Chapter 29, Problem 12STP

Summary Introduction

To write:

The evidence scientists use to propose that the lobe-finned fishes are the ancestors of the amphibians.

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 are found.

Explanation of Solution

Lobe-finned fishes are the ancestors of amphibians. Coelacanths are plump, large, lobe-finned fish. They can grow upto more than 2 meters and weigh about 90 kilograms. It is estimated that they will live for 60 years or more. Modern coelacanths look bigger than those found to be fossils. 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.

Conclusion

Thus, the muscular lobes and joints of lobe-finned fishes are the related evidence that the scientists use to propose that lobe-finned fishes are the ancestors of the amphibians.