acoelomate - acoelomates!   No coelom; mesenchyme...

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Unformatted text preview: acoelomates!   No coelom; mesenchyme fills blastocoel   *Fate of the blastocoel?   obliterated!   “acoelomate” NOT taxonomic classification 1. Classifica0on   K= Animalia   P= Platyhelminthes   C= Trematoda, Monogenea, Cestoda, Turbellaria 2. Organiza0on   Organ level 3. Embryonic Development   Triploblastic ­ 3 germ layers Germ layer Tissue layer Germ layer also forms… Ectoderm Epidermis Skin, notochord, nervous system, inner ear, lens of eye, some skull and jaw bones Mesoderm Mesenchyme Skeleton (vertebral column), muscles, gonads, excretory sys, circulatory sys, peritoneum Endoderm Gastrodermis Gut, pancreas, lungs, liver, diges0ve tract 4. Symmetry   Bilateral   dorsal, ventral, anterior, posterior 5. Skeleton/Support:   hydrostatic skeleton   mesenchyme provides support Transverse muscles 6. Movement/Locomo0on   muscles work against hydrostatic skeleton   longitudinal, circular, transverse muscles 7. Sensory/Nervous System   cephalization   1 direction, anterior mass of ganglia   sensory organs:     Ocelli: light sensing Auricles: chemoreception   advanced forms: ladder like nervous system 8. Diges0on/Feeding   incomplete   EXCEPT Cestoda   intra ­ & extracellular digestion   Free ­living or parasitic oral sucker gut (caecae) 9. Excretory System   protonephridia (flame cells) ­ removes waste/water  10. Circulatory System: diffusion  11. Respiratory System: diffusion   Why can these processes be carried out through diffusion in these organisms? 12. Reproduc0on   monoecious/hermaphroditic   internal fertilization   Parasitic adaptations… Two headed worm experiment Symbiosis Type Host Mutualism Commensalisms  ­ Parasitism Adaptations for parasitic lifestyle 1) digestive system 2) cuticle 3) adhesive organs 4) reproductive capabilities 5) sensory system Some terms:   free living   mobile/motile, sessile   benthic, pelagic, terrestrial, aquatic symbiont Class Turbellaria (Fig 3.2 ­3.4)   free ­living, carnivores   Eversible pharynx, tri ­lobed gut   slime trails & cilia (free ­living adaptation)   reproduction:   Sexual: monoecious (penis fencing!)   Asexual: transverse fission, regeneration Class Trematoda   leaf ­like (“tree” ­matode)   endoparasitic   special adaptations   oral sucker: feeding; ventral sucker:           attachment 2 simple straight caecae Mostly reproductive organs 2 hosts in life cycle, 2nd being a mollusk epidermis modified cuticle some sensory to recognize host Class Monogenea   Intermediate between Trematoda and Cestoda   Parasites of aquatic vertbrates such as fish, turtles, and frogs   Simple life cycles   Seldom cause serious damage to hosts Class Cestoda   Endoparasitic tapeworm w/ vertebrate host   adaptations:   scolex: head region w/ rostellum for attachment   NO digestive system   cuticle   Mostly reproductive organs   monoecious   proglottids: reproductive units   immature   mature (reproductively)   gravid: full of eggs, will fall off and be shed with host feces Phylum Nemer0na marine, free ­living, ribbon worms   *characteristics same as Platyhelminthes except:   1. Classification   P: Nemertina   6. Movement/Locomotion   only longitudinal and circular muscles   8. Digestion/Feeding   COMPLETE!   Free ­living   10. Circulation:   CLOSED! “ Tube w/in a tube” body plan   mouthgutanus   compartmentalization increases efficiency   Rhynchocoel   cavity w/ proboscis (NOT coelomic)   separate from digestive tract (‘rhino’)   Proboscis   muscular tissue w/ poisonous stylet   muscles around rhynchocoel contract to eject at prey   NOT A STRAW   nemertina= unerring Acoelomates (2 phyla) *Draw every slide and at least one representative of every group* Phylum Platyhelminthes RUST MANUAL pages 57-60 1)  Class Turbellaria slides:   Planaria w.m. 3.2, 3.4 3) Class Cestoda slides:   scolex w.m. 3.7 (hooks, scolex, rostellum, immature (ocelli, auricles, tri ­lobed gut, pharyngeal proglottid) pouch, pharynx)   tapeworm proglottids: mature, gravid 3.7   Planaria (3) c.s. 3.2, 3.4 (uterus, ovary, yolk gland, genital pore, p. 24 (pharynx, pharynegeal opening, vagina, testes, sperm duct) epidermis, mesenchyme, tri ­lobed gut, nerve preserved specimens cord) preserved specimens 2) Class Trematoda slides:   Opisthorcis (Chinese liver fluke) w.m. 3.5 Phylum Nemertina slides:   Rhynchocoela c.s. 4.1, 4.2 (uterus, ovaries, testes, intestine, ventral and (epidermis, proboscis, rhynchocoel, nerve cords, oral suckers, seminal receptacle, pharynx, mesenchyme, intestine) esophogus) preserved specimens   Fasciola (Sheep fluke) w.m (oral and ventral suckers, intestine, uterus, mouth) preserved specimens   http://www.youtube.com/watch? v=iyEDPtUThVo&feature=related   http://www.youtube.com/watch? v=HekwSO6dBG0&feature=related   http://www.youtube.com/watch?v=5fx ­ YgcP8Gg&feature=related ...
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This note was uploaded on 06/13/2011 for the course BIOLOGY bsc2011L taught by Professor Dr.tschinkel during the Fall '11 term at FSU.

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