gymnosperms “naked seeds”. general characteristics  vascular  alternation of generations...

Download GYMNOSPERMS “Naked Seeds”. General Characteristics  Vascular  Alternation of generations –Dominant sporophyte –Reduced, dependent gametophyte  Produce

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  • GYMNOSPERMSNaked Seeds

  • General CharacteristicsVascular

    Alternation of generationsDominant sporophyte Reduced, dependent gametophyte

    Produce uncovered seeds

  • 4 Phyla of GymnospermsCycads




  • CycadsMost diverse during age of dinosaursOnly 100 living speciesPalmlike appearancePollen-bearing and seed-bearing cones on different plantsStrobilus of a female cycad

  • GinkgosDiverse during age of dinosaursOne surviving species, Ginkgo biloba Deciduous trees are male or female Seeds are completely exposed

  • GnetophytesShare some traits with angiospermsXylem Cone clusters resemble flower clustersParts of life cycle more like angiosperms

  • Conifers Widest known, largest number of living speciesWoody trees or shrubs Most are evergreenBear seeds on exposed cone scalesMost produce woody cones

  • Pine ConesWoody scales of a pine cone are the parts where megaspores formed and developed into female gametophytesMale cones, where microspores and pollen are produced, are not woody

  • Life cycle of typical conifer

  • CLICK TO PLAYAnimation: Pine Life Cycle

  • Conifer DistributionReproduce more slowly than angiosperms; at competitive disadvantage in many habitatsStill dominate in far north, at higher elevations, and in certain parts of southern hemisphere



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