Plant Lab
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Asconoid Type – Water entering the sponge passes through ostia which are actually openings within doughnut-shaped cells called porocytes, which are found only in asconoid sponges. The water enters the large central cavity called the spongocoel, which is lined with choanocytes. Water exits from the spongocoel through a single large osculum.
Syconoid Type – Water enters the sponge through ostia which are openings between cells, rather than within cells as in asconoid sponges. Water then passes into radially arranged incurrent canals which lead to flagellated chambers lined with choanocytes. Water leaves the flagellated chambers by way of excurrent canals that lead to the spongocoel, which is lined a simple flat epithelium. Water exits from the spongocoel by way of a single large osculum. Note that the body wall of syconoid sponges is thicker than that of asconoid sponges and that the syconoid spongocoel is not lined by choanocytes as is the asconoid spongocoel.
orifera & Cnidaria
Porifera
Type of organism Irregular, asymmetrical, no head, no gut, no discrete organs. Mostly marine. Common name: sponge.
Feeding Hetertrophic (eat other organisms). Canal system with specialized cells that create currents of water and trap food.
Locomotion Mostly sessile, few are free-swimming. Free-swimming juveniles.
Body Support/ Skeleton Silica or calcium carbonate spicules, some spongin protein fibers.
Respiration By simple diffusion.
Osmoregulation Contractile vacuoles.
Reproduction Hermaphrodites (both sex organs present in the same individual), some with separate sexes, vegetative reproduction common. Flagellate, free-living larvae are common.
Information adapted from
Jurd, Richard D. Instant Notes in Animal Biology. Garland Science/ BIOS Scientific Publishers: New York, NY. 2004. p. 7
Comparative Anatomy Focus Simplest form of metazoan (multicellular organisms). Lack organs, systems, digestive tract, and have a very primitive nervous system. Division of labor does exist, however, between the types of specialized cells.
In lab Look at slides of the syconoid sponge. Draw and label the following:
osculum
incurrent canal
prosopyle
apopyle
larvae
pinacocytes
spongocoel
choanocyte
radial canal
Observe the leucosolenia