Vertebrate Classes
All in Chordate Phylum
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All vertebrates have…
 Bilateral symmetry
 Fully developed coelom with
organs
 Closed circulatory system
 Endoskeleton with spinal cord
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Vertebrate Classes
 Fish
 Amphibians
 Reptiles
 Birds
 Mammals
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Orders of Fish
Lamprey and hagfish
(jawless)
bony fish
Shark (cartilage)
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Lampreys/Hagfish
Jawless Fish
 Lampreys attach to fish-parasites
 Have “round sucker like mouths”
• Hagfish are Scavengers of dead and
dying fish on ocean bottom
Sharks, Skates, Rays
• Jaws
• The shark’s mouth has 6 to 20 rows of
backward-pointing teeth
• Some can detect blood from an
injured animal as far as 500 miles
away
• No swim bladder
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Bony Fish
 Most are familiar fishes and include
snake-like eels, salmon, trout, bass,
herring, tallapia and lantern fish
(most fish we eat)
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Bony Fish
 Fishes are the most numerous of all
vertebrates and most widespread in
their distribution
 Ectothermic
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Obtain Oxygen
 Fish obtain O2 through their gills
 Fish can extract 85 % of the
oxygen passing over the gills
 Blood goes to the gills, is oxygenated and
sent to all parts of the body
 Single loop circulation in fish
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•Fish have a two chambered heart.
•This is efficient for the fish since it is
in water, but would not work for land
animals who need more energy.
2 chamber heart
 The disadvantage of a 2 chambered
heart is its slow delivery
 MUCH more energy required to move
on land (or in air) = more O2 needed
faster
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Fish Reproduction
 Usually external fertilization
 Large numbers of eggs are fertilized
during Spawning – when fish reproduce
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Sockeye Salmon
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Barndoor skate (Dipturus laevis)
Cartilage Fish
 Ectothermic
 Sharks, Skates and Rays fertilization
is internal-most are born live
 Some sharks lay eggs
Skate
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Variety of Rays
There are many
different
types of rays
including
stingrays,
electric rays,
butterfly rays,
round rays,
manta rays,
guitarfish,
and sawfish. 16
Early aquatic adaptations
 Teeth (everyone) – evolved from skin
Shift from scavenging
to predation (lampreys)
 Jaws (sharks and bony fish)
provide biting force
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Later aquatic adaptations
 Bony fish evolve swim bladder
 This is an air bag that allows fish to
move up and down in water-called
buoyancy
 sharks sink when not swimming
 Swim bladder adapted to be lungs on
land
Transitional fish /
amphibian?
 Tiktaalik roseae
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Amphibians
Salamander
Frog
Toad
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Amphibians on land
 Four legs are an adaptation to walk on
land-These are adapted fish fins at
right angles from body
 Ectotherms- Body temperature the
same as the surrounding temperature.
 Hibernate or Estivate depending on
climate
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3 Chamber Heart
 2 atria – 1 from body
(deoxygenated), 1 from
lungs (oxygenated)
 1 ventricle – pumps
blood to lungs and body
 O2 through lungs and
moist skin called
coetaneous respiration
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3 chamber heart
Advantage of a 3 chambered heart
Blood getting to body cells faster
(heart pumps directly to body)
 Disadvantage of a 3 chambered heart:
Deoxygenated blood mixes with
oxygenated blood in atria
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Amphibian Reproduction
 Must live near water for 2 reasons
1) External fertilization - Reproduce in water
(lay eggs there)
egg  tadpole  young frog  adult
Called Metamorphosis
2) Go to water to keep skin moist
to obtain oxygen
Bullfrogs Eat Everything
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Reptiles
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Reptiles
turtle
crocodile
snake
Adaptation-Claws
 Strong, bony skeletons
and toes with claws
 Claws-aid in climbing,
digging and movement in
various terrains
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More Reptile Adaptations
 Adaptations evolved which allow
reptiles to live totally on land.
1) Scales to prevent water loss
2) The most important adaptation for
living on land is the
amniotic egg
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Reptilian Scales
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Eggs
 Amniotic egg – has all the water and
nutrients inside for embryo to survive
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Reptile limitations
 Disadvantage of Ectothermy:
1.
