Members of this phylum are
called chordates. A chordate
is an animal that has at least
Phylum Chordata
“Chordates”
for some part of its life 1.) a
dorsal hollow nerve cord; 2.) a
notochord; 3.)Pharyngeal
pouches; 4.)a tail that
extends beyond the anus.
A long supporting rod that
runs just below the nerve
cord. Most chordates have a
Notocord
notochord only when they are
embryos.
Paired structures in the throat
(pharynx) region. In some
chordates (fish & amphibians)
Pharyngeal
Pouches
slits develop that connect the
pharyngeal pouches to the
outside of the body. These slits
may then develop gills used for
gas exchange.
The backbone, which replaces
In vertebrates the dorsal
the notochord in most developing
hollow nerve cord is
vertebrates, is made of individual
called the SPINAL CORD.
segments called VERTEBRAE.
The endoskeleton gives
As a vertebrate embryo
SUPPORT, PROTECT’s the
develops, the FRONT
animal’s body & provides a place
END of the spinal cord
grows into A BRAIN.
2 Subphyla of Chordates
for muscle & ligament
attachment. *The endoskeleton
grows as the animal grows!
Tunicates & Lancelets are
soft-bodied marine animals
LACKING a
that are called “Non-
backbone…but having all
vertebrate chordates”
four characteristics…
FISHES
Aquatic vertebrates; Most
have paired fins, scales, &
gills.
3 Groups/Classes of Fish:
Jawless Fish
Lampreys & Hagfish
Class Chondrichthyes
(Cartilaginous Fish)
Sharks, Rays, Skates &
uncommon fish such as
Sawfish & Chimaeras
Fish with no true teeth or jaws. Skeletons are
made of fibers & some cartilage. They lack
vertebrae & keep their notochord as adults.
Lampreys are filter feeders as larva &
parasites as adults. Hagfish have pink wormlike bodies & 4 short tentacles around their
mouths. They lack eyes. They feed on dead &
dying fish by using a toothed tongue to scrape
a hole in the fishes side (they can tie
themselves in a knot too!)
They have skeletons made up
entirely of cartilage. Most have
tooth-like scales covering their skin
making it feel like sandpaper.
Class Osteichthyes
They have skeletons
(Bony Fish)
made of hard calcified
Ray Finned fish you are most
tissue called bone.
familiar with…
Fish that spend most of their
ANADROMOUS (SALMON)
CATADROMOUS (EUROPEAN EELS)
lives in the ocean but migrate
to fresh water to breed.
Fish that spend most of their
lives in fresh water but
migrate to the ocean to
breed.
FISH REPRODUCTION
OVIPAROUS
Eggs are fertilized internally or externally; the
females lay the eggs & they hatch OUTSIDE the
mother’s body. The embryo gets it’s food from the
yolk in the egg.
OVOVIVIPAROUS
Eggs REMAIN INSIDE the mother’s body after
internal fertilization. Each embryo stays inside its
egg using the yolk for nourishment. The young are
then “born alive” like the young of most mammals.
VIVIPAROUS
After internal fertilization, the eggs remain
inside the mother’s body & get their nutrients
from the mother’s body rather than from
material in an egg. The young are then “Born
alive”.
AMPHIBIANS-frogs, toads,
salamanders, & caecilians
An amphibian is a
vertebrate that, with some
exceptions, lives in water
as a LARVA & on land as
an adult, breathes with
lungs as an adult, has
moist skin that contains
mucous glands, & lacks
scales & claws.
Adaptations that allow
amphibians to live part
of their lives out of
water:
Bones in the limb & limb
girdles became stronger,
permitting more efficient
movement. Lungs &
breathing tubes allowed
them to breathe air. Their
sternum formed a bony
shield that supported &
protected their internal
organs.
Amphibian
Reproduction
Amphibian eggs do not
have shells & tend to dry
out if not kept moist. This
is why most amphibians
must lay their eggs in
water. The male usually
fertilizes the eggs by
external fertilization. In a
few species, including
most salamanders, eggs
are fertilized internally.