Types of Skeletons

• Hydrostatic Skeleton

  • Consists of a fluid-filled cavity.
  • Fluid provides support
  • The pressure that the fluid exerts and the contraction of muscles brings about the animal’s movement.
  • Invertebrate(jellyfish & earthworms)

  Advantages:

  • Animals don’t need a specialised support system as they live in water, which provides support for their bodies.

  Disadvantages:

  • Animals can’t make fast movements
  • Limits the size of the animal
  • Limited to aquatic environments
  • Not enough protection
• Exoskeleton

  • External Skeleton
  • Found in invertebrae(mostly Athropods)
  • Consists of Chitin

  Advantages

  • Supports and protects underlying tissue
  • The inside of exoskeletons are for attachment of muscles, allowing quick movement
  • Prevents animal bodies from drying out.

  Disadvantages

  • Limits size of animal as chitin cannot stretch, therefore animals must shed. After shedding, the new skeleton is soft and leaves the animal vulnerable
  • Big animals can’t have exoskeletons as the skeleton would be heavier and would limit movement.
• Endoskeletons

  • Internal skeleton
  • Consists of bone and cartilage
  • Found in vertebrae

  Advantages

  • Animals can grow as bone and cartilage grow together with the organism.
  • Protects important organs
  • Provided support and gives the body its shape
  • Joints between bones enable flexibility.

  Disadvantages

  • Animals are more vulnerable to heat, cold and drying out.