Origin of Tetrapods, Amphibians and Reptiles - PowerPoint Presentation

Slide1

Origin of Tetrapods, Amphibians and Reptiles

Chapter 34

“Never grow

a wishbone

where your backbone ought to be”

-Clementine

PaddlefordSlide2

Origin of

Tetrapods

First

tetrapods

diverged 365 million years ago (________)________________________and shallow inland lakes with muddy bottoms likely selected for early tetrapodsSlide3

Origin of Limbs

Tetrapod limbs were modification of preexisting body

plan

Single appendicular bones (

humerus and femur) articulate with pectoral or pelvic girdlesBecome larger and stronger

Mesomeres deviate from _______ _____Diversification of limb bones_______________ separate tetrapods from fins of lobe-finned fishSlide4

Evolution of Tetrapods

Increased air breathing capabilities

More efficient lung

Gill arches move to

_________Limbs with digits support tetrapod’s weight on land

Evolution of a _____________ separated head from bodyAllowed for head movementSeparation of ______________

form skull

Supports fore limbs

Fusion of pelvic girdle to spine

Transfers forces from hind legs to bodySlide5

Evolution of Tetrapods

Eusthenopteron

Prehistoric

Sacopterygian

Early forelimb bonesHumerusRadius and ulnaInternal nostrilsPectoral girdle bones attached to skull

AcanthostegaRecognizable limbsSturdy forelimb bones___________________ presentEight digits on each hand

Fore limbs could not bend forward or support weight

Pectoral girdle bones

______________Slide6

Evolution of Tetrapods

Ichthyostega

Reinforced ribcage

Limbs

___________Support weight on landLimited movement on land_____________ presentGills used primarily for respiration

LimnoscelisEarly amphibianSturdy pelvic and pectoral girdlesSharp teeth Terrestrial predatorSlide7

Evolution of

T

etrapods

:

TiktaalikMid to late Devonian (~380 mya)

Tetrapod characteristicsIndependent ___________________Ribs to support weightFront fin bone structure similar to all

tetrapods

Limbs bent at elbow and knee

Flat skull with eye on top of head

Fish characteristics

_____

Scales

FinsSlide8

Class

Amphibia

Amphibians (Frogs, Salamanders, Caecilians)

Approximately 6,150 species

Diverged in the late Devonian

Most go through metamorphosis (“two lives”)Aquatic, gill breathing larvaeTerrestrial, lung breathing adults__________

eggs

: jelly like eggs with ~50%

yolkThin, highly vascularized skinScaleless (except Caecilians)

Cutaneous respirationPoison glands_________________ heartEctothermicSlide9

Class Amphibia

, Order Anura

Frogs and Toads

“without a tail”

~ 5,400 speciesFrogs = smooth skin“Toads” = rough, warty skinShort fore limbs and long hind limbs longM

odified for jumpingHead and trunk fusedTongue attached to front of mouth_______ fertilizationVocalizations in males________ membraneSlide10

Amphibian Metamorphosis

Egg development:

6-21 days

Metamorphosis:0-7 days: tadpole feeds on yolk then attaches to substrate, breathes through external gills7–28 days: tadpole swims freely feeding on aquatic vegetation, breathes through internal gills

4-6 weeks: ___________, skin grows over operculum6-9 weeks: __________ from buds10-12 weeks: froglet with small tail12-16 weeks: adult frogSlide11

Class Amphibia

, Order Urodela

Salamanders and Newts

“bearing a tail”

~ 550 speciesCarnivorousLegs usually at _________ to bodyPrefer dark, damp terrestrial habitats______ fertilization

Spermatophore: packet of spermSmooth skin, except newtsBlunt nose and tails typically flattened on sidesSlide12

Class Amphibia

, Order Apoda

Caecilians

“without legs”

Secondary adaptation~ 170 species___________ diggersTropics and subtropicsScales in some

Sensory tentacles on headInternal fertilization25% oviparous75% viviparousSlide13

Amphibians as Ecological Indicators

_______________: a species whose presence, absence of abundance can be used to assess the biological condition or health of a particular ecosystem

1/3 of amphibian species are at risk of

extinction

Characteristics that make amphibians good indicatorsAquatic and terrestrial habitatsMetamorphosis

Breathe with gills and lungs________Cutaneous respirationSusceptible to environmental contaminants (chemicals)___________ lack shellIntegral part of the food chainHerbivorous tadpoles and carnivorous frogs and toadsSlide14

Amniotes

Amniotic egg

: allowed for embryos to develop in terrestrial environment without __________________.

Two major lineages

Diapsids:

Reptiles, including birdsSynapsids:_________Slide15

Amniotic Egg

Amnion

: inner membrane filled amniotic fluid, which cushions the embryo

Yolk sac

: sac containing nutrients (yolk) for the developing embryo _______: membrane that facilitates gas exchange between the embryo and the air

Allantois: sac that collects _________ _______ produced by the embryoSlide16

Anapsids, Synapsids and Diapsids

Based on number of temporal openings (fenestra)

____________

attachment

Anapsid: no temporal openingsTurtlesSynapsid: single temporal opening

___________Diapsid: two temporal openingsReptiles including birds

Temporal

fenestra

Orbit (eye socket)Slide17

Evolutionary History of Reptiles

Rise in reptiles associated with decline in

__________

~315mya (Carboniferous)

Permian dominated by parareptiles, which were large, stocky herbivoresPermian-Triassic Extinction followed by evolution of Archosaurs (crocodilians, dinosaurs, pterosaurs) and Lepidosaurs (lizards, snake, tuataras)

