26-1 CHAPTER 26 Nonavian Reptiles. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 26-2 Hatching Komodo Lizard

26-1

CHAPTER 26CHAPTER 26CHAPTER 26CHAPTER 26

Nonavian Nonavian ReptilesReptilesNonavian Nonavian ReptilesReptiles

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

26-2

Hatching Komodo Lizard


26-3

DiversityDiversity

The Age of Reptiles lasted over 165 million The Age of Reptiles lasted over 165 million years and included the dinosaursyears and included the dinosaurs

A mass extinction occurred at the end of the A mass extinction occurred at the end of the Mesozoic (meteor) Mesozoic (meteor)

Modern reptiles represent surviving lineagesModern reptiles represent surviving lineages TuataraTuatara is the sole survivor of a group that is the sole survivor of a group that

otherwise disappeared 100 million years agootherwise disappeared 100 million years ago Lizards, turtles, and snakesLizards, turtles, and snakes

DiversityDiversity


26-4

Origin and Early Evolution of AmniotesOrigin and Early Evolution of Amniotes

HistoryHistory Amniotes (animals that have an amnion - Amniotes (animals that have an amnion - reptiles, reptiles,

birds, mammalsbirds, mammals) arose from amphibian-like tetrapods) arose from amphibian-like tetrapods Skulls of amniotes could be Skulls of amniotes could be separated into groupsseparated into groups

based on three patterns of openings in the temporal based on three patterns of openings in the temporal

regionregion Anapsids Anapsids

Have a skull with Have a skull with no temporal openingno temporal opening behind the orbits behind the orbits Modern turtles (arose from diapsid)Modern turtles (arose from diapsid)

Diapsids Diapsids Gave rise to all other traditional “reptiles” (except turtles) and Gave rise to all other traditional “reptiles” (except turtles) and

to birdsto birds Skull has Skull has two temporal openings two temporal openings (Below and above cheek)(Below and above cheek)

SynapsidsSynapsids Mammal-like reptiles with a Mammal-like reptiles with a single pairsingle pair of temporal openings of temporal openings

low on the cheekslow on the cheeks


26-5

Synapsids -One opening

Mammals

Diapsids -2 openings

Birds & Reptiles

Anapsids -No Opening

Turtles


26-6


26-7

These openings are associated with These openings are associated with large muscles that elevate the lower jawlarge muscles that elevate the lower jaw

Changes in jaw musculatureChanges in jaw musculature Might reflect a shift from suction feeding in Might reflect a shift from suction feeding in

aquatic vertebrates to terrestrial feeding aquatic vertebrates to terrestrial feeding



26-8

Characteristics of AmniotesCharacteristics of Amniotes Amniotic EggAmniotic Egg

Amnion, allantois, chorion, and yolk sacAmnion, allantois, chorion, and yolk sac Amnion = surrounds embryo, cushionAmnion = surrounds embryo, cushion Allantois = stores metabolic wasteAllantois = stores metabolic waste Chorion = respiratory surfaceChorion = respiratory surface Surrounding the organism is a porous, parchment-like or Surrounding the organism is a porous, parchment-like or

leathery shellleathery shell Rib Ventilation of the Lungs - Aspiration (draw air Rib Ventilation of the Lungs - Aspiration (draw air

into lungs) by muscles lowering liver - diaphragminto lungs) by muscles lowering liver - diaphragm Thicker and more Waterproof skin - contains Thicker and more Waterproof skin - contains keratin, keratin,

that makes scales, hair, feathers, and clawsthat makes scales, hair, feathers, and claws



26-9


26-10

All amniotes All amniotes Lack gilled larvae and have Lack gilled larvae and have internal fertilizationinternal fertilization

Eliminated the need for aquatic environmentsEliminated the need for aquatic environments Penis is the most common Penis is the most common copulatory organcopulatory organ

Derived from cloacal wall, appears to be an amniote Derived from cloacal wall, appears to be an amniote innovationinnovation



26-11

REPTILES:REPTILES: Jaws of nonavian reptileJaws of nonavian reptile

Efficiently designed for applying Efficiently designed for applying crushing or crushing or gripping force to preygripping force to prey

Larger jaw muscles have mechanical advantage Larger jaw muscles have mechanical advantage over the jaws of fishes which are designed for over the jaws of fishes which are designed for suction feeding or for quick closuresuction feeding or for quick closure

