CHARACTERISTICS OF AMPHIBIANS

Characteristics of AmphibiansModern 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 well-developed 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.