Vertebrates. The Origin of Tetrapods The first vertebrates on land were amphibians in the Devonian (400 mya) May have arose from the rhipidistian

VertebratesVertebrates

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

the Devonian (400 mya)the Devonian (400 mya) May have arose from the rhipidistian (features).May have arose from the rhipidistian (features). Arose in coastal or brackish marine environmentArose in coastal or brackish marine environment

Origin of Origin of TetrapodsTetrapods

Origin of TetrapodsOrigin of Tetrapods

TetrapodsTetrapodsAdvantages of Advantages of TerrestrialityTerrestriality•An increase in metabolism An increase in metabolism and development due to and development due to higher body temperature.higher body temperature.•Energy Energy – An increase of 10 – An increase of 10 degrees Celsius (from 20 degrees Celsius (from 20 degrees (water temp) to 30 degrees (water temp) to 30 degrees (air temp) would degrees (air temp) would allow for allow for a doubling of their a doubling of their metabolic ratesmetabolic rates

TetrapodsTetrapods

Lungs Lungs – To breath air, it – To breath air, it required an increased required an increased vascularization of the vascularization of the air-filled cavity air-filled cavity (a pouch (a pouch from the posterior from the posterior pharynx similar to the pharynx similar to the swim bladder)swim bladder), with a , with a rich capillary network to rich capillary network to form a lung. form a lung.

TetrapodsTetrapodsDouble circulatory systemDouble circulatory system•Fish have a single circuit Fish have a single circuit system – low blood pressuresystem – low blood pressure•The double circulation The double circulation system allows for higher system allows for higher pressure with one circuit pressure with one circuit going to the lungs and going to the lungs and another going to the body. another going to the body.

TetrapodsTetrapodsNasal Openings Nasal Openings •Bony fish have 4 Bony fish have 4 external nares (2 on external nares (2 on each side) which allows each side) which allows water to run across the water to run across the olfactory tissue. olfactory tissue. •Tetrapods have two Tetrapods have two external and two external and two internal nares in the internal nares in the palate. This allows air to palate. This allows air to be drawn in through the be drawn in through the nose. nose.

Tetrapods – General Tetrapods – General CharacteristicsCharacteristics

Body Density - LimbsBody Density - Limbs

Air is Air is 1000 times 1000 times less less buoyant then waterbuoyant then water

• counter the effects counter the effects of gravityof gravity

• homologous homologous structures structures (bones – (bones – humerus, ulna and humerus, ulna and radius). radius).


Body Density - Girdles –Body Density - Girdles –•In fish, the pectoral girdle is In fish, the pectoral girdle is attached to the skull. attached to the skull. •Early tetrapods developed Early tetrapods developed a stronger a stronger shoulder girdle, shoulder girdle, bulky limb bones and well bulky limb bones and well developed musclesdeveloped muscles. . •The pelvic girdle is The pelvic girdle is fused to fused to the backbone the backbone to increase to increase the force that can be the force that can be generated by the hind legsgenerated by the hind legs..


Body Density - Body Density - Vertebrae and Vertebrae and Ribs Ribs – – •Vertebrae have Vertebrae have developed developed zygapophyseszygapophyses. . •The development The development of of ribsribs can also can also protect the lungs.protect the lungs.


Body Density - Skull and NeckBody Density - Skull and Neck

•The skull has been shortened and the snout elongated. The skull has been shortened and the snout elongated. •The head becomes separated from the body by a neck (a The head becomes separated from the body by a neck (a cervical vertebrae) that allows cervical vertebrae) that allows the head to be liftedthe head to be lifted. . •A second vertebrae was then added to allow for a A second vertebrae was then added to allow for a side to side to side movementside movement. .

Tetrapods – Evolutionary History Tetrapods – Evolutionary History

1.1. FishFish

Tetrapods – Evolutionary History Tetrapods – Evolutionary History

““Fishapod” – Fishapod” – TiktaalikTiktaalik (375 mya)(375 mya)

A fish with tetrapod A fish with tetrapod features, this animal features, this animal probably could not probably could not walk on land but could walk on land but could lift itself out of the lift itself out of the water. water.

