The Chordata Chapter 34

The Chordata I Chapter 34 1.General features and earliest groups 2.The neural crest and the origin of the craniates 3.With Gnathostomes come jaws and two pairs of appendages 4.Lateral Lines, Lungs, and Swim Bladders 5.Origin of Tetrapods, Amphibians 6.The Amniotic Egg and the Dinosaur Pelvis

Figure 34.2 Chordate characteristics

Figure 34.4b Subphylum Cephalochordata: the lancelet Branchiostoma

Figure 34.4a Subphylum Cephalochordata: lancelet anatomy

Pikaia, the Burgess-shale chordate, with evident somites

Primitive chordates suggest first steps in their evolution ---

The Chordata I Chapter 34 1.General features and earliest groups 2.The neural crest and the origin of the craniates 3.With Gnathostomes come jaws and two pairs of appendages 4.Lateral Lines, Lungs, and Swim Bladders 5.Origin of Tetrapods, Amphibians 6.The Amniotic Egg and the Dinosaur Pelvis

Figure 34.1 Clades of extant chordates

Figure 34.9 A hagfish A skull of cartilage, but no jaw, no vertebrae

The Chordata I Chapter 34 1.General features and earliest groups 2.The neural crest and the origin of the craniates 3.With Gnathostomes come jaws and two pairs of appendages 4.Lateral Lines, Lungs, and Swim Bladders 5.Origin of Tetrapods, Amphibians 6.The Amniotic Egg and the Dinosaur Pelvis

Figure 34.7 Phylogeny of the major groups of extant vertebrates

Figure Cartilaginous fishes (class Chondrichthyes): Great white shark (top left), silky shark (top right), southern stingray (bottom left), blue spotted stingray (bottom right)

lateral line – first in sharks and rays, homologous to the hair-cell array in the cochlea

Figure 34.12a Ray-finned fishes (class Actinopterygii): yellow perch

Figure 34.12b Ray-finned fishes (class Actinopterygii): long-snouted sea horse

Figure Anatomy of a trout, a representative ray-finned fish

Figure 34.7 Phylogeny of the major groups of extant vertebrates

Figure A coelocanth (Latimeria), the only extant lobe-finned genus

The Chordata I Chapter 34 1.General features and earliest groups 2.The neural crest and the origin of the craniates 3.With Gnathostomes come jaws and two pairs of appendages 4.Lateral Lines, Lungs, and Swim Bladders 5.Origin of Tetrapods, Amphibians 6.The Amniotic Egg and the Dinosaur Pelvis

Figure The origin of tetrapods

Figure Skeleton of Acanthostega, a Devonian tetrapod fish Transitional tetrapods -- feet in place but gills and tail with fin

Figure Amphibian orders: Newt (left), frog (right)

Figure “Dual life” of a frog (Rana temporaria)

The Chordata I Chapter 34 1.General features and earliest groups 2.The neural crest and the origin of the craniates 3.With Gnathostomes come jaws and two pairs of appendages 4.Lateral Lines, Lungs, and Swim Bladders 5.Origin of Tetrapods, Amphibians 6.The Amniotic Egg and the Dinosaur Pelvis

Figure A hatching reptile

Figure Amniotic egg Amnion: cushioning chamber for embryo Chorion: gas exchange to exterior Allantois: disposal sac