Body Plans

• Scientists use body plans to classify animals into groups (phyla)
• Set of morphological characteristics (shape and structure) of an animal's body, as well as the way in which it develops.
• Symmetry and Cephalisation

  Whether the animal is asymmetric, radially symmetrical or bilaterally symmetrical, and if it shows a definite head region
• Number of tissue layers

  Develop in the embryo- two (diploblastic) or three (triploblastic)
• presence or absence of a coelom and a blood stystem
• Number of openings in the digestive tract

  a through gut or not

  'digestive cavity, alimentary canal, enteron'