Acoelomates

• what is an acoelomate?

  An organism without a body cavity.
• name three phylums which are acoelomates?

  Porifera, cnidaria and Platyhelminthes
• what is the phylum Porifera comprised of?

  sponges
• which is the most primitive phylum?

  Porifera
• where do members of the phylum Porifera live?

  in water - the majority are marine
• can members of the phylum Porifera move?

  no, they are sessile
• what is hermaphroditism?


  the conditions of having both male and female reproductive organs
• give four key features of the phylum porifera?

  sponges, most primitive animals, all aquatic, sessile
• what is the phylum cnidaria comprised of?

  stinging animals
• give three examples of animals in the phylum cnidaria?

  jellyfish, sea anemones and corals
• what are the two forms of the phylum cnidaria?

  sessile polyps form - attached and non moving - and mobile medusae form - free swimming
• what is the phylum Platyhelminthes comprised of?

  flat worms
• what is bilateral symmetry associated with?

  moving forward
• what type of symmetry do the phylum Porifera see?

  Asymmetry
• what type of symmetry do the phylum cnidaria see?

  Radial
• what type of symmetry do the phylum Platyhelminthes see?

  Bilateral
• what are the four classes within the phylum Platyhelminthes?


  free living flatworms, flukes, tapeworms and parasitic flatworms
• give three ways in which the phylum Platyhelminthes are adopted for parasitic life?

  reduced sense organs as no need for eyes, attachment organs to attach to the host and hermaphrodites as low chance of finding a partner in the host