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06 BENTHOS. I. Sponges (Phylum Porifera) A. Evolutionary history 1. Fossil sponges are some of the oldest known multi-celled animals . Fossil Sponge Showing a Honey-combed Pore Pattern. Fort Scott Limestone in Bourbon County, Kansas. A. Evolutionary history (continued)
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I. Sponges (Phylum Porifera) • A. Evolutionary history • 1. Fossil sponges are some of the oldest known multi-celled animals
Fossil Sponge Showing a Honey-combed Pore Pattern Fort Scott Limestone in Bourbon County, Kansas.
A. Evolutionary history (continued) 2. In phylogenic studies, sponges have been treated as a sister group to the other animal (= Metazoa) taxa.
Evolutionary history • 3. Recent genetic evidence, however, suggests that the ctenophores may have separated from the other animals before the sponges
Major events of loss and gain in the evolution of early animal tissue complexity are suggested by the analysis of the first representative genome from the ctenophore phylum http://www.sciencemag.org/content/342/6164/1327/F1.large.jpg
I. Sponges (continued) • B. Body parts • Epithelial cells only (no muscle, connective, nor nervous tissue) • Structural protein SPONGIN • (1) Coarse collagen fibers • (2) Responsible for resilient and absorbent properties of sponge skeleton
Spongin Fibers http://media.photobucket.com/user/Zoology1/media/kingdom%20Anamalia/Porifera/Spongefibers2.jpg.html?filters[term]=spongin&filters[primary]=images&filters[secondary]=videos&sort=1&o=0
B. Body Parts of Sponges (continued) 3. SPICULES a. Deposits of… (1) Calcium carbonate (2) Silica b. Function to… (1) …provide structural strength especially in narrow passageways (2) …inhibit predation
Spicules from an Hexactinellid Sponge Figs. 5-9A & B, p. 84
Spicules from modern sponge Magnification = 100X http://media.photobucket.com/user/paulfuentebella/media/Lab%2012/IMAG0164.jpg.html?filters[term]=grantia%20spicules&filters[primary]=images&filters[secondary]=videos&sort=1&o=0
Spicules from a Fossil Sponge Stained Orange by Iron Oxide Lower Ordovician, Idaho http://www.fallsoftheohio.org/Fossil_Sponges.html
I. Sponges (continued) C. Rely upon currents to filter-feed
C. Filter-feeding currents (continued) 1. Water flow a. Enters through external pores into small passageways known as CHOANOCYTE CHAMBERS (1) Lined by cells called CHOANOCYTES (2) Food particles are captured b. Processed water enters a CENTRAL CAVITY c. Waste water leaves via openings called OSCULA [= little mouth; osculum = sing.]
Central Cavity Central Cavity Arrows show locations of oscula
C. Filter-feeding currents (continued) 2. Control of feeding currents a. Some sponges can pass their own weight in water every 5 seconds
Cheap Thoughts By Jack O’Brien How does an organism with no muscles “pump” water through its body?
2. Control of feeding currents (continued) b. BERNOULLI'S PRINCIPLE: (1) A decrease in the X-sectional area of a pipe causes an increase in the velocity of a liquid flowing through that pipe (river moves slowly in wide portions of a canyon and rapidly in a narrows) (2) The volume of a fluid passing by any point remains the same, so a decrease in the X-sectional area at a point results in an increase in flow
The relationship between the area of a tube and the velocity of a non-compressible fluid passing through that tube. (The lengths of the arrows labelled v represent relative velocities of the fluid.) http://titans.s716.ips.k12.in.us/~blachlym/pol/ch-09/5/5.htm
b, BERNOULLI'S PRINCIPLE (continued) (3) Since the X-sectional areas of all the choanocyte chambers is greater than the area of the osculum… (a) …the speed of the water current leaving the sponge at the osculum is greater than the speed of the water currents entering pores and the choanocyte chambers (b) …waste water is carried away from sponge
More Cheap Thoughts By Jack O’Brien Why don’t algae, barnacles and other encrusting or fouling agents grow on sponges?
Biofouling http://www.tvja.org/science/fouling_community_study.htm
Sponges apparently use “chemical warfare” Science 2008, 320: 1030
Currently there are numerous pharmaceutical companies sponsoring research on chemicals produced by sponges and their symbionts looking for medicinal properties. This includes Johnson & Johnson original support of the Harbor Branch Oceanographic Institute in Ft. Meyers, FL now affiliated with Florida Atlantic University
The deep-water submersible Johnson-Sea Link http://en.wikipedia.org/wiki/File:Johnson_Sealink.png
Florida Keys Photo: J. O’Brien, 2011
Poriferans Photo: J. O’Brien, 2011
Large Barrel Sponge Photo: J. O’Brien, 2011
II. Mollusks • A. Adults lack obvious segmentation • B. Specialized structures • 1. RADULA • a. Rasping tongue-like structure • b. Can bore holes in prey or scrape algae from rocks • c Possesses a hhardness value of 6 on the Mohs scale • (1) Diamond hardness is 10 • (2) Harder than poor grades of steel
EM of Radula
Specialized structures (continued) • 2. Muscular FOOT • a. Movement • b. Attachment (limpets & abalone) • 3. Calcareous SHELL • 4. MANTLE • a. Thin layer of tissue under shell • b. Lays down shell • c. Respiratory organ
Specialized structures (continued) • 5. MANTLE CAVITY • a. Space between mantle & body organs • b. Location of GILLS • c. Inhalant and exhalant feeding currents • move through it
II. Mollusks (continued) C. Most marine mollusks have a TROCHOPHORE larva that develops into a VELIGER
Castro & Huber 2003, p. 332 TROCHOPHORE larva Found in Annelids and Mollusks
D. Gastropoda • 1. Most diversified molluscan class (35,000 species) • 2. OPERCULUM • a. On coiled shelled gastropods • b. Hard plate that covers aperture when foot withdrawn • c. Functions • (1) Protection • (2) Prevents desiccation
Operculum of a Whelk http://barnegatshellfish.org/images/whelk/operculum_whelk_bb_01_l.PNG
D. Gastropoda (continued) • 3. Neogastropods • a. Characteristics • (1) Extendible BUCCAL TUBE or PROBOSCIS (snout) with mouth at end • (2) Portion of mantle forms a SIPHON • (3) Shell has a SIPHONAL CANAL
Neogastropods (continued) • Examples • (1) Whelks common in seagrass habitats
Siphonal Canal Siphon Buscyon, Lightening whelk feeding on a bivalve Lippson & Lippson, 1984, Life in the Chesapeake,p. 53
Whelk egg string Photo: J. O’Brien 2013 Common whelklaying eggs Picture: Ron Offermans http://molluscs.at/gastropoda/index.html?/gastropoda/sea/common_whelk.html
Coral Reef Gastropods Photo: J. O’Brien, 2011
Conchs in a Boat Photo: J. O’Brien, 2011