ZOOL 403 Study Guide - Final Guide: Pulmonary Alveolus, Saltwater Crocodile, Lark

• School: University of Calgary
• Department: Zoology
• Course: ZOOL 403
• Professor: Marco Musiani

Document Summary

To examine the common classification scheme for the extant archosaurs (and the opportunity to examine local representatives). To be able to identify the major features of bird groups. Although not as diverse or numerous as other reptilian groups, the crocodylians represent some of the oldest living reptilian forms. Early crocodylians arose in the triassic period and modern forms have existed since the cretaceous. Different taxa resemble each other closely, except in the shape of the skull. (features of the skull are used frequently in the determination of phylogenetic relationships). As such, the nostrils are placed dorsally and can be closed when the individual is submerged. Crocodylians have increased respiratory ef ciency, achieved by a partition between the pectoral and abdominal cavities (analogous to the mammalian diaphragm) and by well-developed pulmonary alveoli. These characteristics are useful when long periods of time are spent underwater.