EEB263Y1Y LECTURE #3.pdf

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Department
Ecology & Evolutionary Biology
Course
EEB202H1
Professor
Gerardo De Iuliis
Semester
Fall

Description
EEB263Y1Y:)LECTURE)#3) Higher)Fishes) ! Usually(have(in(mind(the(bony(fishes ( ! Careful(of(the(definition(of(higher ( ! Sharks(are(highly(evolved(creatures ( ! Primative(vs(Advanced((Basal !(further(away(in(relationship)(+(Derived((Further(along(the( phylogenic(branch)( ! Sharks(are(derived(with(the(loss(of(bony(skeleton(whereas(humans(have(kept(bony(skeleton(that( is(considered(basal( ! Have(in(mind(Osteichthyes((Osteo(“bone”(+(Ichthyos(“fish”) ( ! Bony(fishes(retain(bony(skeleton(and(further(refined(structures(of(skeleton ( ! Teleostomi((Fossil(group(which(is(extinct( (Acanthodil)( ( Osteichthyes) 1. Actinopterygii(( 2. Sarcopterygii((Land(vertebrates(were(derived) ( ) Acanthodii) ! Spiny(shark((have(a(heterocercal(tail,(bony(plates(+(strange(paired(fins (More(than(two(pairs(of( pelvic(+(pectoral(fins(supported(by(stout(bony(spines)( ) Actinopterygii) ! By(far(the(most(successful(by(variation(+(species(number(within(fish ( ! Make(up(about(99%(of(all(living(fishes ( ! Almost(any(fish(you(can(think(of((Adapted(to(all(marine(+(freshwater(habitats) ( ! Also(known(as(the(Ray(Finned(fishes((fins(supported(by(rays(+(poor(muscular(development) ( ! Primitively(1(dorsal(fin(+(ganoid(scales,(nasal(sacks(isolated ( ! Recognize(3(main(kinds:(Basal(group (Chondrostei,(Intermediate ((Holostei(+(Derived(( Teleostei!(not(a(natural(group)(( ! Swim(bladders(can(be(present((Derived(from(a(lung(like(structure) ( ) Sarcopterygii) ! Pretty(dismal(as(only(a(few(are(still(alive ( ! Were(much(more(successful(early(on(in(hstory ( ! Important(in(tetrapod(history((ancestors(of(land(based(vertebrates) ( ! Three(types(of(Lungfish((South(African,(Australian(and(Caoelacanths) ( ! Fossil((Eusthenopteron,(Panderichthys((loss(of(dorsal(fins(+(flattened(skull)(+(Tiktaalik ( ! Fleshy(finned(fishes((fins(with(well !(developed(skeletal(support(+(strong(muscular(development) ( ) Chondrosteans:(Most(primitive(group(of(Actinoptrygians,(still(a(few(alive ( Holosteans:(Gar(pikes( Teleost:)Most(advanced(group ( ( Morphological)Trends)in)Groups ) ) 1. Body)Shape)+)Fin/)Form)Function :)  Early(form=(fusiform(shape(that(is(very(streamlined(like(a(torpedo (  Pectoral(fins(that(are(positioned(low(on(the(body(+(arranged(one(in(front(of(the(other (  Form(present(in(Chondrosteans (  Teleosts((Body(becomes(less(elongated(+(fin(position(differs( –(pectoral(fin(moves(dorsally(+( pelvic(fin(moves(anteriorly,(More(precise(control(rather(than(spe ed,(Pectoral(fins(used(as( brakes,(Moving(in(various(direction,(Can(live(in(multiple(environments )( ( 2. Modifications)with)the)Jaw)Structure :)  Chondrosteans((hyomandibular(slopes(backward(+(acts(as(a(buttress) (  Jaws(long(+(teeth(are(present((good(for(chomping) (  Holosteans((Hyomandibular(becomes(vertical,(premaxilla(+(maxilla(becomes(fused) (  Teleost((Jaw(shortening,(hyomandibular(slopes(forward,(premaxilla(further(expands,(
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