Exercise 3 Poriferans and Cnidarians.pdf

PARAZOANS AND SIMPLEST METAZOANS Phylum Porifera Learning Outcomes At the end of the exercise, the learner will be able to: Describe the organizational and structural features or animals under Phylum Porifera and Phylum Cnidaria. Recognize members of the major classes of Poriferans and Cnidar...

PARAZOANS AND SIMPLEST METAZOANS Phylum Porifera Learning Outcomes At the end of the exercise, the learner will be able to: Describe the organizational and structural features or animals under Phylum Porifera and Phylum Cnidaria. Recognize members of the major classes of Poriferans and Cnidarians. Enumerate the roles that they perform as well as the importance of sponges and corals in our environment. 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 Formation of gemmules Hermaphroditic Anatomy of Sponges SPONGOCOEL Large Central cavity lined with chondrocytes and other cells OSTIA Pores on the side that allow water to flow into the spongocoel OSCULUM Large opening where water exits after passing through the This Photo by Unknown Author is licensed under CC BY spongocoel Anatomy of Sponges Spicules Spongin Classification of Sponges ✔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 Canal Systems of Sponges Ascon Sycon Leucon Enables water to move through the sponge allowing the exchange of gases, food and waste to nearly all body cells. FILTER-FEEDING Canal Systems of Sponges Ascon Canal Systems of Sponges Sycon Canal Systems of Sponges Leucon PHYLUM CNIDARIA Cnidarians exhibit radial or biradial symmetry Defining cell type: cnidocyte, or stinging cell that serve to capture prey or repel predators. 2 distinct body plans: polyp "stalk" and the medusa or "bell“  PHYLUM CNIDARIA 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 Class Hydrozoa includes 3,200 species; Tentacles - contains the cnidocytes both marine and Hydranth – oral end of the freshwater dwellers polyp bearing Hypostome - conical the mouth and elevation tentacles containing the mouth part bud - asexually produced outgrowth basal disc - used for attachment to Solitary Hydra viewed a substrate under SPO  Class Hydrozoa Prepared slide of an Obelia - a This Photo by Unknown colonial hydroid viewed under Author is licensed under CC BY-SA LPO Class Scyphozoa “true-jellyfish” 200 known species Exclusively marine animals with a dominant medusa stage display a characteristic bell- like morphology are free- swimming organisms Class Cubozoa “box jellyfishes” are solitary animals with a reduced polyp stage all marine dwellers contain muscular Pads called pedalia include the most venomous of all the cnidarians Class Anthozoa § 6,100 described species § exhibit a sessile polyp body plan only § all marine dwelling § may be colonial or solitary § e.g. Sea pen, anemones, corals This Photo by Unknown Author is licensed under CC BY PROCEDURE Draw representative sponges in the worksheet provided (Class Calcarea and Hexactinellida) Grantia (Class Hexactinellida) Euplectella (Class Calcarea) WRITE THE Draw representatives of Phylum Cnidaria (Corals SCIENTIFIC and Jellyfish) Coral NAMES OF THE Sponge (label: osculum, ostia) SPECIES YOU’VE Jellyfish (label: head, umbrella, tentacles) DRAWN. Corallite (label: corallite, septa) Answer Activity 3A in the VSU E-learning portal. Answer Activity 3B in the VSU E-learning portal. Answer Activity 3C in the E-learning portal