Tongue is muscular and mobileTongue is muscular and mobile Functions to move food in mouth for mastication Functions to move food in mouth for mastication

and swallowingand swallowing

Characteristics of Nonavian Reptiles Characteristics of Nonavian Reptiles


26-12

Retiles Circulatory System: efficient Retiles Circulatory System: efficient and versatile circulatory systemand versatile circulatory system Right atrium receives deoxygenated blood Right atrium receives deoxygenated blood

and is partitioned from the left atrium and is partitioned from the left atrium which receives oxygenated bloodwhich receives oxygenated blood

Blood doesn’t mix like amphibiansBlood doesn’t mix like amphibians Heart has 2 atria, and 1 divided ventricle Heart has 2 atria, and 1 divided ventricle

(crocodiles have 2 atria, and 2 ventricles)(crocodiles have 2 atria, and 2 ventricles)



26-13Reptile’s Heart

Right atrium

Left atrium

Incomplete divisionVentricle

From body

To lungs

To body

From lungs



26-15

Excretion Urine is produced in the kidneys.

In some reptiles, urine flows in tubes directly into a cloaca.

In others, a bladder stores urine before it is expelled. Water and most salts resorbed in the bladderWater and most salts resorbed in the bladder

Salt is removed by Salt is removed by salt glandssalt glands near the nose, near the nose, eyes, or tongueeyes, or tongue



26-16

The nervous system of reptiles is more The nervous system of reptiles is more complex than that of amphibianscomplex than that of amphibians Brain of reptiles is small, however, Brain of reptiles is small, however, cerebrumcerebrum is is

relatively enlargedrelatively enlarged Enlargement of cerebrum correlated with increase Enlargement of cerebrum correlated with increase

of of sensory information and muscle control during sensory information and muscle control during locomotionlocomotion

Reptiles have Reptiles have good visiongood vision Snakes and many lizards use a highly sensitive Snakes and many lizards use a highly sensitive

sense of smell to find prey and matessense of smell to find prey and mates Olfaction assisted by a Olfaction assisted by a Jacobson’s organJacobson’s organ,, a specialized a specialized

olfactory chamber in the roof of the moutholfactory chamber in the roof of the mouth



26-17

Characteristics and Natural History of Reptilian OrdersCharacteristics and Natural History of Reptilian Orders

Order Testudines (Turtles)Order Testudines (Turtles) Fossils appear Fossils appear 200 million years ago 200 million years ago Shells consist of a dorsal Shells consist of a dorsal carapace carapace and a and a

ventral ventral plastronplastron Outer horny layer of Outer horny layer of keratinkeratin and an inner layer of and an inner layer of

bonebone Bony layer is a fusion of ribs and vertebraeBony layer is a fusion of ribs and vertebrae Lack teethLack teeth and use tough, horny plates for gripping and use tough, horny plates for gripping

foodfood


26-18


26-19Snapping Turtle


26-20

BreathingBreathing Consequence of having a Consequence of having a rigid shellrigid shell

Turtle cannot expand chest to breatheTurtle cannot expand chest to breathe Solve problem by using abdominal and pectoral Solve problem by using abdominal and pectoral

muscles as a “diaphragm”muscles as a “diaphragm”



Form and Function in Turtles

Kidney

Liver Heart

Cloaca

Bladder

Lung Digestive tract


26-22

Nervous System and Senses in TurtlesNervous System and Senses in Turtles BrainBrain is small, less than 1% percent of body weight is small, less than 1% percent of body weight

Some turtles can learn a path through a mazeSome turtles can learn a path through a maze Have a middle and an inner ear but Have a middle and an inner ear but sound sound

perception is poorperception is poor Make few sounds aside from those made during Make few sounds aside from those made during

matingmating Good sense of smell, acute vision, and color Good sense of smell, acute vision, and color

perception about equal to humansperception about equal to humans



26-23

Reproduction and Development TurtlesReproduction and Development Turtles OviparousOviparous Fertilization is internal Fertilization is internal Bury their eggs in the groundBury their eggs in the ground Female lays her eggs in a nest and deserts them Female lays her eggs in a nest and deserts them In some turtle families nest In some turtle families nest temperature temperature

determines sex of hatchlingsdetermines sex of hatchlings Low temperatures produce Low temperatures produce malesmales High temperatures produce High temperatures produce femalesfemales



