Abstract
Many high-altitude vertebrates have evolved increased capacities in their oxygen transport cascade (ventilation, pulmonary diffusion, circulation and tissue diffusion), enhancing oxygen transfer from the atmosphere to mitochondria. However, the extent of interspecies variation in the control processes that dictate hypoxia responses remains largely unknown. We compared the metabolic, cardiovascular and respiratory responsesto progressive decreasesininspired oxygen levels of bar-headed geese (Anser indicus), birds that biannually migrate across the Himalayan mountains, with those of Andean geese (Chloephaga melanoptera) and crested ducks (Lophonetta specularioides), lifelong residents of the high Andes. We show that Andean geese and crested ducks have evolved fundamentally different mechanisms for maintaining oxygen supply during low oxygen (hypoxia) from those of bar-headed geese. Bar-headed geese respond to hypoxia with robust increases in ventilation and heart rate, whereas Andean species increase lung oxygen extraction and cardiac stroke volume. We propose that transient high-altitude performance has favoured the evolution of robust convective oxygen transport recruitment in hypoxia, whereas life-long high-altitude residency has favoured the evolution of structural enhancements to the lungs and heart that increase lung diffusion and stroke volume.
Original language | English (US) |
---|---|
Pages (from-to) | 4186-4194 |
Number of pages | 9 |
Journal | Journal of Experimental Biology |
Volume | 220 |
Issue number | 22 |
DOIs | |
State | Published - Nov 15 2017 |
Keywords
- Altitude
- Cardiac output
- Duck
- Goose
- Metabolism
- Ventilation
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Physiology
- Aquatic Science
- Animal Science and Zoology
- Molecular Biology
- Insect Science