After dinosaurs went extinct, what kept them from coming back?

Question

When they went extinct and life was able to form on earth again what made it so that the same species (dinosaurs) weren't able to re-evolve?

Answer 1

Evolution does not have a goal.  It doesn't say 'okay, we need bacteria, then insects, then fish, then reptiles, then dinosaurs' etc.  When the dinosaurs died off, it wasn't like evolution HAD to make dinosaurs again.  It was more like 'too bad, they had their chance.'

What species evolve is a result of the environment they live in.  The environment was different after the dinosaurs died off, so dinosaurs did not evolve again.

Something to keep in mind is that there is no such thing as 'more evolved.'  We're not any more evolved than chimps, or goldfish for that matter.  We're just *differently* evolved.

Answer 2

they were a killed off none left to reproduce sad but true .

Answer 3

creationism stopped it....

Answer 4

I believe it was the ice age that happened.  What was once dinosaurs species had evolved into creatures that adapted to the present environment.

Answer 5

they were actually much smarter than we give them credit for, and after seeing these nasty little biped hominids scuttling about decided oblivion was the better choice...

Answer 6

Extinct means there are none alive to breed new ones. Which means they can't come back.

Answer 7

It's actually an interesting and original question.

The problem is that evolution is not a preset path from primitive to advanced, with dinosaurs being a step along the way. Evolution is how life adapts to its environment, especially changes in same. And since environment is incredibly complex, and evolution is to some extent random, it can never take the same path twice.

IE the Earth after the impact which killed all the living dinosaurs was very different from the Earth that the dinosaurs evolved in, so evolution took a different path. I we had had the exact same starting conditions, something very like dinosaurs would likely have re-evolved, but we didn't.

Details:

The Earth's atmosphere was different, the Earth's climate was different, the mix of existing life was very different, and even the continents had moved since the dinosaurs first evolved.

Answer 8

No eggs, no babies.

Answer 9

Dinosaurs decided to stay in soil, because Micheal Jackson was too much for them/