26-24

Pond Turtle: Sex determined by temperature


26-25

Galapagos Tortoise Mating


26-26

Green Sea Turtle - herbivore, tropical oceans, only go on land to lay eggs


26-27

Alligator Snapping Turtle: Has pink lure in mouth to attract fish


26-28

Order Squamata: Lizards and Snakes Order Squamata: Lizards and Snakes Account for up Account for up 95%95% of living reptiles of living reptiles Divided into Suborders (Sauria, Serpentes)Divided into Suborders (Sauria, Serpentes) Oviparous and VivipariousOviparous and Viviparious

Associated with Associated with cold climates - cold climates - mother can regulate mother can regulate temperature of youngtemperature of young

Increasing the length of time eggs are kept in Increasing the length of time eggs are kept in oviductoviduct

Young obtain nutrition from yolk sacs, via the Young obtain nutrition from yolk sacs, via the mother, or a combination of bothmother, or a combination of both



26-29

Tokay Gecko


26-30

Suborder Sauria: Lizards Suborder Sauria: Lizards

Geckos Geckos Small, agile, nocturnal formsSmall, agile, nocturnal forms Adhesive toe pads allow them to walk on ceilingsAdhesive toe pads allow them to walk on ceilings

Iguanids Iguanids Include many New World lizards as well as the Include many New World lizards as well as the

marine iguana of the Galápagosmarine iguana of the Galápagos ChameleonsChameleons

Arboreal lizards of Africa and MadagascarArboreal lizards of Africa and Madagascar Many have an extendible tongue Many have an extendible tongue

Suborder SauriaSuborder Sauria


26-31

Large male marine Iguana -feeding underwater on algae.Can stay underwater for 30 minutes. Only marine lizard.


26-32A chameleon snares a dragonfly


26-33

Some have degenerate limbsSome have degenerate limbs Glass lizards are nearly limbless (legless Glass lizards are nearly limbless (legless

lizard)lizard) Movable eyelidsMovable eyelids = lizard. Snakes have a = lizard. Snakes have a

transparent coveringtransparent covering Have an external ear that snakes lackHave an external ear that snakes lack

Suborder Sauria - LizardsSuborder Sauria - Lizards


26-34

The glass lizard - legless. Different from snakes:-Deep flexible groove running along body

-Moveable eyelids


26-35

Conserve water by producing Conserve water by producing semisolid urinesemisolid urine Some can Some can store fat in tailsstore fat in tails to provide energy to provide energy

and metabolic water during droughtand metabolic water during drought Gila monster and beaded lizard are the only Gila monster and beaded lizard are the only

lizards capable of a lizards capable of a venomous bitevenomous bite Lizards keep body temperature relatively Lizards keep body temperature relatively

constant by constant by ectothermyectothermy

Characteristics of Reptilian OrdersCharacteristics of Reptilian Orders


26-36

Gila Monster - venomous- Feeds on birds, nests, mammals


26-37

Suborder Serpentes: Snakes Suborder Serpentes: Snakes Limbless and have lost pectoral and Limbless and have lost pectoral and

pelvic girdles (except in pythons)pelvic girdles (except in pythons) Feeding apparatusFeeding apparatus allows them to eat allows them to eat

prey several times their own diameterprey several times their own diameter Two halves of lower jaw are loosely joined, Two halves of lower jaw are loosely joined,

allowing them to spread apartallowing them to spread apart Skull bones also loosely articulated so Skull bones also loosely articulated so

mouth can accommodate large preymouth can accommodate large prey To allow breathing during the slow process To allow breathing during the slow process

of swallowing, the of swallowing, the tracheal opening is tracheal opening is extendedextended

Characteristics of Reptilian Orders: SnakesCharacteristics of Reptilian Orders: Snakes


26-38


26-39

Eyeballs have reduced mobility, non movable Eyeballs have reduced mobility, non movable eyelideyelid

