Chordates

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Chapter 12 Chordates What is a Chordate?
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Kingdom Animal Phylum (phyla)
Crustaceans Arachnids Centipedes and
Millipedes Insects
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Kingdom Animal Phylum (phyla)

• All chordates have/had these 3 things during
  their development
• ______________________
• ______________________
• ______________________

Vertebrate Chordates Invertebrate Chordates
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?Phylum Cordata (Chordates) ?Subgroups
Vertebrate Chordates Invertebrate
Chordates
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?ALL Chordates have 3 common
characteristics that can be found at some point
in their development 1) notochord 2)
nerve cord 3) gill slits
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Notochord -flexible rod that supports the
animals back -for most, its temporary and
is replaced by a backbone -MOST
backbones are made of hard bone, called
vertebrae (ex humans) -some backbones are made
of cartilage, which is softer than bone and
flexible (ex sharks)
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Nerve Cord -connection between the brain and
nerves that carry messages -develops into what
we call our spinal cord
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Gill Slits -openings in throat of chordate
embryos used for breathing -in most
chordates, gill slits disappear before birth
(ex humans) -in some, gill slits develop
into gills (ex fish) -as adults, we have
lungs
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?Subgroup Invertebrate Chordates (ex
lancelets sea squirts)
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Characteristics of Chordates
- What Is a Vertebrate?

• This lancelet shows the characteristics of a
  chordate a notochord, a nerve cord down its
  back, and gill slits.

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lancelet
INvertebrate Chordate
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sea squirt
INvertebrate Chordate
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sea squirt
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sea squirt
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?Subgroup Vertebrate Chordates (fish,
amphibians, reptiles, birds mammals) ?Groups
of Vertebrate Chordates 1) coldblooded
(ectotherm) -body temp. is regulated by
outside conditions
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-body temp. changes as environmental temp.
changes -generally need to live in climates
that arent very frigid -not really cold
blood (ex fish, amphibians, reptiles)
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2) warm blooded (endotherm) -animal
controls the internal heat it produces
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-body temp. is stable (rarely much
change), and typically warmer than the
surrounding environment -because of stable
temp., these animals can live in a wider
variety of environments (ex birds, mammals)
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Chapter 12 Coldblooded Vertebrates Sections 1
Fish (jawless, cartilaginous bony)
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?General Characteristics of Fish ?vertebrate
chordates ?largest group of vertebrates -more
species of fish than of amphibians, reptiles,
birds and mammals combined
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?most are coldblooded (ectotherm) ?covered
in scales (different types) ?thought to be
first vertebrates (around for 500 million
years)
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1) Breathing ?use gills to remove oxygen from
the water ?gills contain
MANY blood vessels which allows the oxygen
to go right into the blood and to
the rest of the body ?gills also get
rid of carbon dioxide
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fish
2 Chambered Heart
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2) Moving, Feeding Sensing ?fins used to swim
(large surface area to push against the
water) ?most movements are related to
feeding ?teeth adapted for type of food
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?well developed nervous system and sensory
organs ?great senses of sight (better than
us) and smell ?no eyelids (no need)
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?3 Classes (groups) of Fish 1) Jawless
Fish ?earliest vertebrates / least
developed ?cartilage skeleton (flexible)
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?no scales, fins or jaws ?parasites ex
hagfish and lampreys (only 2 types)
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Jawless Fish
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lamprey
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lamprey
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lamprey
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lamprey
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hagfish
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hagfish
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Parasitic fish
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2) Cartilaginous Fish ?cartilage skeleton
?jaws (grasp and crush with great
force) ?paired fins (for balance, swimming
and steering)
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?pointed, tooth-like scales over body (feel
like sandpaper) ?carnivores ?most not dangerous
to humans ex sharks, rays and skates
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?sharks -streamlined body to move
quickly (aerodynamic) -most cannot pump water
over their gills, so they must swim or
sit in currents
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-rows of jagged teeth point backwards
(prevent prey from
escaping) -teeth quickly replaced, if lost
(another row slides into place)
-spend most time hunting
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-see poorly but terrific sense of
smell ex a shark can find a single drop
of blood in 115 L (approx. 58
2L soda bottles)
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dorsal fins
gill slits
caudal fin
pectoral fins
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?rays -most are predators -feed on or near
ocean floor -flat bodies, broad fins they
flap to glide
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manta ray
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sting ray
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flower ray
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-eat mollusks and crustaceans -some have
sharp spines with poison glands on tails for
defense (ex stingray)
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?skates
So, how do you tell a RAY from a SKATE? Visit
this site to learn all the details! http//www.ela
smo-research.org/education/shark_profiles/skate_or
_ray.htm
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skate
pointy
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mermaid's purse
Pouch to hold the eggs of a ray or skate
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mermaid's purse
Pouch to hold the eggs of a ray or skate
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Cartilaginous Fish
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gill slits
Since there is not bone in the gill slits of
sharks, they cannot be opened and closed like
those of bony fish. Therefore, they must
constantly swim or position themselves in a
current in order to get enough oxygen from the
water.
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Notice the darker dorsal side and lighter ventral
side. This is for the purpose of camouflage.
When looking up at the shark, the lighter belly
blends in with the sunlight streaming through the
water. When looking down from above, the water
appears dark. Therefore, the dark dorsal side
allows the shark to blend in. The same is true
for most fish.
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whale shark
Largest fish (filter feeder)
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hammerhead shark
(will use the hammer to abuse its prey)
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great white shark
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great white shark
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great white shark
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nurse shark
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shark teeth (rows)
-Sharks often have up to 8 rows of teeth -Sharks
are estimated to go through about 2,400 teeth in
a lifetime
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tooth shape gives clues about the type of food
eaten
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male shark's claspers
Inserted into the female during mating
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mating sharks
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stingray
Poisonous stinger
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stingray
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stingray
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manta ray
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skate
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skate
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3) Bony Fish ?95 of all fish
species ?skeleton of hard bone ?scales cover
body ?have fins with long, bony rays
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?gill pocket covered with a bony flap
(operculum) that protects the gills and opens
to release water
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operculum
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?swim bladder -an air-filled structure that
the fish regulates to determine buoyancy
-fills or loses air to rise or sink
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swim bladder
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Sharks DO NOT HAVE a swim bladder. So, how
do they stay afloat? Their bodies have
adapted (or compensated) by -having flattened
fins -having lots of oil in their livers
(keeps them afloat) -being able to swim
almost
constantly A resting shark will sink to the
ocean bottom.
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?lateral line -canal (groove) along the side of
the body covered with sensory hairs (like in
our ears) that respond to water pressure
changes and vibrations -helps sense movement
and food
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lateral line
Tiny, sensitive holes are found on the lateral
line
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?digestive system esophagus, stomach
intestine ?reproduce sexually -female lays
eggs and male sprays them with milt (contains
sperm)
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-lay more eggs than most vertebrates because
they are unprotected and vulnerable to
predators ex trout, bass, perch, marlin,
seahorse, etc.
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Because fish eggs are fertilized outside of the
females body, they are unprotected and very
vulnerable to being eaten by other animals
thousands of fish eggs
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What clues might these pictures give scientists?
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Interpretation of Fossils

