Phylum Porifera

The following questions will help you to review the material from the lecture as well as the text. Make sure to take a look at the links to the images and the web sites at the end of the page. I have also included suggested reading material in case you would like to follow up on any of the aspects covered in this section.

1. What is so interesting about the Burgess Shale? What kind of information can zoologists gain from studying the fossils at this site?
2. Approximately when did the first animals appear in the fossil record?
3. What is the importance of the Cambrian explosion? (listen to the excellent BBC program)
   
4. What so unusual about the animal fossils found at the Burgess Shale? Do they differ in any way from the body plans of animal taxa that exist today on our planet?
5. There are two major hypotheses in regards to how multicellularity evolved among animals evolved: the colonial hypothesis and the syncytial hypothesis. How do they differ from each other?
6. Briefly characterize the phylum Porifera.
7. Are sponges symmetric, asymmetric or both? Explain.
8. What kind of cell types exist in a sponge? Briefly describe them and their role within the sponge.
9. Sponges are considered to lack tissues. Explain. What kind of experiment would demonstrate that sponges lack tissues?
10. The choanocyte is an important cellular component of sponges. Briefly describe it structure and function.
11. How does a sponge feed? What do they feed on?
12. What are spicules? What are they made of? Function? Are they useful for zoologists that study the phylum?
13. Do all sponges have spicules? What are spongin fibers?
14. All the cells in a sponge are genetically identical. However, they can be grouped into different cell types that perform different functions. What is the importance of this observation?
15. What are the differences between asconoid, syconoid and leuconoid sponges? What kind of environmental factors may have affected the evolution of these morphologies within the phylum?
16. Many species within the phylum are hermaphrodites. Explain.
17. Briefly describe the life cycle of a typical sponge.
18. Can sponges move at any time in their life cycle? When? Why is this an important fact to consider as one studies the biology of sponges?
19. Several research groups are actively extracting chemicals from different sponge species. What is the purpose of these studies? What is the natural function of these chemical compounds found within the sponge? (see article in the folder - read the first two pages)

• The Cambrian Explosion - A great audio program from BBC about the Cambrian Explosion. Worthwhile listening to. 
• The Cambrian Explosion: A web site exploring the Cambrian from the Royal Ontario Museum
  
• The Burgess Shale - From the Smithsonian Museum of Natural History.  Excellent overview of the different types of fossils found at the Burgess Shale
• First Life with David Attenborough (documentary) [http://www.youtube.com/watch?v=xR-yMiyquG4]
  
• Graphical Overview of Sponge Anatomy
• The Shape of Life Web Site - Sponges - Animal Origins
• Porifera - From UC Berkeley
• Sponges  - From Wikipedia

• Gould: "Wonderful Life - The Burgess Shale and the Nature of History" - Gould explores early animal evolution. A very interesting and thought provoking book.
• Morris: "The Crucible of Creation: The Burgess Shale and the Rise of Animals" - A wonderful and factual little book giving one much to think about. Highly recommended together with Gould's book.
• Brusca/Brusca - "Invertebrates" - Major (and inexpensive) reference book on invertebrates. Good chapter on the sponges. Find it in a library or a used copy online. A great reference for the invertebrates!
  

Page created by: Peter Svensson Updated: October 2015