Classification of Deuterostomes: Vertebrata

what are the two groups all animals belong to?

protostomes or deuterostomes

protostomes development

blastopore develops into the mouth of the animal

deuterostomes development

blastopore develops into the anus and the mouth forms from a separate invagination

deuterostomes further classification

• echinodermata - sea urchins, starfishes

• hemichordata - Pterobranchs, Acorn Worms

• chordata - Urochordata, cephalochordata, craniata

echinodermata what and whi

• marine with a water vascular system and tube feet

• sea lilies

• brittle and basket stars

• sea cucumbers

• sea urchins

• starfishes

hemichordata what and who

• marine with a tripartite body consisting of a proboscis, collar and a trunk

• acorn worms

• Pterobranchs (live at great depths)

chordata what two non vertebrate groups

includes two groups of non-vertebrates

• urochordata - these are mostly the tunicates

• cephalochordata - this includes amphioxus

Collectively these are called the protochordates

What structures are present at some time in all chordates?

• dorsal nerve cord

• gill slits

• Thyroid Gland

• larval Tail

urochordata what and who

• urochordates are marine animals that feed on suspended matter, plankton. Some are sessile as adults and had swimming larvae. Others drift

  • Ascidiacea “Sea Squirts”

  • Larvacea (Appendicularia)

  • Thaliacea

Cephalochordata what and who

• Cephalochordates are marine animals that feed on suspended matter, including microorganisms and plankton. They have several “precursor” structures that resemble structures of chordates

  • Branchiostoma lanceolatus

    • (Amphioxus / Lancelot)

Craniata what do they possess

All craniates possess:

• pharyngeal pouches that become gill slits in fishes and larval amphibians

• thyroid gland

• notochord

• single, dorsal, tubular nerve cord

• post anal tails

craniates what does it include?

living hagfishes and the vertebrates

• hagfishes - have a skull, but lack vertebrae

What do vertebrates include?

• some of the agnathans (without jaws)

  • includes lampreys

  • condrichthyes (cartilaginous fish)

  • osteichthyes (bony fish)

  • amphibia

  • reptilia

  • aves

  • mammalia

vertebrate characteristics

• distinct cephalized head

• distinct trunk

• distinct tail

• well-developed sense organs

• gill arches

• muscularized gut wall

• specialized liver

• specialized pancreas

• well developed endocrine organs

• specialized body cavities

what do the neural crest cells form?

• gill arch skeleton

• cranial motor neurons

• dentine of teeth