Evolution of the Tetrapods

Evolution of the TetrapodsEvolution of the Tetrapods

Evolution of the TetrapodsEvolution of the Tetrapods

VertebratesVertebrates

The Origin of TetrapodsThe Origin of Tetrapods The first vertebrates on land were The first vertebrates on land were

amphibians in the Devonian (400 mya)amphibians in the Devonian (400 mya) Arose from the rhipidistian (a family of Arose from the rhipidistian (a family of

lobed finned fish) (based on morhpology) lobed finned fish) (based on morhpology) or a lungfish (DNA)or a lungfish (DNA)

Origin of Origin of TetrapodsTetrapods

Origin of TetrapodsOrigin of Tetrapods

ClassificationClassification

Phylum: ChordataPhylum: Chordata Subphylum: VertebrataSubphylum: Vertebrata Superclass: GnathostomataSuperclass: Gnathostomata Class: AmphibiaClass: Amphibia

– Order: Urodela (Salamanders)Order: Urodela (Salamanders)– Order: Anurans (Frogs and Toads)Order: Anurans (Frogs and Toads)– Order: Apodans (Caecilians)Order: Apodans (Caecilians)

Class: AmphibiaClass: Amphibia Two lives Two lives

– refers to metamorphosis of many frogsrefers to metamorphosis of many frogs Skin smooth and moist (cutaneous Skin smooth and moist (cutaneous

respiration)respiration) _____ chambered heart with a double _____ chambered heart with a double

circulation systemcirculation system MesolecithalMesolecithal eggs with jelly-like eggs with jelly-like

membranemembrane

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Order: UrodelaOrder: Urodela

400 species400 species SalamandersSalamanders Retain their tail as Retain their tail as

adultsadults Limbs are at right Limbs are at right

angles to the bodyangles to the body CarnivorousCarnivorous Most have Most have internalinternal

fertilization using a fertilization using a __________________________

Axolotl - Axolotl - paedomorphosispaedomorphosisSpermatophore

Order: AnuransOrder: Anurans 3500 species3500 species Frogs and ToadsFrogs and Toads Lose their tail as Lose their tail as

adultsadults Hind limbs are Hind limbs are

adapted for jumpingadapted for jumping Tongue connected to Tongue connected to

front of mouthfront of mouth Secrete mucusSecrete mucus __________ Fertilization__________ FertilizationExternal

Order: ApodansOrder: Apodans

150 species150 species CaeciliansCaecilians Legless and blindLegless and blind Mostly TropicalMostly Tropical __________ __________

FertilizationFertilization Usually give birth Usually give birth

to live young.to live young.

Internal

Gas Gas ExchangeExchange

Conditions for Respiratory Conditions for Respiratory SurfacesSurfaces

Large surface areaLarge surface area ThinThin MoistMoist

Aquatic vs. TerrestrialAquatic vs. Terrestrial Less than ____% Less than ____%

oxygenoxygen Oxygen amounts Oxygen amounts

decrease as the decrease as the temperature temperature increasesincreases

Aquatic animals Aquatic animals use large amounts use large amounts of energy to obtain of energy to obtain oxygen (____%)oxygen (____%)

About _____% About _____% oxygenoxygen

Developed Developed invaginations to invaginations to increase surface increase surface area and decrease area and decrease evaporationevaporation

Terrestrial animals Terrestrial animals may use only 1% - may use only 1% - 2% of its energy to 2% of its energy to obtain oxygenobtain oxygen

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Respiratory SurfacesRespiratory Surfaces

Cutaneous RespirationCutaneous Respiration GillsGills Tracheal SystemsTracheal Systems LungsLungs

Cutaneous RespirationCutaneous Respiration

Direct diffusion of gases between the Direct diffusion of gases between the organism and the environmentorganism and the environment

Found in Porifera, Cnidarians, Found in Porifera, Cnidarians, Platyhelminthes, nematodes, Platyhelminthes, nematodes, Annelids, and some AmphibiansAnnelids, and some Amphibians

Supplements other organisms Supplements other organisms (amphibians)(amphibians)

