I have a Theory (No. 5)

Rubecula

Regarding this thread (started by Adam) http://www.boards.ie/vbulletin/showthread.php?t=2057244905

I have an idea that if conditions are right then birds could evolve to rival Quetzalcoatlus in size. In fact as nothing can fly that is bigger than a Condor according to many scientists of the past. I actually wonder what is the maximum size for any flying creature?

Adam Khor

Rubecula wrote: »

Regarding this thread (started by Adam) http://www.boards.ie/vbulletin/showthread.php?t=2057244905

I have an idea that if conditions are right then birds could evolve to rival Quetzalcoatlus in size. In fact as nothing can fly that is bigger than a Condor according to many scientists of the past. I actually wonder what is the maximum size for any flying creature?

I know this is not a very sciency reply but, I think everything's possible. Pteranodon males had wingspans of 6-9 meters according to different authors- for a very long time they were thought to be the largest flying creatures ever, and even then, scientists believed they had to throw themselves from cliffs (the pteranodonts, not the scientists) in order to become airborn. Now we know that they could probably take off as easily, if not easier than most birds, and their size was actually an advantage rather than a limitation.
The largest flying birds such as Argentavis and this new Pelagornis are comparable in size to Pteranodon (Argentavis would actually be heavier!), so there's no reason to believe that bigger ones couldn´t have existed. I'm sure nature would've "adjusted" them so that their size wouldn´t be an issue. As long as there was enough food, of course.

I know scientists do all those complicated calculations and formulas and computer simulations and what not, to figure out this kind of stuff, but if a Quetzalcoatlus-sized bird was ever found, I would be amazed, but not surprised.

Capt'n Midnight

Insects grow bigger with more oxygen.
http://www.sciencedaily.com/releases/2010/10/101029132924.htm

more oxygen means a slightly denser atmosphere so easier to fly

Adam Khor

Capt'n Midnight wrote: »

Insects grow bigger with more oxygen.
http://www.sciencedaily.com/releases/2010/10/101029132924.htm

more oxygen means a slightly denser atmosphere so easier to fly

Ok, question... what would happen to birds if oxygen levels became higher?

Capt'n Midnight

Adam Khor wrote: »

Ok, question... what would happen to birds if oxygen levels became higher?

They have very efficient lungs.



http://www.pnas.org/content/108/23/9516

Birds that fly over mountain barriers must be capable of meeting the increased energetic cost of climbing in low-density air, even though less oxygen may be available to support their metabolism. This challenge is magnified by the reduction in maximum sustained climbing rates in large birds. Bar-headed geese (Anser indicus) make one of the highest and most iconic transmountain migrations in the world. We show that those populations of geese that winter at sea level in India are capable of passing over the Himalayas in 1 d, typically climbing between 4,000 and 6,000 m in 7–8 h. Surprisingly, these birds do not rely on the assistance of upslope tailwinds that usually occur during the day and can support minimum climb rates of 0.8–2.2 km·h−1, even in the relative stillness of the night. They appear to strategically avoid higher speed winds during the afternoon, thus maximizing safety and control during flight. It would seem, therefore, that bar-headed geese are capable of sustained climbing flight over the passes of the Himalaya under their own aerobic power.

I'm not sure of the scale height but doubling the oxygen would automatically give them another 20% altitude just on air density , and they'd only use half the energy in breathing, Geese wouldn't exactly be eating quick to digest energy rich food like birds of prey.

So could something bigger than a goose fly at sea level ? easily


Then again higher oxygen levels would mean more wildfires so lots more thermals.

Adam Khor

I think it was in Walking with Monsters where they said oxygen levels in the Carboniferous were so high, lightning could cause spntaneous explosive fireballs on the air or something like that... sounds like a nice time to live in :B

I asked about the birds precisely because of their very advanced breathing system. If oxygen is poisonous in large amounts, wouldn´t they be more susceptible to it?

Rubecula

Oxygen is toxic in high concentrations but atmospheric oxygen could never get to that kind of level. Remember EVERYTHING is dangerous if you have too much of it. Atmospheric air pressure would not be noticably higher, but breathing would be easier at higher altitudes. Fuel (food) would burn more efficiently and animal growth would be faster.

Adam Khor

Oh ok...yeah I failed chemistry and physics as I spent the classes doodling dinosaurs and all that :B

Adam Khor

It's a dobsonfly with a 21 cm wingspan; pretty amazing.

http://www.geek.com/science/giant-horrible-monster-bug-with-stinky-anal-glands-found-in-china-1599962/





I wonder how big the larvae (hellgrammite) from this species would be. Those of smaller species get pretty big :