Chapter 29, Problem 31A

Summary Introduction

To explain:

The reason for a species of fish being least affected by the venom of a sea snake

Introduction:

Fish are able to survive in water because of their ability to get oxygen from water. They get oxygen when water enters their mouth and flows across their gills, where oxygen from water diffuses into the blood. Some fish can also breathe through their moist skin. Sea snakes are venomous reptiles that feed on marine creatures by paralyzing them through their venom.

Since some fish have the ability to breathe through gills as well as through their skin, they are able to continue breathing through skin when their gills are damaged by the venom of sea snake. Hence this ability to breathe through skin and gills is important to surviving a bite by a sea snake.

Sea snakes have highly toxic venom that they inject into the body of the prey. The toxin paralyzes the muscles that pump water across the gills of the fishes. The gills become non- functional and the fish die as they are unable to get oxygen from water. Some fish can breathe through gills as well as through moist skin. When these fishes are bitten by sea snake, their gills get paralyzed and they are unable to breathe through gills but they continue to exchange gases through their skin. This helps them to survive the bite of poisonous sea snake.

Answer to Problem 31A

Since some fish have the ability to breathe through gills as well as through their skin, they are able to continue breathing through skin when their gills are damaged by the venom of sea snake. Hence this ability to breathe through skin and gills is important to surviving a bite by a sea snake.

Explanation of Solution

Sea snakes have highly toxic venom that they inject into the body of the prey. The toxin paralyzes the muscles that pump water across the gills of the fishes. The gills become non- functional and the fish die as they are unable to get oxygen from water. Some fish can breathe through gills as well as through moist skin. When these fishes are bitten by sea snake, their gills get paralyzed and they are unable to breathe through gills but they continue to exchange gases through their skin. This helps them to survive the bite of poisonous sea snake.