5 Porifera Canals, Repd

“Porifera : Spicules + Canal System + Reproduction” A presentation compiled from various sources by

Dr. PARVISH PANDYA, Zoology Dept. Bhavan’s College, Andheri. Dr. PARVISH PANDYA’s presentation

Sites from which presentations have been downloaded and later editted. I am indeed thankful to them for their kindness and support : http://esg-www.mit.edu:8001/esgbio/cb/org/organelles.html http://faculty.pnc.edu/jcamp/parasit/parasit.html http://www.amnh.org/rose/hope/creatinghope/ http://www.biology.eku.edu/SCHUSTER/bio%20141/POWERPOINT %20NOTES/Intro%20to%20Protozoa_files/fullscreen.htm http://www.biosci.ohio-state.edu/~zoology/eeob405/ http://www.tulane.edu/~wiser/protozoology/pwpt/ http://www.iep.water.ca.gov/suisun/photos/wildlife.html http://www.uta.edu/biology/marshall/2343/ http://www.uta.edu/biology/faculty/faculty.html http://www.okc.cc.ok.us/biologylabs/Documents/Zoology/PowerPoint.htm http://bio.fsu.edu/ http://www.aw-bc.com/ http://www.nhm.org/ http://www.geo.cornell.edu/eas/education/course/descr/EAS302/presentations/ It is very easy to find mistakes in these presentations…..I request you to kindly rectify them and supply me the modifications needed at [email protected] Thanks a lot and have fun in teaching & learning Zoology…. Dr. PARVISH PANDYA’s presentation

THE PHYLUM PORIFERA

Dr. PARVISH PANDYA’s presentation

INTRODUCTION TO PORIFERA • Unusual animals • Are•originally primarily thought marine, they mostly in shallower were plants waters • Are sessile and attached to substrate or objectsoccasionally on other animals such as crabs • Are the most primitive metazoans and have neither true tissues or organs Dr. PARVISH PANDYA’s presentation

Sponge Cell Types • Pinacocytes- outer cells covering sponge; equivalent of epiderm • Porococytes- cells which line the pores of the sponge; through which water is drawn • Choanocytes- similar to choanoflagellates; collared cells with flagella which create water current and collect food matter or sticky contractile collar. • Amoebocytes- amoeba-like cells found throughout the sponge; store, digest and transport food, excrete wastes, secrete skeleton and also may give rise to buds in asexual reproduction; there are several different types

Dr. PARVISH PANDYA’s presentation

Sponge Anatomy Porocyte Amoebocyte Pinacocyte

Choanocyte

Pechenik, 1996 Dr. PARVISH PANDYA’s presentation

Dr. PARVISH PANDYA’s presentation

Types of Amoebocytes • Large Amoebocytes- distribute food to other cells of sponge; move by way of pseudopods • Archeocytes- undifferentiated sponge cells that can give rise to more differentiated cells such as pinacocytes or porocytes. • Scleroblasts- produce spicules; two types – Calcoblasts- make calcium carbonate spicules – Silicoblasts- make silicious spicules

Dr. PARVISH PANDYA’s presentation

Types of Spicules 4 general types • Monaxon- needle-like or rod-like; straight or curved • Tetraxon- has 4 prongs • Triaxon or Hexaxon- 3 or 6 rayed • Polyaxon- multiple short rods radiating from a common center; burr shaped, star shaped or like a child's jack. – Some species have a mixture of types

Dr. PARVISH PANDYA’s presentation

Dr. PARVISH PANDYA’s presentation

Spongin Give phylum its common name

• Some species have not spicules, but do have spongin • spongin is a type of hardened secreted protein • Some species have both spicules and spongin

Dr. PARVISH PANDYA’s presentation

Mesohyl (=Mesenchyma) • Beneath the pinacocytes - a gelatinous protein layer •it contains the skeletal material (ie. spongin and spicules) and amoebocytes

Dr. PARVISH PANDYA’s presentation

Three Basic Sponge Canal Systems • Asconoid • Syconoid • Leuconoid

Dr. PARVISH PANDYA’s presentation

Dr. PARVISH PANDYA’s presentation

Asconoid Sponges • most primitive and simplistic in structure • have radial symmetry • are tube shaped

Dr. PARVISH PANDYA’s presentation

Asconoid Sponge two basic openings • Ostia- or incurrent pores that open into a central cavity called the spongocoel; it is lined with choanocytes or collar cells • Osculum- the opening of the spongocoel to the outside; this is the opening by which water leaves the sponge Dr. PARVISH PANDYA’s presentation

