Seed Plant Reproduction
    A.  Divisions of Seed Plants
        1.    Gymnosperms - "naked seed" - most have cones
                a.    male cones - small, fleshy, clusters, produce pollen(sperm)
                b.    female cones - large, woody, single, produce ovules(eggs)
        2.    Angiosperms - "covered seed" - flowering plants
                a.    Structures of the flower
                        - pistil - female part, made up of stigma, style, and ovary
                        - stamen - male part, made up of the anther and filament
        3.    Production of gametes in the flower
                a. sperm - cells in the anther undergo meiosis producing haploid cells.  Each of these cells
                     undergoes mitosis producing  2 nuclei.  One of which is the tube cell nucleus. The other
                     nucleus divides again to form 2 sperm cells.  The resulting structure is called the pollen grain
                    (male gametophyte).
                b. egg - a cell in the ovule undergoes meiosis producing 4 haploid cells.  One enlarges to the
                     exclusion of the others.  This cell undergoes three mitotic divisions without cytokinesis
                     resulting in an eight nuclei cell.  Three at one end separate from each other and the other
                     nuclei by cytokinesis.  These cells are called anti-podal cells.  Three nuclei at the open end
                     separate from each other by cytokinesis.  Two are called synergid cells which lie on each
                     side of the single egg cell.  Two nuclei remain in the middle of the embryo sac(
                      (female gametophyte).
        4.    Pollination - transfer of pollen from the anther to the stigma.
                a.    wind
                b.    pollinators - insects, birds, bats
                c.    coevolution - the joint change of 2 species over time to strengthen a relationship between the
                         species.
                           - many flower and their pollinators have coevolved
        5.    Fertilization - double fertilization
                a. pollen tube - a tube grows out of the pollen grain and travels through the style of the pistil to
                       the ovary  where it enters the ovule through the micropyle and connects with the embryo sac.
                b.    embryo - one sperm joins with the egg forming the zygote(2N), which later develops into the
                                       embryo ("baby" plant).
                c. endosperm - the other sperm joins with the two middle nuclei of the embryo sac forming a
                     triploid nucleus.   This part of the embryo sac develops into the endosperm(food source for
                     the embryo).