2/8/19
1
Chapter19
Amphibians:TheFirstTerrestrialVertebrates
Copyright©2016McGraw-HillEduca;on.Allrightsreserved.Noreproduc;onordistribu;onwithoutthepriorwriDenconsentofMcGraw-HillEduca;on.
Evolu=onaryPerspec=ve
• Amphibia– “doublelife”– Frogs,toads,salamanders,caecilians
Copyright©2016McGraw-HillEduca;on.Allrightsreserved.Noreproduc;onordistribu;onwithoutthepriorwriDenconsentofMcGraw-HillEduca;on.
Figure19.3Onehypothesisofevolu=onaryrela=onshipsamongtheTetrapods.
Copyright©2016McGraw-HillEduca;on.Allrightsreserved.Noreproduc;onordistribu;onwithoutthepriorwriDenconsentofMcGraw-HillEduca;on.
SurveyofAmphibians
• OrderGymnophiona– Caecilians– Tropicalburrowersfeedingonsoilinvertebrates– Appearsegmentedbecauseofskinfolds– Fer=liza=oninternal– Larvalstageswithinoviducts
Copyright©2016McGraw-HillEduca;on.Allrightsreserved.Noreproduc;onordistribu;onwithoutthepriorwriDenconsentofMcGraw-HillEduca;on.
Figure19.4OrderGymnophiona(Ichthyophisglu;nosus).
Copyright©2016McGraw-HillEduca;on.Allrightsreserved.Noreproduc;onordistribu;onwithoutthepriorwriDenconsentofMcGraw-HillEduca;on.
• OrderCaudata– Salamanders– Tailthroughoutlife,unspecializedlegs– Terrestrial• LiveinmoistforestfloorliTerwithaqua=clarvae
– Aqua=c• Newts(Salamandridae)• Mostoftheirlivesinwater,mayretaincaudalfin
– Internalfer=liza=onusingspermatophore• Larvaewithexternalgills,tailfin,larvalden==on,andarudimentarytongue• Somepaedomorphic(e.g.,Necturus)
Copyright©2016McGraw-HillEduca;on.Allrightsreserved.Noreproduc;onordistribu;onwithoutthepriorwriDenconsentofMcGraw-HillEduca;on.
2/8/19
2
Figure19.6OrderCaudata.(a)Eggs,(b)larva,and(c)adultofAmbystomamaculatum.
Copyright©2016McGraw-HillEduca;on.Allrightsreserved.Noreproduc;onordistribu;onwithoutthepriorwriDenconsentofMcGraw-HillEduca;on.
Figure19.7TheRedRiverMudpuppyNecturusmaculosuslouisianensis.
Copyright©2016McGraw-HillEduca;on.Allrightsreserved.Noreproduc;onordistribu;onwithoutthepriorwriDenconsentofMcGraw-HillEduca;on.
• OrderAnuraorSalien=a– Frogsandtoads– Adultslacktails,caudalvertebraefuseintourostyle,hindlimbslong,muscularandendinwebbedfeet.
– Fer;liza;onexternal• Eggsandlarvae(tadpoles)aqua;c• Larvaeareherbivores.
Copyright©2016McGraw-HillEduca;on.Allrightsreserved.Noreproduc;onordistribu;onwithoutthepriorwriDenconsentofMcGraw-HillEduca;on.
Figure19.8TheBluePoisonArrowFrog(Dendrobates;nctorius)
Copyright©2016McGraw-HillEduca;on.Allrightsreserved.Noreproduc;onordistribu;onwithoutthepriorwriDenconsentofMcGraw-HillEduca;on.
Evolu=onaryPressures
• Externalstructureandlocomo=on– Skin• Kera=ndepositsmayproducewarts,claws,orotherhardenedstructures.
• Glands– Granularglands—noxiousortoxicsecre=ons– Mucousglands—preventdrying
• Chromatophores– Colorandcolorchanges
Copyright©2016McGraw-HillEduca;on.Allrightsreserved.Noreproduc;onordistribu;onwithoutthepriorwriDenconsentofMcGraw-HillEduca;on.
• Supportandmovement– Skull
• FlaTenedandhasfewerbonyelementsthanfish• Jawstructureandmusculaturemodifiedforcapturingandholdingprey.
