Chapter 28.3, Problem 6MI

Summary Introduction

To summarize:

The characteristics of amphibians.

Introduction:

Amphibians are the animals that belong to the class amphibia of the phylum Chordata. Amphibians are vertebrates that live both on land and water. They are the first cold-blooded animals to have appeared on land. Most species of amphibians live close to water or in damp places. Some are most active at night when the ground is wet with dew. Others live mostly underground, beneath wet leaves or under decaying trees.

Explanation of Solution

The characteristics of amphibians are summarized in the table below:

Characteristics of amphibians
Feeding and digestion	Adult amphibians are predators. After eating food, digestion takes place in the stomach and intestine. The undigested wastes collect in cloaca before exiting the body.
Excretion	Amphibians excrete through feces and urine. Their kidneys filter wastes from the blood. Aquatic amphibians excrete ammonia(ammonotelic), but land amphibians excrete urea(ureotelic)
Respiration	Larvae such as tadpole of a frog breathe or exchange gases through gills and skin. Adult amphibians breathe through lungs and skin.
Circulation	Amphibians have three-chambered heart including two atria and one ventricle. Amphibianshave two circulatoryroutes, one for oxygenation of the blood through the lungs and skin, and the other to take oxygen to the rest of the body (double-loop circulation).
Brain and senses	The forebrain of amphibians detects odors. The nictitating membrane protects the eyes. The tympanic membrane helps in hearing. They cannot regulate body temperature as they are cold-blooded.
Reproduction	The eggs are laid and fertilized in the water. The embryo feeds on yolk during development. The egg hatched into larvae tadpoles. Tadpoles change to adults through metamorphosis