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Earth Science

Insects May Have Had a Hand In Dinosaur Extinction 270

eldavojohn writes "Everyone's got their favorite theories of Dinosaur extinction, but new speculation is rampant in a book that gives cause to believe it may have been disease-carrying insects. Due to the length of their slow and eventual extinction (the 'K-T Boundary'), it is argued that this would more likely be attributed to the spread of disease and the rise of parasitic insects like ticks or biting flies. Are our immune systems the only reason any animals survived?"
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Insects May Have Had a Hand In Dinosaur Extinction

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  • Yes (Score:2, Funny)

    by davidangel ( 1337281 )
    It's all our fault.
  • by cloudkiller ( 877302 ) on Thursday September 04, 2008 @11:04AM (#24874007) Homepage Journal
    someone get me a can of WD40 and a lighter.
    • Re: (Score:3, Informative)

      by catmistake ( 814204 )

      Its amazing how many come up with this solution independently when dealing with unwanted bees nests. Spraying soapy water is FAR more effective, less dangerous, though admittedly, not nearly as cruel or fun.

  • by pzs ( 857406 ) on Thursday September 04, 2008 @11:05AM (#24874017)

    Do insects have hands?

  • Three questions (Score:5, Insightful)

    by A nonymous Coward ( 7548 ) * on Thursday September 04, 2008 @11:07AM (#24874063)

    Why wouldn't this also affect mammals? Is there an implication that dinosaurs had more primitive immune systems? Is any of this more than mere speculation?

    I also would have thought dinosaurs had thicker skin, if for no other reason than having a lot more meat to hold together than the puny mammals of the time. Is this not a factor? Do modern day elephants and rhinoceroses suffer from insect infestations even tho they have thick skins?

    And lastly, I thought recent research had shown that the slow dying theory was just an artifact of the skimpy fossil record, that they did indeed die out very abruptly at the K-T layer. Is my memory wrong here?

    • Re:Three questions (Score:5, Interesting)

      by Chris Burke ( 6130 ) on Thursday September 04, 2008 @11:11AM (#24874129) Homepage

      Why wouldn't this also affect mammals? Is there an implication that dinosaurs had more primitive immune systems? Is any of this more than mere speculation?

      Well this is mere speculation, but the implication isn't necessarily that dinosaurs had a more primitive immune system, it could simply be that it was different. Different diseases infect different animals. It makes sense that if a virulent and deadly disease borne by insects arose in one species of dinosaur, it would have an easier time adapting to others than the newly arisen mammals.

      • Re:Three questions (Score:5, Informative)

        by sm62704 ( 957197 ) on Thursday September 04, 2008 @12:24PM (#24875301) Journal

        You mean like how fleas carrying the plague made rats and humans extinct during the dark ages?

        IIRC insects predate dinasaurs. Sorry, I'm a skep tick.

        The book's author [uky.edu] isn't a palentologist, he is with the Department of Entomology at Oregon State University. He is (like I am now) making claims he does not have the credentials for.

        • Re:Three questions (Score:5, Informative)

          by Chris Burke ( 6130 ) on Thursday September 04, 2008 @12:45PM (#24875669) Homepage

          Uh, the species of rat which carried the Black Death did very nearly go extinct, and it wiped out one third of the population of Europe in just two years, in some areas as much as 60-75%. If that had been combined that with other pressures occurring simultaneously, like extreme changes in the environment, then yes, even two of evolution's greatest generalists could have been brought low.

          I can't say I believe it, but I also don't find it inherently implausible.

          • Re: (Score:3, Informative)

            Humans would not have been "brought low". There are plenty of humans outside of Europe.

      • Re: (Score:3, Informative)

        It makes sense that if a virulent and deadly disease borne by insects arose in one species of dinosaur, it would have an easier time adapting to others than the newly arisen mammals.

        It would...

        Of course, it affected the Flying Reptiles (pternadon, etc.) as well, which weren't Dinosaurs.

        And then there's the Marine Reptiles (ichthyosaurs, mososaurs, that lot), which weren't Dinosaurs.

        A disease that could jump around that far across the biosphere probably isn't going to bypass a bunch of rats. Especially g

    • Re: (Score:3, Interesting)

      by fbjon ( 692006 )
      It would make an interesting anaolgy with computers and the Internet, though. First, everyone is assumed to play by the rules, then suddenly all manner of viruses start to flourish.
    • Re:Three questions (Score:5, Interesting)

      by zappepcs ( 820751 ) on Thursday September 04, 2008 @11:21AM (#24874315) Journal

      Sorry no link, but yesterday there was a story I read that about 8% of human DNA is made up of junk left behind by retrovirus infections. That is to say, we survived those. HIV is a retrovirus. It is not far fetched to believe that Dinosaurs also suffered from disease and virus infections, and that insects could carry these from one animal to another. The general panic over H5N1 should tell you just how serious such a thing can be. If the KT boundary event weakened many dinosaurs, leaving them vulnerable, diseases that were not typically a threat could have become one.

