Plant Reproduction and Development

• Chlamydonas producing gametes or spirogyra undergoing conjugation as example. Similar or identical in size, structure.

  Isogamy
• Fertilization - fusion of two haploid cells to form diploid zygote
• Animal sperm and egg as example, dissimilar in size and structure. What type of union of gametes is it?

  Heterogamy
• Bisexual reproduction involves fusion of gametes from 2 different individuals.
• Hermaphrodites are organisms that have both male and female reproductive organs. Usually invertebrates.
• Sporogenesis - formation of spores by mitosis
• Haplontic Life cycle- haploid stage (gametophyte) is dominant, multicellular and the only diploid stage is the fertilized egg cell.
• Haplodiplontic life cycle- includes multicellular diploid (sporophyte) and haploid (gametophytes) generations.
• Mitotic division produces genetically identical cells.
• The process of pollination is when pollen grains are transferred to the stigma of another flower or plant.
• Meiosis produces genetically diverse cells with half the number of chromosomes as parental cells.
• Fertilization results in zygote formation.
• Gamete production occurs through meiosis.
• Self-fertilization occurs when pollen from one flower reaches the ovules of the same flower.
• Fertilization occurs when sperm from anther fuses with eggs in ovules inside the pistil.
• Asexual reproduction occurs without sexual intercourse, resulting in offspring that are genetically identical to their parent(s).
• Sexual reproduction involves two parents contributing genetic material through gametes.
• Diplontic life cycle- the diploid stage is dominant, multicellular and the haploid stage is represented by the single-celled gametes.
• In plants, the gametophyte generation produces gametes (eggs and sperms) which fertilize to form zygotes.
• The sporophyte generation produces spores which develop into gametophytes.
• Flower- a reproductive shoots that usually composed of four parts- sepals, petals, stamens, and carpels.
• Sepal- modified leaves at the base of flower that protect buds from damage.
• Stamen- male sex organ consisting of anther with microspore mother cells and filament.
• Petal- brightly colored structures that attract pollinators.
• Anther- saclike structure containing pollen grains
• Carpel- female organ that contains ovules or egg cells.
• Filament- stalk supporting the anther
• Pollen grain- male gamete produced by the anther
• Receptacle (Torus)- usually shortened, conical or disk shaped at the upper end of the stalk of the flower.
• Ovary- lower part of the carpel which houses the ovule(s)
• Stigma- sticky surface where pollen is deposited
• Style- elongated tube connecting stigma to ovary
• Calyx, coralla, and receptacle are accessory organs.
• Stamen and pistil are essential organs.
• Calyx- outermost green leaf like structure

  Sepal- lobe of calyx
• Gamosepalous- sepals are united forming a tube.
• Polysepalous- sepals are free from one another
• Corolla- inside the calyx, bright colored delicate petals
• Gamopetalous- petals are united forming a corolla tube
• Polypetalous- free from one another (petals)