Alicia Shull
10-19-15
Endothermy in Bipedal Dinosaurs Dinosaurs are an extinct species that have been fascinating paleontologist’s, and impressing those with recreational interest for centuries. One of the many mysteries associated with dinosaurs is whether or not they were endothermic, exothermic, or a combination of both. It is important to distinguish whether or not dinosaurs were endothermic or exothermic because the determination plays a role in the reconstruction of their ecology. This is due to the fact that endothermic animals are able to live in a wider range of climates than exothermic animals. It also plays a role in their behavior because endotherms are associated with higher levels of activity than ectotherms, and it plays a role …show more content…
When locomotor power requirements were estimated from hip height the vo2 max was greater than current ectothermic capabilities at moderate running speeds for all species, and slow running speeds for all species but the smallest. The five largest species displayed a metabolic output that exceeded the aerobic capabilities of living ectotherms during walking.
The results from the smaller taxa are not as definitive as those of the larger taxa. The smaller species did not exceed ectothermic capabilities until they reached moderate running speeds, and even then they only exceeded the limitations slightly. The smaller dinosaurs could have been ectothermic and may not have ran at moderate or fast speeds, but that contraindicates the evidence associated with their active lifestyle.
Using muscle volume to determine locomotor cost indicated that the five largest species exceeded the vo2 max of ectotherms at all walking and running speeds, and small bipeds exceeded the vo2 max at moderate running speeds. The smallest species archaeopteryx was the only dinosaur that had estimated locomotor metabolic rates that were comparable to the vo2 max in living ectotherms using both hip height and muscle …show more content…
If they were not endothermic they would have needed to have physiological adaptations or limitations on movement that are not seen today in modern terrestrial vertebrates. It is believed by some that dinosaurs could have been ectothermic and that they had a better vo2 max than modern reptiles. This theory can be disregarded because even though dinosaur respiratory systems are not well understood the five largest dinosaurs would have needed 30-90 times greater vo2 max at rest than modern reptiles. Even during slow running the estimated aerobic power for large dinosaurs was 100-500% above the ectothermic maximum for aerobic power. An additional argument was presented they researchers did not know exactly where the center of mass is on dinosaurs and because of this they were unable to accurately measure their locomotor costs. As a result researchers moved the center of mass posterior to be in line with the hip joint. This reduced the locomotor cost by 65%, but the dinosaurs were still well above the ectothermic aerobic
10-19-15
Endothermy in Bipedal Dinosaurs Dinosaurs are an extinct species that have been fascinating paleontologist’s, and impressing those with recreational interest for centuries. One of the many mysteries associated with dinosaurs is whether or not they were endothermic, exothermic, or a combination of both. It is important to distinguish whether or not dinosaurs were endothermic or exothermic because the determination plays a role in the reconstruction of their ecology. This is due to the fact that endothermic animals are able to live in a wider range of climates than exothermic animals. It also plays a role in their behavior because endotherms are associated with higher levels of activity than ectotherms, and it plays a role …show more content…
When locomotor power requirements were estimated from hip height the vo2 max was greater than current ectothermic capabilities at moderate running speeds for all species, and slow running speeds for all species but the smallest. The five largest species displayed a metabolic output that exceeded the aerobic capabilities of living ectotherms during walking.
The results from the smaller taxa are not as definitive as those of the larger taxa. The smaller species did not exceed ectothermic capabilities until they reached moderate running speeds, and even then they only exceeded the limitations slightly. The smaller dinosaurs could have been ectothermic and may not have ran at moderate or fast speeds, but that contraindicates the evidence associated with their active lifestyle.
Using muscle volume to determine locomotor cost indicated that the five largest species exceeded the vo2 max of ectotherms at all walking and running speeds, and small bipeds exceeded the vo2 max at moderate running speeds. The smallest species archaeopteryx was the only dinosaur that had estimated locomotor metabolic rates that were comparable to the vo2 max in living ectotherms using both hip height and muscle …show more content…
If they were not endothermic they would have needed to have physiological adaptations or limitations on movement that are not seen today in modern terrestrial vertebrates. It is believed by some that dinosaurs could have been ectothermic and that they had a better vo2 max than modern reptiles. This theory can be disregarded because even though dinosaur respiratory systems are not well understood the five largest dinosaurs would have needed 30-90 times greater vo2 max at rest than modern reptiles. Even during slow running the estimated aerobic power for large dinosaurs was 100-500% above the ectothermic maximum for aerobic power. An additional argument was presented they researchers did not know exactly where the center of mass is on dinosaurs and because of this they were unable to accurately measure their locomotor costs. As a result researchers moved the center of mass posterior to be in line with the hip joint. This reduced the locomotor cost by 65%, but the dinosaurs were still well above the ectothermic aerobic