GillsGills Found in echino-Found in echino-

derms, mollusks, derms, mollusks, annelids, annelids, arthropods, some arthropods, some vertebratesvertebrates

Countercurrent Countercurrent Gas ExchangeGas Exchange

Countercurrent Gas ExchangeCountercurrent Gas Exchange Maintains gradient over the whole length of Maintains gradient over the whole length of

the capillariesthe capillaries Extracts ____% of the oxygen from the Extracts ____% of the oxygen from the

waterwater80

Tracheal SystemsTracheal Systems Found in arthropodsFound in arthropods TracheaeTracheae

– open tubesopen tubes SpiraclesSpiracles

– openingsopenings TracheolesTracheoles

– contact with cellscontact with cells MuscleMuscle

– increase amount of increase amount of Carbon Dioxide removedCarbon Dioxide removed

Tracheal SystemsTracheal Systems

Diffusion LungsDiffusion Lungs

Found in invertebratesFound in invertebrates Gas moved primarily by diffusionGas moved primarily by diffusion

– may be increased by body movementmay be increased by body movement ModificationsModifications

– snails - cavity with gill modified into lungsnails - cavity with gill modified into lung– scorpions and spiders - invaginations of scorpions and spiders - invaginations of

the abdomen the abdomen

Ventilation Ventilation LungsLungs

Found in Found in amphibians, amphibians, reptiles, mammals reptiles, mammals and birdsand birds

PharynxPharynx LarynxLarynx TracheaTrachea BronchiBronchi BronchiolesBronchioles AlveoliAlveoli

AlveoliAlveoli

Ventilating The LungsVentilating The Lungs _______ Pressure _______ Pressure

BreathingBreathing– pushes air down pushes air down

tracheatrachea– seen in frogs and seen in frogs and

other other amphibiansamphibians

________ Pressure ________ Pressure BreathingBreathing– suction created suction created

by diaphragmby diaphragm– seen in seen in

mammalsmammals

Positive Negative

Negative Pressure BreathingNegative Pressure Breathing

Evolution of the _________ EggEvolution of the _________ Egg

Allows animals to complete their Allows animals to complete their entire life cycle on landentire life cycle on land

Has shell that retains water (or is lost Has shell that retains water (or is lost when kept inside mammals)when kept inside mammals)

Specialized extraembryonic Specialized extraembryonic membranes (not part of the animal)membranes (not part of the animal)

Amniotic

The Amniotic Egg

Evolution of the Amniotic EggEvolution of the Amniotic Egg

Amnion - Protects from dehydration Amnion - Protects from dehydration and mechanical shockand mechanical shock

Yolk Sac - Nutrient storageYolk Sac - Nutrient storage Albumin (egg white) - Nutrient Albumin (egg white) - Nutrient

storagestorage Allantois - stores waste, gas Allantois - stores waste, gas

exchangeexchange Chorion - gas exchangeChorion - gas exchange

AmniotesAmniotes

AmniotesAmniotes

How Reptiles differ from How Reptiles differ from AmphibiansAmphibians

Tough, dry skinTough, dry skin Amniotic eggAmniotic egg Crushing or Crushing or

gripping jawsgripping jaws Copulatory organsCopulatory organs More efficient More efficient

circulatory system circulatory system with a higher blood with a higher blood pressurepressure

More developed More developed lungs (thoracic lungs (thoracic breathing)breathing)

Better water Better water conservationconservation

Better body Better body support and limbssupport and limbs

Better nervous Better nervous systemsystem

ClassificationClassification

Phylum: ChordataPhylum: Chordata Subphylum: VertebrataSubphylum: Vertebrata Superclass: GnathostomataSuperclass: Gnathostomata Class: Reptilia (not real)Class: Reptilia (not real)

– Class: Testudines (Turtles and Tortoises)Class: Testudines (Turtles and Tortoises)– Class: Spenodontia (Tuataras)Class: Spenodontia (Tuataras)– Class: Squamata (Lizards and Snakes)Class: Squamata (Lizards and Snakes)– Class: Crocodilia (Crocodiles and Class: Crocodilia (Crocodiles and

