Chapter 26.3, Problem 6MI

Summary Introduction

To sequence:

The stages in two types of metamorphosis by completing the given flowcharts and also identify each type of metamorphosis.

Introduction:

Most insects undergo metamorphosis. A series of changes that occurs in the life of an insect due to chemical substances in the animal is called metamorphosis. The insect undergoes a series of major changes in the body structure as it develops. In some cases the adult insect does not bear any resemblance to its juvenile stage.

Answer to Problem 6MI

Explanation of Solution

The given flowcharts depicts 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 other insect shows incomplete metamorphosis in which the insect goes through only three stages of development; egg, nymph and adult.

The first stage in the life cycle of an insect is the egg stage. Both the insects have this stage common to them. Insects begin life as a fertilized egg. The egg hatches either into a nymph (incomplete metamorphosis) or a larva (complete metamorphosis).

The next stage is the nymph stage of an insect that undergoes incomplete metamorphosis and 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.

The third stage of an insect undergoing complete metamorphosis is pupa stage. This stage is inactive stage and so the insect does not feed on anything. Pupa stage is absent in life cycle of insect undergoing incomplete metamorphosis.

The last stages are the adult stages of both the insects. They are no longer immature insects but are completely developed insects. The adult insect bears very little resemblance to its juvenile stage.