Pterosaurs couldn't soar, says expert
October 1, 2008
A reproduction of the Thalassodromeus sethi, a specimen of pterosaur is seen at the Museum of Natural History in Rio de Janeiro. A Japanese researcher has put paleo-biologists in a flap by suggesting pterosaurs -- the winged lizards beloved of toymakers and dino movies -- were unable to fly, New Scientist says.
A Japanese researcher has put paleo-biologists in a flap by suggesting pterosaurs -- the winged lizards beloved of toymakers and dino movies -- were unable to fly, New Scientist says.
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Beyond the last sentence of the article, I wonder if Sato has taken this possibility into account.
I haven't read anything about atmospheric pressure in the past, but I do remember reading that the oxygen content in the atmosphere *had* to have been higher, or else those large insects simply could not have existed. (They wouldn't have been able to breathe, never mind fly. Insects use a very different breathing mechanism than we do. On small scales it is very efficient, but it quickly (geometrically in relation to size increases) becomes useless. That's why we don't have large insects on Earth. They can't breathe above a certain size.)
The tuatara (100E6 yr old reptile)lives on the edge of oxygen deficit all the time. When it evolved that certainly could not have been the case so the above also applies. The dragonfly mentioned above and other flying insects would have had a much a higher wing loading than today because the weight increases w/ the cube of size whereas the wing area to the square so the above applies again.
"Pterosaurs couldn't soar" nor could they launch themselves off the ground at todays 14.7 psi atmospheric pressure. They ONLY explanation is much higher atmospheric pressure.
Consider this, if dinosaurs had a blood chemistry similar to the tuatara, i.e. not very good under present day conditions, and at the time of their mass extinction 65E6 yrs ago there was a drastic reduction in air pressure and/or O2 concentration, i.e partial pressure of O2, then that would explain a lot about why they disappeared. They asphyxiated.
In addition i would use a giant fruit bat as a model instead of a bird.
That pterosaur must have been an impressively ugly animal.
Besides, when I was growing up they told us that pterosaurs just glided like flying squirrels. In this sense they are not using their muscles to flap but just to control glide direction.
Therefore, it may be the case that atmospheric oxygen concentrations weren't that different in the time of these insects than now. Assuming significantly higher oxygen concentrations has a lot of problems, such as the drastic increase in flammability of vegetation.
The AFP reporter probably got a bonus for their great work: Sensationalizing conclusions so that they fit conveniently on a Yahoo! Web page and in a 30 second slot in the evening news. They're trying to run a business, not report science accurately. No footnotes, no citations. None of that garbage. Don't need it.
How dare you question the competency and accuracy of our beloved media! If they say that there is proof that pterosaurs could not fly then you have the obligation to suck it up and get with the program. It is suddenly obvious that pterosaurs flopped around on the ground and anyone who would question that is on par with creationists and holocaust deniers - reality challenged heretic!
For shame DoctorKnowledge, for shame!
People, just because the scientists say one thing and the media claims they say something different does not mean that the media are not your rightful overlords.
However this says nothing about atmospheric pressure, which of course would have made a difference too.
http://visual.mer...-bat.php
Note the lack of large breast bones in both cases. Whereas birds have well developed breasts (chuckle).
For those of you who brought up hang-gliding, keep in mind that pterosaurs didn't have convenient access to SUV transport back to higher ground when the wind failed them. Hardly an adaptive trait.
It's also worth pointing out that bumblebees use a radically different mode of flight from birds because their BODIES are radically different. Pterosaurs are a whole lot more like birds or bats than they are like bumblebees.
The O2 partial pressure argument makes sense. A higher overall air pressure would probably also help, although I'm not sure if the paleo record supports that.
Velikovsky (see http://en.wikiped...likovsky ) would suggest that the existence of animals like pterosaurs and meter-wide dragonflies serves as evidence that Earth's gravity was significantly weaker in the deep past. That's an unorthodox view, to be sure, but one that the academic community has never taken seriously enough to refute convincingly.
Finally, there's behavior... lots of animals only go out when conditions are favorable, and I can certainly envision a pterosaur hanging out on his crag and conserving energy for those extra-windy hunting days.
There is evidence for higher O2 content. The atmospheric pressure would have to be different as a result of the change in gas composition and densities. Although the pressure change IMHO would have been negligible.
Why do all these animals (and us) have useless appendixes? Cause when an animal was born without an appendix it had no advantage over those who had one. It didn't have a greater chance of survival, so it didn't thrive (at least, no more than others did).
Same reason we have useless pinky toes, and the same reason we have wisdom teeth.
