Note for BSC 373 with Professor Harris at UA-Lecture 13
Note for BSC 373 with Professor Harris at UA-Lecture 13
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This 14 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 18 views.
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Date Created: 02/06/15
101612 Amniota Mammals reptiles turtles lizards Sphenodon crocodiles birds and heir extinct relatives It is a diverse clade wi h over 20000 living species An extensive fossil record documents the origin and early evolu ion ofAmniota and that record has played a key role in understanding phylogenetic relationships among the living amniotes Oldest amniotes currently known date from the Middle Pennsylvanian Relationships ofthese fossils indicate that amniotes rst diverged into two lines one line Synapsida that culminated in living mammals and another line Sauropsida that embraces all the living reptiles including birds 39 Sauropslda 101612 Amniote Characteristics Most distinctive attribute a large quotamnioticquot egg Most of us are familiar with the hardshelled eggs found in birds First amniotic eggs probably had a exible outer membrane and that a mineralized but still exible outer membrane 39 a synapomorphy of parareptlles and stem eure s The heavily mineralized hard shell is a synapomorphy of archosaurs crocodiles and birds Also appeared at least three tlrhes lh turtles and a few tlrhes lh squarhates llzards and Snakes Oldest known arhhlotlc egg dates rrorh the Lower Trlasslc 220 My but the oldest arhhlote dates rrorh the Upper Caroohlrerous 310 My Eggs orrhosttlr hot all Paleozolc arhhlotes must have had a flexlble poorly rhlherallzed or uhrhlherallzed outer membrane and thus had a low fosslllzatlon potentlal Amniote Characteristics The amniotic egg possesses a unique set of membranes amnion chorion and allantois The amnion surrounds the embryo and creates a uid lled cavity in which the embryo develops The chon on forms a protective membrane around the egg The allantois is closely applied against the chorion where it performs gas exchange and stores metabolic wastes and becomes the urinary bladder in the adult ANAMNIOTIC EGG fish amphibians egg membrane 1 1 Bombna bombn3 Na as F39 etai 1997 Her atolauna Ceska39 L republikgl coROM ldtlng Software Cesk ud jovioa i yolk sac endoderm endC derm mesoderm mesoderm ectoderm ectoderm Eurycea cirrigera from pester Salamanders of Kentucky Touchstone Energy drawing after Romaramp Parsons 1977 This Vertebrate Body W a Saunders 00 Toronto 101612 AMNlOTlC EGG reptiles birds mammals ectodfrm amnion allantois mesoderm mesoderm endoderm allantoic sac amniotic sac yolk sac endoderm Chonon 39 memge m mesoderm ectoderm D endOde39m Phelsuma abbotti D mesoderm Coggeramp Zweifel 1992 Encyclopedia of Reptilesamp Amphibians valhmark Publ inc New York ectoderm drawings after Romeramp Parsnr 1977 The Veneome Body W B Saunders Co Tommo Amniote Characteristics Nutrients for the developing embryo are stored in the yolk sac which is much larger in amniotes than in vertebrates generally Hatchling amniotes also possess an eggtooth and horny caruncle on the snout tip to facilitate exit from their hardshelled eggs Some components of he amniotic egg have been variously modified within Amniota Placental mammals for example have suppressed the egg shell and yolk sac and elaborated the amniotic membranes to enable nutrients and wastes to pass directly between mother and embryo Amniote Characteristics egg together with a penis for 39 VIng larval stage in the lIfe cycle and the abIlIty to bury their eggs enabled amniotes to escape the bonds that confined their ancestors39 reproductive activities to aquatic environments 101612 Amniote Characteristics The comparative aridity ofthe terrestrial environment affects all aspects of amniote biology and notjust their reproduc ive systems Amniotes have a relatively impervious skin that reduces water loss They also possess horny nails that among other things enable them to use their forelimbs to dig burrows into which they can retreat during the heat of the day Amniote Characteristics The comparative aridity The imperative to reduce water loss is equally evident