Taxonomic Hierarchy a Kingdom b Phylum c Class d Order e Family f Genus g Species 1 CLASSIFICATION Cambrian explosion all major body plans formed 100 phyla Different environments adaption results in evolution All exchange structure all circulatory system evolve in response to an increase in body size B Asexual single parent offspring identical to parent Reproduction A Sexual us Organizational grades A Cellular B Tissue C Organ Symmetry Unicellular cells perform basic function Protozoan Multicellular cells cannot live alone metazoan Porifera More complex eumetazoan embryonic germ layer results in tissue layer Cnidaria Tissues work together in an organ A Asymmetry body can not be divided in mirror halves B Spherical symmetry any plane divides the body into mirrored halves C Radial symmetry plane passing through the longitudinal axis divides the body into mirrored half s D Bilateral Symmetry cut in a sagittal plane in two mirrored half s Coelomic Architectures A Acoelomate lack body cavity around gut Platyhelminthes meso Cells completely fill blastocoel no coelomic cavity B Pseudocoelomate cavity derived from blastocoel not mesoderm Nematoda Rotifera Neatomorpha Meso Cells only partially fill blastocoel remaining space not a true coelomic cavity bc its not surrounded by meso C Eucoelomate true coelom lined w mesoderm Annelid Arthropoda Meso Cells fill blastocoel forming surrounding a new cavity PHYLUM PORIFERA The Sponges 1 Characteristics a Multicellular heteratrophs cellular level only b Asymmetrical sessile attached to the ground c Evolution of classes Calcarea Desmospongiae Hexactinellida 2 Canal systems 3 a Asconoid simplest structure generally smaller Water flow Ostia in Spongocoel lined with choanocytes Osculm out b Syconoid increases surface area for filtering Water flow ostium incurrent canal porocyte flagellated radial canal apopyle spongocoel osculum c Leuconoid most complex more efficient water pumping system Water flow ostium incurrent canal prosopyl porocyte radial canal flagellated chamber apopyle osculum 3 Cells a Choanocytes sponge collar of microvilli that can filter and trap food Flagellated beats and creates a water current that pumps particles through the b Pinacocytes outer covering on the sponge tightly packed leathery pinacoderm skin like c Porocytes surround canal openings or pores totipotent stem cells can move through the mesohyle Functions ingest and digest food and transfer nutrients to other cells they can Can contract to regulate water flow d Archaeocytes Amebocytes and can change into any sponge cell e Mesohyle also develop into gametes sex cells spongy part of the sponge Gel and protein matrix where cells and structural elements are embedded spicules and spongin fiber secrete spicules are derived from archaeocytes secrete skeletal fibers made of the structural proteins collagen and Sclerocytes f g Spongocytes sponging 4 Classes 3 based on spicule morphology a Hexactinellida silicious spicules 6 sided hex Glass sponges Syncytial cell layers no distinct cells o Syncytial mass of protoplasm with many nuclei b Desmospongiae mostly silicious spicules and some calcium carbonate Also uses spongin a specific type of collagen for structural support 90 of all sponges fall into this class mostly marine Can exist with just spongin fibers only no spicules c Calcarea calcium carbonate spicules Have unique 3 4 ray spicules not hollow All species are marine Class includes all 3 body canals 5 Feeding a Filter feed phagocytize bacteria and detritus suspended in water b Archaeocytes mostly phagocytize larger particles c Digestion is intracellular 6 Reproduction and life cycle a Asexual budding fragmentation gemmules freshwater Gemmule dense hard ball of archaeocytes protected by spicules and spongin can withstand the harsh conditions of freshwater in the winter freezing most sponges are monoecious produce egg and sperm cells but seldom self b Sexual fertilize Choanocytes become sperm phagocytized by another sponge s choanocyted those become amoeboid one celled protozoa travel through mesohyl and fertilize eggs Parenchymula larvae swims then settles on ground 7 Ecological roles a Often dominate structural elements in marinescapes b c Important for water filtration Influence water chemistry d Provide refuge e Important resource affecting many species interactions RADIATA PHYLUM Cnidaria and Ctenophora 1 Characteristics Phylum Cnidaria hydroids jellyfish sea anemones and coral bear stingers a Solitary or colonial b Most are marine c Tissue grade of organization organized aggregations of cells that coordinate to perform life functions d Diploblastic 2 layers Epidermis formed by the ectoderm outer layer Gastrodermis formed by endoderm inner layer Mesoglea glue in the middle of the 2 layers e Hydrostatic skeleton Polyp fluid filled GVC works with outer longitudinal and inner circular myofibrils Medusa contract myofibrils around the bell force water in and out of subumbrellar surface 2 Cnidae a Cnidarians have contain cnidae ex nematocysts which are organelles in cnidocytes cells that eject stinging or adhesive threads b Operculum the capsule containing the nematocyst c Cnidocil the hair like trigger that when physically contacted causes the cnidocyte to burst and release the nematocyst s threads the cell is destroyed and replaced d Types of cnidae Volvents whip like entangle prey Glutinants sticky secretion that sticks to prey Penetrants barbs and the tips that can deliver a toxin 3 Body types radial symmetry a Polyp b Medusa cylindrical Consists of a body stalk the base is called a pedal disk substrate attachment generally attached to a substrate solitary or colonial Tentacles surround a mouth that faces away from substrate generally upward umbrella shaped Top the bell Generally free floating Tentacles surround a mouth that generally faces downward Moves by jet propulsion tentacles contain nematocysts a GVC gastrovascular cavity one way blind sac gut one opening Digestive enzymes are secreted in GVC 4 Feeding b Intracellular and extracellular digestion Extracellular GVC permits intake of larger prey Intracellular within gastrodermal cells lining the GVC 5 Life cycle reproduction stage a Some species alternate between asexual polyp stage and sexual dioecious medusa Polyp asexual budding fission or pedal laceration Medusa sexual interstial cells gametes which are fertilized o Planula larva forms new polyps b Polyp colonial stage different polyps that share a common GVC
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