basic body plans (10 phyla)

• Phylum Cnidaria shared derived characteristics:

  • cnidocytes
  • radial symmetry
  • diploblastic
• Cnidaria basic body shapes:

  • medusa: oral surface down; swimmers
  • polyp: oral surface up; crawlers
• Cnidaria have gastrovascular cavity type of digestive tract
• Cnidaria have mesoglea, which is a noncellular layer of jelly
• Echinodermata shared derived characters:

  • water vascular system
  • lined with smooth muscle
  • pentaradial as adult
  • bilateral symmetry as larvae
• Chordata shared derived characters:

  • notochord
  • dorsal hollow nerve chord
  • pharyngeal gill arches/slits
  • post-anal tail
• Platyhelminthes shared derived characters:

  • gastrovascular cavity: lost gut
  • rudimentary cephalization: really small brain
  • light sensitive eye spots
• Mollusca shared derived characters:

  • muscular foot
  • mantle
  • radula
  • visceral mass
• Why do molluscs have visceral mass?

  because muscular foot is too big
• What does it mean to have visceral mass?

  internal organs are puhsed to one side/area
• Molluscs develop though a ciliated trochophore larval stage
• Annelida shared derived characteristics:

  (some with)

  • fleshy appendages
  • bristles
• Annelida develop through ciliated trochophore larval stage
• Brachiopoda shared derived characteristics:

  • 2 hinged shells
  • 2 muscles in a pair (open and close)
• Brachiopods have radial cleavage and have the mouth as the second opening
• Nematoda shared derived characteristics:

  • hydrocoel
  • covered with a cuticle
• Arthropoda shared derived characteristics:

  • open circulatory system
  • hard exoskeleton with jointed appendages
• Porifera include: sponges, sea squirts, and corals
• Cnidaria include: sea anemones, jellyfish, corals, and hydrozoans
• Echinodermata include: sea stars, sea urchins, and sea cucumbers
• Chordata include: amphibians, reptiles, mammals, and fish
• Platyhelminthes include: Flatworms
• Mollusca include: snails, clams, slugs, octopus, and cuttlefish
• Annelida include: segmented worms; earthworms, leeches, and tapeworms
• Brachiopoda include: lamp shells(?)
• Nematoda include: round worms, vinegar eel, ascaris, dracunculus, C. elegans
• Arthropoda include: insects, spiders, crustaceans, scorpions, ticks, mites, and centipedes
• Incomplete hexapod metamorphosis: gradual changes; egg, series of nymph stage, adult (reproductive; wings)
• Complete hexapod metamorphosis: 1. Egg 2. Larva 3. Pupa 4. Adult; completely rearrange all body structures at once (single step)
• Biramous legs: branched appendages, single base, one branch coming out and second branch is gill on inside (crustacean)