Gymnosperm & Angiosperm Rise of the seed plants AP Biology 2004-2005 27 Gymnosperm: conifers  Characteristics vascular  heterospory   male vs. female gametophytes seeds   naked seeds (no fruit) pollen   contain male gametophyte life cycle dominated by sporophyte stage   coniferous trees you are familiar with are diploid  reduced (microscopic) gametophyte  reduction of gametophyte protects delicate egg & embryo in protective sporophyte  protected from drought & UV radiation AP Biology 2004-2005 28 Evolutionary trends in land plants  Reduction in gametophyte gymnosperm bryophytes pteridophytes angiosperm AP Biology 2004-2005 29 Early Gymnosperm: ginkgo AP Biology 2004-2005 30 Early Gymnosperm: cycads AP Biology 2004-2005 31 Gymnosperm: conifers AP Biology 2004-2005 32 Cones & naked seeds AP Biology 2004-2005 33 Gymnosperm (Pine) life cycle female gametophyte in cone meiosis meiosis male gametophyte in pollen f e r t ili z a t i o n sporophyte in seed AP Biology 2004-2005 34 sporangium & pollen male male (pollen) cones female female cones pine embryo AP Biology 2004-2005 35 Angiosperm: flowering plants  Characteristics vascular  heterospory   male vs. female gametophytes flower   specialized structure for sexual reproduction seeds within fruit  pollen  life cycle dominated by  sporophyte stage  trees & bushes you are familiar with are diploid  reduced (microscopic) gametophyte AP Biology 2004-2005 36