What made the dinosaur become extinct? There are so many different opinions on this. What do you think?

I'm sticking to the comet/asteroid impact idea, unless something better comes along. The theory seems to explain most of the data, if I'm not mistaken.

Of course, Gary Larson said the real reason was dinosaurs smoking cigarettes.

Although the comet/asteroid theory is very popular, no impact site has been find that dates to the projected time of extinction. Every major extinction has had, in some way, a climate change. One very popular theory that is very possible and includes the climate change is that alot of major volcanic eruptions sent up millions of tons of ash, dust and gases. These would block out the sunlight for an extensive period of time, and poisen the plants. When the plant-eaters died, the meat-eaters would have no food, and would have to eat the contaminated herbivores, and thus creating a chain reaction. The same thing would have happened in the seas. Fish-eating pterosaurs would swoop down and catch a contaminated fish. They would then die and if they had young, the young would die of starvation or of poisening if the parent lived long enough to bring them a contaminated fish.

Plesiosaurs would also eat infected fish and die, their bodies in turn would be eaten by other creatures, effectively creating a chain reaction.

No one is sure how the last 10% of all creatures survived, as mammals, some fish (coelecanth), reptiles (crocodiles, tortoises), some insects and some birds lived on through all of this. It is a mystery, but I am going to support this theory.

Isn't the Gulf of Mexico said to have been formed from a comet or asteroid? Is it from the right time?

I think that Fred Flintstone and the entire Bedrock population had something to do with it!

Have you ever seen the humongous portions of dinasour ribs on their dinner plates??

Yabba dabba Doooo!!!!!!!!

I tried to find a pic of the ribs but couldn't. Just imagine I found one, pasted it here and it was super funny!

(I see ya laughing tree!)

{{{{{ Tree }}}}}


I would think if there was no sun then everything would die. I have also heard the "ice age" story. (I'm not quite sure what that is but it didn't make sense to me)

There have been large climactic shifts in the earth's history, and I'm of the opinion that these could have caused the extinction of dinosaurs.......things like tropical climates turning into arctic-like climates due to ice ages......that kind of thing.

click

The only two theories (to my knowledge) plausibly supported by the evidence have been mentioned (asteroid and volcanoes).

There is a layer of the Earth that is enriched in iridium (the KT or Cretaceous - Tertiary boundary). This enrichment could plausibly be from either ash from volcanic erruptions or debris from an asteroid and occurs at the same depth (and therefore time) as the dinosaurs' extinction.

The asteroid theory is generally regarded as the more likely of the two (although it is thought that the asteroid triggered volcanic eruptions as well). Other evidence for it includes:
- soot that would have been produced from the fires due to the elevated temperature
- alterations in quartz crystals that would only occur with a combination of high temperatures and high pressures.
- an impact crater. Jusork is nearly correct. The Gulf of Mexico was not formed by a crater, but there is one located in it near the Yucatan Peninsula. The crater is the right age to have killed the dinosaurs and the right size to have been responsibly for the iridium in the KT boundary.

LOLOL @ clare and methos!!!