Chapter 16, Problem 3STP

Summary Introduction

Introduction:

An adaptation is a trait shaped by natural selection that increases an organism’s reproductive success by increasing its chance of survival. Fitness is a measure of relative contribution an individual trait makes to the next generation. It is measured as the number of reproductively viable offspring an organism produces in next generation. An adaptation may be changes in the structure, physiology or behavior of an organism to suit to an environment.

Answer to Problem 3STP

Correct answer :

The correct answer is option D. An insect does not respond to a chemical used as an insecticide.

Explanation of Solution

Explanation/justification for the correct answer:

OptionD. An insect does not respond to a chemical used as an insecticide−A physiological adaptation is a change in an organism’s metabolic processes in response to some environmental stimulus that helps it to cope up with the changing environment. An insect develops a physiological adaptation to prevent itself from being killed by an insecticide. It does not respond to a chemical used as an insecticide. Hence this is the correct option.

Explanation for incorrect answer:

Option A. A beaver’s teeth grow throughout its life- The incisors of beavers continue to grow throughout its life. This is a structural adaptation to help beavers in their feeding habits. It is not physiological adaptation.Hence this is not the correct option.

Option B. A chameleon’s skin changes color to blend in with its surroundings- The type of adaptation shown by a chameleon is called camouflage. Camouflageprotects the animals from its predators by blending with the environment. It is a type of morphological adaptation and not physiological adaptation.

Hence this is not the correct option.

Option C. A human sleeps during the day in order to work at night- This is not a physiological adaptation but a temporary adjustment in the lifestyle of the human. It is a kind of behavioral adaptation. Hence this is not the correct option.