SLE204 Lecture Notes - Lecture 2: Lungless Salamander, Gymnophiona, Tetrapod

• School: Deakin University
• Department: Science, Engineering and Built Environment
• Course: SLE204
• Professor: Anneke Veenstra

Document Summary

Lungs evolved from swim bladders developed as outgrowths of pharynx. Double circulation arterial (oxygenated) and venous (deoxygenated) blood flow. Basic limb structure humerus, ulna, radius. Pectoral girdle, fused to skull supports forelimbs flopped around, rather than walked. Pectoral and pelvic girdle muscles to lift body off ground. Ears ribs vertical lots of sites for muscle attachment allows movement on dry land jointed limbs stronger vertebrae finned tail. Class amphibia e. g. frogs, toads, salamanders: live in both aquatic and terrestrial environments during their life, ***need water at some stage during lifecycle*** > eggs desiccate easily (cid:272)oz do(cid:374)"t have hard shell. > external fertilization and reproduction: ectothermic, bony endoskeleton, found everywhere except polar and subpolar regions too cold, circulation 3 chambered heart incomplete partitioning. 2 separate atria; single undivided ventricle with spiral value to aid separation of oxygenated and deoxygenated blood: separate sexes, eggs in jelly-like mass -> must be laid in water.