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06 BENTHOS

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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06 BENTHOS

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  1. 06 BENTHOS

  2. I. Sponges (Phylum Porifera) • A. Evolutionary history • 1. Fossil sponges are some of the oldest known multi-celled animals

  3. Fossil Sponge Showing a Honey-combed Pore Pattern Fort Scott Limestone in Bourbon County, Kansas.

  4. A. Evolutionary history (continued) 2. In phylogenic studies, sponges have been treated as a sister group to the other animal (= Metazoa) taxa.

  5. Evolutionary history • 3. Recent genetic evidence, however, suggests that the ctenophores may have separated from the other animals before the sponges

  6. 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

  7. 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

  8. 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

  9. 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

  10. Spicules from an Hexactinellid Sponge Figs. 5-9A & B, p. 84

  11. 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

  12. Spicules from a Fossil Sponge Stained Orange by Iron Oxide Lower Ordovician, Idaho http://www.fallsoftheohio.org/Fossil_Sponges.html

  13. I. Sponges (continued) C. Rely upon currents to filter-feed

  14. 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.]

  15. Central Cavity Central Cavity Arrows show locations of oscula

  16. Summary of Filter-feeding in Sponges

  17. C. Filter-feeding currents (continued) 2. Control of feeding currents a. Some sponges can pass their own weight in water every 5 seconds

  18. Cheap Thoughts By Jack O’Brien How does an organism with no muscles “pump” water through its body?

  19. 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

  20. 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

  21. 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

  22. More Cheap Thoughts By Jack O’Brien Why don’t algae, barnacles and other encrusting or fouling agents grow on sponges?

  23. Biofouling http://www.tvja.org/science/fouling_community_study.htm

  24. Sponges apparently use “chemical warfare” Science 2008, 320: 1030

  25. Science 2008, 320: 1028

  26. 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

  27. The deep-water submersible Johnson-Sea Link http://en.wikipedia.org/wiki/File:Johnson_Sealink.png

  28. Florida Keys Photo: J. O’Brien, 2011

  29. Poriferans Photo: J. O’Brien, 2011

  30. Large Barrel Sponge Photo: J. O’Brien, 2011

  31. 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

  32. EM of Radula

  33. 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

  34. Keyhole Limpet with Mantle Covering External Shell

  35. 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

  36. II. Mollusks (continued) C. Most marine mollusks have a TROCHOPHORE larva that develops into a VELIGER

  37. Castro & Huber 2003, p. 332 TROCHOPHORE larva Found in Annelids and Mollusks

  38. 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

  39. Operculum of a Whelk http://barnegatshellfish.org/images/whelk/operculum_whelk_bb_01_l.PNG

  40. 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

  41. Neogastropods (continued) • Examples • (1) Whelks common in seagrass habitats

  42. Siphonal Canal Siphon Buscyon, Lightening whelk feeding on a bivalve Lippson & Lippson, 1984, Life in the Chesapeake,p. 53

  43. 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

  44. Coral Reef Gastropods Photo: J. O’Brien, 2011

  45. Conchs in a Boat Photo: J. O’Brien, 2011

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