Must live in warm areas
2.
Cannot be active at night
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Regulating Body
Temperature
 Ectotherm (“cold-blooded”) –
animal does not maintain a constant
body temperature
Outside Temp = Body Temp
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Ectothermy
•Become
sluggish in
very cold
temperature
•Bask in the
sun or seek
shade
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Ectothermy
Advantages
 No energy used to
keep warm
Disadvantages
 Restricted to warm
climates only
 Active only during
day
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Heart
1. Heart of most Reptiles-3 chambers
2. Disadvantage: Oxygenated and
Deoxygenated blood mixes-less
efficient
3. Crocodiles and alligators
have a ventricle that is totally
separated into two pumping
chambers-4 chambers
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Circulation
Double loop circulation
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Transitional bird / reptile
 Archaeopteryx
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Birds
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Birds
 Adaptations for
Flight: Feathers,
wings, hollow bones
 Adaptation for living
on land:
Amniotic Egg like
reptiles
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Endothermy
 Endotherm (“warm-blooded”)
keeping a constant body
temperature
Advantages:
 Can be active even in colder biomes
 Can be active at night
(nocturnal predators)
Disadvantages:
 Requires lots of energy
(must find food often)
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Hummingbirds
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4 chamber heart
2 atria – 1 from body
(deoxygenated), 1
from lungs
(oxygenated)
2 ventricles – 1 pumps
to lungs , 1 pumps to
body
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4 chamber heart
 Even more energy needed for cells
 Birds = energy for flight
 Mammals = energy for large brains
 NO mixture of blood in 4 chamber
heart
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Digestive and Excretory
system
 Food passes from the
mouth cavity straight
to the esophagus.
 The crop stores and
moistens food.
 Then passes through
the gizzard, a muscular
organ that kneads and
crushes the food
Respiratory System
 Air enters nostrils at base of
beakDown trachea past
song boxenters two primary
bronchiito lungs
 75% bypasses the lungs and
flows directly to posterior to
sacssacs connect with air
spaces in bones, filling the
hollow bones with air.
 When bird exhales the carbon
dioxide rich air from the
lungs, oxygen rich air is
forced out of the posterior air
sacs into lungs.
Adapations for Flight
 Air sacs allow birds to take in more
oxygen for cellular respiration
 Hollow bones is a adaptation to decrease
weight take in more oxygen for cellular
respiration.
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Transitional reptile /
mammal
Egg-laying Mammals or Monotremes
Platypus
Echidna
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Evolution and
Adaptations
Mammals belong
to the class
Mammalia,
which includes
4000 species
Most dominant
land animals on
earth.
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Circulatory System
 Mammalian
heart has 4
chambers
 Mammals have a
muscle , the
diaphragm that
aids in lung
breathing
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Adaptations that distinguish
Mammals from other vertebrates:
1. Hair which helps in insulation
2. Mammary glands that produce
milk for the young.
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Mammals
 19 orders of mammals
 17 nourish unborn young by the
placenta
 The others are: egg laying
Monotremes and Marsupials
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Marsupials
 Marsupials give birth to tiny
immature young that crawl to a
pouch on the mothers belly
immediately after they are born.
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Characteristics of
Placental Mammals
 Placental mammals carry unborn young in the
uterus until young can survive in the wild.
 Oxygen and nutrients are transferred from
mother’s blood to baby’s blood
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Placental Characteristics
 The placenta is a
membrane providing oxygen
and nutrients and removal
of CO2 and waste between
the mother and developing
young
 Gestation period is the
time which mammals
develop in mother’s uterus
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Mammals
Hairy Saki-Monkey
 Also endothermic
 Hair helps to insulate, maintain internal
body temperature
Hairy Armadillo
Paraguaian Hairy 60
Dwarf Porcupine
Mammals
 Large brain size (learning / communicating)
 Disadvantage: longer time needed for brain
development
 Solution: longer gestation period in mom and
intensive parental care early on (including milk
from mammary glands)
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The End
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