Phylum: Chordata

Introduction

Characteristics

• Bilateral symmetry
• Anteroposterior axis
• Coelom
• Tube within a tube body plan
• Metamerism
• Cephalization

Characteristics

•  Notochord – In embryo or thru life
• Flexible rod-like cells in a sheath
• Extends length of body
• Acts like axis for skeleton
• First part of endoskeleton in embryo
• Most displaced by vertebrae
• Remains between or within vertebrae as cartilage

Characteristics

• Dorsal Nerve Cord
• Dorsal to digestive system. Anterior becomes brain
• Pharyngeal Pouches & Slits
• Filter feeding & internal gills
• Humans: part of inner ear
• Postanal Tail
• Needed for water propulsion or wagging
• Coccyx in humans

Subphylum: Vertebrata
(or Craniata?)

• Largest & most diverse subphylum
• Brain with cranial nerves
• Endoskeleton with muscle attachment
• Muscles arranged in myomeres
• Coelom
• Endocrine system