Class Amphibia (frogs, toads, salamanders)


Phylum Chordata

(includes the vertebrates)

• i.e. fish, sharks, amphibians, reptiles, birds, mammals

• Notochord, nerve cord, gill slits, tail


Kingdom Animalia

Phylum Chordata

6 classes:

Class Osteichthyes: Bony Fish

Class Chondrichthtyes: Sharks and Rays

Class Amphibia: frogs, toads, salamanders

Class Reptilia: lizards, snakes, turtles, crocadiles

Class Aves: Birds

Class Mammalia: Mammals

Class Osteichtyes: Bony Fish

(salmon, trout, halibut, goldfish!)

•Bony skeleton

•Operculum (gill cover)

•Fish use oxygen in water

•Swim bladder




•Ecological roles: mutualism

•Sensitive to pollution: PCBs, pesticides, mercury

•Fish farms

Class Chondrichthyes: Sharks and Rays

•Skeleton made of cartilage

•Oil in liver (no swim bladder)


•Placoid scales


•9 of 250 shark species are man-eaters

•Shark cartilage used for burn victims

•Find prey by electrical fields

•Key predators in the ocean (maintain a balance)

•Relation to cancer, cataracts

Class Amphibia (frogs, toads, salamanders)

•Double life: semi-terrestrial (land and water)

•Young are aquatic, adults mostly on land


•No scales/Mucus on skin


•Frog life cycle

•No amniotic egg

•Difference between frog and toad?

•Declining amphibians?

•Frog calls

•Poison glands

•Warning coloration

Class Reptilia: snakes, lizards, turtles etc


•Amniotic egg


•No metamorphosis


•Jacobson’s organ (tongue flicking)


•Useful predators

•Venemous snakes/pit vipers

•Importance of alligators (keystone species)

Snake Locomotion

1. Lateral Undulation: most common form

Effective in any habitat

Body pressed sideways against substrate

2. Sidewinding: 2-3 points of body in contact with substrate as they pull forward sideways

3. Concertina: loops of the body used

Used in burrow

4. Rectilinear: body in nearly a straight line

Muscles on ribs move scutes

Used by heavy snakes

Class Aves: Birds

•Feathers, scales on legs



•Reptilian ancestors

•No urinary bladder

•Uropigial gland: oil gland at base of tail

•Uric acid

•Archaeopteryx (primitive bird)

•Many ecological roles

•Owl pellets

•illegal pet trade of exotic birds

Archaeopteryx :

An Early Bird

Altricial: helpless and featherless

Sparrow, eagles

Lay less eggs

Precocial: feathered, independent


Lay more eggs

Class Mammalia: Mammals

•Terrestrial, although some have returned to the water

•Mammary glands (Milk glands)

•Monotremes: Primitive mammals that lay eggs

(Platypus and echidna)

•Live birth, mouse life cycle


•Types of mammals:

Placentals (mouse, humans)

Cetaceans (whales and dolphin)

Carnivores (meat eaters such as bears, wolves)

Ungulates (hooved)

A phylogeny showing the relationships among cetacean families.

Reconstruction of


Reconstruction of

Ambulocetus natans

Reconstruction of