Phylum Porifera 113-120(EDITION 14TH) 109-119 (EDITION 15TH)
Goals for today • Learn to recognized the Phylum Porifera from other animals • Learn the main ‘diagnostic’ characteristics, structures, and their function • Learn about some sponges biology
Phylum Porifera • Most are marine • Freshwater species are found in ponds and streams • Solitary or colonial • Adults are sessile and benthic
Porifera = "pore bearer" These are the simplest metazoans (multi cellular organisms) • No organs, no mouth, no nervous, digestive or circulatory system, only rudimentary nervous integrations. • Little or no tissue organization • No germ layers (so neither diplo- or triploblastic) • Two thin layers of cells (Epidermis and Endodermis) • Some have radial symmetry some do not Parazoa Porifera Cnidaria and Ctenophora Ecdysozoa Deuterostomia Lophotrochozoa Protostomia Bilateria Radiata Parazoa Eumetazoa Ancestral colonial choanoflagellate
Phylum Porifera Main characteristics of sponges are: • Internal skeletons of spiculesor organic fibers (spongin). • Pores and canal systems (asconoid, siconoid, and leuconoid) • Internal cavity= spongocoelthat opens to anosculum
Phylum Porifera • Flagellated sponge feeding cells= choanocytes. • By cooperatively moving their flagella, choanocytes generate a flow of water through the sponges pores, into the spongocoel, and out through the osculum.
Phylum PoriferaFeeding Behavior http://www.youtube.com/watch?feature=player_embedded&v=RmPTM965-1c
Porifera: Classification Classes: Calcarea: • Spicules of calcium carbonate • Needle-shaped or 3-4 rayed spicules • Canal systems asconoid, siconoid, or leuconoid • All marine Hexactinellida(Glass sponges): • 3D, six-rayed spicules • Siliceous spicules (SiO2)forming a network • Body often cylindrical or funnel-shaped. • Canal systems siconoid or leuconoid • All marine, and most deep water spp. Demospongiae: • Siliceous spicules (not six-rayed), spongin or both • Canal system leuconoid • One family freshwater, most marine • Most sponges belong to this class
Porifera: Your Tasks Exercise 7: • Phylum: Porifera (sponges) • Class Calcarea • Genus: Sycon(=Scypha, Grantia)
Porifera: Sycon 2. Take a slide from your box with (Sycon, Grantia, or Scypha) this is a cross section cut: identify the incurrent canal, spongocoel, and the radial canal Water enters the incurrent canals and passes through minute openings called? ____________ Check your book for answers!
Porifera: Sycon What is the apopyle? Check your book!
Porifera: Sycon 3. Take a slide from your box with (Sycon, Grantia, or Scypha) in a longitudinal cross section you would see the following specialized cells: what are their function?
Porifera: Your Tasks Phylum: Porifera (sponges) • Class Calcarea • Genus: Leucosolenia Leucosolenia has an asconoide canal system
Porifera: Leucosolenia • Try to find the osculum. This is a colonial species of tubular individuals in various stages of development osculum
Porifera: Leucosolenia 2. Look into the microscope a slide of Leucosoleniabody and its spicules
Porifera: Your Tasks • Phylum: Porifera • Class Hexactinellida (Glass sponges) • Genus: Euplectella
Porifera: Your Tasks 1. Look at preserved specimens of Euplectella Some species of Euplectella have a commensal relationship with a shrimp species. A young male and female shrimp enter the central cavity and live there. As they grow they become too large to escape through the sieve-like covering of the osulum, and so spend their entire life inside the sponge.
Porifera: Your Tasks • Phylum: Porifera (sponges) • Class Demospongiae • Gemmulas (asexual reproductive structures) -Gemmules are asexual reproductive structures of freshwater sponges and some marine sponges of the class Demospongiae. -Made up of amoebocytes surrounded by a layer of spicules and can survive conditions that would kill adult sponges. What is their function in reproduction?
Important Links Porifera http://faculty.uml.edu/rhochberg/hochberglab/Courses/InvertZool/Quizes/Porifera%20Quiz%201.html http://www.bumblebee.org/invertebrates/Porifera.htm http://bioweb.uwlax.edu/zoolab/Table-Of-Contents.htm