Genbio 2

• Reproduction


  A biological process by which an offspring is being produced by its parent or parents
• Purposes of Reproduction

  • Procreation
  • Quality Improvement
• Procreation


  Reproduction sustains the species so that it does not become extinct
• Quality Improvement


  Allow mixing of genetic materials leading to variation among individuals in a species
• Types of Reproduction

  • Sexual Reproduction
  • Asexual Reproduction
• Sexual Reproduction

  • Involves two parents
  • Each contributes a specialized gamete (an egg or sperm)
  • Fuse to form the fertilized egg or zygote
  • Organism combines the genetic information from each of its parents and is genetically unique
• Fertilization


  The fusion of sperm and egg

  
• Types of Fertilization

  • Internal Fertilization
  • External Fertilization
• Internal Fertilization


  Fusion of male and female gametes that takes place inside the body

  
• External Fertilization


  Fusion of male and female gametes that takes place outside the body

  
• Asexual Reproduction

  • One parent copies itself to form a genetically identical offspring
  • Does not involve gametes, instead parts of a mature organism may develop into new individuals
• Mechanisms of Asexual Reproduction

  • Fission
  • Budding
  • Fragmentation
  • Regeneration
  • Vegetative Propagation
  • Spore Formation

  
• Fission


  Division of the body into two or more new bodies
• Binary Fission


  Parent cell divides into two equal halves called daughter cells
• Multiple Fission


  Organisms divides itself into numerous daughter cells
• Budding


  A new individual arises as an outgrowth (bud) from its parent develops organs like those of the parent and then detached itself
• Fragmentation


  Breaks into two or more parts, with each fragment becoming a complete individual
• Regeneration


  When a lizard loses its tail, it grows a new one
• Vegetative Propagation


  Plants reproduce asexually through their vegetative parts such as leaves, roots, stem, and buds
• Spore Formation


  Specialized reproductive cells called spores are produced by an organism
• Internal Fertilization


  A male animal releases its sperm cells inside the body of a female animal to fertilize an egg
• Ways of Internal Fertilization

  • Oviparity
  • Ovoviviparity
  • Viviparity
• Oviparity


  The fertilized egg forms a shell with the yolk and the developing offspring inside, eggs develop and hatch into young individuals outside the parent's body

  
• Ovoviviparity


  The fertilized egg forms a shell with the yolk and the developing offspring inside the body similar to oviparous animals, the egg stays inside the female parent's body, the yolk becomes the offspring's source of nourishment while developing inside the female body
• Viviparity


  Develop the offspring inside female parent, like ovoviviparous animals, the fertilized egg does not form a hard shell and yolk, the offspring receives nourishment through the parent's body (via placenta)
• External Fertilization


  Parents release sex cells into an external environment, where fertilization takes place, needs a watery environment to prevent the sex cells from drying out
• Some plants grow new plants from fruits and seeds
• Plants form seeds through sexual reproduction
• Plants need to reproduce to produce offspring so that the plant population can still exist and live on Earth
• Sexual Reproduction in Plants

  Female egg and male sperm, flowers, pollens, seeds, fruits, cones
• Fertilization


  Meeting of male and female gametes, needs to happen to produce seeds

  
• Pollination


  Helps facilitate fertilization, transfer pollen grains from an anther (in the male part) and a stigma (in the female part)
• Perfect Flower


  Most flowers are hermaphrodites, they contain both male stamen and female pistil parts in the same flower

  
• Major Parts of Flower

  • Stamen
  • Pistil
• Stamen


  Male reproductive flower parts, produces pollen grains
• Parts of the Stamen

  • Anther
  • Filament
• Anther


  Pollen sac, produces the pollen grains
• Filament


  Supports and makes the anther accessible to the agents of pollination
• Pollen grains


  Powdery materials that contain the male gamete

  
• Pistil


  The female reproductive flower part found at the center of the flower, includes the stigma, style, ovary, and ovules