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S I Section 4 3/31/2011 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Porifera Ecdysozoa Deuterostomia Lophotrochozoa Cnidaria and Ctenophora Cnidaria and Protostomia SSiection 4 Radiata Bilateria Professor Donald McFarlane Parazoa Eumetazoa Lecture 13 Invertebrates: Parazoa, Radiata, and Lophotrochozoa Ancestral colonial choanoflagellate 2 Traditional classification based on Parazoa – Phylum Porifera body plans Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Parazoa 4 main morphological and developmental Sponges features used Loosely organized and lack Porifera Ecdysozoa Cnidaria and Ctenophora tissues euterostomia photrochozoa D 1. o Presence or absence of different tissue L Multicellular with several types of types Protostomia cells 2. Type of body symmetry Radiata Bilateria 8,000 species, mostly marine Parazoa Eumetazoa 3. Presence or absence of a true body No apparent symmetry cavity Ancestral colonial Adults sessile, larvae free- choanoflagellate 4. Patterns of embryonic development swimming 3 4 1 3/31/2011 Water drawn through pores (ostia) into spongocoel Flows out through osculum Reproduce Choanocytes line spongocoel Sexually Most hermapppgggphrodites producing eggs and sperm Trap and eat small particles and plankton Gametes are derived from amoebocytes or Mesohyl between choanocytes and choanocytes epithelial cells Asexually Amoebocytes absorb food from choanocytes, Small fragment or bud may detach and form a new digest it, and carry to other cells sponge Spicules (skeletal fibers) or spongin 5 6 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Radiata – Phylums Cnidaria Water Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. and Ctenophora Radiata (b) Typical vase Radial symmetry shape of sponges Porifera Ecdysozoa Choanocyte Mostly marine Deuterostomia Lophotrochozoa Epithelial cell and Ctenophora Osculum a Flage llum OlOnly 2 em bryon ic germ Collar Cnidari Nucleus layers Amoebocyte Protostomia Water Diploblastic Spicule Radiata Bilateria Spongocoel Ectoderm and Ostium endoderm Parazoa Eumetazoa Mesoglea connects Mesohyl layers Spicule (c) Cross section of sponge morphology 7 8 2 3/31/2011 Phylum Cnidaria 2 different body forms First clade with true tissues Sessile polyp – tubular body with tentacles Gastrovascular cavity for extracellular surrounding opening (mouth and anus) digestion Motile medusa – umbrella-shaped body with a mouth on the un ders ide surroun de d by Allows ingestion of larger food particles tentacles Advance over sponge’s intracellular digestion Cnidocytes contain nemotocysts True nerve cells arranged in nerve net Hairlike trigger – cnidocil No central control organ Some sticky while other sting Simple muscles and nerves Not true muscles (not of mesoderm origin) 9 10 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Mouth/ Tentacle anus Bell Epidermis Phylum Ctenophora (from ectoderm) Mesoglea Comb jellies Gastrodermis Less than 100 species- all marine and look (from endoderm) like jellyfish Gastrovascular Eig ht rows of cili a on sur face bea t for cavity propulsion 2 long tentacles without stinging cells Colloblasts secrete sticky substance Mouth/ Tentacle First complete gut – mouth and anus anus Hermaphroditic (a) Polyp (b) Medusa 11 Bioluminescent 12 3 3/31/2011 Lophotrochozoa Flatworms, rotifers, lophophorates, mollusks and annelids Traditionally, bilaterally symmetrical animals split into those with no coelom (platyhelminthes), pseudocoleomate (nematodes and rotifers) and remaining coelomate phlya Molecular data suggests a different grouping with the deuterostomates separate and the protostomates divided into the Lophotrochozoa (Platyhelminthes, Rotifera, Lophophorata, Mollusca and Annelida) and the Ecdysozoa 13 14 Phylum Platyhelminthes Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Lophotrochozoa Flatworms Lack a specialized Rotifera Porifera Annelida Mollusca respiratory or circulatory Ecdysozoa euterostomia d Ctenophora atyhelminthes