      It's also possible that the combination of several things, including climate change after the KT boundary event, worked together to cause depopulation.

    • My question would be, if these insects were either large enough, or had the ability to penetrate the thick hide of a dinosaur, what chance would a small mammal have had from one of them?
      • Re:Three questions (Score:5, Insightful)

        by ColdWetDog ( 752185 ) * on Thursday September 04, 2008 @11:34AM (#24874537) Homepage

        My question would be, if these insects were either large enough, or had the ability to penetrate the thick hide of a dinosaur, what chance would a small mammal have had from one of them?

        A proto-mosquito the size of turkey is flying around.

        OK, you're a six story tall dinosaur ...
        Or a three inch tall proto-mouse.

        Who's gonna get bit?

        • by gnud ( 934243 )
          Could an exoskeleton support a proto-mosqito that big, with our gravity?
          • by TheRaven64 ( 641858 ) on Thursday September 04, 2008 @12:47PM (#24875697) Journal
            Well, if you believe the so-called theory of gravity, then that's a question, however if you believe the scientific theory of Intelligent Falling then the answer is obvious - they were lifted by the creator. Yet more evidence that IF is true and should be taught in schools.
          • Re: (Score:3, Informative)

            Dragonfly fossils with 70 cm wingspans have been found.
            • Re: (Score:3, Interesting)

              by jollyreaper ( 513215 )

              Dragonfly fossils with 70 cm wingspans have been found.

              Would they require just a higher oxygen content or also a thicker atmosphere to fly?

              • Re: (Score:3, Informative)

                Wiki [wikipedia.org] tells all. Researchers have debated whether a higher O2 content would be needed to support insects of that size. My guess is yes.
            • Re: (Score:3, Insightful)

              by dwye ( 1127395 )

              > Dragonfly fossils with 70 cm wingspans have been found.

              Contemporaneous with dinosaurs, or in the Carboniferous Period?

              If they weren't around when the dinosaurs were, then they had no more effect than cavemen had.

          • Re: (Score:3, Interesting)

            by Convector ( 897502 )
            It's more an issue of oxygen than gravity. Insects have a very primitive respiratory system. They basically just diffuse gases through their exoskeleton, so their size is limited by the oxygen content of the atmosphere. This was high during the Devonian, hence the 70 cm dragonflies mentioned by another poster. I also recall hearing about spiders that predated on those dragonflies, but I don't have any sources to back that up.
        • Actually, there is no evidence that insects of the late Cretaceous got that large. The size of insects is limited by the concentration of oxygen in the air. This is because they do not have lungs per say but have a system that delivers oxygen to their tissues by diffusion. (This oversimplifies the actual case but you get the idea.) In the early Paleozoic there was much more oxygen in the air (about 30% vs, 20% now). This allowed insects to get much larger than today. Although I don't have figures on t

    • Re:Three questions (Score:5, Insightful)

      by MightyYar ( 622222 ) on Thursday September 04, 2008 @11:30AM (#24874469)

      Why wouldn't this also affect mammals?

      And more importantly - why do we still have birds? Birds are supposed to be direct decedents of dinosaurs, and they seem to handle disease pretty well (judging by the state of NYC pigeons).

      • by DrYak ( 748999 )

        Birds indeed lack the anti-parasite IgE system.
        But like mammals they need to groom their feathers/furs and birds have evolved flexible necks (like mammals have evolved flexible backs, or in elephant's case, flexible trunck), and thus they can bite and remove parasites.

        • Re: (Score:3, Interesting)

          by MightyYar ( 622222 )

          But an elephant can't reach it's back... and neither can many other large mammals. Of course, there are birds that love to ride around on them and eat any insect stupid enough to latch on. I guess there wasn't yet an equivalent?

    • And lastly, I thought recent research had shown that the slow dying theory was just an artifact of the skimpy fossil record, that they did indeed die out very abruptly at the K-T layer. Is my memory wrong here?

