Concepts | Questions | Media Resources |
30.1 Evolution and Classification of Animals
Animals are multicellular heterotrophs exhibiting at least some mobility.
Animals are grouped according to level of organization, symmetry, body plan, pattern of embryonic development, and presence or absence of segmentation. | 1. What is cephalization? Answer 2. What ancestor gave rise to all animals? Answer | Essential Study Partner CharacteristicsArt Quiz Animal Kingdom PhylogenyAnimation Quiz Symmetry in Nature |
30.2 Introducing the Invertebrates
Sponges are multicellular, with limited mobility and no symmetry.
Cnidarians are radially symmetrical, with two tissue layers.
Planarians are bilaterally symmetrical, with a definite head region.
Roundworms have a pseudocoelom and the tube-within-a-tube body plan.
|
3. What level of organization is exhibited in the sponges? In the flatworms? Answer4. What two anatomical features are present in the roundworms that are not present in sponges, cnidarians, or flatworms? Answer | Essential Study Partner Sponges Radial Phyla Bilateral/No Coelom PseudocoelomatesArt Quizzes Cnidarian Body Plan Body Plans for Bilaterally Symmetrical Animals |
30.3 Mollusks
Mollusks have a muscular foot (variously modified), and a visceral mass enveloped by a mantle.
| 5. What two significant evolutionary advances are seen in the mollusks? Answer6. Bivalves exhibit an open circulatory system. How does an open circulatory system differ from one that is closed? Answer | Essential Study Partner MollusksArt Quiz Mollusk Body Plan |
30.4 Annelids
Annelids are segmented, with a well-developed, true coelom.
| 7. What evolutionary advancement is evident for the first time in the annelids? Answer8. What specialization that resulted from the tube-within-a-tube body plan is seen among the annelids? Answer | Essential Study Partner Annelids |
30.5 Arthropods
Arthropods have jointed appendages and an exoskeleton that must be periodically shed.
| 9. Why are arthropods, especially insects, so successful and abundant? Answer | Essential Study Partner ArthropodsArt Quizzes Insect Structure - Internal Decapod Crustacean - Lobster MetamorphosisCase Studies Cicada Woodstock Mosquito Coast |