Alligators)Alligators)

Reptile Reptile RadiationRadiation

Synapsids Synapsids (therapsids) - (therapsids) - led to led to mammalsmammals

SauropsidsSauropsids– _________ _________

(turtles)(turtles)– _________ (all _________ (all

others)others)

Anapsid

Diapsid

Class: Testudines (Chelonia)Class: Testudines (Chelonia) Protective ShellProtective Shell

– Carapace (top)Carapace (top)– Plastron (bottom)Plastron (bottom)

Land and Sea -Land and Sea -Evolved on land Evolved on land and returned to and returned to water (lay eggs water (lay eggs on land)on land) Largest,

Leatherback Sea Turtle (2,000 lbs!)

Class: Testudines (Chelonia)Class: Testudines (Chelonia)

No _____No _____ Most move legs Most move legs

to breathe to breathe TDS (low:male TDS (low:male

high:female)high:female)

teeth

Class: SphenodontiaClass: Sphenodontia ______________________

– Two living speciesTwo living species

(New Zealand)(New Zealand)– Not a True Lizard Not a True Lizard

(no external ears, (no external ears, different teeth)different teeth)

– Very Primitive Very Primitive (similar to (similar to mesozoic reptilesmesozoic reptiles

– Well developed Well developed eye below skin?eye below skin?

Tuataras

Class: SquamataClass: Squamata LizardsLizards

– geckos, iguanas, geckos, iguanas, skinks, chameleonsskinks, chameleons

terrestrial, burrowing, terrestrial, burrowing, aquatic, arborealaquatic, arboreal

moveable eyelids (in moveable eyelids (in most)most)

Paired copulatory Paired copulatory organsorgans

Class: SquamataClass: Squamata Tongue usually not Tongue usually not

bifurcatedbifurcated Lower jaw loosely Lower jaw loosely

connected to skullconnected to skull TSD (female to male)TSD (female to male) ____________________________Parthenogenesis

Class: SquamataClass: Squamata




Gila MonsterGila Monster – –

• One of two One of two poisonous lizardspoisonous lizards

• Protein in saliva Protein in saliva studied to treat studied to treat diabetes.diabetes.

Class: SquamataClass: Squamata SnakesSnakes Lack limbsLack limbs Lack moveable Lack moveable

eyelidseyelids


Bifurcated tongue Bifurcated tongue _________ organ_________ organ Pit Vipers (Loreal Pit Vipers (Loreal

Pits)Pits)

Jacobson’s


VenomVenom– ViperidaeViperidae (Folding (Folding

Fangs)Fangs) RattlesnakesRattlesnakes

– ElapidaeElapidae (Fixed (Fixed Front Fangs)Front Fangs)

Cobras, Sea Snakes, Cobras, Sea Snakes, Coral SnakesCoral Snakes

– neurotoxicneurotoxic– hemotoxichemotoxic




Feeding Feeding AdaptationsAdaptations

Teeth curved and pointed inwardTeeth curved and pointed inward Hinged __________ boneHinged __________ bone Bones of jaw are attached by Bones of jaw are attached by

muscles and ligamentsmuscles and ligaments Moveable palateMoveable palate Elastic skinElastic skin No sternumNo sternum

Quadrate

Class: CrocodiliaClass: Crocodilia Largest living Largest living reptilesreptiles

Most closely Most closely related to related to dinosaursdinosaurs

Complete Complete secondary ________secondary ________

Four chambered Four chambered heart (?)heart (?)