      I think both exists in the fossil record. There was a massive die-off at the K-T layer however there does exist some evidence of a slow die-off around the K-T layer. The question is whether the slow-die off wasn't a misinterpretation of the fossil record and if it existed, what caused it. Certainly

    • by Comboman ( 895500 ) on Thursday September 04, 2008 @12:02PM (#24874983)
      Reptiles actually have great immune systems. Crocodiles are frequently injured in territorial fights, yet their open wounds do not get infected in the less-than-antiseptic environments they live in. Scientist are currently studying them to try to figure out why their immune systems work so much better than ours. Then again, they are one of the few families of reptiles that survived the extinction, so maybe that had something to do with it.
      • by Anonymous Coward on Thursday September 04, 2008 @01:17PM (#24876195)

        Antibacterial != antiviral. Their immune systems are very good at protecting against bacterial infection in those environments (and some reptiles, like the kimodo dragon actually have nasty bacteria living in their saliva that acts as a natural poison to weaken prey) but viral immunology is completely different. And viral mutations can move quickly though a population where they were previously benign.

    • Re:Three questions (Score:5, Interesting)

      by GargamelSpaceman ( 992546 ) on Thursday September 04, 2008 @12:09PM (#24875111) Homepage Journal

      Here's a wild ass guess that could explain it, but for which I have no evidence.

      Meteor impacts and lava flows alter the earth's climate. In general this favors warm blooded creatures.

      It also shakes things up in the plant world perhaps *causing* the explosion in flowering plants ( which actually happened first, meteors and volcano disasters or flowering plants, I don't know, this is just a wild ass guess with no supporting research )

      The explosion in flowering plants and their insect symbiotes, also stimulates insect evolution. Sexual reproduction in plants creates a huge new set of insect poisons and insect niches, kicking insect evolution into overdrive as they adapt and change over ( a fairly short ) time. For a time there seemed to be a new disease carrying or food destroying insect evolving every (insert short period of time here).

      Relative to Megafauna that typically lives long, insect and plant evolution can happen in a flash. The megafauna ( ie the large dinos ) die. Better able to evolve fast are small dinosaurs and mammals, however the mammals mostly win out because of their warm bloodedness which gives them the edge as temperatures fluxuate wildly because of the volcano eruptions..

      I think even today long lived megafauna would adapt more slowly to a rapidly changing environment than small animals like rats and cockroaches. They may go extinct leaving empty niches for the remaining small life forms to evolve ( quickly since they are small and short lived ) to fill.

      I don't think reptiles are inherently more primitive or less able to adapt than mammals. Immune systems evolve faster if each generation lives for a shorter timespan. If you are smaller, then your population can be bigger on a given landmass giving you more chances to evolve. That's what did the dinos in. Their size.

      • which actually happened first, meteors and volcano disasters or flowering plants, I don't know,

        I'd be willing to bet meteors and volcanoes have been going on a lot longer than flowering plants have been around. Sorry, I know what you were saying, but this is slashdot.

        I do like to just say it was a whole lotta luck that lead to things being the way they are today. I find it just as likely the early mammal-type critters in our lineage simply being under this mound, as opposed to that mound, when catastrophe struck thus giving us the genes we have as opposed to those genes, which might have been superio

    • Too busy to find refs at this time, but IIRC: crocodilians have a remarkable immune system, due to them living mostly in swamps (moist, warm and dirty!) and hurting each other frequently in territorial battles.
      And they do have thick skins.

    • Mammals of the period were quite small, and presumably had much faster lifecycles than most dinosaurs... their immune systems would evolve faster. Also, the shorter lifecycle might prevent the disease from developing in a full-blown form: even if normal mice could catch AIDS, it wouldn't kill them because they'd die of old age before developing symptoms anyway.

    • Re:Three questions (Score:5, Insightful)

      by lysergic.acid ( 845423 ) on Thursday September 04, 2008 @12:22PM (#24875273) Homepage

      while i'm not a zoologist, i'd imagine that if the article is correct, and this was when insects first became a significant vector for disease transmission, then it's plausible that neither dinosaurs nor mammals would have had the immune system to defend themselves against illness.

      it's much harder to adapt to a brand new class of diseases than it is to adapt to new variations of an existing form illness. so the attrition rate for evolving a suitable defense would have been extremely high.

      as for why mammals would survive while dinosaurs didn't, it may have been because mammals reproduced much quicker. animals with shorter life cycles and higher reproduction rates tend to adapt to environmental changes much more easily. in the time it takes for a large dinosaur to go through 2-3 generations of changes, a small mammal such as a rodent may have gone through 20-30 generations or more. so in times of crisis small animals are much more likely to survive than larger ones.

      another factor could be that, because mammals were at the bottom of the food chain, they tended to be nocturnal and live in burrows. being underground could perhaps have also protected them from the global catastrophes that were ravaging dinosaur populations. they probably didn't have as specialized of diets as the dinosaurs did, so when flowering plants began replacing the normal vegetation that herbivorous dinosaurs depended on, plant-eating mammals weren't affected. they also wouldn't have been affected by the mass population die-offs that would have starved the carnivorous dinosaurs.

      lastly, insects would have provided a valuable new food source for primitive mammals. dinosaurs may have grown too large to do the same. and whenever animals at the top of the food chain are removed from an ecosystem, the animals at the bottom of the food chain flourish. so all of this would have contributed to the rise of the mammals.

