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Unformatted text preview: Vascular Plants I I 10-26-2008 I. Microphylls vs. Megaphylls Leaves have two functions gathering light for photosynthesis + CO2 for carbon fixation most efficient = flattened 1) microphylls = single vascular vein 1 theory of volution leaves possibly evolved from sterile and reduced sporangia Ex. Of microphyll = club moss (lycophytes) 2) megaphylls = multiple vascular veins hypothesized evolution = 3 steps. 1) Dichotomous overtopping (unequal split one branch = larger and more dominant and upright than the other half of the branch that split)ex. Large trees have enormous branches with small branches 2) Planation branches changed from a 3D plane into a 2D plane (flattened out) more efficient photosynthetic arrangement 3) Webbing fills in photosynthetic tissue between these branches leaves I I. Overview of vascular plant clades Look at diagram from Lecture Slides Rhyniophytes only known from fossil record, now extinct. Dichotomous branching. No leaves or roots. Photosynthetic stem....
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This note was uploaded on 03/15/2010 for the course BIS 1C 22222 taught by Professor Dehesh during the Spring '08 term at UC Davis.
- Spring '08