New insight into the evolution of the vertebrate respiratory system and the discovery of unidirectional airflow in iguana lungs.

ABSTRACT: The generally accepted framework for the evolution of a key feature of the avian respiratory system, unidirectional airflow, is that it is an adaptation for efficiency of gas exchange and expanded aerobic capacities, and therefore it has historically been viewed as important to the ability of birds to fly and to maintain an endothermic metabolism. This pattern of flow has been presumed to arise from specific features of the respiratory system, such as an enclosed intrapulmonary bronchus and parabronchi. Here we show unidirectional airflow in the green iguana, a lizard with a strikingly different natural history from that of birds and lacking these anatomical features. This discovery indicates a paradigm shift is needed. The selective drivers of the trait, its date of origin, and the fundam

SUBMITTER: Cieri RL 

PROVIDER: S-EPMC4260542 | biostudies-literature | 2014 Dec

REPOSITORIES: biostudies-literature