In addition to tagmatization, the exoskeleton with paired jointed appendages and the necessity of molting, one type of arthropods, the insects, undergo metamorphosis. Metamorphosis may be complete or incomplete. In the case of complete metamorphosis, the immature stages of the insect look nothing like the adult. An example of this is the caterpillar that changes into a butterfly. In incomplete metamorphosis, the immature stages resemble the adult.
Arthropods have a significant impact on people in several ways.
Some arthropods have a positive imact on us. We use such arthropods as the lady bug and praying manthis to rid our gardens of pests. We use a by-product of the immature stages of a moth to produce silk cloth. Arthropods also have an impact on us in negative ways. There are approximately five classes.