Note for BSC 373 with Professor Harris at UA-Lecture 10
Note for BSC 373 with Professor Harris at UA-Lecture 10
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This 11 page Class Notes was uploaded by an elite notetaker on Friday February 6, 2015. The Class Notes belongs to a course at University of Alabama - Tuscaloosa taught by a professor in Fall. Since its upload, it has received 19 views.
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Date Created: 02/06/15
The Rise of Teleosts Modem quotmes All modernday species ca 2526k Early Cenozoic 50 mybp zeaallyozlgnwem39day genera Late Cretaceous 70 mybp zlong mday families ca39 Middle Cretaceous 100 mybp Six major orders Late Jurassic 150 mybp Explosive radiation Late Triassic 200 mybp First appearance The Rise of Teleosts What characters made teleosts Hurstm so successful 7 Feeding mechanisms Greateriaw mobility opened humane e y up newtropnic possibllltleS N lt quot allowed for Specialization of mouth pane which lead exploitation of Specialized c V 97 food resources 7 Caudal fin locomotory complex Progressive change in r 7 caudalrfin complex frorn am e i i strongly asymmetrical heterocercal to moderately asymmetrical abbreviate heteroceral to 39syrnrnetncal39 homocercal lam l teleosts 39 The Rise of Teleosts Heterocercal tail is designed to provide lift Needed by thickscaled heavily armored primitive actinopterygians to get offthe bottom Axis of rotation ofthe tail is oblique pushing down and back Results in upward and forward rotation of the posterior portion of the sh Somersault effect counteracted by the large horizontally inserted pectoral ns acting as planing devices new mamum m myquot pawl m The Rise of Teleosts Homocercal caudal fin designed for thrust Axis of rotation is vertical so it pushes directly backward resulting in forward motion Two advantages Increased efficiency in horizontal swimming because all thrust is horizontal Increased versatility paired ns are now ee to evolve other locomotory functions Results in pectorals moving up the body and pelvics moving forward both providing greater maneuverability The Rise of Teleosts Acquisition of the homocercal tail associated with two other trends in actinopterygian evolution Loss of heavy bony armor and heavy scalation no longer requiring a body plan that requires lift from the caudal complex Modification of lungs to act as hydrostatic organs swim bladder again no longer requiring a body plan that requires lift from the caudal complex Evolutionary trends in Teleosts Reduc ion of bony elements either through fusion or loss Fewer more ossi ed vertebrae 6080 in many elopomorphs vs 3040 in ostariophysans vs 24 in percoids Evolutionary trends in Teleosts Reduction of bony elements either hrough fusion or loss Fewer more ossified vertebrae Fewer bones in skull Reduction of number of bones in gape maxilla becomes excluded from gape Fewer bones in caudal skeleton Reduced number of fin ray elements in paired fins In percoids many bony elements have been reduced to minimal numbers and are fixed For example nearly all percoids have 7 branchiostegal rays 24 vertebrae l5 pelvin fin formula 17 caudalfin rays Evolutionary trends in Teleosts Dorsal n shifts in position and use Placement and function of paired fins Caudal fin and gas bladder modification Feeding apparatus modification M 6 x 41 74 O Inf ND J53ltT3 x CQVY 0 Jlt Q XKlt3 C kx 333 quotNMQ7 Tag amp quot E 17 quotW M g NJ Jaws of Primitive Jawed Fishes Placoderrni earliest kind ofjawed fishes extinct but diverse fossil record Jaws of these fishes were endochondral bone Chondrichthyes best living examples of fish with endochondral jaws CRANIAL SKELETON Of A SHARK Jaws of Primitive Jawed Fishes Jaws of more derived vertebrates are made of dermal bone elements Palatoquadrate cartilage evolves to form part of suspensorium palatine bone and part of quadrate In primitive tetrapods forms part of the roof of the mouth palate in mammals part of it forms the incus one ofthe three inner ear bones Mandibular cartilage in derived fishes forms the articular connecting the articular