bio

• Reproduction


  Biological process of producing offspring from their parent/s
• Types of reproduction


  • Asexual
  • Sexual
• Asexual reproduction


  • Does not involve gametes
  • Genetically identical to the parent
  • No mate needed
• Sexual reproduction


  • Use of sex gametes
  • Fusion of male and female zygote
  • Genetic variability
  • Needs two parents
• Asexual reproduction in animals


  • Binary fission
  • Budding
  • Fragmentation
• Binary fission


  • Separation of body into two
  • Common in single celled organisms
  • Occurs in paramecium
• Budding


  • New organism develops from an outgrowth from the parent body known as a bud
  • Once grown, the new organism detaches from the parent body
  • Examples: HYDRA, Saccharomyces cerevisiae
• Fragmentation


  • Parent body will break into several pieces where each piece grows into a new individual
  • Example: Starfish
• Asexual reproduction in plants

  • Vegetative propagation
• Vegetative propagation


  • Plant part such as stems, leaves, roots or turions are used to reproduce new plant
  • Natural VP (without human interference)
  • Artificial VP (with human interference)
• Parthenogenesis


  • Offspring without the need of male organism
  • Example: Comodo dragon
• Male reproductive system


  • Testes
  • Seminiferous tubules
  • Regulated by hormones (GnRH, FSH, LH)
• Female reproductive system


  • Ovaries
  • Oogenesis
  • Estrogen and progesterone secretion
  • Fallopian tubes
  • Uterus (endometrium and myometrium)
• Gametogenesis


  1. Production of gametes

  2. Polar body (no ability to fertilize)

  3. Ovum (has ability to fertilize)
• Fertilization


  Sperm enters the egg
• Implantation


  1. Blastocyst secretes HCG

  2. Progesterone level is very high to prevent menstruation
• Embryonic stage


  1. Formation of 4 membranes (yolk sac, allantois, amnion, chorion)

  2. Development of placenta

  3. Organ formation

  
• Fetal stage


  Organs differentiate further and grow
• Gonadotropin-releasing hormone (GnRH)


  Pituitary gland stimulates the release of LH and FSH
• Luteinizing hormone (LH)


  • Male: Causes testes to secrete testosterone
  • Female: Causes ovulation and secretion of progesterone
• Follicle-Stimulating Hormone (FSH)


  • Male: Causes testes to produce sperm
  • Female: Causes growth of ovarian follicle and secretion of estrogen
• Structure of a flower

  • Stamen
  • Carpel/Pistil
• Stamen


  • Male portion of a flower
  • Made up of anther and filament
  • Anther produces haploid pollen grains by meiosis
• Carpel/Pistil


  • Female portion of a flower
  • Stigma (sticky to trap pollen)
  • Style (hollow tube connecting stigma and ovary)
  • Ovary (produces female gametes/ovules)
• Monoecious


  Stamens and pistils occur on separate flowers, but the same plant
• Dioecious


  Staminate and pistillate flowers occur on separate plants
• Sporophyte


  Diploid, produces haploid spores by meiosis in sporangia

  
• Gametophyte


  Haploid, produces gametes via mitosis; gametes fuse to form a zygote that develops into a sporophyte
• Male gametophyte


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


  The ovule inside the ovary contains the megasporangium; within each megasporangium, a megasporocyte undergoes meiosis generating 4 megaspores (3 small, 1 large)
• Pollination


  Transfer of pollen from an anther to a receptive stigma
• Fertilization


  One egg and sperm combine, forming a diploid zygote, the future embryo
• Double fertilization


  One sperm fuses with the ovum, another sperm fuses with the polar nuclei to become the endosperm (food for the early embryo)
• Embryo development


  1. Ovules become the seed

  2. Ovary matures into fruit
• Seed germination


  1. Resumption of growth and development after a period of seed dormancy

  2. Epigeous germination (cotyledon above ground)

  3. Hypogeous germination (cotyledon below ground)
• Plant hormones


  • Auxins
  • Cytokinins
  • Gibberellins
  • Ethylene
  • Abscisic acid
• Autotrophic nutrition


  Plants can produce their own food
• Heterotrophic nutrition


  Animals cannot produce their own food
• Parts of the digestive system

  • Mouth
  • Esophagus
  • Stomach
  • Small intestines
  • Large intestines
  • Anus
• Digestive process


  1. Ingestion

  2. Digestion

  3. Absorption

  4. Elimination