1.1. Fish CharacteristicsFish Characteristics– ScalesScales– FinsFins– Gills and lungsGills and lungs

2.2. Tetrapod Tetrapod CharacteristicsCharacteristics– NeckNeck– RibsRibs– Fin skeletonFin skeleton– Flat skullFlat skull– Eyes on top of skullEyes on top of skull

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, moist (cutaneous respiration), and glandular Skin smooth, moist (cutaneous respiration), and glandular

(toxins)(toxins) Three chambered heart with a double circulation systemThree chambered heart with a double circulation system Mesolecithal eggs with jelly-like membraneMesolecithal eggs with jelly-like membrane

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

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 Tongue connected

to front of mouthto front of mouth Secrete mucusSecrete mucus

Order: ApodansOrder: Apodans

150 species150 species CaeciliansCaecilians Legless and blindLegless and blind

Evolution of the Amniotic EggEvolution of the Amniotic 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)

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 - Nutrient storageAlbumin - Nutrient storage 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) - led (therapsids) - led to mammalsto mammals

SauropsidsSauropsids– Anapsids??? Anapsids???

(turtles)(turtles)– Diapsids (all Diapsids (all

others)others)

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

Evolved on land Evolved on land and returned to and returned to water (lay eggs water (lay eggs on land)on land)

Protective ShellProtective Shell– CarapaceCarapace– PlastronPlastron

Class: SphenodontiaClass: Sphenodontia

TuatarasTuataras– Two living speciesTwo living species

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

(no external ears)(no external ears)– Very Primitive Very Primitive

(similar to mesozoic (similar to mesozoic reptilesreptiles

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

Class: SquamataClass: Squamata

LizardsLizards– geckos, iguanas, skinks, geckos, iguanas, skinks,

chameleonschameleons terrestrial, burrowing, terrestrial, burrowing,

aquatic, arborealaquatic, arboreal moveable eyelidsmoveable eyelids Paired copulatory organsPaired copulatory organs Lower jaw not attached Lower jaw not attached

to skullto skull






SnakesSnakes Lack limbsLack limbs Lack moveable Lack moveable

eyelidseyelids Jacobson’s organJacobson’s organ Pit Vipers (heat)Pit Vipers (heat) VenomVenom

– neurotoxinsneurotoxins– hemolytic enzymeshemolytic enzymes





Feeding Feeding AdaptationsAdaptations

Teeth curved and pointed inwardTeeth curved and pointed inward Hinged Quadrate boneHinged Quadrate 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

Class: CrocodiliaClass: Crocodilia Largest living Largest living

reptilesreptiles Most closely Most closely

related to related to dinosaursdinosaurs

Complete Complete secondary palatesecondary palate

Four chambered Four chambered heartheart

Nest temperatureNest temperature

Dinosaurs and PterosaursDinosaurs and Pterosaurs

Dinosaurs Dinosaurs – OrnithischianOrnithischian– Saurischian (closely Saurischian (closely

related to birds)related to birds) PterosaursPterosaurs

– flying reptilesflying reptiles

Class: AvesClass: Aves


FeathersFeathers Hollow BonesHollow Bones WingsWings EndothermEndotherm Organs reducedOrgans reduced Beak without teethBeak without teeth No bladderNo bladder


Wishbone – Called a Furcula made up of Wishbone – Called a Furcula made up of the fused clavicles. the fused clavicles.

Class: AvesClass: Aves Muscles – Muscles –

– Pectoralis muscle pulls wing downPectoralis muscle pulls wing down– Supracoracoideus raises wing Supracoracoideus raises wing

The Origin of BirdsThe Origin of Birds

FeathersFeathers Beak with teethBeak with teeth Long TailLong Tail Wing with clawWing with claw

The Origin of BirdsThe Origin of Birds

Sinoauropteryx - Sinoauropteryx - protofeathers?protofeathers?