• Fossils most often form in layers of sedimentary
  rock.

Vertebrate History in Rocks
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Interpretation of Fossils

• The pattern of vertebrate evolution is branching.

Vertebrate History in Rocks
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Bony Fishes
- Fishes

• A bony fish has jaws, scales, a pocket on each
  side of the head that holds the gills, and a
  skeleton made of hard bones.

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Bony Fish
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salmon
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snakehead fish
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salmon
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fish lift
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catfish
brown trout
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perch
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Australian Lungfish
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lionfish
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seahorse
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flying gunard
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flounder
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lungfish
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coelacanth
Thought to be extinct for 80 million years, in
the 1930s, the coelacanth was discovered living
in the waters off of Africa. People there had
been using the skin to patch bicycle tires!
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coelacanth
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fish eggs
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pufferfish
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heaviest fish
ocean sunfish
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fastest fish
sailfish
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clownfish
MIMICRY
4-eyed butterfly fish
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Sharks
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?There are 350 species of sharks. ?Most sharks
live in saltwater. A few can live in
freshwater. ?Shark bodies are built to cruise
effortlessly.
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?More than ½ a sharks body weight is muscle.
This makes them heavier than sea water. They
must swim to avoid sinking.
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?The large, oil-rich liver of a shark helps with
buoyancy because oil is more buoyant than water.
It takes up more than 30 of a sharks weight.
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?Sharks can drown if they are not swimming and
not in a direct current. ?Sharks have tooth-like
scales.
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?Although sharks live in saltwater, they dont
get dehydrated because their body fluids are
saltier than the water. ?Sharks are keen for
LIGHT colors because they resemble the pale
bellies of fish (yellow, white, sliver).
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?Sharks have limited eyesight but an EXCELLENT
sense of smell. ?Sharks first smell their
food, then see it. ?The hammerhead shark beats
up its prey with its head (ex rays).
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?Not all sharks have sharp teeth. Those that
feed on mollusks have flat teeth for crushing.
?Sharks really dont eat much. They dont need
to because they are coldblooded and dont need to
make energy to keep warm. They eat only about 10
of their weight a week.
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?About 50-75 people are attacked by sharks each
year. Less than 12 die. You have more of a risk
of dying from lightning, a crocodile attack or
dog attack. ?Some shark babies will eat the
other babies in the womb, BEFORE birth.
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The larger species of sharks bear live young,
while some of the smaller varieties lay eggs.