Amphibian Lecture
Anatomy of Amphibians
General Amphibian Traits
 ____________pods

Skeleton mostly _____________________

3-5 digits on ________________________ (most 4) / 5 digits on _________________ limb

______ chambered heart –_______ atria and ________ ventricle

No dermal ________________________

Skin _____________________ and ______________________

Most with indirect development, some with tadpole larvae

____________________ as larvae/juveniles, ________________ present but may degenerate, some with
dermal respiration
What obstacles did amphibians face when moving onto land?
 The initial problems…….
1. Widely fluctuating _________________________________ (air)
2. Loss buoyancy - time to deal with _____________________
3. Need to conserve_______________________, different nitrogenous waste

More problems….
4. Water tight ______________________
5. Reproductive problems eggs need to be placed somewhere they won’t be disturbed
6. Sensory receptor issues eyes need to deal with_______________________ distances
7. Ears need to hear______________________________ frequencies
General Anatomy Highlights….
THE SKIN:
Two layers ____________________________________________
Specialized structures: ____________________________(found in the epidermis)
Mucous gland: secrete a clear, slimy, mucus that maintains a thin film over the outside of the skin
Granular gland: Concentrated on the head Produces a poison, toxic to predators
Coloration of the Skin
Pigment cells chromatophores
 Melanophores: _______________________________________________
 Iridophores: __________________________________________________
 Xanthophores: ________________________________________________
 Combination of the above produce the outside color of the skin we see
The Skin Continued
The skin has a major role in: Osmoregulation and Thermoregulation
The skin is highly __________________________________, has a high surface area, and is a major source of gas
exchange.
SENSES
 Ears: Hearing -reception of __________________________ and helps maintain ______________________
 Hearing is important:
1. attract a __________________________
2. _________________________________
3. _________________________________ call (GET OFF ME!)
4. _________________________________ call
 Lateral Line System Present
 Eyes
o ____________________________________ placed
o ________________ and _____________________
o Terrestrial and arboreal _______________________ Eyes
o __________________________- relating to burrowing or living underground / little to no eyes
o Upper ______________________________is fixed
o Lower lid called ____________________________membrane (protects and moistens)
 Nasal Organs
o Nose used in _______________________________________
o Jacobson’s organ an _________________________________ organ, allows organism to perceive
pheromones, or chemical messages, from other animals of the same species.
Circulatory System and Respiration
o ______________chambered heart: 2 atria, 1 ventricle
o
Lungs
o Main function – ________________________________
o aid in vocalization (______________________________)
o Highly _______________________________ thin wall, large surface area
o
Gills  found in ____________________________stage
Digestion
o Not too crazy, one end is in, the other is out.
o Carnivores, have teeth
o Large intestines (new structure)
Urinary and Reproductive Systems
 Kidney- regulate ____________________and ______________________balance

Gonads Testes and ovaries very different
o Frogs will lay eggs and ________________________________ mass
o _____________________________fertilization
Order Gymnophiona (Apoda) (Caecilians)
• _________________________________
• Burrowing or aquatic
• Tropical
• _________________________________ fertilization
• Oviparous & viviparous species
• Direct development in most
Order Caudata (Urodela)
 AKA ________________________________
 Have a _________________
 Divergence in respiratory mechanisms
 ______________________________________prevalent
 ________________________________ fertilization
Order Anura
 Frogs & Toads
 No ________________________________
 ___________________________________ fertilization
 Indirect development in most
Frog or Toad?
 Frogs
o Associated with more aquatic habitats
 Toads
o Thicker skins
o Dryer habitats
Metamorphosis
 Shift from an aquatic embryonic stage to a terrestrial stage and maturation/growth.
 Dramatic in FROGS.
 Change in skin structure, loss of lateral line, lungs develop, behavior changes, feeding changes,
locomotion changes, physiological changes.