Nest temperature Nest temperature (female/male)(female/male)

palate

Dinosaurs and PterosaursDinosaurs and Pterosaurs

Dinosaurs Dinosaurs – OrnithischianOrnithischian– SaurischianSaurischian– PterosaursPterosaurs– flying reptilesflying reptiles

Animal Structure Animal Structure and Functionand Function

(4(4thth exam) exam)

Animal NutritionAnimal Nutrition

Nutritional Nutritional RequirementsRequirements

UndernourishedUndernourished– not enough not enough

caloriescalories OvernourishedOvernourished

– too many caloriestoo many calories ________________________

– missing one or missing one or more essential more essential nutrientsnutrients

Malnourished

Essential NutrientsEssential Nutrients

Essential Amino AcidsEssential Amino Acids Essential Fatty AcidsEssential Fatty Acids Essential VitaminsEssential Vitamins Essential MineralsEssential Minerals

Essential Amino AcidsEssential Amino Acids

Found in proteinsFound in proteins– 20 different types20 different types

8 essential in adult 8 essential in adult humans (9 infants)humans (9 infants)

all in animal proteinsall in animal proteins vegetarians need to vegetarians need to

eat grains and beanseat grains and beans

__________ – Essential in infantsHistidine

Essential Fatty AcidsEssential Fatty Acids

Unsaturated fatty acidsUnsaturated fatty acids– used to make phospholipids for used to make phospholipids for

membranesmembranes

Essential VitaminsEssential Vitamins

Fat SolubleFat Soluble– stored in fatstored in fat– ______________________

Water SolubleWater Soluble– excreted in urineexcreted in urine– B complex and CB complex and C

D, A, K, E

Essential MineralsEssential Minerals

Inorganic nutrientsInorganic nutrients– Calcium & PhosphorousCalcium & Phosphorous

bonesbones

– IronIronanemiaanemia

– IodineIodinethyroid hormonesthyroid hormones

– Sodium, Chlorine, & PotassiumSodium, Chlorine, & Potassiumnerve function, water regulationnerve function, water regulation

Food TypesFood Types

HeterotrophicHeterotrophic– HerbivoresHerbivores– CarnivoresCarnivores– OmnivoresOmnivores– InsectivoresInsectivores

Feeding AdaptationsFeeding Adaptations

Suspension Suspension FeedersFeeders


Substrate FeedersSubstrate Feeders


Fluid FeedersFluid Feeders


Bulk FeedersBulk Feeders

Intracellular DigestionIntracellular Digestion

Inside cellsInside cells All animalsAll animals Exclusive in:Exclusive in:

– ProtistaProtista– PoriferaPorifera

Extracellular DigestionExtracellular Digestion

Outside cellsOutside cells All animals above the spongesAll animals above the sponges Two TypesTwo Types

– __________________________________– __________________________________

Gastrovascular CavityAlimentary Canal

Gastrovascular Gastrovascular CavityCavity

One openingOne opening Found in Found in

Cnidaria and Cnidaria and PlatyhelminthesPlatyhelminthes

Alimentary CanalAlimentary Canal

Two openingsTwo openings Allows for specializationAllows for specialization

– MouthMouth– PharynxPharynx– EsophagusEsophagus– CropCrop– GizzardGizzard– StomachStomach– IntestineIntestine– AnusAnus

Mammalian DigestionMammalian Digestion Accessory GlandsAccessory Glands

– salivary glandssalivary glands– pancreaspancreas– liver (emulsification)liver (emulsification)– gallbladdergallbladder

Peristalsis Peristalsis SphinctersSphincters ““Food”Food”

– bolusbolus– acid chymeacid chyme– fecesfeces

Macromolecule DigestionMacromolecule Digestion

Carbo Protein NucleicAcids

Fat

Mouth Initial

Stomach Initial

Intestine Main Main InitialMain

InitialMain

Dentition and Dentition and DietDiet

Nonmammal Nonmammal vertebratesvertebrates

CarnivoresCarnivores– canines canines

(grasping/puncturing)(grasping/puncturing)– incisors (tearing)incisors (tearing)– molars and premolarsmolars and premolars

(crushing and grinding)(crushing and grinding)

HerbivoresHerbivores OmnivoresOmnivores

Digestive TractsDigestive Tracts

CarnivoresCarnivores– ________ ________

digestive digestive systemsystem

– small small cecumcecum

HerbivoresHerbivores– ________ ________

digestive digestive systemsystem

– large cecumlarge cecum

shorter

Longer

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Evolution of the Tetrapods