with the quadrate to suspend the lowerjaw In mammals part of it becomesthe malleus another inner ear bone Dermal Jaws of Actinopterygians and Sarcopterygians Upper jaw consists of SKULL OFA PRlMlTIVE ACTINOPTEKYGIAN FISH two dermal elements Premaxilla Maxilla Lowerjaw is called the dentary ln primitive actinopterygians maxilla was large expanded posteriorly and sutured to bones in the cheek mostly the preopercle immobile relative to cranium Evolution of Upper Jaw in Actinopterygians Most significant evolutionary change begins with freeing posterior end of maxillary bone from bones in the cheek Posterior end of maxilla loses connection to cheek now mobile relative to cranium When the mouth is opened the maxillae rotate forward and downward to close off corners of mouth ln teleosts additional evolutionary changes further increased mobility of upperjaw A ball and socket joint developed between head of maxilla and palatine bone Evolution of Upper Jaw in Actinopterygians SKULL OF A DERWED PRETELEOSTEAN ACHNOPTERYGIAN A c w sxuus or ACTINOPTERVGIANS A Sturgeon ancestor 5 Annie c flaps Evolution of Upper Jaw in Actinopterygians Evolution of the premaxilla and maxilla Inclusion to exclusion of maxilla in the gape n highly evolved teleosts anterior end of premaxilla develops an ascending process that extends upward and backward to overlap the snout J2 Allows the jaw to be protruded away from the snout J3 The maxilla now functions as leverto help thrust the premaxilla forward In addition bony connection between premaxilla and snout in lower teleosts is replaced with a more flexible cartilaginous and connective tissue hinge Evolution of Upper Jaw in Actinopterygians Functional Considerations Loosening the premaxilla from the cranium would seem to weaken the bite How do teleosts compensate for this disadvantage Categories of sh feeding 7 Hit and run Used by mustlyfastrsvvlmmmg upen vvaterflshes Rrrn unaws used fur prung and grasping redurres a rmjavv cunstrumun and large puvverful musclestu shutjavvs quickly and rmly 7 Filter feeders Open tnerr muuths and huld them upen nnrre snrnrnrng Functional Considerations Categories of sh feeding 7 Hit and run 7 Filter feeders e Gape and suck Depends un apnrtym create surnerent negauve pressure in suckem rndwrdual fund rterns In both lter feeders and gapeandsuck feeders strength of bite not as important more imponant is shape and size of mouth when open Functional Considerations Gape and suck feeding Most fish are gapeandsuck 39 l J feeders Don t grab hold of prey or bite off pieces but engulf whole individual prey items Accomplished partly by extending jaws around prey and by creating a negative pressure in the buccal cavity Effectiveness ofthis method depend on Degree to which the mouth cavity can be expanded Suddenness with which the mouth cavity can be expanded Biomechanics of Feeding Primitive Teleost Primitive gapeandsuck feeding mechanism in Elops Lowerjaw is hinged to the quadrate A Maxilla forms ballandsocket joint with palatine bone B Both maxilla and lower jaw are connected by a double layer of skin which folds and unfolds as mouth opens and closes A CRANIUM 0 Gilli ax j m fr N 39 H susrmsomm IAW MECHANISM or ElOPS quwm z A PRIMITIVE rmosr A Biomechanics of Feeding Primitive Teleost Primitive gapeandsuck feeding mechanism in Elops Ligamentous connection 0quot amp Dquot connects posterior end of maxilla to lower jaw As lowerjaw is depressed posterior end of maxilla is pulled forward No upperjaw protrusibility x 39J 393quot l gig Jsz s 39 F39 l l gtAgt I E 4J nm unv Biomechanics of Feeding Derived Teleosts More advanced gapeandsuck feeding mechanism Development of ascending process of premaxilla When mouth opens maxilla acts as a lever to push premaxilla forward ascending process slides and maintains contact with cranium PROTRUSIBLE JAWS lN A PERCIFORM FISH Biomechanics of Feeding Derived Teleosts More advanced gapeandsuck feeding mechanism Development of ascending process of premaxilla When mouth opens maxilla acts as a lever to push premaxilla forward ascending process slides and maintains contact