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Download Flowering Plants • Transformation of Gymnosperms to Angiosperms
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Division Magnoliophyta (Anthophyta): Flowering Plants • Transformation of Gymnosperms to Angiosperms – Sporophylls needed to evolve into stamens and carpels (forming a flower) – The most primitive angiosperms have stamen that are very flat and the stamen lack filaments 1 Division Magnoliophyta (Anthophyta): Flowering Plants – Carpels are also very leaflike – Evolution of double fertilization and the formation of endosperm 2 Division Magnoliophyta (Anthophyta): Flowering Plants – Evolution of vessel elements and sieve tubes – Leaves • • • • Became broad Reticulate venation Polymorphic Had functions other than photosynthesis 3 Origin and Early Evolution of the Angiosperms • C.E. Bessey developed a theory of evolution for angiosperms based upon a Magnolia type flower being the most primitive – “ranalean” flower – Flower contains all of the floral parts • • • • Sepals Petals Stamens Carpels – All parts arranged spirally – Carpels superior 4 Origin and Early Evolution of the Angiosperms – Wood very similar to that of gymnosperms – Evolution of insect pollinators (bees, butterflies, beetles, and flies) also occurred at the same time as the above advances were appearing Angiosperm evolution still a wide open question – great opportunity for research 5