in the density of renal tubules in the metanephn39c kidney of amniotes in the larger size oftheir water resorbing large intestines and in the full differentiation ofthe Harderian and lacrimal glands in the eye socket whose antibacterial secretions help to moisten and along with a third eyelid the nictitans to further protect the eye from desiccation An extensive system ofmuscle stretch receptors that enables ner coordination and greater agility during locomotion their enlarged lungs which are the only remaining organs ofgas exchange owing to the loss of gills and the complete loss ofthe lateral line system other vertebrates use to detect motion in water 101612 Amniote Characteristics Many ofthese features are rarely preserved in fossils There are some novelties in the skeleton that are no less diagnostic of am niotes Have at least two pairs of sacral ribs instead ofjust one pair stronger ribcage with Costa muscles for breathing Have an astragalus bone in the ankle instead of separate tibiale intermedium and proximal centrale bones Have paired spinal accessory 11th and hypoglossal 12th cranial nerves incorporated into the skull in addition to the ten pairs of cranial nerves present in amphibians Loss of labyrinthodont teeth Amniote Characteristics Amniote Characteristics Amniotes are commonly divided into four subgroups on the basis of fenestrae holes literally means windows fenestra is singular in the skull Fenestrae are thought to serve several possible purposes Most o en they are to increase the area and improve the alignment or the attachment of major muscles They also serve to allow an area that expands outward for muscles that would otherwise be in a con ned space They lighten the skull without compromising strength They occasionally have a gland in them although this is unusual 101612 Amniote Characteristics Anapsid skull type the primitive condition for am niotes Skull has an entire unfenestrated suture between the postorbital directly behind the eye socket and squamosal directly behind the postorbital bones of the skull Exhibited by morphologically primitive quotstem reptilesquot of the Carboniferous the grotesque herbivorous pareiasaurs ofthe Permian and turtles Triassic Recent Turtles and pareiasaurs are closely related and are members of the taxonomic grouping Anapsida Only living anapsids are turtles Amniote Characteristics r N Orbit Sq m Sq P2 40 mm H k a Anapsid b Synapsid Upper temporal ha c Dmpsld Lower temporal d bar quotEuryapsidquot From Kardong1998 Amniote Characteristics Synapsid skull seen in mammals and their more reptile like ancestors features an opening temporal fenestra on either side of the skull located below the postorbitalsquamosal suture Temporal fenestrae allow for the development of stronger muscles to work the jaw and facilitate attachment of these muscles to the skull Nonmammalian synapsids called protomammals or quotmammallike reptilesquot first appear in the Pennsylvanian and were the rst highly diverse and successful terrestrial carnivores among the amniotes The early Permian pelycosaurs included quotsailbackedquot forms with a series oflong neural spines covered by a eshy quotsailquot Pelycosaurs mammals and the morphologically intermediate therapsids form Synapsida Mammals only living synapsids Amniote Characteristics a Anapsid 39 b Sjnapsld U pper temporal bar V39 39 Lower d Dimetrodon temporal bar to Diapsid quotEuryapsidquot From Kardon1998 101612 Amniote Characteristics Diapsid skull has two openings behind the orbit one above and one below the suture between the postorbital and squamosal bones Diapsids include living lizards snakes the lizardlike tuatara of New Zealand and crocodiles as well as the extinct dinosaurs though their descendants the birds survive and pterosaurs r Orbit 39 P0 39 3 7 w a Anapsid Amniote Characteristics Two lineages within diapsids Archosaurs crocodiles pterosaurs dinosaurs their common ancestor and all of its descendants including birds developed additional openings the antorbital fenestra in front ofthe eye and the mandibular fenestra on the side ofthe lowerjaw They have teeth that are set in sockets convergent with mammals in this respect