with cranium In addition ligaments have evolved to connect upperjaw bones to cranium Stabilize the upperjaw and provide for mobility Crossed pattern of ligaments provides multidirectional strength and flexibility for protrusion Biomechanics of GapeandSuck Feeding To summarize the action As the mouth opens the floor of the mouth lowers and the sides expand This great and sudden increase in volume creates negative pressure a vacuum which results in water rushing into the mouth The inflow of water into the mouth carries in the prey item A pair of oral valves membranes prevent water from escaping anteriorly Once the jaws close the floor of the throat is raised the sides of mouth contract and water is forced out posteriorly through the gills All of these movements are made possible by complex series of bones muscles and tendons Biomechanics of Gape andSuck Feeding Nellrocrarlllllll no Ltvatnr l 39 llynmamlllmla K in mm were lt Suspensurium 0nrculir apparatus in strrnanynidws Hyoid Apparatus in Primitive Actinopterygians Primitive actinopterygians sturgeons paddle shes gars Opening ofmou h is entirely dependent on lowering of oor of throat Only one biomechanical method by which the mouth can open hyoid coupling Mechanics of hyoid coupling Lowerjaw depression is initiated by contractions of epaxial and hypaxial muscles 7 Contraction of epaxial muscles causes head to rotate upward relative to bodies axis 7 Contraction of hypaxial muscles especially those on the cleithrum causes a backward and downward rotation of the pectoral girdle Hyoid Apparatus in Primitive Actinopterygians m min nlmcull lpuul must mum in V uzrzulnr annulale law IIIIV xrlnlelhlal m Plnlllllnl Bybl un a e cltllnmm mm upmlus l lllpaml must l lrn slernnlryrimrm 10 Hyoid Apparatus in Primitive Actinopterygians Opening ofmou h is entirely dependent on lowering of oor ofthroat Only one biomechanical method by which the mouth can open hyoid coupling Mechanics of hyoid coupling Lowerlaw depression is initiated by contractions or eanial and nyanial muscles Anterlorlyi tne cleitnra are attacned to tne nyoid apparatus by the sternohyoideus muscle 7 Tnis muscle alsci contracts so that tne backward and downwards mbyement is transmitted to ma nybid Hyoid Apparatus in Primitive Actinopterygians lnxial must in lmtnr Dilemuli nmular Hummus Ilium lm luizrlwal l ilypaxiil must l in Elemnhynnlltls Hyoid Apparatus in Primitive Actinopterygians Opening ofmou h is entirely dependent on lowering of oor ofthroat Mechanics of hyoid coupling cont Lowerlaw depression is initiated by contractions oi eanial and nyanial muscles Anterlorly tne cleitnra are attacned to tne nyoid apparatus by tne sternohyoideus muscle Because tne nyoid lies between and is attacnedto tne lower law tne downwards and backwards pull on tne nyoid apparatus is transmitted to tne lowerlaw An indirect method ofopening the mouth because movement ofthe epaxial and hypaxial muscles is required to initiate action 11 Opercular Coupling in Derived Actinopterygians Bow n and teleosts have developed opercular coupling a second moreorless independent system for opening the mouth that does not involve creating suction Opening ofmouth initiated by contraction ofthe levator operculi Causestne opercleto swlng up and backward Because the sub and lnter opercle are attached tms up andrbackwards moyement ls transmltted yentrally tnrougn out all elements or the opercular apparatus The lnteropercle pulls back on lowerlaw by means or a strong llgamerlt Opercular Coupling in Derived Actinopterygians n hum mun inuial mils Upper a l39lpeuulxt altpmlus runmm clutirun lllunml must l m Siemvllynl lus Opercular Coupling in Derived Actinopterygians Opercular coupling Opening ofmouth initiated by contraction ofthe levator operculi Advantage Necessary preaoaptatlon ror tnose nsn tnat reed by rllpplrlg at rocks and coral plckrup small prey plteorr and crusn coral e g surgeonflsheS parrotflshes wrasses tnggernsnes etc Denyedteleosts possess both gaperandrsuckfeedlng and the opercular coupllrlg mecnamsm 12
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