reproductive system

• Reproduction


  The biological process by which offspring are produced from their parent or parents
• Types of reproduction


  • Asexual reproduction
  • Sexual reproduction
• Asexual reproduction


  • Does not involve gametes, instead parts of mature organism may develop to new individuals
  • Offspring is genetically identical to the parent
• Binary fission

  1. Separation of the body into two new bodies

  2. Common in single-celled organisms
• Budding


  1. A new organism develops from as an outgrowth from the parent body known as bud

  2. Once grown, the new organisms detaches from the parent body
• Fragmentation

  The parent body will break into several pieces where each piece grows into a new individual
• Vegetative propagation

  1. A plant part such as stems, leaves, roots or turions are used to reproduce new plant

  2. Natural vegetative propagation (without human interference)

  3. Artificial vegetative propagation (with the need of human interference)
• Sexual reproduction


  • Use of sex cells (gametes)
  • Involves the fusion of male and female gametes to form a zygote
  • Genetic variability
• Male reproductive system

  • Testes – male reproductive organs
  • Seminiferous tubules – produce sperm (spermatogenesis)
  • Regulated by hormones (GnRH, FSH, LH)
• Female reproductive system

  • Ovaries
  • Oogenesis - development of ovarian follicles (formation of egg cell)
  • Secretion of estrogen and progesterone
  • Fallopian tubes (oviducts) - area where fertilization occurs
  • Uterus (womb) - endometrium, myometrium
• Animal development


  1. Gametogenesis - production of gametes

  2. Fertilization

  3. Implantation

  4. Gastrulation

  5. Embryonic stage - formation of 4 membranes, development of placenta, organ formation

  6. Fetal stage - organs differentiate further and grow
• Blastocyst


  • Will secrete HCG (hormone used to detect pregnancy)
  • Progesterone level is very high to prevent menstruation
• Hormonal regulation of animal reproduction

  • Gonadotropin-releasing hormone (GnRH) stimulates the release of Luteinizing hormone (LH) and Follicle-Stimulating Hormone (FSH)
  • Pituitary gland secretes the 2 gonadotropic hormones: FSH (causes testes to produce sperm in males, causes growth of ovarian follicle and secretion of estrogen in females) and LH (causes testes to secrete testosterone in males, causes ovulation and secretion of progesterone in females)
• Stamen


  • Male portion of a flower
  • Made up of an anther and a filament
  • The anther produces haploid pollen grains by meiosis
  • Most flowers have multiple stamens
• Carpel/Pistil


  • Female portion of a flower
  • Stigma - sticky, to trap pollen
  • Style - hollow tube which connects stigma and ovary
  • Ovary - produces female gametes (ovules)
• Types of plant sexual reproduction

  • Monoecious - stamens and pistils occur on separate flowers, but the same plant
  • Dioecious - staminate and pistillate flowers occur on separate plants
• Monoecious plants


  • Cucurbita Maxima
• Dioecious plants

  • Carica papaya
• Gametophyte

  Stage of the life cycle of a plant that is haploid; stage that produces gametes via mitosis; these gametes fuse to form a zygote that develops into a sporophyte
• Sporophyte


  Stage of the life cycle of a plant that is diploid; it is the most recognizable structure in most flowering plants; it produces haploid spores by meiosis in structures called sporangia
• Male gametophyte development


  Inside the anthers' microsporangia, male gametophytes divide by meiosis to generate haploid microspores, which, in turn undergo mitosis and give rise to pollen grains (containing 2 sperm nuclei and tube nucleus)
• Pollen grains


  Contains two cells: one generative cell, cell that will become the pollen tube cell
• Female gametophyte development

  1. The ovule inside the ovary contains the megasporangium

  2. Within each megasporangium, a megasporocyte undergoes meiosis generating four megaspores; three small and one large
• Pollination

  1. The transfer of pollen from an anther to a receptive stigma

  2. Agents: Animals, wind, water, humans
• Fertilization

  1. One egg and sperm combine, forming a diploid zygote, the future embryo

  2. Double fertilization - fuses with the polar nuclei to become the endosperm, which serves as food of the early embryo
• Embryo development

  1. Ovules become the seed

  2. Ovary matures into fruit
• Seed germination and growth

  1. Germination - is the resumption of growth and development after a period of seed dormancy

  2. Epigenous germination

  3. Hypogenous germination
• Hormonal regulation of plant growth and development