31. Invertebrates

Which two animal groups are classified as ecdysozoans?

The arthropods superficially resemble earthworms in that both groups __________, yet the two are distinctly different because arthropods, but not earthworms, __________.

What is the process of ecdysis in arthropods?

What is the name of the tough outer covering constructed by ecdysozoans?

A major characteristic of arthropods is __________.

In arthropods, molting is necessary because __________.

Complete metamorphosis __________.

An unidentified species of animal displays the following characteristics: bilateral symmetry, a complete digestive system, an open circulatory system, distinct body segmentation, and a series of molting stages during growth. To which of the following animal phyla does this species most likely belong?

In most insects, gas exchange is accomplished by __________.

The majority of animal species are __________.

Sowbugs are really crustaceans, not insects. Therefore, a sowbug does not have __________.

Which of the following animals is most closely related to spiders?