    • Why wouldn't this also affect mammals? Is there an implication that dinosaurs had more primitive immune systems? Is any of this more than mere speculation?

      Yes, indeed, Immunoglobuline E which are responsible for combating parasites are only found in mammals [wikipedia.org]. Not in birds (the other groupe of dinosaurs' descendants). Thus we could speculate that dinosaurs laked them.
      That's one less way to combat them.

      As a side note, IgE are also responsible for allergic reaction in modern humans. Probably we aren't exposed to lots of parasites in the developed world - in most people the IgE system just stays idle, but in a few individual who had the misfortune to inherit the w

    • It didn't have to be an insect borne disease. There are plenty of other ways that a disease can get into the bode. Direct air or waterborne transmission are only two of the alternatives. It could have been disease or some other reason that resulted to population decline. The famed asteroid hit could have been the straw that broke the camels back but not the main reason for extinction.

  • by PhilHibbs ( 4537 ) <snarks@gmail.com> on Thursday September 04, 2008 @11:09AM (#24874095) Homepage Journal

    Any disease that wipes out its host will have to evolve to be less deadly, or it will run out of hosts. So it's not really right to say that it's our immune systems that allowed animals to survive - the evolution of an immune system and the diseases that it fights go hand-in-hand. There is some competition, with diseases finding new ways to get around immune responses, but also some co-operation, as an overly-effective disease will destroy its own ecosystem and thus die out.

    • by MaxEmerika ( 701730 ) on Thursday September 04, 2008 @11:30AM (#24874479)
      Diseases that are transmitted directly from host to host tend to evolve to be less deadly for the exact reasons you describe. Diseases that are transmitted through an intermediary (like insects) can afford to be much more aggressive against their final hosts. That said, this theory still sounds fishy to me. These diseases were so devastating that they managed to drive two orders of animals to total extinction?
    • How does this account for highly infectious and deadly diseases?

      Take ebola [wikipedia.org] for instance. In particular the strain that broke out in Zaire [stanford.edu].
      • by jandrese ( 485 ) <kensama@vt.edu> on Thursday September 04, 2008 @11:45AM (#24874703) Homepage Journal
        Ebola isn't exactly as common as a cold you know. In fact it's a great example of a disease that wipes out its own hosts too quickly to spread very well. The only saving grace of Ebola is that it's extremely infectious, so over small and tightly knit populations it is devastating. It's the kind of diesease where the traders will come to a village for the next month's trade and find it dead, not the kind where you wipe out 3/4 of Europe.
      • Re: (Score:2, Informative)

        by AvitarX ( 172628 )

        It's not a human disease.

        Whatever its primary host is, it can't be as bad as it is to humans.

      • by PhilHibbs ( 4537 )

        How long has that been around for? Has it been allowed to annihilate large areas and therefore forced to evolve in reaction to its own virulence? Does it have another host population in which it is less fatal, therefore making it irrelevant to the virus that any humans that happen to come into the area die?

    • So, mammal immune systems may have been the reason dinosaurs died out; something might be less deadly to the mammals, but they could still spread it to the dinosaurs...
    • by Moraelin ( 679338 ) on Thursday September 04, 2008 @11:50AM (#24874807) Journal

      Well, I don't think it's necessarily that simple. There are plenty of diseases that outright kill.

      Probably the most obvious example is the bubonic plague, a.k.a., the Black Death. It eventually killed all 3 types of hosts involved in plague outbreaks:

      - the rats (which were eventually replaced by a different and more robust species of rat, as, yes, the old one almost went extinct),

      - the flea (the bacteria essentially plug its stomach, so it ends up perpetually hungry, sucking blood until it barfs it right back and infests a new host. Eventually it starves to death.)

      - the humans

      Early outbreaks of the Black Death killed 80% of the infected people and massively depopulated Europe. Nowadays you'd only have about 50% chance to die of it. Our immune system did evolve somewhat.

      But if you combine it with other factors, e.g., a changing climate or whatever, and it could have driven a less resourceful species extinct. As I was saying, the black rats that were the co-hosts in those outbreaks did go pretty much extinct.

