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Spongia (Porifera) Immobile, most are marine, a few freshwater. No obvious tissues and organs divisions. No mouth and digestive tract, there is a spongcoel inside. Named Porifera as well – ostium, osculum. Suspension feeders: choanocytes. Mesohyl, amoebocytes: digesting, transport nutrients to other cells, and produce materials for skeletal fibers. Inner skeleton is one of the factor for classification: spicules or spongin fiber. Strong ability of regeneration. Anatomy of a Sponge Azure vase sponge (Callyspongia plicifera) Feeding of Choanocytes Food particles Flagellum in mucus 襟細胞 Choanocyte 襟細胞 Collar 出水孔 Choanocyte Osculum 海綿腔 Spongocoel 入水孔 Pore 骨針 表皮層 Epidermis Water flow 中膠層 Mesohyl Phagocytosis of food particles Amoebocyte Spicules 變形細胞 Amoebocytes 變形細胞 Observations Slides: 1. Grantia spicules (p.136) Specimens: 1. Grantia – stereomicroscope, spicules (p.136) 2. Spongillidae – stereomicroscope, spongin (p.136) 3. Euplectella (Venus’ Flower Basket ) – Skeletonspicules (p.136) Slide: Grantia spicules p. 136 • In the mesohyl, it is the secretions from Amoebocyte. • Many kinds of spicules. Observations Specimens: 1. Grantia – stereomicroscope, spicules (p.136) 2. Spongillidae – stereomicroscope, spongin (p.136) 3. Euplectella (Venus’ Flower Basket ) – Skeletonspicules (p.136) Specimen:The Skeleton of Euplectella aspergillum (Venus’ Flower Basket) has a skeleton that is made from a glass-like substance and is also as fragile as glass, thus its name “Glass Sponge.” (p.136) The Skeleton of Euplectella Euplectella aspergillum Cnidarians p.137 Gastrovascular cavity, a single opening to this cavity functions as both mouth and anus. There are tentacles arranged in a ring around their mouth, and has cnidocytes have nematocyst inside. Can protect and capture prey. Prey 被補食者 Tentacle 觸手 “Trigger” Thread discharges Cnidocyte 刺絲胞 發射出刺絲 Thread(coiled) There are two variations on the body plan: the sessile polyp and motile medusa. 水螅體型 水母體型 口/肛門 胃水管腔 胃皮層 中膠層 表皮層 口/肛門 Polyp - asexual reproduction: budding - sexual reproduction: egg, sperm Medusa - sexual reproduction: egg, sperm Cnidaria Class Hydrozoa: Usually has two stages on the body plan (polyp and medusa), such as Obelia. Hydras is the one of freshwater species, and only has polyp stage. Class Scyphozoa: In the life cycle, the medusa generation is obviously and dominate; the polyp generation is small and degenerate, such as Aurelia aurita. Class Cubozoa: For example: sea wasp Class Anthoxoa: Only has Hydras, such as Actinia and Coral. Observations Slides: 1. The asexual budding of Hydra 2. The hydroid colony of Obelia Specimens: 1. Physalia(p.137~138) 2. Jellyfish 3. Sea anemone 4. Coral 5. Obelia 6. Hydra – stereomicroscope, Plan, Budding, Ovaries, Spermaries 水螅 (Hydra) Hydra reproduce in two ways: asexually and sexually. Slide: The asexual budding of Hydra 觸手(Tentacles) 芽體(Bud) 畫圖記錄 藪枝螅 (Obelia) Oblia have both the polyp and medusa stages in their life cycle. 營養水螅體 Feeding polyp 水母體 生殖水螅體 Medusa Reproductive polyp Medusa bud MEIOSIS 水母芽 Gonad 生殖腺 ASEXUAL REPRODUCTION (BUDDING) 無性生殖 1 mm Portion of a colony of polyps Key Haploid (n) Diploid (2n) Developing polyp Egg SEXUAL REPRODUCTION Sperm 有性生殖 FERTILIZATION 浮浪幼蟲 Zygote 受精卵 Planula (larva) Mature polyp Slide: Obelia hydroid colony 水母芽 (Medusa buds) 觸手(Tentacles) 生殖水螅體 (Reproductive Polyp) 畫圖記錄 營養水螅體 (Feeding polyp) 圍鞘 (perisarc) Observations Specimens: 1. Physalia(p.137~138) 2. Jellyfish 3. Sea anemone 4. Coral 5. Obelia 6. Hydra – stereomicroscope, Plan, Budding, Ovaries, Spermaries Specimen: Physalia p.138 Portuguese man-of-war It is a colonial hydrozoan that is composed of several types of modified polyps and medusae. 浮體 (gas-filled bladder) 觸手 (Tentacles) The tentacles contain several types of modified polyps and medusae. Report • Draw and describe : 1. Grantia spicules 2. Hydra with bud 3. Obelia hydroid colony • Question 1. Compare the mechanisms of food digestion in Sponges and Cnidarians.