BIOL 198 Module 7 Objectives with Complete Solutions

BIOL 198 Module 7 Objectives with 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. Define segmentation and cephalization, and identify the advantages of these features. Segmentation: body divided into repeating subunits. Advantages include increased flexibility and mobility, potential for regeneration Cephalization: Describes the development of a structure at one end of the body that has specialized feeding and sensory structures. This is advantageous because it allows for the gathering and processing of sensory information, as well as the rapid consumption of located food. Understand the basic phylogenetic tree for animals, including the evolution of symmetry, germ layers, body cavities, segmentation, and cephalization. (You may want to look at the tree as you answer this). See studio manual or web materials. The first common ancestor of all animals diverged into protozoa and the rest. Porifera is the first animal phylum to diverge (asyemmetrical, rest are radially or bilaterally symmetrical). The Cnidaria phylum diverges soon afterward (last common ancestor between cnidaria and other animals with the most ancestral form of radial symmetry