      The bacterium itself, well, essentially the immense majority of those which caused such an outbreak, eventually died together with its hosts. You'd think that would be a very strong evolutionary pressure to evolve into something less suicidal. Essentially each outbreak ended up in a near wipe-out of the bacteria population. You have an advantage if you don't do that, no? But said evolution towards more benign versions just didn't happen. The humans evolved to have better chances of survival, but the bacterium seems to have stayed just as nasty as ever.

      Basically what I'm saying is that there is no divine plan to save you, so to speak. The bacterium doesn't know whether it's heading towards extinction together with its hosts. As long as there are still _some_ available hosts, it didn't go extinct yet, and it can continue just as well.

      Additionally, some bacteria can infect more than one host, or can survive decently in the ground without a host. For the latter, even killing all hosts immediately, still isn't really a problem. The former killing one of the hosts isn't much of an impediment either, as long as other hosts can survive (or breed faster than they're killed.)

      So for example a hypothetical disease which could infest both dinosaurs and mammals, but only killed dinosaurs, could jolly well keep doing so ad infinitum.

      Now I'm not saying that this is necessarily how the dinosaurs died out. Just that evolution works in perverse and mysterious ways.

      • Re: (Score:2, Informative)

        by tertrures ( 1238098 )

        Early outbreaks of the Black Death killed 80% of the infected people and massively depopulated Europe. Nowadays you'd only have about 50% chance to die of it. Our immune system did evolve somewhat.

        That's straightforward natural selection. A significant part of the world population is descendant of the surviving 20% which were naturally more resistant to the plague.

        (Unless you are not a creationist, in which case you will have to find your own perfectly irrational explanation all by yourself.)

    • by hey! ( 33014 ) on Thursday September 04, 2008 @12:00PM (#24874951) Homepage Journal

      There is also some evidence that disease agents may confer a kind of symbiotic advantage on their hosts.

      Hantavirus, for example, is relatively harmless rodent populations that harbor it. However it can be deadly to immunologically naive populations that might move in and displace them. So it is possible that infectious agents may help their hosts guard their ecological niche. We can see something of the opposite effect in the introduction of European diseases to North American populations living in what were more hygienic conditions.

      The idea that alterations in insect populations and the geographic range of diseases may have played a role in a mass extinction event is a sobering one. Ecological disruption tends to cause geographically isolated infectious agents to spill out, especially in a world connected by global commerce. And we are in the middle of the mother of all ecological disruptions: global climate change.

      Take Malaria, a constant presence in the tropics for as long as can be remembered. Malaria is special among vector transmitted diseases in that it does not have a significant animal reservoir: malaria pathogens specialize in one closely related group of species, say monkeys but not apes. So human malaria species specialize in humans, which potentially makes them eradicable.

      This is important, because with climate change, the boundaries of Malaria carrying mosquitoes is shifting, not only away from the tropics, but to higher altitudes. Mexico city is in a malarial latitude; it is altitude of nearly 13,000 feet that keeps the Anopheles mosquito genus in check. Perturb the climate slightly, and the third largest metropolitan area in the world will provide over twenty million new hosts for Malaria protozoan. As a capital city, it has air links world wide.

      I will give another example of how ecological disruption is tied to diseases. A friend of mine married into a family that lived on an island. Everyone in that family had contracted Lyme disease at some point in their life. The problem was the ecosystem needed a top-level predator, but humans had wiped out wolves over a century earlier. This disturbed the ecosystem, because without a top level predator, the only thing keeping the rodent population in check was how much food there was available, and disease. That disease spilled over into the human population.

      Now a few decades ago, a small population of Western Coyotes swam out the island and established itself. They took down most of the deer herd, then turned to the rats, voles and other small mammals. Ticks have gone from being a plague of almost unimaginable proportions to being relatively rare. Imagine the amount of biomass in even a small coyote. Now imagine the ecosystem is using that biomass to generate ticks.

      Of course, there aren't as many deer, and they make a hell of a racket at night, but on the plus side Lyme disease seems to have become much more rare. Attempts to eradicate the coyotes failed, because while they fill the wolf niche in the environment, they're much, much more adapted to living alongside humans. So overall, the coyotes have restored the disrupted ecology humans had "improved" by eliminating the wolves.

  • by jellomizer ( 103300 ) on Thursday September 04, 2008 @11:13AM (#24874173)

    Insects actually beat us to land before us vertebrates. I would suspect that they would adapt to be parasites a lot earlier then it took for Dinosaurs to evolve. And Dinosaurs were actually very successful group that lasted for a long time (and had a wide variety of species) I doubt that even a potent parasite could kill them all off maybe just a couple of species.

