Complete the following questions. It will be regarded as prior knowledge for the practical and / or application questions that will be discussed during the contact sessions. 1. Discuss the position of the Porifera in the animal kingdom. 2. Describe the characteristics of the Porifera by completing TABLE 1. 3. Describe the three types of canal systems of Porifera with the aid of labelled drawings. 4. Describe the different cell types in the body of a sponge and name the function(s) of each. 5. Illustrate, describe and discuss the functioning of chaonocytes. 6. Describe the spicules of sponges with reference to form, function and the material of which they consist. 7. Briefly describe how reproduction occurs in Porifera. 8. Briefly describe the ecological importance of Porifera. Control your own answers. Discuss problems during contact session Practical Microscope work of slides and / or fresh/preserved material will be studied during the contact session.
Study unit 3 23 3.2 PHYLUM CNIDARIA On completion of this study section you should be able to: Name the general characteristics of the phylum Cnidaria. Name the distinguishing characteristics of the classes Hydrozoa, Scyphozoa and Anthozoa with examples in each class and compare them with one another regarding general structure. Identify, draw and label whole specimens, cross and/or longitudinal sections of examples of the phylum Cnidaria as seen on available permanent slides, fresh and /or preserved specimens, photographs, micrographs and/or diagrams Compare the organisation and functions of the different cell types in the body wall of an asconid sponge with that of a simple polyp like Hydra and discuss the developmental trend towards tissue formation. Critically discuss the meaning of the following aspects referring to the phylum Cnidaria: diploblasticity, radial symmetry, polymorphism and colonial forms. Describe the geographical distribution and characteristics of Physalia utriculus (blue bottle) as a Southern African representative of the phylum Cnidaria Sources Prescribed sources: Mader and Windelspecht pp. 528-529 Appendix 1 and 3