Bio - Lesson 1

• Reproduction


  A fundamental biological process in which new individuals are produced from their parents
• Types of reproduction in animals

  • Asexual reproduction
  • Sexual reproduction
• Asexual reproduction


  Parent produces genetically similar/identical offspring
• Modes of asexual reproduction

  • Budding
  • Fission
  • Fragmentation
  • Regeneration
  • Parthenogenesis
• Budding


  Organism develops from an outgrowth due to cell division at a particular site on parent (e.g. Hydra)
• Fission


  An organism grows and duplicates its genetic material then divides into two
• Fragmentation


  Organisms splits into fragments, each of which develop into mature clones
• Regeneration


  Occurs when a body part is detached from the parent. This part grows and develops into a completely new individual
• Parthenogenesis


  Organisms develops from unfertilized egg cell (e.g. insects, lizards, Komodo dragon, sharks)
• Sexual reproduction


  Production of gametes via meiosis; fusion of male and female gametes (fertilization)
• Modes of sexual reproduction

  • Ovuliparity
  • Oviparity
  • Viviparity
  • Ovoviviparity
• Ovuliparity


  External fertilization. Egg cells released into the environment and fertilized by males (e.g. Molluscs, arthropods, fishes and most frogs)
• Oviparity


  Internal Fertilization. Expulsion of undeveloped eggs rather than live young
• Viviparity


  Development of embryo within parent (Give birth to live young)
• Ovoviviparity


  Embryos develop in eggs and hatch within parent (e.g. some fish, amphibians and reptiles)
• Types of hermaphrodites


  • Sequential hermaphrodites
  • Simultaneous hermaphrodites
• Sequential hermaphrodites


  Individual born as one sex but can later change into the opposite sex
• Simultaneous hermaphrodites


  Individual born both male and female sexual organs at the same time