BIOL 1108 Lecture Notes - Lecture 15: Guard Cell, Stoma, Cuticle
Document Summary
The evolution of land plants from aquatic ancestors introduced a major challenge for photosynthesis: how to get enough carbon dioxide without drying out. Leaves have a waxy cuticle and stomata, both are important in regulating carbon dioxide gain and water loss. Xylem allows vascular plants to replace water evaporated from leaves with water pulled from the soil. Phloem transports carbohydrates to the non-photosynthetic portions of the plant for use in growth and respiration. Roots expend energy to obtain nutrients from the soil. Core concept 1: the evolution of land plants from aquatic ancestors introduced a major challenge for photosynthesis: how to get enough carbon dioxide without drying out. Plant phylogenies: cladogram from previous slide flipped: ancestors to land plants: green algae. Stand up, not dry out, get gas out of gas: angiosperms: flowering plants, closely related to ferns. Core concept 2: leaves have a waxy cuticle and stomata, both are important in regulating carbon dioxide gain and water loss.