    • by LWATCDR ( 28044 ) on Thursday September 04, 2008 @12:01PM (#24874969) Homepage Journal

      This whole thing is very short on facts as far as I can tell.
      1. Dinosaurs and insects existed together for far longer than humans have been around.
      2. Saying Dinosaur is like saying mammal. There is a HUGE variety in them. The idea that bugs wiped them out seems very far fetched.
      3. Birds are still around and they seem to be the descendant of Dinosaurs.
      So yea this is just a little far out. But then Dinosaurs becoming totally extinct is just way too odd but that did happen well except for the line that became birds.
      I blame Homer.

  • How could you? Just because your text is tiny is no reason to take out your frustration on those who have normal sized text!
  • by Zymergy ( 803632 ) * on Thursday September 04, 2008 @11:14AM (#24874217)
    Short answer: Maybe... But if so, it is a small part of what let them survive...
    Don't diseases and insects ALMOST ALWAYS follow other natural disasters where there are numerous dead and dying creatures on the land and in the water?
    Besides, sharks have awesome immune systems (some scientists say they actually have the BEST immune systems) and many varieties of sharks also went extinct at the same extension period as well numerous species of plants...
    Does the author mean to imply that plants also survived the insects and diseases because of their 'immune systems'? I did not realize that plants had immune systems??...
    Guess I'll go RTFA...
  • Stupidity (Score:5, Insightful)

    by MightyMartian ( 840721 ) on Thursday September 04, 2008 @11:15AM (#24874227) Journal

    This is a dupe, and what's more, it may be the most inane and retarded theory of dinosaur extinction out there. Dinosaurs weren't a single group, but an incredibly large and diverse family. This is like claiming that a set of epidemics could kill off all mammals or all birds. It's fucking stupid people.

    • by kat_skan ( 5219 )

      This is like claiming that a set of epidemics could kill off all mammals or all birds.

      How many avian and mammalian species are susceptible to flu?

      • Probably many, but no single influenza strain appears contagious to substantial enough numbers of species to ever cause the kind of extinction event these guys are referring to. Not even the most virulent flus could wipe out all of humanity, let alone, say, all primates.

  • nah (Score:4, Interesting)

    by circletimessquare ( 444983 ) <circletimessquare@gm a i l . com> on Thursday September 04, 2008 @11:17AM (#24874269) Homepage Journal

    parasites and disease don't generally lead to the extinction of their hosts, as you tend to go extinct yourself

    after an initial population decimation, in which the hosts suffer, then the parasite/ disease suffers a dramatic population decrease. more resistant strains of host emerge, and then more benign strains of parasite disease emerge. the parasite/ disease can't afford to threaten its own existence by being too virulent and deadly

    however, i am willing to bet we, us mammals, killed off the dinosaurs. nothing like a few little rodents chewing on the slowly reproducing eggs of nesting dinosaurs to decimate the population

    in fact, the only surviving dinosaurs of the egg-chewing rodent crisis were the ones who could nest in trees, offering some protection from the ground dwelling egg chewers. of course, we call these dinosaurs birds today

    • Re: (Score:3, Funny)

      by m85476585 ( 884822 )

      in fact, the only surviving dinosaurs of the egg-chewing rodent crisis were the ones who could nest in trees, offering some protection from the ground dwelling egg chewers. of course, we call these dinosaurs birds today

      Ever heard of squirrels?

  • I personally believe the distinction was caused by a bug riddled asteroid that caused volcanic eruptions when it crashed into the earth.

  • by smellsofbikes ( 890263 ) on Thursday September 04, 2008 @11:19AM (#24874299) Journal

    Reptiles have perfectly good immune systems: in the case of alligators, they're better than human ones [planetark.com]. However, since reptiles are cold-blooded, the seasonal temperature variation means reptiles have suppressed immune function during cold periods [google.com], so they'd be predisposed to higher mortality from disease after a meteorite strike or extensive volcanic activity puts enough debris in the atmosphere to reduce the Earth's temperature.
    The Black Death spread across Europe and the Mideast in less than 4 years [wikipedia.org] -- individual diseases can move very quickly. The idea that the rise of a class of disease vectors, biting insects, might've gradually led to higher mortality, is interesting, and something I'd never read about.

    • Re: (Score:3, Interesting)

      by MozeeToby ( 1163751 )

      And what, exactly, do modern reptiles have to do with ancient dinosaurs? Almost all modern theories of dinosaur evolution state that they are more related to modern birds than modern reptiles. Furthurmore, most modern research (3 decades or more) indicates that at least the majority of dinosaurs were warm blooded.

      • >most modern research (3 decades or more) indicates that at least the majority of dinosaurs were warm blooded.

