PHYLUM CHORDATA
Includes all vertebrates and two groups of
invertebrates
 Have four characteristics during some stage of
their life;

 Notochord
 Dorsal
nerve chord
 Pharyngeal pouches/gill slits
 Postanal tail
NOTOCHORD
Is a stiff flexible rod of cells that runs dorsally
the length of the body
 provides a strong surface for muscles to attach
 usually present in the embryo of vertebrates
but becomes reduced when the backbone
develops

DORSAL NERVE CHORD

is a hollow tube where the anterior end enlarges to
form the brain and the posterior end forms the spinal
cord
PHARYNGEAL POUCHES

out pockets in the pharynx develping into gills for
aquatic organisms and jaws, inner ear, tonsils for
terrestrial organisms
POSTANAL TAIL

Aquatic chordates possess this characteristic as an
adult

acts as a form of propulsion in the water
PHYLUM CHORDATA
Deuterostomes
 Coelomates
 Divided into three subphyla:

 Vertebrata
(95% of all chordate species)
 Cephalochordata
 Urochordata
SUBPHYLUM CEPHALOCHORDATA
Includes lancelets
 Keep notochord, dorsal nerve chord,
pharyngeal pouches, and postanal tail
 They live in warm, shallow waters where they
wiggle backwards into the sand.
 Cilia pull water into their pharynx where food is
trapped in the slits entering the intestines to be
digested.

SUBPHYLUM UROCHORDATA
Includes sea squirts (tunicates)
 Bodies are covered with a thick tough covering
called tunic.
 Sessile barrel-shaped animals that live on the
bottom of the sea.
 Larval forms possess all four chordate
characteristics but loose them during
metamorphosis.
 As adults they have a pouch-like pharynx with slits,
are filter-feeders and hermaphrodites.

SUBPHYLUM VERTEBRATA
at some stage they have a notochord, dorsal
nerve chord, pharyngeal pouches, and a
postanal tail
 distinguished from other subphyla by three
characterisitics;

 Vertebrae
 Cranium
 endoskeleton
of bone or cartilage
THE MAJOR GROUPS OF VERTEBRATES




Class Agnatha (lampreys and hagfish),
 elongated eel-like bodies, lack jaws, paired fins, and bone
Class Chondricthyes (sharks, rays, and skates)
 predatory fish have jaws and paired fins, their skeleton is
made of cartilage, skin is covered in a unique scale
Class Osteichthyes (bony fish)
 they have jaws, boney skeleton
Class Amphibia (Amphibians)
 skin is thin, lay eggs in water and have an aquatic larval
stage
THE MAJOR GROUPS OF VERTEBRATES
 Class
Reptilia (Reptiles)
 skin is dry and scaly, eggs are laid on land
and protect the embryo from drying out
 Class Aves (Birds)
 they have adapted for flight through wings,
hollow bones, unique respiratory system
 Class Mammalia (Mammals),
 they grow hair and nurse their young