Chapter 28, Problem 22A

Summary Introduction

Introduction:

Fishes live in aquatic habitats like lakes, seas, rivers, ponds, etc. Some fishes live in complete darkness at the bottom of the deep ocean whereas others live in the freezing water of the Polar Regions and have special proteins in their blood to keep the blood from freezing. There are about 24,600 species of living fishes found.

Answer to Problem 22A

Correct answer:

The correct answer is option (A) Lobe-finned fishes are the ancestors of amphibians.

Explanation of Solution

Explanation/justification for the correct answer:

Option (A) Lobe-finned fishes are the ancestors of amphibians. The lobe-finned fishes have muscular lobes and joints similar to those of tetrapods. Tetrapods are the four-footed animals with legs that have feet and toes that have joints. So, the correct answer is option (B).

Explanation for incorrect answer:

Option (B) Lobe-finned fishes are similar to amphibians because they both have fins. The lobe-finned fishes have muscular lobes and joints similar to those of land vertebrates. So, this is an incorrect option.

Option (C) Lobe-finned fishes are most closely related to hagfishes. Lobe-finned fishes are most closely related to tetrapods. So, this is an incorrect answer.

Option (D) Lobe-finned fishes are similar to amphibians because they both have lateral lines as adults. Lobe-finned fishes are the ancestors of amphibians as they have muscular lobes and joints. So, this is an incorrect answer.