Phylum Chordata - Mediapolis Schools
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Transcript Phylum Chordata - Mediapolis Schools
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