Module 4: Marine Invertebrates I Kingdom Animalia
Kingdom Animalia Contains the largest number of species We will split them into 2 large groups Invertebrates- Animals w/o a backbone Vertebrates- Animals w/a backbone
Phylum Porifera- The Sponges Sponges are attached to the substrate (sea floor).
Sponge Structure Pores- channels that allow water to enter the organism. Specialized cells- Collar Cells- found inside the pores. Have flagellum to move water. Bits of plankton and organic material are filtered out. Trapped in the collar
A simple sponge. Its surface is perforated by small openings (incurrent pores) formed by tubelike cells (porocytes), which open into the internal cavity. A gelatinous middle layer contains the skeletal elements (spicules and spongin fibers) as well as amebocytes active in digestion, waste removal, and spicule and spongin formation. Flagellated collar cells (choanocytes) line the internal cavity, create currents to move water containing oxygen and food into the sponge, and engulf and digest food particles. Water and wastes are expelled through the ostium opening, whose size can be altered to regulate water flow through the sponge.
Amebocytes- special cells that pick up food from the water They are mobile Found in jellylike layer Perform digestion, make skeletal structures and repair any damage to the sponge
3 basic body types Which type has the largest surface area? Why is this important? Asco Sycon Leucon
Phylum Porifera- Sponges Sponges are filter feeders! Some can filter up to 20x their own volume of water in 1 minute. Sponges can get clogged They secret lots of mucus to cleanse their surface They provide shelter for mutualistic organisms
Special Attributes of Sponges Aggregation- If a sponge is broken up into tiny pieces, the pieces will reassemble forming a new individual. Spicules- provide internal support for a large sponge ( skeleton ) Several types. Used to classify Silica (glass) or calcium Spongin- tough elastic protein fibers for support
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Reproduction in Sponges Asexually Regeneration- a broken off piece can grow into a new, separate individual identical to the original. Budding- parent develops a small outgrowth that pinches off and becomes new individual. Gemmule- when temperatures reach freezing, the sponge surrounds a group of cells with a shell of spicules allowing it to survive until better conditions.
Reproduction in Sponges Sexual Usually collar cells develop into gametes. Eggs stay in the sponge Sperm are released into the water. When sperm finds egg, fertilization occurs. Forms planktonic larva= amphiblastula It is released into the water until it settles on the bottom
Larva- An immature stage of an animal that appears different from the adult stage.
Metamorphosis A complete morphological (form and structure) change from larval to adult form
Questions If sponges cannot move around, how can they be distributed throughout the ocean? The amphiblastula is carried by currents until it settles thus relocating. While swimming in a tropical ocean, a diver finds a large, cup-shaped sponge big enough for him to swim inside. What type of support would this sponge probably have? Hard spicules and elastic spongin.
Porifera review What does porifera mean? Describe 2 special cells found in sponges. Explain one method of asexual reproduction in sponges. What is a gemmule? Explain sexual reproduction in sponges.
Phylum Cnidaria What organisms make up phylum Cnidaria? Jellyfish, corals and sea anemones are members Sometimes called coelenterates because they have a coel ( seel ) - large body cavity. have specialized tissues that do special jobs.
Symmetry Symmetry- when you can split an organism into at least 2 identical halves, it is symmetrical. 3 types of body symmetry Spherical symmetry- any cut through the center results in identical halves Radial Symmetry- any longitudinal cut through the center results in identical halves Bilateral Symmetry- where only on longitudinal cut through the center results in identical halves.
Radial Bilateral Which is which?? Spherical
Body structure Cnidarians are radially symmetrical- NO true head, front or back. Oral side = mouth side (look for tentacles) Aboral Side = opposite the mouth Polyp- attached stage Medusa- free swimming stage
Polyps and Medusa Both have a central mouth surrounded by tentacles Tentacles have nematocysts- stinging structures Both have a gastrovascular cavity- digests foods here. Only one opening- not true gut
Do the handout as you watch. The Phylum Cnidaria - Documentary - YouTube
Life cycle of cnidarians Budding (asexual) produces polyps. The polyps can keep budding new polyps, but if the conditions are good, then immature medusa form. These mature into adults, which reproduce sexually to produce the larva which makes new polyps on the sea floor, and the cycle begins again.