5) Seedless Vascular Plants

5) Seedless Vascular Plants - AP Biology Seedless Vascular...

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AP Biology Seedless Vascular Plants - Began to evolve during the Carboniferous period - Phylum Lycophyta (club mosses), Pterophytes (Horsetails), 1) a) Life Cycles with Dominant Sporophytes Start to have branched sporophytes with independent sporophyte (not dependent upon gametophytes anymore for nutrients or water) Sporophytes are larger & more complex; reduced gametophyte stage b) Vascular Tissues (Tissues that conducts substances): Xylem and Phloem Show vascular tissues ( Aglaophyton major ) according to the fossil records: Figure 1 Xylem = conducts water and minerals by tracheid (dead specialized cells) = move upward; lignified (strengthened) by polymer called lignin Phloem = conducts organic compounds (i.e sugars, amino acids, and etc.) = move downward; consist of alive cells Significance of lignified vascular tissue: made the plants grow taller and give much more stronger support against the gravity Taller & stronger structured plants resulted in winning the competition for
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5) Seedless Vascular Plants - AP Biology Seedless Vascular...

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