Phylum - Chordata
Characteristics - have a
notochord and a dorsal
nerve cord at some point in
their life cycle.
A dorsal nerve cord is a
tube of nervous tissue just
above the notochord.
A notochord is a firm tissue
mass along the dorsal side.
includes tunicates, colonial drifting
salps, and larvacean.
Tunicates pump water to filter
Salps are gelatinous free-
Larvaceans are tadpole-like
planktonic organisms thought to
resemble the theorized ancestor
includes 25 species of lancelet.
Small filter feeders resemble
vertebrates, except they lack
A notochord that has
developed into a spinal
cord protected by
vertebrae (spine) and a
head with a brain.
Vertebrates consist of
the most complex
Eddie and the Hagfish
Class Agnatha: jawless fish.
Species include lampreys and hagfish.
Represent the ancestor of bony fish / sharks.
Subphylum Vertebrata - Class: Agnatha
5 - 8
4. Why are lampreys and hagfish important fish in
5. What characteristics does phylum Chordata have?
6. What animals are in subphylum Urochordata?
7. What animals are in subphylum Cephalochordata?
8. What are the characteristics of subphylum vertebrata?
9. What animals are in class Agnatha?
10. What happened to the notochord in vertebrates?
FYI: During the Cambrian period (500 million
yrs. Ago) the first of three gill arches on a
jawless fish evolved into the first jaws.
Jaws allowed vertebrates to become very
5 - 10
includes sharks, rays
Sharks and rays share
a basic anatomy.
jawed fish, that lack a
swim bladder, and have
5 - 11
Cartilage saves energy. Saving
energy is one of the things that
have made them successful
Sharks have a sense of smell
that detects incredibly diluted
Sharks have a “conveyor belt” of
multiple rows of teeth.
The new teeth swing into place as
old teeth wear out and fall away.
Sharks and rays have lateral lines – that
detect water motion and vibrations.
Unique to sharks & rays is electroreception –
the ability to sense tiny electricity created by
muscles and nerves.
Sharks and rays have organs called ampullae
of Lorenzini which you can see as visible pits
near their snouts used to detect the electrical
Fewer, but more mature
Most fertilize eggs
Males deposit sperm
in the female via a pair
of organs called
Females lay egg
cases in which the
juveniles develop for
up to six months.
A few shark species are ovoviviparous – the
eggs hatch within the mother’s body.
They give birth to live young rather than egg
Shark size ranges from hand-sized to the
whale shark – the largest fish.
Whale sharks can reach 14m/46 feet.
Basking sharks can reach 10m/33 feet.
Megamouth sharks can reach 6m/20 feet.
All three are filter feeders that consume
Planet in Peril
1. What type of animals are in class chondrichthyes?
2. List four characteristics of sharks & rays.
3. What is the ampullae of lorenzini for?
4. What are lateral lines for?
5. What is special about shark teeth?
8. Which gender of sharks has claspers?
9. What are two ways sharks give birth?
10. What is the largest fish in the world?
Many sharks are in
danger of going extinct
due to human activities.
Sharks are typically not
dangerous to humans –
we don’t taste good to
5 - 19
Sharks in Peril
3. Sport Fishing
Sharks in Peril
Shark Fishing TX
5 - 24
Rays, skates and guitarfish
Ray anatomy is suited to life
on sandy bottoms or
Adapted to midwater are the
eagle ray and manta ray.
Pectoral fins have become
“wings” that stretch forward
over the gills and are fused
to the sides of the head.
No longer need a tail for
swimming, (the tail has
become a defensive whip
in some species.)
Rays literally fly through
The largest rays are
mantas with wingspans
exceeding 8 meters (26
Like the largest shark, the
mantas feed on plankton.
The Secret World of
Sharks and Rays
1. What animals are in class chondrichthyes?
2. What are two differences b/w fish and
3. What are lateral lines for?
5. What part of a shark’s body became the “wings”
6. What is the tail of the ray used for?
7. What is the largest ray?
8. At what depth in the water do most rays live in?
9. What do the largest rays feed on?
Chondrichthyes Review - 2
Sharks in Peril
5 - 27
Sharks in Deep Trouble
Yao Ming 姚明 Shark Fin Soup
Title: Sharks in Peril
Write an essay that includes the three topics listed
below. Your essay should be persuasive in protecting
the world’s sharks that are left. Typed, double space,
Vocabulary will be checked.
Shark fin soup
Shark sport fishing
Introduction paragraph (1)
Paragraph per topic discussed (3)
Conclusion paragraph (1)
5 paragraphs all together (typed)
HW: Essay – due in four days
Characteristics: jawed fish
with bone skeletons.
Most have scales.
Most control buoyancy
using oxygen gas
exchanged to and from
blood circulation to a swim
(This allows many species
to hover nearly
motionless in midwater.)
Most bony fish reproduce externally.
The female lays her eggs, the male immediately
Produce a vast number of off-spring with only a
few expected to survive to maturity.
Bony fish have lateral lines that
detect water vibrations.
Most open ocean and schooling
fish have a torpedo-like
streamlined shape for speed.
This fusiform shape is
spindle-like, slightly broader at
the head and a V-shaped tail.
This makes them fast
Most open-ocean and schooling
fish have a lighter underside and
dark topside for concealment.
Bony fish living in reefs and on the
bottom use survival strategies
more diverse and include
concealment and armor instead
For this reason, you see far
more diversity in color,
shape, and size among reef and
Important in worldwide
of all fish caught
come from this
2. Order Gadiformes
includes cod, pollack,
haddock, whitings, etc…
A sixth of the world’s fish
Alaskan pollack, the haddock
and whitings are important
Historically, worldwide fisheries
have influenced politics and
Important fish in California
Return of the
Schools of Fish
Do other animals do this?
- Next slide
1. What does “osteo” mean?
2. Swim Bladder
4. Lateral line
5. Open Ocean
6. What are most fish color shading that live in the open
7. What are two defenses reef fish use?
8. What common fish belong in Clupeiformes?
9. What common fish belong in Gadiformes?
10. What are some concerns regarding salmon?