The Deuterostomes

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The Deuterostomes

• BIOL 102 Lab

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The Deuterostomes

• The Echinoderms -
• Know the primary characteristics and classes of
  this phylum.
• Identify the external features of a sea star.
• The Chordates-
• Know the chordate traits and the sub-phyla.
• Study the slides of tunicate and identify the
  structures shown in fig.15.2 and 15.4.
• Study the slides of Amphoxious and identify the
  structures shown in fig. 15.5 and 15.6-15.8.
• Complete a life function sheet for this phylum.

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Phylum Echinodermata

• All marine and free-living.
• Larvae are bilaterally symmetrical.
• Adults are pentaramous.
• Cutaneous gas exchange.
• Calcareous endoskeleton with a dermal layer of
  ossicles and spines.
• Water canal systems that bear tube feet.
• Well-developed coelom.

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Phylum Echinodermata

• Water canal used for locomotion, feeding,
  respiration and excretion.
• Fairly simple reproductive system located in the
  coelom.
• Most dioecous.

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Echinoderm Classes

• Class Stelleroidea sea stars, brittle stars.
• Class Crinoidea sea lilies and feather stars.
• Class Echinoidea sea urchins and sand dollars.
• Class Holothuroidea sea cucumbers.

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Fig. 14.3
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Phylum Chordata

• The deuterostome line of evolution contains only
  a few phyla, with the vertebrates and the
  echinoderms comprising the majority.
• Of the chordates. Approximately 95 are
  vertebrates.
• The chordates are one of the most diverse and
  successful of all animal groups.

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The Chordate Traits

• Pharyngeal gill slits
• Hollow nerve cord
• Dorsal notochord
• Post-anal tail
• ALL chordates have these traits at some point in
  their life cycle, including humans!

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Chordates, cont.

• Major Characteristics of Phylum Chordata
• Bilateral symmetry  segmented body
   triploblastic  well-developed coelom.
• Notochord (a skeletal rod) present at some stage
  in life cycle.
• Single, dorsal, tubular nerve cord  anterior end
  of cord usually enlarged to form brain.
• Pharyngeal gill slits present at some stage in
  life cycle.
• Postanal tail, usually projecting beyond the anus
  at some stage but may or may not persist.

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Chordates, cont.

• Segmented muscles in an unsegmented trunk.
• Ventral heart, with dorsal and ventral blood
  vessels  closed blood system.
• Complete digestive system.
• A cartilaginous or bony endoskeleton present in
  the majority of members (vertebrates).

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Chordate Subphyla

• Subphylum Urochordata - tunicates and sea
  squirts.
• Subphylum Cephalochordata - lanclets.
• Subphylum Vertebrata ours!

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Tunicates
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