Chapter 18

Bilateral symmetry in animals is best correlated with a. an ability to see equally in all directions. b. the presence of a skeleton. c. motility and active predation and escape. d. adaptation to terrestrial environments.

Jon found an organism in a pond, and he thinks it's a freshwater sponge. His friend Liz thinks it looks more like an aquatic fungus. How can they decide whether it is an animal or a fungus? a. See if it can swim. b. Figure out whether it is autotrophic or heterotrophic. c. See if it is a eukaryote or a prokaryote. d. Look for cell walls under a microscope.

Which of the following groupings includes the largest number of species? (Explain your answer.) a. invertebrates b. arthropods c. insects d. vertebrates

Which of the following animal groups does not have tissues derived from mesoderm? a. annelids b. echinoderms c. cnidarians d. flatworms

Molecular comparisons place nematodes and arthropods in clade Ecdysozoa. What characteristic do they share that is the basis for the name Ecdysozoa? a. a complete digestive tract b. body segmentation c. molting of an exoskeleton d. bilateral symmetry

Match each description on the left with the corresponding term on the right. a. annelids b. nematodes c. sponges d. arthropods e. flatworms f. cnidarians g. molluscs h. echinoderms i. chordates The simplest animal with a complete digestive tract

Match each description on the left with the corresponding term on the right. a. annelids b. nematodes c. sponges d. arthropods e. flatworms f. cnidarians g. molluscs h. echinoderms i. chordates Earthworms and leeches

Match each description on the left with the corresponding term on the right. a. annelids b. nematodes c. sponges d. arthropods e. flatworms f. cnidarians g. molluscs h. echinoderms i. chordates Lacks a body cavity

Match each description on the left with the corresponding term on the right. a. annelids b. nematodes c. sponges d. arthropods e. flatworms f. cnidarians g. molluscs h. echinoderms i. chordates Have a muscular foot and a mantle

Compare the structure of a planarian (a flatworm) and an earthworm with regard to the following: digestive tract, body cavity, and segmentation.

Name two phyla of animals that are radially symmetric and two that are bilaterally symmetric. How do the general lifestyles of radial and bilateral animals differ?

One of the key characteristics of arthropods is their jointed appendages. Describe four functions of these appendages in four different arthropods.

A marine biologist has dredged up an unknown animal from the seafloor. Describe some of the characteristics that could be used to determine the animal phylum to which the creature should be assigned.