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 sporophyte fertilization AP Binio loseedgy 2004-2005 34 sporangium & pollen male male (pollen) cones female AP Bifoelomgyale cones pine embryo 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 Angiosperm: flowering plants AP Biology 2004-2005 37 Co-evolution: flowers & pollinators AP Biology 2004-2005 38 Angiosperm: fruiting plants AP Biology 2004-2005 39 Angiosperm life cycle AP Biology 2004-2005 40 Flower . Modified shoot with 4 rings of modified leaves sepals petals stamens . male carpals . female AP Biology 2004-2005 41 AP Biology 2004-2005 42 Angiosperm life cycle male gametophyte in pollen fertilization female gametophyte in ovary sporophyte in seed AP Biology 2004-2005 43 AP Biology 2004-2005 44 Angiosperm . Flowering plants flowers and fruit monocots . 1 seed leaf . leaves with parallel dicots . 2 seed leaves . leaves with net-like venation AP Biology 2004-2005 45 Dicot . dicots 2 seed leaves leaves with net-like venation broad leaf plants AP Biology 2004-2005 46 Monocot . monocots 1 seed leaf leaves with parallel grasses, grains, bulbs AP Biology 2004-2005 47 Evolutionary trends . Vascular tissue tubes for transport non-vascular . bryophytes - mosses vascular . pteridophytes - ferns . gymnosperm - conifers . angiosperm - flowering plants . Evolutionary advantage? adaptation to dry terrestrial conditions allows increased size (think trees!) AP Biology 2004-2005 48 Evolutionary trends . Sperm dissemination flagellate (swimming) sperm . bryophytes - mosses . pteridophytes - ferns wind-blown or animal-carried pollen . gymnosperm - conifers . angiosperm - flowering plants . Evolutionary advantage? adaptation to dry terrestrial conditions . eliminated water requirement for fertilization AP Biology 2004-2005 49 Evolutionary trends . Seeds seedless plants . bryophytes - mosses . pteridophytes - ferns seed plants . gymnosperm - conifers . angiosperm - flowering plants . Evolutionary advantage? adaptation for reproduction in diverse terrestrial environments . resistant, dispersal stage AP Biology 2004-2005 50 Evolutionary trends . Reduction of gametophyte gametophyte dominant . bryophytes - mosses sporophyte dominant, free living gametophyte . pteridophytes - ferns sporophyte dominant, reduced gametophyte . gymnosperm - conifers . angiosperm - flowering plants . Evolutionary advantage? adaptation for reproduction in diverse terrestrial environments . reduction of gametophyte protects delicate egg & embryo in protective sporophyte . protected from drought & UV radiation AP Biology 2004-2005 51 Evolutionary trends . The 4 groups represent 4 great episodes in the evolution of land plants evolution of land plants from ancestral . green algae → mosses evolution of vascular plants . ferns evolution of seeds . gymnosperm evolution of flowers . angiosperm AP Biology 2004-2005 52.