BIO 200LLB Lecture Notes - Lecture 26: Vascular Plant, Phloem, Xylem
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BIO 200LLB Full Course Notes
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Evidence that green algae are the ancestors. Were probably filamentous green algae growing along the edges of ponds that seasonally dried out. Were small and did not have vascular tissue. They were bathed in water or lived in moist environments. Dna evidence says bryophytes originated 515 mya at the same time that arthropods invaded the land. Bryophytes (mosses, liverworts, hornworts) lack vascular tissue- small plants (515 mya) Tracheophytes (ferns and seed plants) have vascular tissue - can be large (450 mya) Specialized cells that conduct fluids and nutrients from place to place in the organism. Xylem = cells specialized to carry h2o and minerals. Phloem= cells specialized to carry h2o and sugar. Gametes dry out and may not disperse properly. They live in moist environments and they survive drying out - suspended animation. Living in moist environments and being able to become dormant when conditions are dry.