Chapter 29, Problem 3STP

Summary Introduction

Introduction:

The given figure shows life cycle of two insects. One depicts the complete metamorphosis where the insect goes through a series of changes in body structures as it develops from an egg into an adult. There are four stages of development; egg, larva, pupa and adult. The adult insect bears very little resemblance to its juvenile stage. The other insect shows incomplete metamorphosis in which the insect goes through only three stages of development; egg, nymph and adult.

Answer to Problem 3STP

Correct answer:

The correct answer is option C. 2, 6

Explanation of Solution

Explanation/justification for the correct answer:

Option C. 2, 6− The stage 2 is the nymph stage of an insect that undergoes incomplete metamorphosis and stage 6 is the larva stage of the insect undergoing complete metamorphosis.

The nymph is a heavy feeder. As it eats and grows, it molts several times to become an adult. The larva is the free- living, worm like stage of an insect often called caterpillar. Larvae eat huge amount of food to supply the energy needed for tremendous growth. As it eats and grows, it molts several times.

Hence this is the correct option.

Explanation for incorrect answer:

Option A. 1, 5 − The stages 1 and 5 represent the first stage in the life cycle of an insect, the egg stage. Insects begin life as a fertilized egg. The egg hatches either into a nymph (incomplete metamorphosis) or a larva (complete metamorphosis). The eggs do not feed on anything.

Hence this is not the correct option.

Option B. 1, 7- The stage 1 is the egg stage of an insect that undergoes incomplete metamorphosis whereas stage 7 is the pupa stage of the insect undergoing complete metamorphosis. Both these stages are inactive stages so they do not feed.

Hence this is not the correct option.

Option D. 4, 8− The stages 4 and 8 are the adult stages of both the insects. They are no longer immature insects but are completely developed insects.

Hence this is not the correct option.