This document discusses chordates and vertebrates. It notes that vertebrates have backbones and belong to the phylum chordata. It also describes two other chordate groups, lancelets and tunicates. Key characteristics of chordates include having a tail, nerve cord, pharyngeal pouches and notochord. The document then focuses on characteristics of vertebrates like their backbone and skull. It classifies vertebrates as either warm-blooded or cold-blooded. Finally, it outlines the three classes of fish and characteristics like breathing with gills and reproduction through external fertilization.

2. • Animals that have a Chordates
backbone are called
vertebrates.
• Vertebrates belong
to phylum chordata
(called chordates)
• Vertebrates make up
largest group of
chordates

3. •Two other groups of chordates are
lancelets and tunicates
•Much simpler than vertebrates (no
backbone or well developed head)

4. Chordate Characteristics
• 1) Have a tail (some only have a tail
during embryo stage)
• 2) Hollow nerve cord —in
vertebrates it is called spinal cord
• 3) Pharyngeal pouch —develop into
gills or other body parts as embryo
matures
• 4) Notocord —stiff but flexible rod
that gives body support
– In most vertebrates, embryo’s
notocord is replaced by a
backbone

5. Vertebrate Characteristics
– Have a backbone (strong
but flexible column of bones
called vertebrae)
– Have well developed head
protected by skull (made of
bone or cartilage)
• Cartilage is tough material that
flexible parts of ears and nose
are made of
– Skeletons of vertebrate
embryos are cartilage and
harden into bone

6. Are Vertebrates
Warm or Cold?
• Birds and
mammals are
endotherms (warm
blooded)
– Use energy
released by
chemical reactions
in the body to stay
warm

7. • Fish, amphibians,
and reptiles are
ectotherms (cold
blooded)
– Depend on their
surroundings to
stay warm

8. Fish Characteristics
• More than 25,000 species
of fish
• All fishes share several
characteristics:
– (1) Born to swim
• use fins to steer, stop,
and balance
• scales are bony
structures that cover
and protect body and
lower friction

9. – (2) Making Sense of the
World
• have senses of vision,
hearing, and smell
• have a lateral line
system (row of sense
organs that detect
water vibrations)
– (3)Underwater Breathing
• use gills to breathe
(organ that removes
oxygen from water)
• gills also remove
carbon dioxide from
the blood

10. – (4) Making More
Fish
• most fish
reproduce by
external
fertilization
• females lay
eggs in water
and male
drops sperm
on them

11. Kinds of Fishes
• Three classes of fishes still
living today:
– (1) Jawless fishes
• first fishes (have been
around for half a billion
years)
• Two kinds: hagfish and
lampreys
• Smooth, slimy skin and
round, jawless mouth
• No backbone, but does
by a skull, brain, and
eyes

12. Cartilaginous Fishes
– (2) Cartilaginous Fishes
• skeleton never changes to
bone; stays cartilage
• have fully functional jaws
• strong swimmers and expert
predators
• excellent senses of sight and
smell
• to stay afloat, they store a lot
of oil in their liver, which
helps them be buoyant
• Examples: skates, stingray,
sharks

13. Bony Fishes
– (3) Bony Fishes
• largest class of fish (95%
of all fishes are bony
fishes)
• very different from other
fishes—skeleton made of
bone and body covered by
bony scales
• Unlike other fishes, they
can rest in one place
without swimming because
they have a swim bladder
(gas-filled sac that helps
fish be more buoyant)

14. • Two main groups:
ray-finned and
lobe-finned
– Ray finned:
eels, herrings,
trout, minnows,
perch
– Lobe finned:
lungfishes

15. Hagfish:
jawless
Shark:
cartilaginous
Trout:
bony

16. Stingray:
cartilaginous
Lungfish:
bony
Lamprey:
jawless