The function of the appendix is not fully understood, there are theories that suggest it was usefull for primates to digest leaves,as a tool to build up resistanse to diseases or to give a safe haven too good bacteria for our digestive system.To say its useless would be inaccurate,its not well understood yet.Same applies to pinky toes and wisdom teeth.
Inherited features that become "useless" are suppost to disappear over many generations, often they seem to get alternative functions tough.If the function gives the species more of an advantage than the energy it requires to have the function disadvantages them it is a usefull feature and will stay.
Anyone have data on this. I am thinking the range is broad. So this would support an increase in O2 from 20% (today) to 22%.
I would add that CO2 level is what triggers the unconscious breathing reflex in animals not O2 level.
The Apollo 1 fire was at 16 psi (2 psi above standard atmospheric pressure) and 100% O2.
This is a misconception. Useless things will only disappear if the creature has a better chance of survival without them. If the useless thing has no effect on the creature, positive or negative, then the item will remain their forever, unchanging, except by random chance.
Hence pinky toes. Something that use to be useful, but no longer is. But having it won't kill you. It doesn't help, but it doesn't hurt. So it stays. Humans have quite a few different minor bits and pieces that are like this.
Pitch Black had pterosaurs and they flew! maybe that is where they came from and the reason for the mass extinction!
In all seriousness, if at 400 ppm all plants will die from photosynthesis shutting down, then we are all dead in a few decades... but I seem to recall reading evidence that CO2 levels have been radically higher than today... And I recall reading about greenhouses that have additional CO2 pumped in to levels well above today's - and the plants thrive. Temperatures well warmer than today's would add atm pressure, at the very least due to some gas no longer being dissolved in the seas. And I am sure the planet has lost a bit of atm gas that has escaped into the void of space since then.
Pinky toes aren't useless btw. The outer toe (I say that b/c birds have three) provides greater stability, especially for us high center-of-gravity bipeds. Oh and hang gliders do not stay aloft indefinitely.
The wings had to have a purpose; I doubt they were nimble and could climb trees (or cliffs) like flying squirrels. It is unlikely that we have stumbled upon some rare, freakish genetic anomalies that would have died out in one generation.
There are many conclusions we can make (and have made) through science and math that are ridiculous... 1*0=(?)10*0, no heavier-than-air flying machines (birds, bees, bats?), can't pass speed of sound (bullets, shooting stars?). They defy history and the examples given that are around us.
The only way for gravity to be less back then (as far as I know) is if fundamental properties of the universe have considerably changed in that time frame. That may help explain the observed inflation in the universe (maybe incl. dark energy and dark matter), the existence of matter beyond the visible universe, not to mention how an infinitely dense point defied gravity in the Big Bang. But this is 100 million years ago, not 12 billion, even if Argentinosaurus was from the same time period and near-unfathomably huge. Atm properties (pressure, thermals, et al.), physiology, and flight mechanics (not to mention human error and lack of knowledge) sound like simpler explanations.
As for the Bible comment, there are many belief-sets that talk of a time of giants, not just Judeo-Christian stories; I find it interesting to compare ancient stories (e.g. floods, giant creatures, dragons, quetzalcoatl) to archeological and geologic evidence. Before it gets started, lets keep religion out of this; ancient stories are fun, preachy-ness from any belief-set (including atheism) doesn't belong here. Remember: Topic=Pterosaurs
Read it again! at 27% O2 and
The higher atmosphere pressure cannot be sufficient explanation for a big wings of pterosaurs and giant dragonflies.
On the contrary, in the higher pressure of atmosphere or other ambient, the animal able to have smaller wings/flippers(see marine animals like a dolphins, whales, sharks, various fishes, etc.). More, they must to have much smaller wings/flippers because in the higher pressure of ambient they need to be much more stronger (with better and durable bones and muscles) to resist to higher pressure of ambient.
All these I said in the 1997.
The bigger wings useful only in the smaller atmosphere pressure conditions. They works as sails, in this case.
The giant dragonflies could break their wings in modern atmosphere pressure and modern gravity, because flying insects must flapping their wings more quicker than birds.
For giants of the past, we have many other problems connected with their weight and sizes that cannot be explained by higher atmosphere pressure and higher O2 content.
The modern giraffe have problems with blood pressure because he have big height about 7-8 meters. Brachiosaur had about 20 meters of height!
High oxigen content can explain the higher metabolism (and mobility of animals), but cannot increase the durability of organic materials in the bones and muscles.
IMHO, the content of bones and muscles is similar for dinosaurs and modern reptiles.