animal diversity

• metazoa basal traits


  multicellular, heterotrophic, blastula developmental stage
• choanoflagellates do not have blastulas
• sponges are the most basal animals
• characteristics

  body symmetry, number of tissue layers, embryo development, and body cavity presence
• porifera (sponges)


  contain none of the characteristics or segmentation
• cnidaria (corals & jellyfish)


  radial, diploblastic, no coelom, no segmentation. Have medusa or polyp life stages
• acoela (flat worms)

  bilateral, acoelomate, triploblastic, no segmentation. flat bodied
• echinodermata (starfish)


  most closely related to chordate. radially as an adult, bilateral larvae. triploblastic, coelomate, tissues & organs, with complete digestive system. anus from blastopore.
• chordata(humans)

  bilateral, tissues & organs, triploblastic, coelomate, segemented. anus from blastopore with complete digestive system with other complex body systems
• dorsal hollow nerve cord


  neural tube that extends along a chordate’s back; will become the adult organism’s brain and spinal cord 
• notochord


  flexible rod that provides skeletal support; if retained into adulthood, muscles attach to it and pull against it to generate movement
• pharyngeal slits


  a series of grooves located between arches in chordate embryos; in most chordates, they open to allow water to enter the organism, creating a means of feeding and/or gas exchange
• post-anal tail


  skeletal and muscular elements that extend past the end of the organism’s digestive tube; function in locomotion, but can be greatly reduced in some animals 
• metazoa


  "multicellular animals"
• eumetazoa


  true tissues
• bilateria


  bilateral symmetry
• deuterostomia


  blastopore develops into anus (echinodermata, chordata)
• Protostomia


  blastopore develops from mouth (Mollusca, Arthropoda, Annelida)
• lophotrochozoa

  triploblastic (contains mesoderm) acoela, chordata, echinodermata, mollusca, annelida, nematoda, arthropods
• Ecdysozoa


  shedding exoskeleton. (nematoda & arthropods)
• endoderm


  inner cell wall that develops into gut cavity
• ectoderm


  outside cell wall that develops into external covering
• mesoderm

  lies between ectoderm and endoderm walls in triploblastic animals, develops into complex body systems
• poiferia use flagellas to move water through filtration systems
• insects are hexapoda and the most diverse group of animals
• organ systems developed in Acoela
• triploblastic blastulas developes in bilateria
• lophotrochozoa refers to a feeding strcture consisting of trochophore larvae that use cilla to help move and feed