Most Archosaurs extinct by end of CretaceousSquamata radiation during CenozoicTestudines origin __________Slide18

Class Reptilia

Diverged ~ 310

mya

(Carboniferous)

Scales made of ________Internal fertilizationMost oviparousLay eggs on landEctothermic, poikilothermsIncomplete

________Four ordersTestudinata (turtles)Squamata (snakes and lizards)Crocodillia

(crocodiles and allies)

Rhynchocephalia

(tuataras)Slide19

Characteristics of Amphibians and Reptiles

Characteristics

Amphibians

Reptiles

Metabolism

EctothermicEctothermic

Skin texture

Smooth,

thin, permeable skin

Tough, scaly skin

BreathingGills and lungs

Well developed lungs

(thoracic breathing)

Reproduction

Internal and external

fertilization

Internal fertilization with copulatory organs

Egg

Jelly-like egg with no shell

Amniotic egg

with shell

Circulatory

system

Three-chambered

heart

Three-chambered

heart with chambered ventricle, 4 chambered heart in crocodilians

Jaws

Weak, used for gripping

Strong

, used for crushing or grippingSlide20

Class Reptilia, Order Testudines

Turtles and Tortoises

Origin remains uncertain

_______ skull

Bony or cartilaginous shell from fusion of vertebrae and ribs

Carapace, Plastron, ScutesTortoise = terrestrialTurtles = live in or near waterHerbivorous and carnivorousBeaks (no teeth)

Two groups

Cryptodira

Pluerodira

Scutes

Carapace

Fused vertebrae

Ribs

Neck

PlastronSlide21

Class Reptilia, Order Testudines

CryptodiraRetract head __________ into shells

12 scutes on plastron

Includes

most extant turtlesSea turtlesTortoisesPond turtlesSlide22

Class Reptilia, Order Testudines

Pluerodira

Retract head by __________ to the side

13 scutes on plastronSlide23

Class Reptilia, Order Sphenodontia

Tuataras

Two extant species

Endemic to New Zealand

_______ skull preservedNo ears or eardrums________ of teeth on upper jaw__________Slow growing, long lived >100 years

Temperature of eggs influences sex

Parietal eyeSlide24

Class Reptilia, Order Squamata

Lizards and Snakes

Largest order of reptiles, second largest order of vertebrates

~ 9,000

Diverged in the Triassic periodSnakes evolved from ____________ their skin/scalesFlexible upper jaw with movable quadrate boneForked tongue in some

Chemical reception__________: paired copulatory organ

Quadrate boneSlide25

Worm lizards

~ 180 species________: adapted for burrowing and life underground

Usually legless

Elongate bodies

Rudimentary eyesNo outer earsCarnivorousClass Reptilia, Order SquamataSlide26

Class Reptilia, Order Squamata

Lizards

~6,000 species

All continents except Antarctica

Terrestrial, burrowing, aquatic, arborealLegs and external ears Movable

_______Herbivorous and carnivorousRange from 16mm to 3m_________: detach tailsRegenerationGood visionCommunication and locating Parthogenesis in someSlide27

Class Reptilia, Order

Squamata

Snakes

~2,900

speciesAll continents except AntarcticaTerrestrial, burrowing, aquatic, arborealDiverged from lizards_______________

(anal spurs)Lack movable _______Lack external _______________CarnivorousConstrictors or venomousJacobson’s

Organ

Loreal

pits

Highly mobile jaws>200 vertebraeSlide28

Feeding Adaptations in Snakes

Teeth curved and pointed inward

Hinged ___________

Bones of lower jaw are attached by muscles and ligaments

Moveable palateElastic skinNo ________Slide29

Sensory Adaptations in Snakes

Jacobson’s organ

(

Vomeronasel

organ): olfactory sense organ used to detect _______________Present in many amphibians, reptiles and mammalsSnakes deliver odorants to organ with tongue

Heat sensing organs: facial pits lines with thermoreceptors capable of sensing minute changes in temperature_________: pit vipers Labial pits: some boas and pythonsLower jaw transmits ground vibrations to cochlea

Nostril

Nostril

Labial pits

Loreal

pitSlide30

Poisonous vs. Venomous

Poisonous

: toxins that are absorbed or ingested, often secreted by the animal

Venomous

: toxins that are ________ _______, usually with stingers, or fangsThree families of snakesVipers, Elapsids, ColubridsTwo venomous lizards

Gila monster and komodo dragonToxins___________: disrupt nerve functionHemotoxin: hemolytic enzymes cause blood clottingSlide31

Families of Venomous Snakes

Viperidae

:

P

uff adders, rattlesnakes, cooperheads, cottonmouthsHollow, ______________Ellipitcal pupilsHemotoxin

venomElapsidae: Seas snakes, taipans, coral snakes, death adders, mambas, cobrasHollow, fixed fangsRound pupilsNeurotoxic venom

Colubridae

:

Boomslang

, mangrove snake, vine snake___________

Most are mildly venomousSlide32

Class Reptilia

, Order Crocodilia

Crocodiles, Alligators, Cayman, Gharials

Diverged around 85

myaClosely related to birds and dinosaurs Archosaur lineage5

unwebbed digits front, 4 webbed backComplete ______________Four chambered heartForamen of Panizza_________ membrane

: transparent third eyelid used for protection or to moisten eye

Nest temperature influences sexSlide33

Alligators vs. Crocodiles

Crocodile

Lower teeth ______

Narrow, pointed snout

AlligatorLower teeth ________Blunt, rounded snout