Lophophorata n D system to transport gases Pl Respire by diffusion Cnidaria a Lophotrochozoa Among first animals with active predatory lifestyle Protostomia Radiata Bilateria First with 3 embryonic germ layers – triploblastic Bilaterally symmetrical Parazoa Eumetazoa Mesoderm key innovation – led to more with a head sophisticated organs Acoelomate – lacking fluid-filled cavity 15 16 4 3/31/2011 Digestive system incomplete 4 classes Distinct excretory system with Turbellaria – Free-living, Planaria protonephridia and flame cells Monogenea – Fish flukes Light sensitive eyespots or ocelli Cestoda – Tapeworms, parasitic Cerebral ganglia receive input 2 separate host species in life cycle Retain nerve net with beginning of more Trematoda – Flukes, parasitic centralized nervous system More complex life cycle with multiple hosts Sexual or asexual reproduction Chinese liver fluke, Clonorchis sinensis Most hermaphroditic but do not self fertilize Blood flukes, Schistosoma spp., most common parasitic trematode infecting humans 17 18 Lophophorata Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Lophotrochozoa 3 closely related phyla Phoronida, Bryozoa, Rotifera Porifera Annelida Mollusca Ecdysozoa phophorata Brachiopoda uterostomia d Ctenophora tyhelminthes o e n L D All possess a Pla lophophore – ciliary Cnidaria a Lophotrochozoa feeding device that also Protostomia functions in respiration Radiata Bilateria True coelom Parazoa Eumetazoa 19 20 5 3/31/2011 Phylum Mollusca Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Lophotrochozoa Over 100,000 species Soft body with, in many species, Rotifera Porifera Annelida protective external shell Mollusca Ecdysozoa Lophophorata Deuterostomia Body has 3 par ts and Ctenophora Platyhelminthes Foot, visceral mass and mantle Lophotrochozoa Cnidaria Coelom confined to small area Protostomia around heart Radiata Bilateria Parazoa Eumetazoa Open circulatory system Metanephridia Radula – unique tongue-like organ 21 22 Most shells complex 3 layered and secreted by mantle Separate sexes although some hermaphroditic External fertilization – some internal ((ykey to snails colonizing land) Trocophore larvae develops into veliger with rudimentary foot, shell and mantle 8 classes with 4 common Polyplacophorans, gastropods, bivalves and cephalopods 23 24 6 3/31/2011 Polyplacophorans – chitons Gastropods – snails, slugs and Phylum Annelida nudibranchs Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Largest class, shells can be reduced or lost, Rings are distinct Lophotrochozoa most marine or freshwater but some colonized land segments separated by a septum Rotifera Porifera elminthes Annelida Mollusca erostomia cdysozoa hophorata Ctenophora t h Bivalves – clams, mussels, oysters E Lop Deu Cephalopods – octopuses, squids, Segmentation has Platy nautiluses advantages and Cnidaria Lophotrochozoa Most morphologically complex, fast-swimming 1. Repetition of components Protostomia marine predators, closed circulatory system provides backup Radiata Bilateria Beaklike jaw, only nautilus has external shell, 2. Coelom acts as hydrostatic Parazoa Eumetazoa some have foot modified into muscular siphon skeleton for propulsion 3. Permits specialization 25 26 Digestive system complete and unsegmented Double transport Sexual reproduction involves 2 individuals system (sometimes separate sexes, others Circulatory system and hermaphroditic) with internal fertilization coelomic fluid Asexual reproduction by fission carries nutrients, wastes and 15,000 species respiratory gases All annelids except leeches have setae on each segment 27 28 7 3/31/2011 2 classes Polychaeta – marine worms Most species rich, many long setae Clittelata Subclass Oligochaeta – terrestrial and freshwater worms (earthworms) Role in conditioning soil through castings Subclass Hirudinea – leeches Primarily freshwater, hirudin (anticoagulant), may be used in reattachment surgeries, generally external parasites 29 30 8.
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