exercise 3 (Porifera and Cnidaria).pdf

Exercise No. 3 Poriferans and Cnidarians Phylum Porifera Poriferans are considered one of the simplest invertebrates. Defining cell type is called choanocyte. Most familiar organism are the sponges. Sponges ✓There are at least 5,000 named species of sponges ✓Their body structure faci...

Exercise No. 3 Poriferans and Cnidarians Phylum Porifera Poriferans are considered one of the simplest invertebrates. Defining cell type is called choanocyte. Most familiar organism are the sponges. Sponges ✓There are at least 5,000 named species of sponges ✓Their body structure facilitates the movement of water for feeding, excretion, and gas exchange. ✓Reproduce by sexual as well as asexual methods (fragmentation, budding, or formation of gemmules) and are hermaphroditic ✓4 classes (based on the type of spicule or the (skeletal spikes of silica or calcium carbonate) 1. Calcarea has calcareous spicules 2. Hexactinellida with six-rayed siliceous spicule 3. Demospongiae have siliceous spicules, spongin or both 4. Sclerospongiae or coraline sponges have multilayered calcium carbonate skeletons Phylum Porifera Sponges Excretory structure or a large opening where water current exits after passing through the spongocoel Are tiny pores that lets water and nutrient flows inside the sponge Large, central cavity of sponges lined by a variety of cell types with unique functions Phylum Porifera Sponges Phylum Porifera Sponges Canal Systems of sponges enables water to move through the sponge allowing the exchange of gases, food and waste to nearly all body cells. Ascon Sycon Leucon sponges' filter feeding PHYLUM CNIDARIA Cnidarians exhibit radial or biradial symmetry and 99% are marine species. Defining cell type called cnidocyte, or stinging cell that serve to capture prey or repel predators. 2 distinct body plans: polyp "stalk" and the medusa or "bell“ Gastrovascular cavity serves both digestive and circulatory functions with gas exchange by diffusion between cells and the environment. 10,000 described species 4 classes 1. Class Hydrozoa 2. Class Scyphozoa 3. Class Cubozoa 4. Class Anthozoa 4 classes of cnidarians Class Tentacles - contains Hydrozoa the cnidocytes Hydranth – oral ✓includes end of the polyp Hypostome - 3,200 bearing the conical elevation species; mouth and containing the tentacles ✓both marine mouth part and freshwater bud - asexually dwellers produced ✓have a outgrowth polyp or medusa form basal disc - used for attachment to a substrate Solitary Hydra viewed under SPO 4 classes of cnidarians Class Hydrozoa Prepared slide of an Obelia- a colonial hydroid viewed under LPO 4 classes of cnidarians Class Scyphozoa ✓“true-jellyfish” ✓200 known species ✓exclusively marine animals ✓with a dominant medusa stage ✓display a characteristic bell-like morphology ✓are free- swimming organism 4 classes of cnidarians Class Scyphozoa 4 classes of cnidarians Class Cubozoa ✓box jellyfish ✓are solitary animals ✓with a reduced polyp stage ✓all marine dwellers ✓contain muscular pads called pedalia ✓include the most venomous of all the cnidarians 4 classes of cnidarians Class Anthozoa ✓6,100 described species ✓exhibit a sessile polyp body plan only ✓all marine dwelling ✓may be colonial or solitary ✓Ex. Sea pen, anemones, corals References Brown, T. W. (2015). Retrieved from https://commons.wikimedia.org/wiki/File:A_Guantanamo_sponge_-a.jpg Dooley, K. (2010, December 3). flickr. Retrieved from https://www.flickr.com/photos/12836528@N00/6159273286 Clark, M.A., Douglas, M., Choi, J. 2018. Biology 2e. OpenStax. Retrieved from Openstax: https://openstax.org/books/biology- 2e Deretsky, Z. (2011, January 4). National Science Foundation. Retrieved from https://www.nsf.gov/news/mmg/mmg_disp.jsp?med_id=65101&from=search_list Parsons, D. (2005, August 25). flickr. Retrieved from https://www.flickr.com/photos/dan90266/37269957/ Keats, D. (2011, September 1). flickr. Retrieved from https://www.flickr.com/photos/93242958@N00/6237703397 Acharya, S. (2008, October 11). Wikimediacommons. Retrieved from https://commons.wikimedia.org/wiki/File:Chrysaora_Colorata.jpg Arthurfogo7. (n.d.). Wikimediacommons. Retrieved from https://commons.wikimedia.org/wiki/File:Cubozoa.jpg Bielecki, J., Zaharoff, A. K., Leung, N. Y., Garm, A., & Oakley, T. H. (2014, June 5). Plos One. Retrieved from https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0098870 Seascapeza. (2012, November). Wikimedia commons. Retrieved from https://commons.wikimedia.org/wiki/File:Carybdea_branchi9.jpg Bielecki, J. (2, February 2012). Wikimediacommons. Retrieved from https://commons.wikimedia.org/wiki/File:Tripedalia- cystophora-Bielecki.jpg Spragg. NZ, B. (2007, October 27). flickr. Retrieved from https://www.flickr.com/photos/volvob12b/10062178943/ Maragos, J., & U.S. Fish and Wildlife Service. (2011, March 27). flickr. Retrieved from https://www.flickr.com/photos/usfwspacific/5565696408/ Hobgood, N. (2006, November 30). Wikimediacommons. Retrieved from https://commons.wikimedia.org/wiki/File:Veretillum_sp.(Sea_pen).jpg