Reproductive Strategies

• What are the two disadvantages of external fertilisation?

  
  

  Wasteful number of eggs

  Fertilisation not certain
• What are two advantages of external fertilisation?

  • Large number of gametes to avoid predation
  • Courtship rituals bring gametes closer
• Where does external fertilisation take place?

  Water
• Advantages of internal fertilisation:

  • Fertilisation more certain
  • Fewer gametes needed
  • Protective shell / yolk
• Disadvantages of internal fertilisation:

  • finding a mate
  • fewer reproduction opportunities
  • longer gestation
• Where do eggs develop in ovipary fertilisation?

  Outside
• Advantages of ovipary fertilization:

  • more yolk
  • more protection
  • parental care
• Ovipary fertilisation types and egg amounts:

  • Aquatic: many eggs with small amounts of yolk (less energy)
  • Land: very few eggs
• Disadvantage of aquatic ovipary fertilisation:

  often very little parental care
• Disadvantage of land ovipary fertilisation:

  susceptible to predators
• Are eggs fertilised internally or externally in Ovovivipary fertilisation?

  
  

  Internally
• Advantages of ovovivipary fertilisation:

  • large amount of yolk
  • protection from predators
  • young born fully developed
• Definition of vivipary fertilisation:

  • internal fertilisation
  • eggs do not have shell
  • born live
• Advantage of vivipary fertilisation:

  • reduced egg numbers
  • nourishment & protection
  • provide parental care
• A) Shell

  B) Yolk sack

  C) Albumin

  D) Allantois

  E) Embryo

  F) Amniotic fluid

  G) Amnion

  H) Chorion

  
• What provides nutrition for the embryo in an amniotic egg?

  Yolk sack
• What acts as a resevoir for nitrogenous wastes?

  Allantois
• What prevents dehydration and mechanical injury?

  Amniotic fluid
• In which form of fertilisation eggs kept inside then hatch internally?

  Ovovivipary