BIOL108 Lecture Notes - Lecture 29: Vascular Tissue, Nostril, Desiccation

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

Document Summary

Evolutionary steps from sea to land: internal nostrils. First component of the tetrapod body plan to evolve (before the origin of limbs) Originally used to smell, but now can gulp in: tetrapods: only one pair of external/anterior nostrils, evolved independently in two lineages: lungfish and tetrapods. Tetrapod: the transition from life in water to life on land, lobe fins limbs. Limbs had joints that allowed vertebrates to move onto land and hence became. Why transition to life on land: continental drift: pangaea, plants colonize forests, arthropods and other invertebrates colonize land = lots of food, aquatic predators. Fewer competitors on land: new niches! Challenges of terrestrial life for organisms adapted to aquatic life: gravity. Terrestrial animals need to have some sort of supporting tissue: desiccation. Terrestrial organisms need some form of skin or coat to keep precious body fluids from leaking out and to protect the embryo: respiration. Substances are in air, so new structures needed to breath: reproduction.