Tetrapoda Lab 8
Exam Next Week!
(Chapters 18, 19, and 20)
•! I will grade today’s lab for you before
you go, so you can take it with you to
study.
Taxonomy of phylum Chordata
•! Subphylum Urochordata – sea squirts
•! Subphylum Cephalochordata - amphioxus
•! Subphylum Vertebrata
–! Superclass Pisces
•! Class Agnatha
•! Class Chondrichthyes
•! Class Osteichthyes
–!Superclass Tetrapoda
•! Class Amphibia
•! Class Reptilia
•! Class Aves
•! Class Mammalia
Phylum Chordata
–! 4 defining characteristics
•! Notochord
•! Dorsal, hollow nerve cord
•! Pharyngeal gill slits
•! Post-anal tail
(a) Chick embryo
Gill
pouches
Post-anal
tail
(b) Human embryo
Amphibia: salamanders and
newts, frogs and toads, and
caecilians
Jaw
Bones
Legs
Amniotic egg
Milk / Fur
Feathers
Class: Amphibia
Amphibia
•! Ectothermic - can’t heat itself
•! Still tied to water
•! 3-chambered heart
•! Tetrapod legs to side of body
Colostethus
Class: Amphibia
Class: Amphibia
Frog external anatomy (no scales; naked)
•! Know the difference between a frog and a
toad (parotoid gland)
Tympanic
membrane
•! Cross-section slide (skin):
epidermis, dermis, mucous glands,
poison glands
American toad
www.wickersham.us/anne/frog.htm
Class: Amphibia
•!Frog larva
Tadpole
Bull Frog
Class: Reptilia Turtles,
Tortoises, Lizards, Snakes,
Crocodiles, Alligators, Tuatara
Class: Reptilia
•! Ectothermic (except shivering pythons)
Class:
Reptilia
•! No longer tied to water (amniotic egg)
•! 3-chambered heart
(4 in Croc and some monitor lizards)
•! Tetrapod legs to side of body
Class: Reptilia (amniotic egg)
Reptile scales
Epidermal in origin
Fish skin
Reptile scales
Reptile scales
•! For keying, look in the center of the
back
•! Turtle -
Class: Reptilia
Know the carapace (dorsal) and plastron (ventral)
Scale type: Bony Dermal Plates
Bony Dermal Plates
•! Turtle -
Class: Reptilia
Know the carapace (dorsal) and plastron (ventral)
Scale type: Bony Dermal Plates
male's plastron
is concave
female's plastron
is flat
Class: Amphibia & Reptilia
Keying:
•! Use the dichotomous keys to determine
the taxonomy of the amphibian and
reptile specimens in lab.
Characteristics for Keys
Cloacal opening
Longitudinal Slit
Characteristics for Keys
Pupil of eye
Pupil Vertical
Pupil not Vertical
Transverse Slit
Characteristics for Keys
PIT between eye and nostril
Characteristics for Keys
Characteristics for Keys
Parasphenoid (or vomerine) teeth
Tongue bicornuate behind
Roof of mouth
Tongue attached in the front
Class: Aves (birds)
Class: Aves
•!
Endothermic
•! Feathers (modified scales)
•! Flight (some exceptions)
•! Hollow bones (why?)
•! Crop and Gizzard (no teeth)
•! 4-chambered heart
•!
Amniotic egg
Class: Aves (birds)
Bird feathers
Types: Down, filoplume, contour
warmth
Class: Aves (birds)
Bird feathers
Contour (flight) Feather
Construction:
Quill (Calamus), Shaft (Rachis)
Flight
Decoration
Class: Aves (birds)
Bird feathers
Contour (flight) Feather
Construction:
Barbs, Barbules
Class: Aves (birds)
Bird beaks and feet:
Maxilla
(upper bill)
Mandible
(lower bill)
Class: Mammalia
•! Endothermic
There are three major groups of
mammals
1.! Monotremes - the egg-laying mammals.
•! Hair (insulates the body)
•! Mammary glands, (produce milk; nourish young)
•! 4-chambered heart
echidna
2.! Marsupials - the so-called pouched
mammals (short gestation period)
Example: kangaroos, wallabies
Platypus with pups
3.! Placentals - most mammals
–! Have a relatively long
gestation period
–! Complete embryonic
development occurs
within the mother
Figure 18.22C
Amniota:
Anapsida: turtles and tortoises
Diapsida:snakes, lizards, crocodiles, alligators, birds
Synapsida: mammals
Jaw
Bones
Legs
Amniotic egg
Milk / Fur
Feathers