Exam 31: Animal Phylogeny, Acoelomates, and Protostomes

Sponges have been abundant since the Cambrian period, especially in shallow coastal areas.

Members of the ____ ("jointed feet") Ecdysozoan phylum have a segmented body encased in a rigid exoskeleton made of chitin plus other materials.

Members of the ____ Lophotrochozoan phylum include earthworms, bristle worms, and leeches.

Members of the ____ Cnidarian lineage exist primarily as cube-shaped medusae, are active swimmers, and produce one of the deadliest toxins made by animals.

Members of the ____ Ecdysozoan phylum include insects, spiders, crustaceans, millipedes, and centipedes.

The gut develops from the ____in most animal embryos.

Members of the ____ subphylum, including spiders, ticks, mites, scorpions, and horseshoe crabs, have fanglike appendages used for biting prey and pedipalps used as grasping organs, sensory organs, or walking legs.

Describe some of the advantages of segmentation.

Members of the ____ subphylum, including shrimp, lobsters, and crabs, generally have five pairs of appendages on their heads: two pairs of antennae and three pairs of mouthparts, including mandibles.

Members of the ____ lineage, including slugs and snails, may have a shell, and most undergo torsion during development.

Members of the ____ lineage, known as bristle worms, are found primarily in marine environments and are characterized by the presence of parapodia.

Animals are ____ organisms, and their cells ____ cell walls.

Most Hydrozoan polyps form sessile colonies that develop asexually from one individual.

In most eumetazoans, the muscles of the body wall are derived mainly from which embryonic cell layer?

What are some similarities between cephalopods and vertebrates?