11

ReptilesReptiles

22

Key features of ReptilesKey features of Reptiles

1.1. Strong, bony skeletons and toes Strong, bony skeletons and toes with with clawsclaws

2.2. Two pairs of limbs, except Two pairs of limbs, except snakessnakes

3.3. Legs positioned vertically for Legs positioned vertically for support of body and movement support of body and movement on landon land

33

External Structural External Structural Adaptations for LandAdaptations for Land

1.1. ClawsClaws-aid in climbing, -aid in climbing, digging and movement digging and movement in various terrainsin various terrains

2.2. Toes modified into Toes modified into suctions cupssuctions cups aid in aid in climbingclimbing

3.3. Absence of limbs Absence of limbs Snakes use scaly Snakes use scaly

skin and highly skin and highly developed skeletal developed skeletal and muscular and muscular systems to movesystems to move

44

Ectothermic MetabolismEctothermic Metabolism

1.1. Regulate their temperature by Regulate their temperature by basking in the sun or seeking basking in the sun or seeking shadeshade

2.2. Become sluggish in very cold Become sluggish in very cold temperaturestemperatures

3.3. Intolerance to cold limits their Intolerance to cold limits their geographic rangegeographic range

55

Temperature RegulationTemperature Regulation

Regulate their temp Regulate their temp by behaviorby behavior

Bask in sun to Bask in sun to speed up speed up metabolismmetabolism

Hide in shade Hide in shade to prevent to prevent overheating overheating

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Reptiles ContinuedReptiles Continued1.1. Dry, scaly skin, almost watertightDry, scaly skin, almost watertight

2.2. Amniotic eggs, almost watertightAmniotic eggs, almost watertight Contains a water and food supplyContains a water and food supply

3.3. Respiration through well developed lungsRespiration through well developed lungs Grape shaped chamber called Grape shaped chamber called alveolialveoli Alveoli increase the respiratory Alveoli increase the respiratory

surface area for gas exchangesurface area for gas exchange Strong muscles in rib cage help to Strong muscles in rib cage help to

move air in and outmove air in and out

77

RespirationRespiration

Well developed Well developed lungslungs Tissues Tissues

involved in gas involved in gas exchange are exchange are located inside located inside bodybody

Kept moist in Kept moist in even in the even in the driest driest environmentsenvironments

88

HeartHeart1.1. Ventricle of heart partly divided by a Ventricle of heart partly divided by a

septumseptum

2.2. Still incomplete separation of Still incomplete separation of oxygen-rich and oxygen-poor bloodoxygen-rich and oxygen-poor blood

3.3. Crocodiles and alligators Crocodiles and alligators

have a ventricle that is totally have a ventricle that is totally separated into two pumping separated into two pumping chamberschambers

99

CirculationCirculation

Double loop circulationDouble loop circulation

1010

ReproductionReproduction1.1. Internal fertilizationInternal fertilization

2.2. Many reptiles are oviparous-young Many reptiles are oviparous-young hatch from eggshatch from eggs

3.3. Some lizards and snakes are Some lizards and snakes are ovoviviparous-female retains eggs in ovoviviparous-female retains eggs in her body until shortly her body until shortly

before hatching or hatching before hatching or hatching

may occur inside her bodymay occur inside her body

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Excretion Excretion

Conserve water by excreting Conserve water by excreting nitrogenous wastes in dry or pasty nitrogenous wastes in dry or pasty form as crystals of uric acidform as crystals of uric acid

1212

11stst Orders of Reptiles Orders of ReptilesSquamataSquamata

Snakes and lizardsSnakes and lizards lower jaw is loosely connected lower jaw is loosely connected

to skull allowing mouth to open to skull allowing mouth to open wide to accommodate large wide to accommodate large preyprey

Lizards can regenerate tail, but Lizards can regenerate tail, but will not have vertebraewill not have vertebrae

