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Did Insects Kill the Dinosaurs?
Ponca City, We Love You writes "Asteroid impacts, massive volcanic flows, and now biting, disease-carrying insects have been put forward as an important contributor to the demise of the dinosaurs. In the Late Cretaceous the world was covered with warm-temperate to tropical areas that swarmed with blood-sucking insects. A theory explored by researchers at Oregon State suggests these bugs carried leishmania, malaria, intestinal parasites, arboviruses and other pathogens. Repeated epidemics may have slowly-but-surely worn down dinosaur populations while ticks, mites, lice and biting flies tormented and weakened them. 'After many millions of years of evolution, mammals, birds and reptiles have evolved some resistance to these diseases,' says Researcher George Poinar. 'But back in the Cretaceous, these diseases were new and invasive, and vertebrates had little or no natural or acquired immunity to them.' The confluence of new insect-spread diseases, loss of traditional food sources, and competition for plants by insect pests could all have provided a lingering, debilitating condition that dinosaurs were ultimately unable to overcome."
It might work! But only if that insects - along with carrying various diseases - also carried giant, planet-killing asteroids with them. If we just call the "Dinosaur Period" the Jurassic through Cretaceous, that lasted from 200 million years before now to 65 million years before now (+/- 5-10 million years). I find it kind of hard to swallow that Dinosaurs couldn't build up an immunity to disease over a period of 135 [i]million[/i] years. Viruses can evolve and change hundreds of times in the course of a human lifetime (which you can't even measure with Geologic time). If Viruses were around for 135 million years when Dinosaurs were around, the Dinosaurs had to have pretty hefty immune systems to be able to cope with all the new viruses evolving. And considering that they actually lasted until a giant rock fell out of the sky, I'd say that getting head colds probably didn't do them in.
Give a man a fire and he'll be warm for a day. But light a man on fire and he'll be warm for the rest of his life.
'But back in the Cretaceous, these diseases were new
They were new? I am by no means an authority on the subject, but from what I remember learning about evolution, one-celled-organisms came along before cell colonies. Further, small cell colonies (bugs and such) came around before big ones (dinosaurs and such). I even recall learning that the first self-replicating DNA strands were much more virus-like than bacteria-like...since the whole membrane and organelle system didn't come about until a bit later.
So, by the time the dinosaurs were around, the world should have already been densely populated with viruses, bacteria, and small bugs which could find the guts of a dinosaur to be fertile breeding grounds.
I really don't see how these things, and the diseases they cause, could have come around after the fact. Maybe some more sinister versions of them, more specifically targeted at the dinosaurs of the day, came around after the fact, but I don't think that alone would account for a mass extinction.
If you have corrections to offer, don't hold back (not that you would).