WILD 3580 1st Edition Lecture 20Outline of Last Lecture I. Order Gymnophiona II. Sensory Reception III. Reproduction Outline of Current Lecture I. ReptilesII. Evolution of Reptiles III. ClassificationCurrent LectureI. Reptiles - Characteristics 1. Amniotic Egg- 4 extraembryonic membranes a. Chorion: outer most layer for gas exchangeb. Amnion: contains the amniotic fluid i. Creates its own embryonic and aquatic environment to prevent defecationii. Less dependent on water for reproduction c. Yolk sac: provides nourishment d. Allantois: gas exchange and waste storage 2. Internal fertilization- have copulatory organs a. Turtles and crocs- penisb. Snakes and lizards- hemipenes 3. Pulmonary respiration a. All reptiles have lungs i. Ancestral condition is 2 functional lungsii. Some snakes have only one right functional lungsiii. Some turtles (softshells) can obtain cutaneous respiration through their skin near the cloaca gas exchange These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.b. Breathing- negative pressure ventilation i. Creation of a low pressure area by movements of the thoracic cavity ii. Snakes and Lizardso Contraction and relaxation of the intercostal muscle (rib muscles) iii. Crocodilianso Contraction of the muscular diaphragm iv. Turtleso Specialized muscles on the non-shell parts of the body 4. Epidermal scales – made of beta keratina. More alpha keratin in the skin impermeable to water 5. Single occipital condyle- point articulation where first vertebrates come in contact with skull II. Evolution of Retiles - Began when Osteolepiforms were ancestors of amphibians - Formation of occipital condyles and amniote eggs - Became part of the diapsid group - Synapsid group: mammals derived from the opening in the skull (fasa), indentation increases surface area for attaching jaw muscles o Single temporal opening - Euryapsid group: single temporal opening higher up in the jawo Eureptiles- early reptiles - Anapsid group: no temporal openings creating turtles - Diapsid group: 2 temporal openings leading to modern reptiles III. Classification- Class Reptilia- Subclass Archosauria o Order Testudines- Turtles (anapsids) Suborder Cryotidrira- “hidden necks” Suborder Pleurodira- “side necks” not able to retract their heads in the shell- Only in the southern hemisphere o Order Crocodylia- crocodilians Family Alligatoridae Family Crocodylidae Family Gavialidae- Gharials, only one living species - Subclass Lepidosauria o Order Squamata- lizards and snakes Suborder Serpentes- snakes Siborder Lacertilia- lizards o Order Sphenodontida- tuataras (lack hemipenes cloaca
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