Science Magazine Volume 327, No. 5963, pp. 338-340
DOI: 10.1126/science.1180219
Unidirectional Airflow in the Lungs of Alligators
C. G. Farmer and Kent Sanders
http://www.sciencemag.org/cgi/content/full/327/5963/338
A new report published by two University of Utah biologists in Science Magazine provides experimental evidence for unidirection flow of inhaled and exhaled air in the lungs of alligators.
The researchers showed that even though living alligators (no scientific name provided, but abstract indicates American alligators Alligator mississippiensis were studied) lack the air sacs and pneumatic bones that allow living birds to efficiently take in oxygen, the soft-tissue arrangement nevertheless allows for a more circular breathing pattern than in other living air-breathing vertebrates (e.g. mammals have more of a 'tidal' breathing mechanism whereby incoming and outgoing air are mixed between the nose and the lungs).
While the new study provides fascinating possibilities for inferences to be made regarding the evolution of aerobic and metabolic efficiency of extinct archosaurs such as non-avian dinosaurs, the authors took it a little too far with their concluding "story" about how all archosaurs (including all dinosaurs) may have had this type of efficiency.
Given the evidence for unidirection air flow in lungs of alligators and birds, the concept of a phylogenetic bracket, or the use of extant organisms to infer morphology/behavior/physiology of intermediate extinct relatives, points to a possibility of non-avian dinosaurs sharing these features. However, it was done without undeniably strong evidence in this study; four individuals from a single alligator species (and please, even Wikipedia provides a scientific name for the American alligator in a non-scientific description!) were used in this study, to infer a common feature among animals spanning hundreds of millions of years (back to the Triassic).
Quite a stretch even to a non-science type, I would say.
I believe the main issue does not necessarily lie with the authors themselves. One should not expect the field of science to take giant leaps in every research paper; but nowadays researchers are often "forced" to make outlandish conclusions just to get into a more popular journal. More "Science" and less "Magazine", please?
~Jack
DOI: 10.1126/science.1180219
Unidirectional Airflow in the Lungs of Alligators
C. G. Farmer and Kent Sanders
http://www.sciencemag.org/cgi/content/full/327/5963/338
A new report published by two University of Utah biologists in Science Magazine provides experimental evidence for unidirection flow of inhaled and exhaled air in the lungs of alligators.
The researchers showed that even though living alligators (no scientific name provided, but abstract indicates American alligators Alligator mississippiensis were studied) lack the air sacs and pneumatic bones that allow living birds to efficiently take in oxygen, the soft-tissue arrangement nevertheless allows for a more circular breathing pattern than in other living air-breathing vertebrates (e.g. mammals have more of a 'tidal' breathing mechanism whereby incoming and outgoing air are mixed between the nose and the lungs).
While the new study provides fascinating possibilities for inferences to be made regarding the evolution of aerobic and metabolic efficiency of extinct archosaurs such as non-avian dinosaurs, the authors took it a little too far with their concluding "story" about how all archosaurs (including all dinosaurs) may have had this type of efficiency.
Given the evidence for unidirection air flow in lungs of alligators and birds, the concept of a phylogenetic bracket, or the use of extant organisms to infer morphology/behavior/physiology of intermediate extinct relatives, points to a possibility of non-avian dinosaurs sharing these features. However, it was done without undeniably strong evidence in this study; four individuals from a single alligator species (and please, even Wikipedia provides a scientific name for the American alligator in a non-scientific description!) were used in this study, to infer a common feature among animals spanning hundreds of millions of years (back to the Triassic).
Quite a stretch even to a non-science type, I would say.
I believe the main issue does not necessarily lie with the authors themselves. One should not expect the field of science to take giant leaps in every research paper; but nowadays researchers are often "forced" to make outlandish conclusions just to get into a more popular journal. More "Science" and less "Magazine", please?
~Jack
