Vertebrate Characteristics
Classification Review
a.
Taxonomy- classifying organisms and assigning each organism a
universally accepted name.
b.
Kingdom, Phylum, Class, Order, Family, Genus, Species
a.
c.
In order from most general to most specific
Acronym-Kings Play Chess On Fine Grain Sand
Carolus Linnaeus
Classification of Vertebrates
a.
Phylum: Chordata
Common Characteristics:
notochord, pharyngeal gill slits, hollow dorsal nerve cord
b.
Sub-phylum: Vertebrata
Common Characteristics:
backbone that supports and protects spinal cord, endoskeleton, distinct
head with skull and brain
Lancelet
Tunicate
Part A: Overview of Vertebrate Classes
Only ~ 4.5% of all animal species are vertebrates (~62,000). ~50% are fish.
1.
Vertebrate Class Definitions
a.
Fish - aquatic vertebrates that are characterized by scales, fins and
pharyngeal gills. There are 3 main groups: jawless, cartilaginous and
bony. Ex. Lamprey, dogfish shark, perch.
b.
Amphibians - vertebrates that are aquatic as larvae and terrestrial as
adults. They breathe with lungs as adults, have a moist skin with glands
and lack scales and claws. Ex. Frog, salamander, newt.
c.
Reptiles - vertebrates that have lungs, scaly skin and a special type of
egg (amniotic). They live entire life out of water. Ex. Snake, lizard,
turtle.
d.
Birds - endothermic, reptile-like vertebrates with feathers, two legs used
for walking and perching and wings that usually don’t have claws. Ex.
Pigeon, hawk, eagle.
e.
Mammals - endothermic animals with fur or hair, and mammary glands
that produce milk to nourish young. Almost all give birth to live young.
Ex. Human, whale, fetal pig.
Part B: Important Evolutionary Advances
Jaws- Fish
•
The first fishes to be found in abundance in the fossil record were
jawless. These are limited to eating small particles of food by filterfeeding and vacuum suction.
•
Jaws in fishes made it possible for them to eat plants and other
animals and defend themselves by biting.
•
Disadvantage-digestive system had to develop for new diet
Strong Skeleton- Amphibian Adults
•
The first amphibians had strong limb bones and girdles for
movement unsupported by water.
•
The ribs formed a cage that supports and protects the internal
organs.
•
Adult amphibians have more mobility and habitat availability
•
Disadvantage- new environment, predators
Eggs- Reptiles
•
Reptiles evolved from amphibians when climatic changes caused
destruction of amphibian habitat.
•
Reptilian eggs are surrounded by a shell and several membranes
that create a protected environment for the embryo.
•
These “amniotic eggs” contain nutrient-rich yolk used by the embryo
for food.
•
Disadvantage- predators, change in habitat.
Internal Temperature Control- Birds and Mammals
•
Fish, amphibians and reptiles are ectothermic. The have an internal
body temperature that varies with external (environmental
conditions) due to a slow metabolism.
•
Birds and mammals are endothermic. They maintain a relatively
high and constant internal body temperature that is regulated
internally due to a fast metabolism.
•
This adaptation is very important for animals living in habitats where
temperatures and seasons are variable.
•
Disadvantage- more food must be consumed
Iguana
Polar Bear
Penguin

Feeding and Digestion
Herbivorous Digestive Systems
Carnivorous Digestive Systems
-Can eat constantly
-Long coiled digestive system which
helps break down plant material
-Iguanas
-Teeth are flat for breaking down
cellulose rather than for tearing meat
-Shorter digestive system so meat
won’t rot
-Sticky tongue (frogs and salamanders)
to catch insects
-Snakes swallow animals wholeunhinge jaw
-Birds: beaks & claws; crop & gizzard;
large intestine absent or reduced
BENEFITS:
Increases time for complete digestion
Allows symbiotic bacteria to digest
cellulose
BENEFITS:
Sharp teeth tear meat
Short tract speeds enzymes that convert
meat to energy
Part C: Comparing Structure and Function Among Vertebrates

Feeding and Digestion
Digestive Systems

Respiration
Fish
Gills
• Oxygen rich water is pumped over gill filaments where gas exchange occurs.
• Oxygen poor water is pushed out through openings in the sides of the pharynx.

Respiration
Why do endotherms need more oxygen than ectotherms?

Respiratory Systems and Lungs
Similarities
Lungs- adult amphibians, reptiles,
birds, mammals.
2 lungs- reptiles, birds, mammals
Gas exchange occurs in lungs
Differences
Gills- fish, amphibian larva
Skin or lining of mouth- amphibians
Reptiles- more spongy lungs which
are more efficient than amphibians.
Strong muscles around rib cage.
Snakes- one lung.
Fish- some have lungs, lungfish
Birds- air sac allow for one way
flow of air where lungs constantly
receive oxygen rich blood
Mammals- diaphragm increases
volume of lungs and pulls air into
lungs
Benefits
Lungs are more efficient than gills or skin gas exchange
More surface area= more efficient

Circulation/Internal Transport
Heart Chambers and Circulatory Systems

Circulation/Internal Transport
SINGLE LOOP
Fish: Closed system
from heart to gills,
from gills to the rest
of the body and back
to heart. Two
chambers in heart.
Deliver
oxygen
and
nutrients
to cells
and
remove
wastes.
DOUBLE LOOP
Adult Amphibians: one loop
carries oxygen poor blood
from heart to lungs, other
loop carries oxygen rich
blood from heart to rest of
body. Has 3 chambers.
Reptiles: 3 chambers but
more efficient due to septum
in ventricle. Crocs and
Alligators have 4 chambered
heart.
Birds and Mammals: 4
chambers. Complete
separation of oxygen rich and
oxygen poor blood= most
efficient.

Circulation/Internal Transport
Heart Chambers and Circulatory Systems
The DOUBLE loop creates one loop from the heart to the
lungs and a second loop is from the heart to the body.
Double loop circulation allows for the development of more
advanced lungs - more spongy and highly branched.

Reproduction
Definitions
•
Oviparous: a vertebrate that lays eggs that develop outside the
mothers body. Most fish- salmon. Most reptiles and birds have
amniotic eggs.
•
Ovoviviparous: a vertebrate whose eggs develop inside the
mother’s body but are not nourished directly by the mother’s body.
Some reptiles-snakes & lizards. Guppies.
•
Viviparous: a vertebrate who bears live young and directly
nourishes the unborn young by the mother’s body.
Fertilization
Internal:
External:
Eggs are fertilized
INSIDE the mother’s
body.
Eggs are fertilized
OUTSIDE the mother’s
body.
Adults release eggs and
sperm into the
surrounding water and
sperm swim to the eggs
to fertilized them.
To increase chances,
huge numbers of eggs
and sperm are released.
Most amphibians (except
salamanders)
Allows
for the
species to
reproduce,
to
continue
on
Sperm is deposited
into the body of the
female.
Female’s
reproductive system
covers the embryos
with protective
membranes and a
shell
Reptiles, birds,
mammals
Fertilization
Drawbacks
Benefits
External Fertilization (fish
and amphibians)
Large number of offspring
produced
Internal Fertilization (birds,
mammals, reptiles)
With attention and maternal
care, high percentage of
offspring survive
No specialized reproductive
structures needed
Low percentage of offspring
survive with no parental care,
eggs lost to predators
Only small number of
offspring produced
Need specialized reproductive
structures