a Comparative Test of the Correlated Evolution of Flightlessness and Relative Brain Size in Birds
Abstract Secondary flightlessness has evolved independently many times in birds. Morphological changes in the pectoral girdle and flight feathers and changes in body size have been associated with the evolution of flightlessness, and it has also been suggested that flightless birds have relatively s...
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ftsmithonian:oai:repository.si.edu:10088/215 2023-05-15T16:22:56+02:00 a Comparative Test of the Correlated Evolution of Flightlessness and Relative Brain Size in Birds Iwaniuk, Andrew N. Nelson, John E. James, Helen F. Olson, Storrs L. 2004 160986 bytes application/pdf http://hdl.handle.net/10088/215 en_US eng Journal of zoology Iwaniuk, Andrew N., Nelson, John E., James, Helen F., and Olson, Storrs L. 2004. " a Comparative Test of the Correlated Evolution of Flightlessness and Relative Brain Size in Birds ." Journal of zoology . 263 (3):317–327. 0952-8369 http://hdl.handle.net/10088/215 59964 Journal Article 2004 ftsmithonian 2020-09-09T18:28:45Z Abstract Secondary flightlessness has evolved independently many times in birds. Morphological changes in the pectoral girdle and flight feathers and changes in body size have been associated with the evolution of flightlessness, and it has also been suggested that flightless birds have relatively small brains. We therefore tested whether flightlessness is related to changes in relative brain size. Relative brain size was compared between volant and flightless species using both conventional statistics and modern comparative methods within nine taxonomic groups. No significant difference was found between flightless and volant species in six of these groups, regardless of whether body mass or tibiotarsal measurements were used as estimates of body size. Species with relatively smaller brains compared with their volant relatives were the great auk Pinguinus impennis, the kakapo Strigops habroptilus and some species of penguin. Thus, we found no evidence of a general correlation between the evolution of secondary flightlessness and the evolution of relatively small brains in birds. This suggests that neural requirements are not significantly different between flightless and volant species, although our methods may have overlooked subtle neurological changes that do not result in markedly different endocranial volumes. NH-Vertebrate Zoology NMNH Article in Journal/Newspaper Great auk Pinguinus impennis Unknown |
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ftsmithonian |
language |
English |
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Abstract Secondary flightlessness has evolved independently many times in birds. Morphological changes in the pectoral girdle and flight feathers and changes in body size have been associated with the evolution of flightlessness, and it has also been suggested that flightless birds have relatively small brains. We therefore tested whether flightlessness is related to changes in relative brain size. Relative brain size was compared between volant and flightless species using both conventional statistics and modern comparative methods within nine taxonomic groups. No significant difference was found between flightless and volant species in six of these groups, regardless of whether body mass or tibiotarsal measurements were used as estimates of body size. Species with relatively smaller brains compared with their volant relatives were the great auk Pinguinus impennis, the kakapo Strigops habroptilus and some species of penguin. Thus, we found no evidence of a general correlation between the evolution of secondary flightlessness and the evolution of relatively small brains in birds. This suggests that neural requirements are not significantly different between flightless and volant species, although our methods may have overlooked subtle neurological changes that do not result in markedly different endocranial volumes. NH-Vertebrate Zoology NMNH |
format |
Article in Journal/Newspaper |
author |
Iwaniuk, Andrew N. Nelson, John E. James, Helen F. Olson, Storrs L. |
spellingShingle |
Iwaniuk, Andrew N. Nelson, John E. James, Helen F. Olson, Storrs L. a Comparative Test of the Correlated Evolution of Flightlessness and Relative Brain Size in Birds |
author_facet |
Iwaniuk, Andrew N. Nelson, John E. James, Helen F. Olson, Storrs L. |
author_sort |
Iwaniuk, Andrew N. |
title |
a Comparative Test of the Correlated Evolution of Flightlessness and Relative Brain Size in Birds |
title_short |
a Comparative Test of the Correlated Evolution of Flightlessness and Relative Brain Size in Birds |
title_full |
a Comparative Test of the Correlated Evolution of Flightlessness and Relative Brain Size in Birds |
title_fullStr |
a Comparative Test of the Correlated Evolution of Flightlessness and Relative Brain Size in Birds |
title_full_unstemmed |
a Comparative Test of the Correlated Evolution of Flightlessness and Relative Brain Size in Birds |
title_sort |
comparative test of the correlated evolution of flightlessness and relative brain size in birds |
publishDate |
2004 |
url |
http://hdl.handle.net/10088/215 |
genre |
Great auk Pinguinus impennis |
genre_facet |
Great auk Pinguinus impennis |
op_relation |
Journal of zoology Iwaniuk, Andrew N., Nelson, John E., James, Helen F., and Olson, Storrs L. 2004. " a Comparative Test of the Correlated Evolution of Flightlessness and Relative Brain Size in Birds ." Journal of zoology . 263 (3):317–327. 0952-8369 http://hdl.handle.net/10088/215 59964 |
_version_ |
1766011046512820224 |