Amniote Characteristics Two lineages within diapsids Lepidosaurs are represented in the recent by lizards snakes and the tuatara The tuatara primitiver retains two well de ned temporal fenestrae I Lizards and snakes share a common ancestry in which the lower temporal bar has been lost I Snakes have further lost the upper temporal bar that primitively separates the upper and lower fenestrae so that the two openings are con uent in snake skulls This loss of bone comprises part of a trend towards increased skull exibility in lepidosaurs snakes are especially talented at swallowing relatively large and dif cult prey In contrast archosaur skulls are typically more massive 101612 Amniote Characteristics Amniote Characteristics Euryapsid skulls reptiles with euryapsid skulls are descendents of diapsids in which the lower temporal fenestrae have closed leaving a single temporal fenestra above the postorbitalsquamosal suture on either side Euryapsids are completely extinct con ned to the Mesozoic Era and most euryapsids in the fossil record were adapted to the marine realm including plesiosaurs and ichthyosaurs which were streamlined cruisers and predators of sh Because ofdiapsid ancestry euryapsids are included with archosaurs and lepidosaurs in the taxonomic group Diapsida 101612 Synapsids and Sauropsids Parallel evolutionary trends in the two lineages illustrate the adaptive zones available to amniotes on land Both lineages developed fastmoving predators and Prey Both lineages evolved powered flight Both lineages evolved parental care and complex social systems Both lineages had species that became endothermal Locomotion Early tetrapods moved wi h lateral undulations of the trunk Similar to salamanders and lizards Axial bendingquot Limbs and feet are used in alternate pairs to grip and push on the substrate Problem axial muscles are responsible for two essential functions Bending the trunk unilaterally for locomotion Compressing the rib cage bilaterally to ventilate the lungs Two process cannot occur simultaneously Locomotion 0 Early tetrapods moved with lateral undulations of the trunk Similar to salamanders and lizards Axial bendingquot Limbs and feet are used in alternate pairs to grip and push on the substrate Problem axial muscles are responsible for two essential functions As a consequence only short bursts of speed are possible Quickly go into anaerobic metabolism 101612 Locom ti n Mlllllllllll 1 Sustained locomotion requires separation of respiration from locomotion Synapsids Upright posture with limbs held more beneath the trunk Limbs in this I V position can move ea 4 a fore and aft without bending the trunk Locomotion Synapsids Upright posture with limbs held more beneath the trunk Limbs in this position can move fore and aft without bending the trunk Evolution ofthe diaphragm Coupled with movements of the viscera While running 1O Locomotion Sustained locomotion requires separation of respiration from locomotion Sauropsids Bipedal locomotion Velociraptor and birds Incorporated pelvic movements and the ventral ribs gastralia in lung ventilation see Fig 114 Crocodiles have axial bending but use three methods to increase respiration Movement of ribs Movement of the liver Rotation of the pubic bones 101612 Iv mum tuty Hahnscrim rimt lvl ulll lm m lm Respiration With increased locomotory ability comes the need for increased gas exchange Evolution of complex lungs Synapsids alveolar lungs Sauropsids faveolar septate lungs Faveoli small chambers that open from a common Space A Figure ll 7 Thu lung and air sac svstcm ol the budgerigar only the Ian gt m 1 1m ramblldl sun illm y diverticulum m lht hum 4 a 6ah tnnmnl Mrsach 7 pambmnrhml lung 11 Respiration With increased Iocomotory ability comes the need for increased gas exchange Evolution of complex lungs Synapsids Sauropsids faveolar septate lungs The large air sacs are poorly vascularized and do not participate in gas exchange 7 lrlstead ruhctloh as reservolrs that store alrourlhg parts or the respll39atol39y cycle to create a ol lervvay flow otalr through the lung 101612 hm ml Respiration Evolution of complex lungs Sauropsids faveolar septate lungs The large air sacs are