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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."
Admittedly I didn't RTFA, but are these scientists saying that the dinosaurs WEREN'T killed by the huge Chixulub asteroid? I thought it had been pretty much established that that was what happened (iridium concentrations at the K-T boundary, 65M-year old impact crater, 70% of other species kicking the bucket at the same time, etc.)
It seems very unlikely that a whole planet of dinosaurs were killed by insects. It is actually very difficult for insects to cover an entire continent, let alone move from continent to continent. In current times, insects stowaway on ships and planes to travel large distances and between continents. Also, if this were true regarding reptiles, what about crocodiles? They've been living much longer than any of the dinosaurs and the lived in conditions where mosquitoes thrive. How do you explain them?
You're mistaken on the principle of parasitism, possibly confusing it on some level with symbiosis. Parasites don't need to keep a host alive. Many parasites kill their hosts (as intended). Parasitic wasps, for instance, lay eggs inside their hosts which then hatch with the larva proceeding to eat the host from the inside out. Such wasps are in fact sometimes used as a "natural" method of pest control.
I like basketball!!1!
Although "Dinosaur" is used very widely, and often used to refer to extinct reptiles like the Pliseosaur, Pteridon, or Leoplurodon; the groups wiped out were, properly speaking, the Therapods (popularly the T-Rex, Velociraptors, and their kin) and the Sauropods (Brachiasaur, Triceritops, etc). Neither of these groups survived the mass extinction at the end of the Cretatious period.
Sharks are sharks, Ceolocanths are fish, and Aligators are reptiles. Although all three forms date back very nearly how they look now to the time of the dinosaurs, it would be an equivocation to call them "dinosaurs" when discussing the "extinction of the dinoasurs".
Apologies for spelling, mine is pretty poor.
"and the Sauropods (Brachiasaur, Triceritops, etc)"
Triceratops wasn't a sauropod. Like other marginocephalians, it was a member of one of three orithischian (bird hipped) groups (the other two are threophora which includes armoured dinosaurs such as ankylosaurus and stegosaurus, and ornithopods such as the hadrosaurs). Sauropods were saurischian (lizard hipped), and are therefore more closely related to therapods than either are to the ornithischians.
I'm not going to change your sheets again, Mr. Hastings.
They were not claiming that these diseases did not exist until this time. They are saying that the diseases adapted to insects and used the insects as carrying agents at far back as the cretaceous period, maybe longer.
We have always been at war with Eurasia!
"In other terms, birds are descendants and cousins of dinosaurs, but they are not a species of dinosaur."
Sorry, but that was an example of the common misconception I was trying to point out. Contrary to your proposal, birds _are_ a group of species of dinosaurs.
If all mammals, except the bats for example, went extinct, your favorite bat would not seize or stop being a mammal. And the number of very specific adaptations of the bats would NOT set them apart (sonar, leathery wings, wrinkled noses, large ears, etc). The bats would remain inside the mammal group, just as all the bird species remain inside the dinosaurs. Bats are specialized mammals and birds are specialized dinosaurs.
If a mosquito born disease would kill all mammals, the bats would die out too. Therefore it was probably not a disease that killed all dinosaurs and spared that group we now call birds.
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You are correct. My post contained an unfortunate typo.
I'm not going to change your sheets again, Mr. Hastings.