GEN BIO 4th Qtr

• Asexual Reproduction


  • Requires only one plant
  • Produces genetically identical individuals without the fusion of gametes
• Artificial Plant Propogation

  reproduction with a little help from humans
• Sexual Reproduction


  • Requires two parents
  • Involves the fusion of gametes
  • Produces genetically different offspring
• Parts of a Flower

  • Corolla
  • Ovary
  • Sepal
  • Calyx
  • Petals
  • Stamens
  • Pollen
• Stamens


  • Male reproductive part
  • Consist of a filament with an anther at the tip
  • Anthers contain pollen sacs where male gametophytes are produced
  • Filament holds the anther
• Carpels


  • Female reproductive part
  • Consist of an ovary, stigma, and often a style
  • Ovary is the enlarged base of the carpel where the ovules are located
  • Ovules are the structures where the female gametophytes are produced
  • Stigma is the upper part of the carpel that receives pollen
• Pollination


  The arrival of pollen on a receptive stigma
• Pollination vector


  Environmental agent that transfers pollen grains from one plant to another
• Pollinator


  Animal pollination vectors such as insects or birds
• Nectar


  Sweet food that rewards pollinators
• Life Cycle of Flowering Plants


  1. Sporophyte (diploid, spore-producing plant body)

  2. Gametophyte (haploid, gamete-producing structure)

  3. Megaspore (haploid spore that gives rise to an egg-producing gametophyte)

  4. Microspore (haploid spore that gives rise to a pollen grain)
• Double Fertilization


  1. One sperm cell fuses with the egg and forms a diploid zygote

  2. Second sperm cell fuses with the endosperm mother cell and forms a triploid cell which gives rise to endosperm (nutritive tissue in seeds of flowering plants)
• Zygote


  Develops into an embryo
• Endosperm


  A fertilized angiosperm enriched with nutrients
• Seed


  A mature ovule that consists of an embryo sporophyte, its food reserves, and a seed coat protective covering
• Classification of Fruits


  • True fruit (only ovarian wall and its contents)
  • Accessory fruit (floral parts expand with developing ovary)
  • Simple fruit (one flower, single or fused carpels)
  • Aggregate fruit (one flower, several unfused carpels)
  • Multiple fruit (individually pollinated flowers fuse)
  • Dry (dehiscent, indehiscent)
  • Fleshy (drupe, berry, pepo, hesperidium, pome)
• Asexual Reproduction of Animals


  • Budding
  • Fragmentation
  • Binary fission
  • Parthenogenesis
• Sexual Reproduction in Animals


  Gametes of two parents combine at fertilization
• Hermaphrodites


  Sexually reproducing animals that can make both eggs and sperm
• Sequential hermaphroditism


  Some fish switch from one sex to another over the course of a lifetime
• External fertilization


  Occurs in some vertebrates, bony fishes, and amphibians where eggs and sperm are released into the water
• Internal fertilization


  Sperm enter the female's body and fertilize the egg
• Reproductive Strategies with Internal Fertilization


  • Oviparous (eggs develop and hatch outside the mother's body)
  • Ovoviviparous (eggs are retained and embryo develops within the mother's body)
  • Viviparous (young develop within the mother's body and get nourishment directly from the mother's blood)
• Placenta


  Organ that facilitates the exchange of substances between the animal and embryonic bloodstreams
• Gonads


  Specialized reproductive organs where gametes develop (ovaries produce eggs, testes produce sperm)
• Oogenesis


  Process of egg formation
• Spermatogenesis


  Process of sperm formation
• Ovary


  Produces and releases oocytes, secretes hormones estrogen and progesterone
• Oviduct


  Hollow tube connecting ovary to uterus, where fertilization usually occurs
• Uterus


  Hollow, pear-shaped organ where embryo develops during pregnancy
• Vagina


  Extends from the cervix to the body opening, organ of sexual intercourse and birth canal
• Vulva


  The external female sex organs
• Egg Production and Release


  All oocytes produced before birth, one released per 28-day cycle starting at puberty
• Menstrual Cycle


  Governed by hormones GnRH, FSH, LH which stimulate follicle maturation and ovulation
• Once the egg is fertilized


  It prevents menstruation from occurring
• Premenstrual syndrome (PMS) is a recurrence of symptoms caused by cycle-associated hormonal changes
• Menopause


  Occurs when all follicles in ovaries have been released or disintegrated, menstrual cycles cease
• Penis


  Male organ of intercourse, contains spongy tissue that fills with blood during sexual excitement
• Seminiferous tubules


  Located in testes, where sperm cells are produced, contain diploid male germ cells and nurse cells that support sperm development
• Estrogen


  Trigger development of female secondary sexual characteristics, maintain lining of reproductive tract