poorly vascularized and do not participate in gas exchange Trachea branches into a pair of primary bronchi one passing into each lung Secondary bronchi branch 39om each primary bronchus and several parabronchi open 39om each secondary bronchus Millions of short interconnected chambers called air capillaries branch from each parabronchus e The alrcaolllahes lhterthhe closely Wlth vascularcaplllarles e Alrflovv aho bloodilovv pass lh opposlte dll eCIlOl lS but they are not exactly parallel e Crosscurrent exchange system 12 um 11113111115111 11111 W1 111111111 1171111111111 11111111111111111111111111 1 11111111111111 1111111 11111111 1111111 U11111111111111111111111 1111 11111111111 11 1111 1111111111 gt 1 1x ist zw 111111111111111111111111111b111 1111111 1111 1 11111111111111111111111 111 11111111 111 1111111 11111111 11111111111111 1111111111W 115111111111 1 1 1111 511111111 1111111101 111111111 5111 111111111111111111 5711 111111 111111111 111111111 11 11111111 111111111 111111111 111111111 11111111111111111111111 11111 1111111111 11111111111111 111111111111 11111111 111111n111111111 111111 1111 1111111111 1111 1111 111111 8111111 1111111 11111111111111111 1 11111 11111111111 11111111 1 11 1111111 11111 1111111111 1111 111111 11111 11 1111 111111111 1 111 111111111111111111111 11 111 11111 111111 111111 11111111111111 111111 111111 1111111111111 111 111111111111111 11111111 111 11111 111111111111111111 11111111111111 1111 11111 1111111 111111 1111 1 11111111111 1111111 1111 1111 11111 111111111 111111111 111 11111111111 111111111111111111 1111111111111 1111111 1511 11111111 1 111 11111 1111 1111111111 11111111111m1111 111 1111 111111 151 111 11111111111111 1111111111111111111111 111 11111111 1111111 11111111111111111 111111 11111111111111101 11111111111111111 111 1111 1111 m 11 1111 1111111111111111111111 1111m1111111111111 11 11111111111 1 11111111111 11111111Il 13 1lquotquotquot 111111111 111111 1111111 11111111111 411111 M111111111111111111 111111111 111111111111111111 1111111 11 1111111111111 1111 1 11111111 1111111 1 1511111111111 1111 101612 11111 1111 739 quot 11111111 11111 1111 WWW 1111m111w1 111111 1111 1111111111111311111111 111111111115111111quot 111 11111111111 11111111 11111 1111111111111 11 111111111 11111111111111111 11111111 11111111 111111111 1111111111 1111111111n1111 111111111111111111111111111111 1111111111 1111311111111 w11111111111111111111111111 11111111111111 1111111111 1111111111 1111 1111111111 11111111 111111 11 rm 111 11 111 4111 11111111111111111 N111 m1 111 1111 111111 1 1111111111111111511111111 511 11 11111111111119 Emu 11111111 U111111111111111111111111111 1111 11111111111 m11111m11ns111111 111111 1111 11111quot111111111 11111 11111 1 111111 1111111111 1 1 11111111111111111111111111 1 11 111111111 11111111 1111111111 1111 1 1111 11111111111 111111 011111 1111 1111 111 1111111111m111 11111111111111111111 11111111411111111 11111111111 111 11111 1111 111111111111111 111111 111111 11 11111111111111 11111111111111111111111111 111 511111 Ume 111111 1111111111 11 11 11111 r111111111111 11 111111111111111111111111111111 11111 1111111 1111111 1111111 1111111111111 11 11111111 111111 1111111111 11111111111111111111111111111111111111111111 111111 11111 111111uM111111111111111111111 111111 11511115 w 11M 1M1 11111111111111 11 11111111111111 1x11 1111M11111111111111 1111111111111 11111111111111 11111111 111111131 1111 11111111111111 1111 1111 11111 111111 11111111 1113111 1 W111 1111 111111 1111 1111111111111111111111111111111 111111111111111111111111111111 111111111 11 1111 14111111 111111111 1111 1111 11111 1111111 111111111111111111111 11111111 111111 11111111 11111 1w1111111111v111 11111 111111 1111111111 11111 1 1 11111111111111 11111111 111 111 111111111111x1111111111 51111 111111 111111 13 Renal System Synapsids excrete urea and developed a kidney that is extraordinarily effective in producing concentrated unne Sauropsids synthesize and excrete uric acid and recover the water that is released when it precipitates 101612 Bowman 5 capsule Glomemlus t l lermediary 39lx Perilubular camuanos Collecting duct Mammalian nephron Lizard nephron 14
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