Post on 21-Mar-2020
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INVERTEBRATES (animals without a backbone)
• found in the Kingdom Animalia
• 97% of all animal species
PHYLUM PORIFERA (pore bearers)
• sponges
• considered plants until 1765
• simplest multicellular animals
• cellular organization
• no true tissues, organs, movable parts, nor appendages
PHYLUM PORIFERA (pore bearers)
• mostly marine (~9000 species)
• adults are sessile filter feeders
• sessile - attached to substrate
• diversity of shapes, sizes, colors, habitats (found at low tide to 3.5 miles deep)
PORIFERA SKELETON
• asymmetrical
• 2 skeleton compositions: spicules or spongin
• spicules – made of silica (glass) or calcium and offer protection
• spongin – protein based flexible fibers; used as commercial sponges (bath sponges)
PORIFERA CELLS
• choanocytes (collar cells) – cells used to filter nutrients and move water through the sponge by beating the flagella; mucus-like substance traps nutrients; primary feeding cells of sponges
PORIFERA CELLS
• amebocytes (wandering cells) – secrete spongin and spicules; movable cells that transport and store food particles; used for repair; look like a amoeba
• pinacocytes (epidermis) – thin flattened cells that cover the sponge
PORIFERA WATER FLOW
• water enters in through the tiny pores (ostium) into the central cavity of the sponge (spongocoel) which is lined with choanocytes and leaves through the large opening on top of the sponge (osculum)
PORIFERA ORGANIZATION AND MORPHOLOGY
• morphologically, the bodies of sponges exhibit three distinct types based on the organization of their internal canal systems
1) Asconoid
2) Syconoid
3) Leuconoid
PORIFERA ORGANIZATION AND MORPHOLOGY
1) Asconoid – simplest type; shaped like a tube or vase with a single osculum
PORIFERA ORGANIZATION AND MORPHOLOGY
3) Leuconoid – most complex and most common; numerous canals that lead to chambers
PORIFERA CLASSIFICATION
• 1) Class Demonspongiae – leuconoid form only; bath sponge - spongin gives the sponge its softness and absorbency
Pione vastifica- boring sponge
Haliclona- electric blue sponge
PORIFERA CLASSIFICATION
• 2) Class Calcarea – asconoid, syconoid, leuconoid form; most primitive group
ex: Scypha