Most have Most have poor visionpoor vision Arboreal snakes in tropical forests have highly Arboreal snakes in tropical forests have highly

developed visiondeveloped vision Lack external earsLack external ears Can Can feel vibrationsfeel vibrations at low frequencies, at low frequencies,

especially vibrations carried in the groundespecially vibrations carried in the ground Chemical sensesChemical senses rather than vision or rather than vision or

hearing are main senses used to hunt preyhearing are main senses used to hunt prey

Characteristics of Reptilian Orders : SnakesCharacteristics of Reptilian Orders : Snakes


26-40

Parrot Snake -tree snake of Central America


26-41

Jacobson’s organs Jacobson’s organs Pair of pits in the roof of the mouthPair of pits in the roof of the mouth Lined with olfactory epitheliumLined with olfactory epithelium Forked tongue picks up scent particles and Forked tongue picks up scent particles and

conveys them to this organconveys them to this organ SkinSkin is infolded between scales is infolded between scales

When stretched by a large meal, the skin is When stretched by a large meal, the skin is unfoldedunfolded



26-42

Blacktail Rattlesnake - flicks tongue to smell surroundings.Scent particles are transferred to Jacobson’s organs on roof of mouth.


26-43

Lateral -Uses groundirregularities

Concertina-Uses force

Against trees

Sidewinder-Throws body

forward in loops

Rectilinear- Use muscles onribs to contract

and relax

Snake LocomotionSnake Locomotion


26-44

Pit vipers, such as rattlesnakesPit vipers, such as rattlesnakes Have “Have “pitspits” with nerve endings sensitive to heat ” with nerve endings sensitive to heat

emitted by warm-bodied birds and mammalsemitted by warm-bodied birds and mammals Viper fangs are hollow and hinged to inject venom Viper fangs are hollow and hinged to inject venom

when snake strikeswhen snake strikes Of an average of 8,000 snake bites each year in Of an average of 8,000 snake bites each year in

the U.S., only about 12 result in deaththe U.S., only about 12 result in death Nonvenomous snakes Nonvenomous snakes

Kill prey by constriction or by biting and Kill prey by constriction or by biting and swallowing swallowing



26-45

Pit Organ:Can sense temperature

changes of 0.003º C.


26-46

Nonvenomous African House Snake- constricting a mouse


26-47

Spectacled Cobra -Flattened neck showsa threatening display.


26-48

Snakebite and ToxicitySnakebite and Toxicity Most snake venoms are a Most snake venoms are a complex combination of complex combination of

venom typesvenom types NeurotoxinsNeurotoxins act on the nervous system, causing act on the nervous system, causing

blindness or inhibit respirationblindness or inhibit respiration Hemorrhagin typeHemorrhagin type venoms break down blood venoms break down blood

vesselsvessels Blood leaks into tissue spacesBlood leaks into tissue spaces

Sea snakes and the Australian tiger snakeSea snakes and the Australian tiger snake have have the most deadly venom per unit volumethe most deadly venom per unit volume

Characteristics of Reptilian OrdersCharacteristics of Reptilian Orders


26-49

The Venom Gland is a modified salivary gland, connected by a duct to a hollow fang.


26-50

World total for deaths from snakebiteWorld total for deaths from snakebite is is about 50,000 to 60,000 each yearabout 50,000 to 60,000 each year

Less thanLess than 20% of all snakes are 20% of all snakes are venomous,venomous, although venomous species although venomous species outnumber nonvenomous species by 4 to outnumber nonvenomous species by 4 to 1 in 1 in AustraliaAustralia



26-51

ReproductionReproduction Most are oviparous and lay shelled eggs Most are oviparous and lay shelled eggs Others, including pit vipers, are ovoviviparousOthers, including pit vipers, are ovoviviparous A few snakes are viviparousA few snakes are viviparous Female snakes can store sperm and lay several Female snakes can store sperm and lay several

clutches of fertile eggs long after a single matingclutches of fertile eggs long after a single mating



26-52

Order Sphenodonta: The Tuatara Order Sphenodonta: The Tuatara Only 2 living speciesOnly 2 living species in New Zealand in New Zealand Once widespread across New Zealand, Once widespread across New Zealand,

the 2 species are now restricted to the 2 species are now restricted to small islandssmall islands

