Evolution of Avians' Lungs

[Johnny Pneumatic]

Avian lungs are far better than mammal lungs. I'm curious, do we know when they began to evolve their type of lungs from what reptiles have? Do we know what the different stages of their evolution could have looked like; and what the selection pressures were that made them evolve lungs like that?

 

[John Bentley]

Avian lungs are far better than mammal lungs. I'm curious, do we know when they began to evolve their type of lungs from what reptiles have? Do we know what the different stages of their evolution could have looked like; and what the selection pressures were that made them evolve lungs like that?

In what way(s) are they better?

 

[geni]

Avian lungs are far better than mammal lungs. I'm curious, do we know when they began to evolve their type of lungs from what reptiles have? Do we know what the different stages of their evolution could have looked like; and what the selection pressures were that made them evolve lungs like that?

Since they are soft tissue I suspect any knowlage is limited.

 

[Rolfe]

They're better because they don't have dead space. The air goes through the lung into the air sacs, allowing more efficient oxygen exchange. Then you get a second crack at it during the exhale. Oh, and having some of the air sacs in bones does two jobs, as it makes the bones light.

Come on, John, you know this stuff....

Rolfe.