Exam 17: The Early Tetrapods and Modern Amphibians

The decline in amphibian populations,particularly frogs,may be attributed to habitat destruction,environmental pollutants,depletion of ozone,and random population fluctuations.

Most amphibians remain dependent on their aquatic environment because of their method of reproduction.

Evidence points to the ray-finned fishes (Actinopterygii)as the closest relatives to the terrestrial vertebrates.

The frogs and toads are the most familiar but least numerous amphibians.

Frogs typically lay eggs in water,but some exhibit _____________ development,in which the tadpole stage is bypassed,and the frog that emerges from the egg appears as a miniature adult.

____________ are carnivorous in both the adult and larval stages.

Although most amphibians have a larval metamorphosis in their life cycle,there are some that retain a permanently aquatic,larval morphology throughout life.

The tetrapods originated in the Devonian period of the Paleozoic era.

Frogs and toads belong to the order ________,a name that means "without a tail."

Some salamanders (such as the mud puppy Necturus),that retain features as adults that were found only in the larval stages of their ancestors,are said to be ____________.

The mud puppy Necturus

Some frogs tolerate ill effects of freezing by accumulation of glucose and glycerol in the body fluids. Multiple Choice Questions

The frog heart has two atria and a single,undivided ___________.

Most of our familiar frogs belong to the large family

Viviparity is common among the caecilians.

The Caudata

Amphibians typically have webbed feet,but lack _____________ on their toes.

Some salamanders have neither lungs nor gills.

The double circulation of tetrapods consists of a circulation serving the body and a circulation serving the lungs.

A 350 million-year-old fossil called Ichthyostega was