Did mozzies, not a meteor, do for the dinosaurs?

cnredd · #1 (**permalink**) 01-06-2008, 09:52 PM

Quote:

The theory goes that dinosaurs were wiped out after an asteroid smashed into the Earth 65million years ago.

But now it has been suggested they were sent into eternity by an equally catastrophic but somewhat smaller threat - biting insects.

Disease spread by mosquitoes, mites and ticks was probably the major factor that finished off the reptiles, say scientists.

The insects could have also made it harder for dinosaurs to survive by changing the nature of plant life.

Bees and other pollinators helped promote the rapid spread of flowering plants, leading to the loss of vegetarian dinosaurs' traditional food sources. As the planteating dinosaurs declined, so would their predators.

The theory helps explain why dinosaurs took so long to die off, say husband-and - wife team George and Roberta Poinar.

According to the most widely accepted explanation, the dinosaurs vanished after an asteroid or comet hit the Earth between the Cretaceous and Tertiary periods.

Another theory is that they were driven to extinction by massive volcanic eruptions in India, which led to extreme climate change.

But George Poinar, a courtesy professor of zoology at Oregon State University, points out that they did not disappear immediately.

Their extinction was drawn out over hundreds of thousands or even millions of years.

An asteroid impact should have led to an abrupt extinction, and climate change would probably also have wiped them out in a relatively short time, he said.

But emerging diseases spread by biting insects, combined with the spread of flowering plants, and competition with insects for plant resources, was "perfectly compatible" with a lengthy process of extinction.

The Poinars outline their theory in What Bugged The Dinosaurs? Insects, Disease And Death In The Cretaceous, published by Princeton University Press.

The professor said examination of insects preserved in amber found organisms which can cause malaria, dysentery "and other abdominal disturbances".

I have a problem with this, because it contradicts how evolution is supposed to work...

Immune systems surely would "kick in" after "hundreds of thousands" of years...

I could imagine something like a Black Plague happening that wouldn't give enough time for the body to combat, but that clearly didn't happen given the time involved...

saltwn · #2 (**permalink**) 01-09-2008, 10:15 AM

I don't know, but I never did buy the old asteroid theory. It's just too far fetched.
It could be something simple like competition with smarter mammals. Which is how they think Neanderthal disappeared. DNA proved he was never our ancestor after all, but a distant cousin instead.
But what would be a predator to a dinosaur? That's another question. Because a lot of them were so huge, we find it difficult to imagine any other animal could have developed into something that could take down a dinosaur. Disease is certainly a possibility, especially if several new ones developed every few years.
Maybe the changes in climate did produced dino killers!

Spencer Collins · #3 (**permalink**) 01-09-2008, 09:18 PM

And this interesting debate will continue. I agree,it seems like their immune systems would have been well developed over that space of time. Who knows what evil lurks among the microbes?.

saltwn · #4 (**permalink**) 01-10-2008, 01:57 AM

Quote:

Originally Posted by Spencer Collins

And this interesting debate will continue. I agree,it seems like their immune systems would have been well developed over that space of time. Who knows what evil lurks among the microbes?.

The Shadow knows...