Caudipteryx - true Caudipteryx - true feathersfeathers

Bird ClassificationBird Classification

8600 species of 8600 species of bird (28 orders)bird (28 orders)– 60% are 60% are

passeriformes passeriformes (perching birds)(perching birds)

Two major TypesTwo major Types– RatitesRatites

Ostriches, EmusOstriches, Emus

– CarinatesCarinates Song birdsSong birds

Class: MammaliaClass: Mammalia

HairHair EndothermicEndothermic Mammary glandsMammary glands Live birth (2 exceptions)Live birth (2 exceptions) Teeth differentiationTeeth differentiation Jaw modified to incorporate bones into Jaw modified to incorporate bones into

inner earinner ear

The Evolution The Evolution of the Mammalof the Mammal

Reptile’s lower jaw made up of Reptile’s lower jaw made up of several bonesseveral bones

Reptile’s middle ear made up Reptile’s middle ear made up of one boneof one bone

Mammal’s lower jaw made up Mammal’s lower jaw made up of one boneof one bone

Mammal’s jaw joint has shiftedMammal’s jaw joint has shifted Mammal’s middle ear made Mammal’s middle ear made

up of three bonesup of three bones

Mammal ClassificationMammal Classification

MonotremesMonotremes– lay eggslay eggs– no nipplesno nipples

MonotremeMonotreme


MarsupialsMarsupials– born earlyborn early– develops in pouchdevelops in pouch

MarsupialsMarsupials

MarsupialsMarsupials


PlacentalsPlacentals– Eutherian mammalsEutherian mammals– development in uterus joined by placentadevelopment in uterus joined by placenta

ProboscideaProboscidea

SireniaSirenia

EdentataEdentata

RodentiaRodentia

LagomorphaLagomorpha

CarnivoraCarnivora

ArtiodactylaArtiodactyla

CetaceaCetacea

PerissodactylaPerissodactyla

ChiropteraChiroptera

InsectivoraInsectivora

Primate EvolutionPrimate Evolution

Ancestral primate (arboreal) (65 mya)Ancestral primate (arboreal) (65 mya)– binocular visionbinocular vision– opposable thumbopposable thumb

ProsimiansProsimians– lemurs, tarsiers pottoslemurs, tarsiers pottos


Ancestral primate Ancestral primate (arboreal) (47 mya)(arboreal) (47 mya)– binocular visionbinocular vision– opposable thumbopposable thumb

““Ida” – Missing LinkIda” – Missing Link– No clawsNo claws– Lack a tooth combLack a tooth comb– Short limbsShort limbs– Short faceShort face– Talus – corner of leg/footTalus – corner of leg/foot


Anthropoids (50 mya)Anthropoids (50 mya)– MonkeysMonkeys

Old WorldOld World– External nares close togetherExternal nares close together– Opposable thumbsOpposable thumbs– Calloused ischial tuberositiesCalloused ischial tuberosities


Anthropoids (50 mya)Anthropoids (50 mya)– MonkeysMonkeys

New WorldNew World– Broad flat nasal septumBroad flat nasal septum– Nonopposable thumbNonopposable thumb– Prehensile tailPrehensile tail

Primate EvolutionPrimate Evolution Hominoids (30 mya)Hominoids (30 mya)

– apesapes

Human EvolutionHuman Evolution Brain SizeBrain Size Jaw SizeJaw Size BipedalismBipedalism Reduced Reduced

Size Size difference difference in sexesin sexes

Family Family StructureStructure

Human EvolutionHuman Evolution

SahelanthropusSahelanthropus (6.5 million years (6.5 million years

ago)ago)


Laetoli FootprintsLaetoli Footprints (3.5 million years (3.5 million years

ago)ago)


Australopithecus Australopithecus (3.24 million (3.24 million

years ago)years ago)


Homo genus Homo genus (2.4-1.6 mya)(2.4-1.6 mya)– Homo sapiens Homo sapiens

(200,000 years (200,000 years ago)ago)


NeanderthalsNeanderthals(40,000 years old)(40,000 years old)


Turkana Boy Turkana Boy ((Homo ergasterHomo ergaster))

(1.7 million years (1.7 million years ago)ago)

Between Between H. H. habilis habilis andand H. H. erectuserectus

Origin of Modern HumansOrigin of Modern Humans

Out of Africa Out of Africa (monogeneus)(monogeneus)– all races of humans all races of humans

evolved from an evolved from an ancestor in Africaancestor in Africa

MultiregionalMultiregional– Each race evolved Each race evolved

from regional from regional populations of populations of Homo erectusHomo erectus

Documents

Vertebrates. The Origin of Tetrapods The first vertebrates on land were amphibians in the Devonian (400 mya) May have arose from the rhipidistian