CHARACTERISTICS OF
AMPHIBIANS
Characteristics of Amphibians
Modern amphibians
share several key
characteristics:
 Most species change
from an aquatic larval
stage to a land adult
form. This
transformation is called
metamorphosis.
Characteristics of Amphibians


Most have moist, thin skin with no gills.
Skin is equipped with numerous mucus glands that
supply a lubricant that keeps the skin moist in air.
African Reed Frog
Characteristics of Amphibians

Larvae exchange oxygen and carbon dioxide
through their gills and skin. Most adults lose their
fills and respire through lungs and skin.
Characteristics of Amphibians

All adult amphibians are carnivorous, with insects
and other arthropods as the most commonly
consumed prey. Most amphibian larvae are
herbivores, feeding on algae, bacteria, or tiny
green plants.
Characteristics of Amphibians

Most have 4 pairs of limbs. Feet, if present, lack
claws and are often webbed.
Characteristics of Amphibians

Are ectothermic (external-heat).
(Amphibians are ectothermic, which means their
blood temperature rises and falls with that of the
surrounding environment)
Characteristics of Amphibians

Are oviporous. Eggs lack multicellular membranes
or shells. They are usually laid in water or in moist
places and in most species are fertilized externally.
Characteristics of Amphibians

Many show parental care, guarding their eggs and
keeping them moist.
Poison Arrow Frog
Characteristics of Amphibians

Cloaca are the primary
excretory organs.

A muscular cavity at the
end of the large
intestine through which
digestive wastes, urine
and eggs or sperm
leave the body.
Characteristics of Amphibians

A 3-chambered heart. Does not mix oxygen and
deoxygenated blood very much. Little mixing
increases the amount of oxygen that is delivered to
the tissues.
Characteristics of Amphibians

The amphibian circulatory system is divided into two
separate loops. One loop carries blood between
the heart and lungs. The other loop carries blood to
the organs and tissues in the body and returns it to
the heart. This “double loop” circulation delivers
blood to the body faster. Double-loop circulation
occurs in amphibians and is now used by them and
all other vertebrates.
Characteristics of Amphibians

The senses of hearing, smell, and sight are welldeveloped in most amphibians. Sound receptors
are located in the inner ear, which is embedded
within the head. Sounds are transmitted to the inner
ear by the tympanic membrane, or eardrum.
Characteristics of Amphibians

The olfactory lobes, which are the center of the
sense of smell, are larger in amphibians than in fish.
The eyes can blink and are covered by a
transparent, movable membrane called a nictitating
membrane. Additionally, there is a continuous
communication among most areas of the body.