        I hadn't read about that, and I'd be interested in seeing more. My understanding, based on what I have read, is that many dinosaurs were essentially non-homeostatic and may have used feather-like body coverings to vary their insulation to regulate their body temperatures, rather than using metabolism and feedback systems for thermoregulation.

        • Re: (Score:3, Informative)

          by MozeeToby ( 1163751 )

          To be fair, it's a combination of an active metabolism and temperature inertia. Looking into it further after reading your response, it seems it isn't as cut and dry as I had thought. In fact, it isn't even agreed upon what exactly is meant by 'warm blooded'. Though dinosaurs' metabolism did produce heat and regulate body temperature, the shear size of many dinosaurs also helped maintain body temperature. Depending on what part of the fossil record you study, it appears possible to draw valid conclusion

          • Up until 50 years ago, dinosaurs were just large lumbering lizards. Now our knowledge is increasing and many of the assumptions are drying up. No doubt more of your current assumptions about "facts" are going to change.
            • Re: (Score:3, Funny)

              by 1u3hr ( 530656 )
              Up until 50 years ago, dinosaurs were just large lumbering lizards.

              That's the most extreme version of "young earth creationism" I've come across. Where do they teac that? Utah?

    • by jimicus ( 737525 )

      The Black Death spread across Europe and the Mideast in less than 4 years [wikipedia.org] -- individual diseases can move very quickly.

      Very true, however it is a little known fact that very few dinosaurs were building boats and travelling the world.

    • Reptiles have perfectly good immune systems: in the case of alligators, they're better than human ones

      Assuming the theory is correct (a big if), then the only reptiles to survive would have been the ones with particularly good immune systems :)

  • by BobMcD ( 601576 )

    "We can't say for certain that insects are the smoking gun, but we believe they were an extremely significant force in the decline of the dinosaurs," Poinar said. "Our research with amber shows that there were evolving, disease-carrying vectors in the Cretaceous, and that at least some of the pathogens they carried infected reptiles. This clearly fills in some gaps regarding dinosaur extinctions."

    I'm failing to see any link between the rise of insects and the decline of dinosaurs. I accept that insects and their diseases were on the rise, and that plant life probably changed because of this. Still, though, we have a gap:

    What about all the other life on earth?

    I seem to recall being bitten by a tick once or twice in my lifetime. They're not dinosaur-exclusive.

    Likewise, large animals other than dino's depended on that plant life, and many existed in astonishing numbers until the industrial revolutio

  • A Book? (Score:4, Interesting)

    by whisper_jeff ( 680366 ) on Thursday September 04, 2008 @11:25AM (#24874397)
    "...speculation is rampant in a book that gives cause to believe..."

    Speculation? In a book? Get back to me when there's evidence in multiple books and scientific journals. Speculation in one book isn't cause to believe squat.

    (Could biting insects have caused deaths? Of course but extinction? Highly doubtful and, as I said, until it's discussed more widely than speculation in one book, I'll file that theory away as nothing more than what it is - speculation in one book.)
  • I read that as... (Score:4, Informative)

    by The Ultimate Fartkno ( 756456 ) on Thursday September 04, 2008 @11:26AM (#24874409)

    "Incest May Have Had a Hand In Dinosaur Extinction" and giggled myself silly.

  • Fast extinction (Score:5, Insightful)

    by Geoffrey.landis ( 926948 ) on Thursday September 04, 2008 @11:33AM (#24874521) Homepage

    Due to the length of their slow and eventual extinction

    Do note that the "fact" that the Cretaceous-Ternary extinction event was "slow" is not well established; there are many palentologists who cite evidence that it was, in fact, extremely rapid, and the apparent "slowness" is a statistical artifact of the discontinuous nature of the fossil record. The microfossil record, which is much more continuous, seem to show very rapid extinction.

    The dinosaurs lasted for about 165 million years. It seems rather unreasonable to think that they coexisted with insects prefectly well for 164.9 of those 165 million years, and then suddenly every dinosaur species died of insect-borne infestation in the last 0.1% of their reign-- including the ocean-dwelling dinosaurs. And including a lot of other marine life. And microbiota. And many species of plants.

  • There's evidence that the environment was already stressed at the time due to unknown factors, possibly volcanic eruptions. Under such conditions, insects and infections may have increased their effects, similar to how drought results in beetle infestations in trees because the trees' defenses are weakened, which is a problem now in the US.

    The meteor may not have been the sole cause, but it put the dinos over the top; a kind of perfect storm. It's possible that similar-sized meteors hit before without any n

  • by lantastik ( 877247 ) on Thursday September 04, 2008 @11:43AM (#24874657)

    One day God came down and asked the dinosaurs if there was anything they wanted. They responded that they wanted to see what the future was going to be like. God opened a vision for them and at first they were excited at all the tasty bi-peds walking around and all the lush vegetation provided by global warming.

