Download Class Amphibia:

Frog Dissection Notes
Class Amphibia (781-798 in textbook):
I. Examples: salamanders, frogs, newts
II. Habitat: aquatic when young, land & water as adults
III.
Symmetry: bilateral
IV.
Metamorphosis:
1. Larva: (commonly called tadpoles):
a. Breathe with gills
b. Fins for swimming
c. Fish-like circulatory system
2. Adults:
a. Breathe with lungs
b. Lose tail and develop legs
c. More advanced circulatory system
V.
Protection from predators
1. Skin covered in mucus – keeps moisture in; slippery to predators
2. Skin loosely attached – predators can’t grip them
3. Camouflage
4. Some are poisonous – bright colors warn predators
VI. Life Processes:
A. Support and Movement:
1. Backbone and skeleton - cartilage
2. No ribs to protect internal organs
3. Large hind legs specialized for jumping
B. Feeding and Digestion:
1. Diet: carnivores
2. Process:
Capturing food – tongue attaches at front of mouth; 2 sets of
teeth to hold onto prey
Swallowing food – closes eyes & push them down against roof
of mouth
Drinking water – they don’t – they absorb water through skin
3. Digestion:
a. esophagus – moves food to stomach
b. stomach – stores food; digests protein
c. small intestine – digests most food, absorbs nutrients
d. large intestine - absorbs water, packages waste
e. liver – makes bile to digest fat
f. gall bladder – stores bile
g. pancreas – make enzymes to digest fats, protein & sugars
4. Path of food – mouth  esophagus  stomach  small intestine
 large intestinecloacaanus
C. Response:
1. Brain – well-developed
2. Nerves – well-developed
3. Eyes –on top of head – Why? sightline near surface, predators
4. Ears - located behind eyes What are they called? Typanic membrane
5. Nose – on top of head – breathe & swim
6. Tongue – attaches at front of mouth
D. Excretion:
1. kidneys – filter waste and produce urine for excretion
2. bladder – stores urine
3. cloaca – list all the things that can leave the frog body through the
cloaca: sperm, eggs, urine, solid waste
E. Internal transport:
1. Cold blooded - cannot control their internal body temperature
2. Heart – 3-chambered
3. Closed circulatory system - blood vessels
4. Spleen: makes red blood cells
F. Respiration: gills when larva; lungs & skin as adults; breathe through
nares on top of head
G. Reproduction:
1. Separate males and females
2. Male attracts female by: making sounds with vocal sacs under chin
3. Females lay eggs that are fertilized externally by the male.