– Vertebralcolumn–providessupport&flexibilityonland• Zygapophysesonvertebraepreventtwis=ng• Singlecervicalvertebra• Singlesacralvertebra
– Sternum• Supportsforelimbsandprotectsinternalorgans
– Pelvicgirdle• Ilium,ischium,pubis• Supportshindlimbs
Copyright©2016McGraw-HillEduca;on.Allrightsreserved.Noreproduc;onordistribu;onwithoutthepriorwriDenconsentofMcGraw-HillEduca;on.
2/8/19
3
Figure19.9Skeletonsofamphibians
Copyright©2016McGraw-HillEduca;on.Allrightsreserved.Noreproduc;onordistribu;onwithoutthepriorwriDenconsentofMcGraw-HillEduca;on.
Figure19.10.Salamanderlocomo=on.
Copyright©2016McGraw-HillEduca;on.Allrightsreserved.Noreproduc;onordistribu;onwithoutthepriorwriDenconsentofMcGraw-HillEduca;on.
• Nutri=onandthediges=vesystem– Carnivoresasadults– Herbivoresaslarvae
• Preycapture– Flip-and-grab(figure19.11)
Copyright©2016McGraw-HillEduca;on.Allrightsreserved.Noreproduc;onordistribu;onwithoutthepriorwriDenconsentofMcGraw-
HillEduca;on.
Figure19.11Flip-and-Grabfeedinginatoad.
• Circula=on,gasexchange,andtemperatureregula=on– Adapta=onsforlifedividedbetweenaqua=candterrestrialhabitats.• Cutaneousgasexchangeresultsinbloodreturningtoheartbeinghighlyoxygenated.
Copyright©2016McGraw-HillEduca;on.Allrightsreserved.Noreproduc;onordistribu;onwithoutthepriorwriDenconsentofMcGraw-HillEduca;on.
Figure19.12Diagramma=crepresenta=onofananurancirculatorysystem.(a)Heartandaor=carches.(b)Ventralviewoftheheart.
Copyright©2016McGraw-HillEduca;on.Allrightsreserved.Noreproduc;onordistribu;onwithoutthepriorwriDenconsentofMcGraw-HillEduca;on.
• Gasexchange– Cutaneousrespira=on• Highlyvascularskinpromotesgasexchange
– Buccopharyngealrespira=on• Moistsurfacesofmouthandpharynx
– Pulmonary• Buccalpumpmechanismcreatesposi=vepressure(figure26.18).
– Larvaeandsomeadultsuseexternalgills.
Copyright©2016McGraw-HillEduca;on.Allrightsreserved.Noreproduc;onordistribu;onwithoutthepriorwriDenconsentofMcGraw-HillEduca;on.
2/8/19
4
Figure26.18Ven=la=oninamphibians.
Copyright©2016McGraw-HillEduca;on.Allrightsreserved.Noreproduc;onordistribu;onwithoutthepriorwriDenconsentofMcGraw-HillEduca;on.
• Temperatureregula=on– Ectothermic– Behavioraltemperatureregula=on• Cooling
– Nocturnal– Burrowing
• Warming– basking
Copyright©2016McGraw-HillEduca;on.Allrightsreserved.Noreproduc;onordistribu;onwithoutthepriorwriDenconsentofMcGraw-HillEduca;on.
• Nervousandsensoryfunc=ons– Vertebratebrainfromthreeembryologicalsubdivisions
– Sensoryreceptors• Skinreceptors• Laterallinesystem• Chemorecep=on
– Nasalepithelium,mouth,skin
Copyright©2016McGraw-HillEduca;on.Allrightsreserved.Noreproduc;onordistribu;onwithoutthepriorwriDenconsentofMcGraw-HillEduca;on.
• Sensoryreceptors– Vision
• Sightfeeders• Binocularvision• Eyestructureandfunc=on(figure19.13)
– Nic=ta=ngmembranelubricatesandwasheseye.– Accommoda=onbylensmovement
– Hearing• Air-bornevibra=ons
– Tympanicmembrane– Stapes(columella)
• Substrate-bornevibra=ons– TransmiTedthroughfrontappendagesandpectoralgirdle
Copyright©2016McGraw-HillEduca;on.Allrightsreserved.Noreproduc;onordistribu;onwithoutthepriorwriDenconsentofMcGraw-HillEduca;on.
