Amphibians like frogs, toads, newts, and salamanders are characterized as having two pairs of limbs, lungs for aerial respiration in addition to aquatic respiration through their skin, a three-chambered heart, and indirect development where young possess gills before metamorphosing into adults. They have smooth, glandular skin without scales except in caecilians, and pentadactyl limbs without claws. Amphibians exhibit traits that fall between fully aquatic and terrestrial vertebrates.

1. C.P.Anitha Devi
AMPHIBIA CHARACTERS

2. Vertebrates with two pairs of limbs, a pair
of forelimbs and a pair of hind limbs
: name Tetrapoda.
class Amphibia : frogs,toads,
newts, salamanders and worm-like caecilians.
border line between the aquatic and
terrestrial modes of life.
Gr. amphi=dual, bios=life

3. •aquatic as well as aerial respiration.
•lungs, skin and buccal lining
•Skin smooth, slimy and
glandular……. NO exoskeleton
caecilians have minute
scales embedded in the skin.
G
E
N
E
R
A
L
C
H
A
R
A
C
T
E
R
S

4. Poikilothermic vertebrates
Two pairs of pentadactyl limbs.
The digits are without claws.
skull has two occipital condyles
(bicondylic)
Teeth are homodont and acrodont.
G
E
N
E
R
A
L
C
H
A
R
A
C
T
E
R
S

5. Heart is three-chambered with two atria
and one ventricle.
Sinus venosus is well developed, three
pairs of aortic arches.
Renal portal and hepatic portal systems
There are ten pairs of cranial nerves.
G
E
N
E
R
A
L
C
H
A
R
A
C
T
E
R
S

6. Kidney is of the opisthonephric type
Amphibians are ureotelic.Urinary bladder
is present
Fertilization is external except in caecilians.
Indirect development, possess gills for
respiration in water.
G
E
N
E
R
A
L
C
H
A
R
A
C
T
E
R
S

8. Hyla
Tiger salamander,

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