Asconoid Sponge Design • Imposes definite size limits to sponges due to the problem of water flow •The spongocoel contains such a large volume of water that it is hard to push it our rapidly

Dr. PARVISH PANDYA’s presentation

Asconoid sponges • Most primitive • Forms clusters of tubes • Small tube shaped with radial symmetry • Simple route : ostia spongocoel osculum Pechenik, 1996

Dr. PARVISH PANDYA’s presentation

Syconoid Sponges • next level of complexity – walls are invaginated – allowing for greater surface area over which water can pass

• typically vase shaped like the asconoid sponges • radial symmetry

Dr. PARVISH PANDYA’s presentation

Syconoid Structure • helps to rectify some of the water movement problem – increasing the surface area • so there are more choanocytes to water volume

– decreasing the spongocoel volume

• these sponges able to get bigger than asconoid Dr. PARVISH PANDYA’s presentation

Syconoid sponges • More advanced but still retains radial symmetry • Higher degree of invagination (body wall folds) • Route : Dermal ostia

Pechenik, 1996 Pechenik, 1996 Dr. PARVISH PANDYA’s presentation

Incurrent canals prosopyles radial canals spongocoel osculum

Dr. PARVISH PANDYA’s presentation

Leuconoid Sponges • highest level of complexity in sponges • lost radial symmetry and are very irregular in shape and may attain large sizes • invaginated canals are even further invaginated and folded to from small flagellated chambers

Dr. PARVISH PANDYA’s presentation

Leuconoid Sponge Design • further increase in surface area makes these sponges highly efficient in moving and filtering water • spongocoel is gone except for canals that lead to the osculum- or there may be a series of excurrent openings •spongocoel is gone except for canals that lead to the osculum- or there may be a series of excurrent openings

•the largest sponges; most hydrologically efficient Dr. PARVISH PANDYA’s presentation

Leuconoid sponge • Highest degree of evagination • Flagellated chambers replace radial canals

Pechenik, 1996

Dr. PARVISH PANDYA’s presentation

Sponge Reproduction •Sexual •Asexual

Dr. PARVISH PANDYA’s presentation

Asexual Reproduction in Sponges • two types: – Budding- fragmentation of body wall, buds appear as outgrowth on sides of sponge • when they reach a certain size they drop off and settle to bottom to form a new sponge

– Gemmules- occurs only in freshwater sponges • gemmules are groups of food laden amoebocytes that deposit a hard covering of spicules around them • formation is triggered by environmental conditions such as decreased temperatures • they allow the sponge to pass the winter or periods of drought • after which the outer covering breaks open and a new sponge develops Dr. PARVISH PANDYA’s presentation

Sexual Reproduction in Sponges • gametes formed by amoebocytes • there are both hermaphroditic and dioecious species – most hermaphroditic species produce eggs and sperm at different times so they do not self fertilize

• sperm is released into environment via osculum and is brought in by another sponge via ostia • fertilization takes place in parent sponge • zygote is expelled - it drops to bottom and begins to develop Dr. PARVISH PANDYA’s presentation

Dr. PARVISH PANDYA’s presentation

Class Calcarea • spicules composed of calcium carbonate • spicules are monaxons or tri or quadraxons • all three types of sponges exhibited • All less than 10 cm high – ex. Leucosolenia and Grantia

• found in shallow coastal waters • all are marine Dr. PARVISH PANDYA’s presentation

Class Hexactinellida (glass sponges) • Spicules always triaxon or hexaxon and fused to form a lattice like skeleton • cup or vase shaped with well developed spongocoel • most beautiful example is Euplectella - venus flower basket • chiefly live in 500-1000 meter depth • are syconoid sponges • all are marine • may have commensal relationship with shrimp where a male and female live inside the sponge; get trapped inside when they out-grow the pores Dr. PARVISH PANDYA’s presentation of sponge

Class Demospongiae • spicules are monaxon and tetraaxon • variously shaped some are huge • all are leuconoid •all but one family is marine- Spongillidae- is freshwater about 150 freshwater species this is the group from which we get our commercial sponges •spicules are silicious if present otherwise skeleton is made of spongin or both •this is the group from which we get our commercial sponges Dr. PARVISH PANDYA’s presentation

Class Sclerospongiae • proposed in 1970 to include 6 species from Jamaica • have silicious spicules and spongin • are leuconoid sponges •also have an outer covering composed of calcium carbonate

Dr. PARVISH PANDYA’s presentation

Dr. PARVISH PANDYA’s presentation