dinosaurs did survive into Laramide time - the birds are still around (admittedly that's begging the issue, but it's not unreasonable to ask how they managed to survive when so many their brethren were killed).

• Dinosaurs were already fast becoming endangered species before the Chicxulub impact. Increased volcanic activity such as the Deccan Traps in modern day India was slowly killing many species. Between 68 to 60 million years ago 150,000 km2 of igneous rock was deposited in places more than 2 km thick. The bulk of the eruptions occurred about 66 million years ago near modern day Mumbai. These eruptions lasted as little as 33,000 years but the effect on the environment would have been staggering. Dust and debris thrown into the atmosphere along with sulphur dioxide would have cooled the earth. Also many poisonous gases would also have been released. Studies on modern day birds suggest that these poisonous gases not only directly killed dinosaurs but also caused thinning of the shells of their eggs which meant that many would fail to hatch.

• It has also been suggested that disease killed off the dinosaurs. A very deadly and contagious disease 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.
• When the continents broke up, they couldn't get to new feeding grounds when theirs were exhausted

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It mst also be pointed out that the avian type dinosaurs (the birds), did not become extinct and are living today.

Answer 3

We think a huge comet or asteroid killed the dinosaurs.

We don't know for sure, but we have evidence. A crater several miles in diameter has been found, with proof of extreme shockwaves meeting up at the exact opposite side of the globe and causing a massive earthquake. The combination of asteroids, shock waves, earthquakes, volcanoes caused by earthquakes, and the ash from all of those forces combined blocking out the sun for years because of its quantity and dinosaurs breathing the ash, the dinosaurs didn't stand a chance. We do not know if it was a chain reaction, such as the ash blocking the sun killing the plants, which starved the herbivores to death, which starved the carnivores to death. Some people believe there was a volcano that blew its top and was so huge, the lava swept across the globe. But I say, if that happened, the lava would have melted all evidence of dinosaurs, bones and eggs, for example. I have seen the massive crater with my own eyes, and so I believe that an asteroid's shockwaves killed the dinosaurs.

But, feel free to decide for your self.

Answer 4

there are lots of theries of how the dinosaurs became extinct and no one can really say which one is forsure the correct answer.

Answer 5

Because of the Boulder that had fell down onto the earth and killed them all and they didn't have any food or shelter so what they did was they were trying to find it and what happened mostly died

Answer 6

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Answer 7

asteroid impact

Answer 8

A harmful genetic mutations