Overview of Tetrapods

Tetrapods

Overview of Tetrapods

• Four limbs with digits
• Tetra = "four", Pods = "feet"
• Limbs: are able to support weight on land
• Efficient for walking
• Head: is separated from body by a neck
• Could look up and down
• Then side to side
• Pelvic girdle: is fused to backbone
• where hind limbs are attached
• Adults lack gills
• Gills become ears, glands and structures during development

Evolution of Tetrapods

• Devonian lobe-finned fish
• Likely used lungs to breathe air
• Used robust fins to move on land
• Tiktaalik: Fossil of key early tetrapod evolution
• Had fish features
• Fins
• Gills
• Lungs
• Scales
• Had tetrapod features
• Ribs: Provide structure to take a full breathe of air
• Neck and Shoulders: Allows movement of the head
• Front limbs had same skeletal structure as all tetrapods
• Humerus attaches to two bones (radius and ulna) followed by the wrist
• More robust pelvis
• Could likely prop itself up and move on land