Molting occurs in bothMolting occurs in both

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SquamataSquamata1.1. Order consists of 5,640 species of Order consists of 5,640 species of

lizards and snakeslizards and snakes2.2. Loosely jointed upper jaw and Loosely jointed upper jaw and

paired reproductive organs in paired reproductive organs in malesmales

3.3. Lizards-presence of limbsLizards-presence of limbs4.4. Common lizards- iguanas, Common lizards- iguanas,

chameleons, skinks and geckoschameleons, skinks and geckos5.5. Live everywhere except AntarcticLive everywhere except Antarctic6.6. Special adaptations- agility and Special adaptations- agility and

camouflagecamouflage7.7. 2 species are venomous- Gila 2 species are venomous- Gila

monster (SW U.S.) and beaded monster (SW U.S.) and beaded lizard (western Mexico)lizard (western Mexico)

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1.1. Blend with Blend with background background chameleons- remain chameleons- remain inconspicuous inconspicuous

2.2. Horned lizards- Horned lizards- spiked armor,when spiked armor,when disturbed they disturbed they inflate,hiss and squirt inflate,hiss and squirt blood from eyesblood from eyes

3.3. Skinks and geckos- Skinks and geckos- lose their tails and lose their tails and regenerate-escape regenerate-escape from predatorsfrom predators

4.4. Most lizards are Most lizards are small- .3m in length; small- .3m in length; iguanas- 1m in lengthiguanas- 1m in length

5.5. Largest lizards- Largest lizards- monitors- Komodo monitors- Komodo Dragon (Indonesia) Dragon (Indonesia) 3m (9.8 ft) in length, 3m (9.8 ft) in length, 140 kg (308.6 lbs)140 kg (308.6 lbs)

Squamata Continued

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Adaptations of SnakesAdaptations of Snakes

1616

MovementMovement

1.1. A snake has a backbone A snake has a backbone of 100 to 400 vertebrae, of 100 to 400 vertebrae, with a pair of ribs with a pair of ribs attached attached

2.2. Provides the framework Provides the framework for thousands of musclesfor thousands of muscles

3.3. Interaction of bones, Interaction of bones, muscles, and skin muscles, and skin enables a snake to move enables a snake to move various ways:various ways:

Example:Example: side windingside winding

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FeedingFeedingSnakes eat animals, but lack Snakes eat animals, but lack

structural adaptations common to other structural adaptations common to other carnivorescarnivores

Snakes do not see or hear well, have no Snakes do not see or hear well, have no limbs, and teeth and small mouth cannot rip limbs, and teeth and small mouth cannot rip and grind fleshand grind flesh

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Locating PreyLocating Prey 1.1.Snakes evolved a sense of smell Snakes evolved a sense of smell

which they use to locate their prey which they use to locate their prey 2.2.Flicks its forked tongue to gather Flicks its forked tongue to gather

chemicals from the environment chemicals from the environment 3.3.Transfers chemicals to two pits in Transfers chemicals to two pits in

the roof of the mouth-the roof of the mouth-Jacobsons Jacobsons organorgan where nerves are highly where nerves are highly sensitive to the chemicalssensitive to the chemicals

4.4.Some snakes inject Some snakes inject toxic venomtoxic venom by by biting with fangs and injectingbiting with fangs and injecting

5.5.HemotoxinsHemotoxins-attack the circulator -attack the circulator system-disrupt the clotting of system-disrupt the clotting of blood. blood.

6.6.NeurotoxinsNeurotoxins-disrupting the nerve -disrupting the nerve pathways-dangerous to respiratory pathways-dangerous to respiratory and heart functions.and heart functions.