    Then as the vision continued, they saw something they thought no living being should ever have to endure. They saw that Carlos Mencia was going to be famous and that people would eventually experience his comedy in one form or another. The dinosaurs decided that they would never subject their heritage to such atrocities.

    They begged and pleaded for God to take their lives. God replied, "I love you and that is not my way." The dinosaurs were persistent and they begged and pleaded some more. God finally agreed, saying, "Since I love you, I will take your lives, but you must endure horrible plagues, famine, and natural disasters." For the dinosaurs, it was worth it and they agreed.

    We can all learn something from our reptilian, bird-like ancestors.

  • by techess ( 1322623 ) on Thursday September 04, 2008 @11:45AM (#24874697)

    Scientists have shown that the moon is moving away at a tiny yet measurable distance from the earth every year. If you do the math, you can calculate that 85 million years ago the moon was orbiting the earth at a distance of about 35 feet from the earth's surface. This would explain the death of the dinosaurs. The tallest ones, anyway.

    • Re: (Score:2, Informative)

      by AJNeufeld ( 835529 )
      The moon recedes at about 4cm/year, and is currently about 40,000,000,000 cm away. So, assuming the rate of recession was constant (which it wasn't), and started within 35 feet of the Earth (impossible), the tall dinosaurs (and the short ones) would have had to duck or dodge the moon as it passed by them 10,000,000,000 years ago ... not 85 million years ago. As recent as 85 million years ago, the moon would have been a mere 1% closer to the Earth that it is now.
  • by wilkinc ( 1247844 ) on Thursday September 04, 2008 @12:11PM (#24875135)
    From the wikipedia page about the Cretaceous-Tertiary extinction event: Mosasaurs, plesiosaurs, pterosaurs and many species of plants and invertebrates also became extinct. Does this insect argument explain the fact that plesiosaurs, plants and invertebrates also went extinct?
  • Butterflies (Score:4, Funny)

    by DebateG ( 1001165 ) on Thursday September 04, 2008 @01:05PM (#24875989)
    It was probably the butterfly. No one ever suspects the butterfly...
  • Do you have, like, a cartoon demonstrating how it works?

  • Don't know why nobody has said this yet, but...

    I, for one, welcome our dinosaur-eating insect overlords.

  • Not plague by insect (Score:4, Informative)

    by Oligonicella ( 659917 ) on Thursday September 04, 2008 @01:36PM (#24876581)
    Allow me to repeat something that has been said before:

    Dinosaurs were not a tightly knit group, they were widely divergent. Any cause for the extinction must account for mosasaurs, elasmosaurs, icthyosaurs, pterasaurs and many mammalian groups as well. Plague by insect ain't that cause. For what it's worth, my degree is biology with specialization in entomology.
  • by Scribbler'sEmporium ( 1310863 ) on Thursday September 04, 2008 @04:45PM (#24879627)
    Reptiles have immune systems which work for them. They are cold blooded as was mentioned above. Reptiles (in general) have specialized cells which do phagocytosis (even very primitive organisms have this), lymphoid tissue (gut-associated etc) but not lymph nodes, lyphocytes differentiated into B cells and T cells. What they don't have is the variety of immunoglobulin classes that mammals have. ie Their antibody is IgM-like and IgG-like (IgY), but not IgD, IgE and class switching is either slow or non-existent. Birds were the first (phylogenetically) to exhibit lymph nodes and multiple Ig classes, and class switching. Furthermore reptiles don't seem to be able to do the memory (amnestic response) very well. To say that the reptile system is better (or as good as) the mammalian system is non-sensical. They both work have worked to keep species alive for many millions of years and they both continue to evolve. The key is that they work for each in their own envirnmoment. The immune system of a cold blooded animal is by necessity different from a warm blooded animal because bacteria have adapted to grown so much faster at warmer temperatures. If the immune system cannot respond rapidly (ie memory response) then that individual dies. If you look at the evolution of the immune response it appears to have taken several leaps rather than evolving gradually and steadily. These events coincide with changes which could alter the microbiological pressure on animal species. (see the Silurian period and the development of immunoglobulin and T-cell receptors, also the important RAG 1 and RAG2 genes). If reptiles were evolving into birds and there was a change from cold-blooded to warm-blooded at the same time you would expect to see a shift in the immune system capabilities --- and we do. Insects, while vectors of disease likely had little to do with this shift (Achem's razor) http://www2.ncseweb.org/kvd/exhibits/immune/immune_evo_annotated_bib.html [ncseweb.org]

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