BIOL108 Lecture Notes - Lecture 30: Tetrapod, Continental Drift, Nostril

• School: University of Alberta
• Department: Biology (Biological Sciences)
• Course: BIOL108
• Professor: Lien Luong

Document Summary

Not first life on land, just the first vertebrate (land plants ~ 475 mya, arthropods ~ 450 mya, vertebrates ~ 365 mya) Continental drift -> pangaea: coastal regions became land-locked. Plants (esp. seed-bearing) beginning to colonize land -> forests. Arthropods and other invertebrates colonizing land -> lots of food. Internal nostrils (opening from the nasal sac into the roof of the mouth): First component of the tetrapod body plan to evolve (well before the origin of limbs) Origin: displacement of posterior external nostril (p) to upper jaw and displacement of posterior nostril to roof of mouth. Tetrapods: only one pair of external/anterior nostrils (a) Evolved independently in two lineages: lungfish & tetrapods. Allows tetrapods to breathe air through the nose using lung ventilation and to smell outside of water. The transition from life in the water to life on land: Lobe-fins -> limbs with joints allow vertebrates to move onto land ->