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Reproduction Reproduction

1.1. Most male snakes Most male snakes rely on the scent of rely on the scent of female snakes of heir female snakes of heir own speciesown species

2.2. Before mating, a male Before mating, a male and female snake and female snake may glide alongside may glide alongside by side, with the male by side, with the male stroking the female stroking the female with his chin and with his chin and flicking his tongue flicking his tongue over her body over her body

3.3. Fertilization is Fertilization is internalinternal

2020

Reproduction ContinuedReproduction Continued1.1. Most snakes are Most snakes are

oviparousoviparous2.2. Female lays eggs that Female lays eggs that

hatch outside her bodyhatch outside her body3.3. To break out a hatchling To break out a hatchling

uses a special tooth uses a special tooth which is lost soon afterwhich is lost soon after

4.4. Other snakes are Other snakes are ovoviviparous ovoviviparous

5.5. Female carries the eggs Female carries the eggs in her body in her body throughout development throughout development

6.6. Young are born liveYoung are born live7.7. All newborns must fend All newborns must fend

for themselves, relying for themselves, relying on their many on their many specialized adaptations specialized adaptations for survival on landfor survival on land

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Defense Defense 1.1. Natural selection resulted in modifications for Natural selection resulted in modifications for

defense.defense.2.2. Camouflage is beneficial for both seeking prey Camouflage is beneficial for both seeking prey

and hiding from predators. and hiding from predators. 3.3. Many snakes are green and blend with foliageMany snakes are green and blend with foliage4.4. Others are brown and hide against the bark of Others are brown and hide against the bark of

treestrees

2222

Swallowing and Digesting Swallowing and Digesting PreyPrey

1.1. A snakes upper and A snakes upper and lower jaws are lower jaws are hinged and move hinged and move independently. independently.

2.2. when unhinged, the when unhinged, the jaws stretch to allow jaws stretch to allow the mouth to open the mouth to open extremely wide. extremely wide.

3.3. While swallowing it While swallowing it whole the snake thrusts whole the snake thrusts its windpipe into the its windpipe into the throat, allowing the throat, allowing the snake to breathe snake to breathe

4.4. The process of can take The process of can take several hoursseveral hours

2323

Defense ContinuedDefense Continued

1.1. Some ward off Some ward off danger by rapidly danger by rapidly changing body changing body shapeshape

2.2. Extending a hood Extending a hood like cobras like cobras

3.3. Some hissSome hiss4.4. Others make Others make

mechanical noises mechanical noises 5.5. Such as the rattle Such as the rattle

of the rattlesnake.of the rattlesnake.

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22ndnd Order of Reptiles Order of ReptilesCheloniaChelonia

Turtles and tortoisesTurtles and tortoises Hard bony shell-dorsal Hard bony shell-dorsal

is carapace and is carapace and

ventral is plastronventral is plastron Lack teeth, but have beaksLack teeth, but have beaks Many herbivores but some are Many herbivores but some are

carnivorescarnivores

2525

CheloniCheloniaa

1.1. Order consists of about 265 Order consists of about 265 species of turtles and species of turtles and tortoisestortoises

2.2. Tortoise are terrestrial Tortoise are terrestrial 3.3. Turtles live in waterTurtles live in water4.4. Body covered by a shell made Body covered by a shell made

of hard plates- 2 parts- a of hard plates- 2 parts- a carapace and plastroncarapace and plastron

5.5. Retractable headRetractable head6.6. Forelimbs of a marine turtle Forelimbs of a marine turtle

have evolved into flippers and have evolved into flippers and freshwater turtles have freshwater turtles have webbed toeswebbed toes

7.7. Migratory behavior of sea and Migratory behavior of sea and river turtles river turtles

8.8. Returns to land to lay eggsReturns to land to lay eggs

2626

33rdrd Order of Reptiles Order of Reptiles CrocodiliaCrocodilia

Crocodiles and alligatorsCrocodiles and alligators Most closely related Most closely related

to dinosaursto dinosaurs Aggressive carnivoresAggressive carnivores Care for their young after Care for their young after

hatchinghatching

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CrocodilianCrocodilian1.1. Order composed of 20 species Order composed of 20 species

of large lizard-shaped reptiles- of large lizard-shaped reptiles- crocodiles, alligators, caimans crocodiles, alligators, caimans and gavials  and gavials 

