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Characteristics of P h y l u m P o r i f e r a1. Cellular level of organization (no organs or tissues)2. Have UNIQUE flagellated collar cells called choanocytes that drive water throught the canals and chambers3. Adults are sessile suspension-feeders; larval stages are motile4. Body wall consists of 3 components:Epidermis with incurrent pores (has pinacocytes and porocytes)Mesohyl (middle layer)= a non-cellular , protein matrix containing spicules, spongin, and ameobocytes (archeocytes= totipotent turn to sperm)inner layer with choanocytes5. Skeletal elements consists of spicules (made of calcium carbonate or silicon dioxide) and/or spongin (protein fibers)6. Ameobocytes are totipotent -> can develop into all other sponge cell types7. Three body types (not classes) based on complexity (degree of folding)Characteristics of P h y l u m C n i d a r i a1. Tissue level of organization (no organs)2. Dipoblastic : (2 tissue layers):Outer epidermis (derived from ectoderm)Inner gastrodermis( Derived from endoderm)3. Meso glea= non-cellular middle layer that provides support between two tissue layes4. Radially Symmetrical and the primary body axis is oral-aboral5. Have specialized STINGINIG CELLS call cnidocytes that have unique organelles called nematocysts within them. These nematocysts are like mini-harpoons that can be ejected and used for ANCHORAGE, DEFENSE, AND PREY CAPTURE.6. The GVC ( gastrovascular cavity) is saclike and had only one opening which serves and both mouth and anus. In addition to its role in DIGESTION, it also functions as a HYDROSTATIC SKELTON7. Respiration and excretion take place via diffusion.8. Nervous system is a simple NERVE NET.9. 2 body forms that may occur in the life cycle:polyp=sessilemedusa-motile10. Typically planula larvae ( ciliate and motile)Characteristics of Organ level of organization1. Tripoblastic (3 tissue layers):outer epidermis(derived from ectoderm)middle mesenchyme (mesoderm)Inner gastrodermis (endoderm)2. Acoelomate-> no body cavity (coelom). Instead the body is filled with the middle cell layer called the mesenchyme3. Bilaterally symmetrical and flattened dorsoventrally4. Incomplete digestive system-> has only 1 opening (gut is absent in parasitic cestoda)5. Cephalization: concentration of sense organs and nervous system at the anterior end of the animal. LADDER-LIKE nervous system6. Protonephridia (flame bulbs/cells) are excretory and osmoregulatory structures7. Monoecious (hermaphroditic)PHYLUM8.Characteristics of P h y l u m NEMERTINA1. Organ level of organization 2. Tripoblastic (3 tissue layers) :outer epidermis(derived from ectoderm)middle mesenchyme (mesoderm)Inner gastrodermis (endoderm)3. Acoelomate -> no body cavity (coelom)4. Bilaterally symmetrical and UNSEGMENTED 5. Complete digestive system-> has only 2 opening mouth an anus6. CLOSED circulatory system 7. Has a PROBOSCIS that is surrounded by a cavity called a RHYNCHOCOEL and is dorsal to the gut.8. CEPHALIZATION 9. PROTONEPHRIDIA (FLAME BULBS/CELLS)= Excretory an Osmoregulation10. most are DIOECIOUS Characteristics of P h y l u m ANNELIDA1. Organ level of organization 2. Tripoblastic (3 tissue layers) :outer epidermis(derived from ectoderm)middle mesenchyme (mesoderm)Inner gastrodermis (endoderm)3. EUCOELOMATE 4. Bilaterally symmetrical 5. DEVELOPMENT= they are PROTOSTOMES (COELOM DEVELOPS BY schizocoelous mode and the blastopore becomes the MOUTH)EMBYRO HAS SPIRAL DETERMINATE CELL CLEVAGE6. METAMERISM: segments both internally and externallyrepeating INTERNAL systems are separated by SEPTA (Tissue walls)some annelids show TAGMOSIS7. COMPLETE DIGESTIVE SYSTEM with regional specialization8. CLOSED circulatory system with blood containing HEMOGLOBIN9. PAIRD NEPHRIDIA (excretion and osmo)10. Some dioecious and some hermaphroditic/monoecious11. polychaetes have free swimming trochophore larvaP h y l u m CHORDATA1. Organ level of organization 2. Tripoblastic (3 tissue layers) :3. Deuterostomes (entercoelous coelom formation; indeterminate development; radial cell cleavage)4. Bilaterally symmetric5. Four chordate characteristics are present at SOME stage of development:1)Pharyngeal gill slits2) Dorsal Hollow nerve cord3) Dorsal notochord4) post anal tail5) endostyle (some say)6. COMPLETE DIGESTIVE with regional specialization7. CLOSED CIRCULATORY system with ventral contractile blood vessel or heart8. Dioecious or hermaphroditic; fertilization may be external or

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FSU BSC 2011L - Phylum Porifera

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