Figure19.13Amphibianeye.
Copyright©2016McGraw-HillEduca;on.Allrightsreserved.Noreproduc;onordistribu;onwithoutthepriorwriDenconsentofMcGraw-HillEduca;on.
• Excre=onandosmoregula=on– Kidneys
• Dorsalbodywall– Nitrogenouswastes
• Ammoniaandurea– Osmoregula=on
• Inwater– Excreteexcesswaterandconserveions
» Kidneysandurinarybladder• Onland
– Conservewaterwithbehaviorsthatpreventloss» Nocturnal» Bodyposture» Cocoons» Cutaneousabsorp=on» Storageinlymphsacsandurinarybladder
Copyright©2016McGraw-HillEduca;on.Allrightsreserved.Noreproduc;onordistribu;onwithoutthepriorwriDenconsentofMcGraw-HillEduca;on.
2/8/19
5
Figure19.14Waterconserva=onbyanurans.
Copyright©2016McGraw-HillEduca;on.Allrightsreserved.Noreproduc;onordistribu;onwithoutthepriorwriDenconsentofMcGraw-HillEduca;on.
• Reproduc=on,development,andmetamorphosis– Dioecious– Fer=liza=onusuallyexternal– Developmentusuallyinwater– Courtship• Salamanders
– Olfactoryandvisualcues• Anurans
– Tac=leandauditorycues
Copyright©2016McGraw-HillEduca;on.Allrightsreserved.Noreproduc;onordistribu;onwithoutthepriorwriDenconsentofMcGraw-HillEduca;on.
Figure19.15Amplexus.
Copyright©2016McGraw-HillEduca;on.Allrightsreserved.Noreproduc;onordistribu;onwithoutthepriorwriDenconsentofMcGraw-HillEduca;on.
• Vocaliza=on– Maleanurans– ATractfemalestobreedingareas– Establishbreedingterritories– Speciesspecific
Copyright©2016McGraw-HillEduca;on.Allrightsreserved.Noreproduc;onordistribu;onwithoutthepriorwriDenconsentofMcGraw-HillEduca;on.
Figure19.16aAnuranvocaliza=on.
• Parentalcare– ATendanceateggclutchbyeitherparent
– Eggtransport
Copyright©2016McGraw-HillEduca;on.Allrightsreserved.Noreproduc;onordistribu;onwithoutthepriorwriDenconsentofMcGraw-HillEduca;on.
Figure19.17Rheobatrachus(nowpresumedex=nct)femalesbroodedyoungintheirstomachsandyoungemergedthroughtheirmouths.
• Metamorphosis– Controlledbyneurosecre=onsofhypothalamus,anteriorpituitarygland,andthyroidgland.
– Salamandersandcaecilians• Rela=velyminorchanges
– Anurans• Tadpoletofrog
– Limbsandlungsdevelop– Tailisreabsorbed– Skinthickens– Changesinheadanddiges=vetract
Copyright©2016McGraw-HillEduca;on.Allrightsreserved.Noreproduc;onordistribu;onwithoutthepriorwriDenconsentofMcGraw-HillEduca;on.
2/8/19
6
Figure19.18EventsofmetamorphosisintheCaliforniared-leggedfrogRanatemporaria.(a)Youngtadpoles.(b)Latertadpole.(c)Youngfrog.(d)Adultfrog.
Copyright©2016McGraw-HillEduca;on.Allrightsreserved.Noreproduc;onordistribu;onwithoutthepriorwriDenconsentofMcGraw-HillEduca;on.
AmphibiansinPeril• One-thirdofamphibianspeciesthreatenedwithex=nc=on.• Water-andairbornepollutantsquicklypenetratethin
permeableskin.• Threats
– Clear-culngforestsanddevelopment– Chytridfungus– Climatechange
• Conserva=on– Popula=onmonitoring– Collec=ngrestric=ons– Wetlandconserva=on– Climate-changereversal
Copyright©2016McGraw-HillEduca;on.Allrightsreserved.Noreproduc;onordistribu;onwithoutthepriorwriDenconsentofMcGraw-HillEduca;on.