2.2. Crocodilians live in or near Crocodilians live in or near water in tropical/ subtropical water in tropical/ subtropical regions of the worldregions of the world

3.3. Crocodiles-nocturnal animals; Crocodiles-nocturnal animals; Africa, Asia and AmericasAfrica, Asia and Americas

4.4. Alligators-China and southern Alligators-China and southern U.S.U.S.

5.5. Caimans-Central America, some Caimans-Central America, some in Floridain Florida

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1.1. CarnivorousCarnivorous

2.2. Eyes on head, Eyes on head, nostrils on top of nostrils on top of snout snout

3.3. See and breathe See and breathe while in waterwhile in water

4.4. Parental care- Parental care- both parents both parents care for young care for young by carrying in by carrying in jaws until jaws until developmentdevelopment

2929

44thth Order of Reptiles Order of ReptilesRhynchocephaliaRhynchocephalia

TuatarasTuatarasTwo species native to Two species native to

New ZealandNew ZealandMost active at low Most active at low

temperaturestemperatures

3030

RhynochocephaliaRhynochocephalia1.1. Only living species-New Only living species-New

ZealandZealand2.2. Resembles a large Resembles a large

lizard about 60 cm longlizard about 60 cm long3.3. Parietal eye-Parietal eye-functions functions

as a thermostat-as a thermostat-protects from protects from overheatingoverheating

4.4. Active at low Active at low temperatures, feed at temperatures, feed at night on insects, worms night on insects, worms and small animalsand small animals

3131

310 million 310 million years ago… years ago… reptiles were reptiles were the the first first vertebrates to vertebrates to make the make the complete complete transition to transition to life on landlife on land Limited competition for Limited competition for

the insects and plants the insects and plants that could be used as that could be used as food on the landfood on the land

An increase in An increase in competition for food competition for food and space among all and space among all the life-forms in the life-forms in aquatic environments aquatic environments

3232

Adaptations to Adaptations to LandLand

3333

Adaptations to Adaptations to LandLand

AAmnioticmniotic Egg EggLegsLegsLungsLungsScales or platesScales or plates

3434

AAmnioticmniotic Egg Egg

5.5. AllantoisAllantois stores the nitrogenous wastes stores the nitrogenous wastes produced by the embryo until the egg hatchesproduced by the embryo until the egg hatches

1.1. An egg with a An egg with a protective membrane protective membrane and a porous shell and a porous shell enclosing the enclosing the developing embryodeveloping embryo

2.2. Egg forms a Egg forms a “nursery”“nursery” to protect the embryoto protect the embryo

3.3. Egg derives its name Egg derives its name from the from the amnionamnion, the , the thin membrane thin membrane enclosing the salty enclosing the salty fluid in which the fluid in which the embryo floatsembryo floats

4.4. Yolk sacYolk sac encloses the encloses the yolk, a protein rich yolk, a protein rich food supply for the food supply for the developing embryodeveloping embryo

3535

1.1. The chorion regulates The chorion regulates the exchange of oxygen the exchange of oxygen and carbon dioxideand carbon dioxide between the egg and the between the egg and the outside environmentoutside environment

2.2. Amniote egg is Amniote egg is surrounded by a surrounded by a leathery shellleathery shell that may that may be hard in some species be hard in some species (Birds) because of the (Birds) because of the presence of calcium presence of calcium carbonatecarbonate

3.3. The male places the The male places the sperm inside the female sperm inside the female before the shell is before the shell is formed. This is called formed. This is called internal fertilizationinternal fertilization, , makes water transport makes water transport of sperm unnecessaryof sperm unnecessary

3636

Origin and Origin and EvolutionEvolution

From the studies of From the studies of fossils and fossils and comparative comparative anatomy, biologists anatomy, biologists infer that reptiles infer that reptiles arose from a group arose from a group of ancestral reptiles of ancestral reptiles called cotylosaurs, called cotylosaurs, which lived about which lived about 310 million years 310 million years ago.ago.

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The End