Loss of the tuatara populations caused Loss of the tuatara populations caused by human by human introduction of nonnative introduction of nonnative speciesspecies which preyed upon the tuatara which preyed upon the tuatara Tuatara are vulnerable because they have Tuatara are vulnerable because they have

slow growth and reproductive ratesslow growth and reproductive rates

Characteristics of Reptilian Orders: TuataraCharacteristics of Reptilian Orders: Tuatara


26-53

Tuatara - living reptile fossil


26-54

Lizard-like and live in burrows Lizard-like and live in burrows Slow growingSlow growing and may live to 77 years and may live to 77 years

of ageof age Well-developed 3rd Well-developed 3rd median eyemedian eye on on

head, buried beneath skinhead, buried beneath skin

Characteristics of Reptilian Orders: TuataraCharacteristics of Reptilian Orders: Tuatara


26-55

Order Crocodilia:Order Crocodilia: Crocodiles and Alligators Crocodiles and Alligators Relatives gave rise to the of dinosaurs and to Relatives gave rise to the of dinosaurs and to

birdsbirds There are 3 families of modern crocodilians There are 3 families of modern crocodilians

Alligators and caimansAlligators and caimans are found primarily in the are found primarily in the New World and have a broader snoutNew World and have a broader snout

CrocodilesCrocodiles are widely distributed, narrow snout are widely distributed, narrow snout One species of Gharial One species of Gharial (gavial)(gavial) occurs in India occurs in India

and Burma and has a very narrow snoutand Burma and has a very narrow snout

Characteristics of Reptilian Orders: CrocodilesCharacteristics of Reptilian Orders: Crocodiles


26-56

Nile Crocodile: 4th Tooth of Lower Jaw is visible,

Longer, pointed snout

American Alligator: Wider shorter snout

Darker colloration

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Gharial:Growth on snout

in males only. Makes noise to attract females.


26-57

All have long, well-reinforced skull and jaw All have long, well-reinforced skull and jaw musculature for a powerful bitemusculature for a powerful bite

Thecodont dentitionThecodont dentition Teeth are set in socketsTeeth are set in sockets

Four-chambered heartFour-chambered heart Alligators and crocodiles are Alligators and crocodiles are oviparousoviparous

Usually 20–50 eggs are laid in mass of vegetationUsually 20–50 eggs are laid in mass of vegetation Unguarded nests are easily discovered and raided Unguarded nests are easily discovered and raided

by predatorsby predators High nest temperaturesHigh nest temperatures produce males produce males Low temperaturesLow temperatures produce females produce females

Opposite of turtlesOpposite of turtles



1. Most reptiles reproduce with

a.external fertilization and external development.

b.internal fertilization and internal development.

c. internal fertilization and external development in water.

d.internal fertilization and external development in shelled eggs.

QUIZ


1. Most reptiles reproduce with

a.external fertilization and external development.

b.internal fertilization and internal development.

c. internal fertilization and external development in water.

d.internal fertilization and external development in shelled eggs.

QUIZ


QUIZ

2. The amnion sac of a reptile egg functions as a

a.membrane that exchanges oxygen and carbon dioxide for the embryo.

b.membrane that stores wastes produced by the embryo.

c.source of nutrient-rich food for the developing embryo.

d.shock-absorbing fluid-filled sac protecting the embryo.


QUIZ

2. The amnion sac of a reptile egg functions as a

a.membrane that exchanges oxygen and carbon dioxide for the embryo.

b.membrane that stores wastes produced by the embryo.

c.source of nutrient-rich food for the developing embryo.

d.shock-absorbing fluid-filled sac protecting the embryo.


QUIZ

3. Reptiles with the most well-developed hearts include

a. turtles and alligators.

b.crocodiles and turtles.

c.crocodiles and alligators.

d.alligators and lizards.


QUIZ

3. Reptiles with the most well-developed hearts include

a. turtles and alligators.

b.crocodiles and turtles.

c.crocodiles and alligators.

d.alligators and lizards.


QUIZ

4. The two parts of a turtle or tortoise's shell are

a. terrapin and plastron.

b.carapace and plastron.

c.carapace and terrapin.

d.terrapin and carapace.


QUIZ

4. The two parts of a turtle or tortoise's shell are

a. terrapin and plastron.

b.carapace and plastron.

c.carapace and terrapin.

d.terrapin and carapace.

Documents

26-1 CHAPTER 26 Nonavian Reptiles. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 26-2 Hatching Komodo Lizard