BSC 2011L MIDTERM FINAL Cambrian explosion 570million years ago 100 phyla had already evolved represents all major modern body plans Natural groups organisms that are evolutionarily closely related monophyletic descended from a common ancestor Systematics science of taxonomy and reconstruction of phylogeny Taxonomy scientific classification ordering and naming Phylogeny evolutionary history of organisms Node of a tree represents a common ancestor of monophyletic Taxonomic hierarchy kingdom phylum sub phylum class subclass order family genus species common name Genus species Phylogenetic studies can reveal erroneous classification Different environment adaptations What drives animal diversification functional and physical constraints evolutionary constraints Life functions acquiring digesting food growth reproduction movement body form supp environmental stimuli exchange materials Investing resources more eggs less parental care or fewer eggs more care Movement optimizes favorable conditions escape unfav conditions Body support internal external hydrostatic Tracheal tube info large insect oxygen is depleted before air reached inner cells if tube diameter stays same tracheal volume must become much larger to accommodate for this issue surface area increased using intestinal villi anterior head posterior tail dorsal back ventral belly side medial midline lateral sides distal far from core proximal near frontal plane dorsal ventral halves sagittal plane right left halves transverse plane cross section anterior posterior Kingdom Animalia Porifera Phylum Symmetry asymmetrical Organization cell grade Locomotion sessile No nervous system Circulation transport respiration diffusion Feeding suspension filter feeder intracellular digestion Reproduction monoecious sexual asexual modes Asexual without gametes budding fragmentation gemmules ball of archaeocytes protected by collagen and spicules live in harsh conditions regeneration due to totipotent cells Sexual fusion of egg and sperm choanocytes become sperm and are released broadcast spawning sperm is captured by other sponges choanocytes phagocytized and then become amoeboid to travel to fertilize the egg fertilize egg becomes a parenchymula or amphiblastula larva larva exits parent sponge swims then settles and becomes a new sponge Amoebocytes Archaeocytes can become sperm eggs Spongocoel inner cavity Choanocytes flagellated collar cells that bring in water food line spongocoel Incurrent Pores Ostia ostium pores in sponge wall Osculum where the water exits Pinacocytes outer sponge cells together make up the pinacoderm Porocytes surround pore openings can contract to regulate water flow Sclerocytes secrete stiff skeletal elements called spicules Spongocytes secrete skeletal fibers of collagen sponging Mesohyl gelatanious matrix under pinacoderm Skeleton spicules sponging fibers Ecological roles structural elements in marinescapes important for water filtration influence water chemistry provide refuge snapping shrimp baby spiny lobsters Body Plan Asconoid Most simple very small basic in out water flow Syconoid more surface area less volume contraints by folding the surface Prospyle pore from outside to inner radial canal Apopyle pore from radial canal into spongocoel Radial Canal flagellated Incurrent canal Leuconoid lose distinct spongocoel often multiple ascula flagellated chambers more efficient water pumping Class Hexactinellida glass sponges silicious spicules don t have distinct cells cell layers are syncytial outer pinacorderm inner choanosyncytium synconoid or leuconoid Demospongiae mostly silicious spicules and sponging fibers mostly marine leuconoid Calcarea three and four rayed carbonate spicules include all body types all marine Cnidaria Phylum Hydroids jellyfish sea anemones coral Eumetazoa multicellular with true tissue Symmetry radial Organization tissue level diploblastic Support hydrostatic skeleton longitudinal myofibrils circular lateral myofibrils GVC gastrovascular cavity one opening Locomotion slow swimming sessile Sensory nervous nerve net rhopalia statocysts ocelli in medusa Osmoregulation excretory diffusion Feeding carnivorous Extracellular digestion digestive enzymes in GVC break food into smaller particles Intracellular digestion particles absorbed and further digested by gastrodermal cells lining gut Reproduction asexual sexual Two tissue layers epidermis ectoderm gastrodermis endoderm Polyp solitary or colonial asexual tentacles around the mouth Medusa bell shape swims sexual Cnidocyte contain cnidae nematocytes hair trigger cnidocil volvents whip like entangle prey glutinants sticky secretion penetrants have barbs at tips Cell types Epitheliomuscuar cells in epidermis Nutritive muscular cells in gastrodermis stem cell like interstitial cells Class Hydrozoa hydoids Polyp predominant asexual budding pedal disks gland cells for attachment detachment Siphonophores colony of specialize polymorphic polyps Medusa sexual Velum inner shelf contracts bell to propel Statocysts for equilibrium Polymorphism in polyp colony gastrozooid gonozooid dactylozooid pneumatophore Hydrozoan life cycle Hydrocorals aka fire coral Scyphozoa bud gametes planula larva settlement growth differentiation Dioecious 4 gastric pouches Rhopalium sense organ contains statocyst and ocellus life cycle sexual reproduction settlement scyphistoma stobila asexual reproduction ephyra Staurozoa split off from class Scyphozoa solitary polyp octomerous 8 tentacles Anthozoa solitary and colonial only polyp symbiotic photosynthetic algae called zooxanthellae hard corals and sea anemones calcareous skeletons monoecious dioecious Sub class sea anemones and hard corals mutualsitic zooxanthellae enhance coral ability to deposit calcium carbonate warming sea temp kills zooxanthellae coral bleaching soft corals sea fans sea pens sea pansies flexible gorgonin protein tube anemones thorny black coral GVC divided into chambers by septa Acontia threads with nematocyst and gland cells Siphonoglyph ciliated groove down side of pharynx maintains H20 current Sexual life cycle release of gametes with external gametes blastula diploblastic gastrula planula larva young polyp Asexual budding fission pedal laceration Cubozoa box jellyfish prominent medusa lethal stings Platyhelminthes Phylum Symmetry bi lateral anterior posterior axis triploblastic acoelomate Locomotion via ciliated epithelial cells circular longitudinal muscle Circulation transport diffusion Nervous
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