Lesson 6 - Lesson 6 Structure and Evolution of flowers Flowers evolved in angiosperms Morphology o Complete flower(has all four whirls in the lower

Lesson 6 - Lesson 6 Structure and Evolution of flowers...

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Lesson 6 02/08/2015 ° Structure and Evolution of flowers Flowers evolved in angiosperms Morphology o Complete flower (has all four whirls in the lower right of the picture) o Incomplete flow (lacks one or more whirls) ° ° ->the calyx is the outermost whirl of flower parts and protects the flower bud ° -> corolla functions to attract pollinators ° -> the androecium is a collective term for all of the stamen (the male structures of a flower) ; the anther houses the microcell mother cells ° -> gynoecium consists of one or more carpels the ovary of the carpel contains the ovules , the slender neck of the carpel is called the style which has pollen receptive stigma at the tip ° Trends in Floral specialization/symmetry Fusion of parts that were once separate Reduction in number parts (wild geranium is a reduction compared to more primitive plants) Radial symmetry
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Bilateral symmetry (orchid raven below) ° -> the bottom two pictures are the normal and mutant snap dragons ; the left one has bilateral symmetry and the right one has radial symmetry ° Gamete production Alternation of generations o Diploid & haploid generations o Pollen grains Microgametophytes (male gametophyte pollen grains) o Embryonic sac Megagametophytes (female gametophyte embryonic sac)
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->the flower is part of the sporophyte generation and the gametophytes are very small and contained within the gametophyte ->there are two types of gametophytes ( Microgametophytes and Megagametophytes) this picture shows the development of both gametophytes ->Formation of pollen: microspores through cell differentiation become pollen which contains two cells, tube cells have a pollen tube and the generative cell that will divide to form two sperm ->Formation of
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