BIOL 198 Module 7 Test Questions and Complete Solutions

Identify the characteristics that distinguish animals from other types of organisms. Multicellular Heterotrophic Motile Reproduce sexually Use aerobic metabolism Lack cell walls Have life cycles that include development from undifferentiated cells Have a variety of body plans Distinguish between asymmetry, radial symmetry, and bilateral symmetry. Asymmetry: no particular organization Radial symmetry: Circularly organized. If cut in half vertically, the halves will look similar. Bilateral symmetry: Organized with left or right halves Identify the three germ layers that form the tissue types found in most animals, and describe the tissues that come from each germ layer. The three germ layers are called ectoderm, mesoderm, and endoderm. The ectoderm gives rise to the skin and nervous system. The mesoderm gives rise to muscles and bones. The endoderm gives rise to internal organs. Define the different types of body cavities and identify the advantages that animals with body cavities have compared to animals without body cavities. Acoelomate: No cavity. The areas between the ectoderm and endoderm is filled with cells made of mesoderm. Pseudocoelomate: A fluid-filled cavity is present, but only the outside is lined with mesoderm and organs are not completely anchored. Eucoelomate: A more complex fluid-filled cavity with mesoderm lining all internal organs and structures. Tissues derived from mesoderm also anchor organs in place. Advantages that a eucoleomate has over a pseudo- or acoleomate include but are not limited to: Organs are anchored in place and protected Organs can become more specialized and complex. Independent movement of internal organs and body wall is possible. Internal fluid can protect the internal environment and aid in movement of materials. Enables function as a hydrostatic skeleton.