Vertebrate Structure and Function
Part 1 - Comparing Structure and Function
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
Part A: Overview of Vertebrate Classes
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
a.
b.
Jaws in Fishes
•
Fish are considered to be the most primitive living vertebrate.
•
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.
•
The evolution of jaws in fishes made it possible for them to eat plants
and other animals and defend themselves by biting.
Strength of Skeleton in Amphibians
•
Amphibians probably evolved from lobe-finned fishes. These
organisms faced many challenges transitioning from water to land.
•
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.
c.
d.
Eggs in Reptiles
•
Reptiles evolved from amphibians when climatic changes caused
destruction of amphibian habitat. These organisms had to survive
their entire lives on land.
•
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.
Temperature Control in 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.
Part C: Comparing Structure and Function Among Vertebrates

Feeding and Digestion
a.
Jaws and Teeth
Part C: Comparing Structure and Function Among Vertebrates

Feeding and Digestion
a.
Jaws and Teeth

Feeding and Digestion
b.
Digestive Systems

Respiration
a.
Lungs

Respiration
Fish

Circulation/Internal Transport
a.
Heart Chambers and Circulatory Systems

Reproduction
a.
Definitions
•
Oviparous: a vertebrate that lays eggs that develop outside the
mothers body
•
Ovoviviparous: a vertebrate whose young develop inside the
mother’s body but are not nourished directly by the mother’s body.
•
Viviparous: a vertebrate who bears live young and directly
nourishes the unborn young by the mother’s body.
b.
Fertilization
•
•
External: 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.
Internal: eggs are fertilized inside the mother’s body.
•
Sperm is deposited into the body of the female.
•
This makes it possible for the female’s reproductive system to
cover the embryos with protective membranes and a shell after
fertilization.