Class Reptilia

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Class Reptilia

• Chapter 20

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Class Reptilia

• Reptilia - to creep
• Turtles, crocodiles, lizards, snakes, worm
  lizards, and tuatarans

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Class Reptilia

• First vertebrates to have amniotic eggs
• Extraembryonic membranes
• Protect the embryo from desiccation
• Albumen
• Cushions
• Moisturizes
• Food source
• Yolk - supplies food

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Class Reptilia

• Other adaptations for land
• Impervious skin
• Keratin epidermal scales
• Horny tales
• Water conserving kidneys
• Enlarged lungs

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Class Reptilia

• Subclass Anapsida lack openings in the temple
• Turtles
• Subclass Diapsida
• Lower and upper openings in the temporal region
  of the skull
• Snakes, lizards, and tuataras
• Subclass Synapsida single dorsal opening in the
  temporal region of the skull

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Class Reptilia

• Characteristics of reptiles
• Skull with one surface
• Respiration by lungs
• Metanephric kidneys
• Internal fertilization
• Amniotic eggs
• Very dry skin with keratinized scales
• 17 orders of Reptilia
• 4 Living orders of Reptilia

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Class Reptilia

• Order Testudines
• Tortoise and turtles
• 225 Species of turtles
• Bony shell
• Limbs from internal ribs
• Keratinized beak

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Class Reptilia

• Carapace - dorsal portion of shell
• Plastron - ventral portion of shell
• North American box turtle has hinges
• Eight cervical vertebrae

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Class Reptilia

• Long Life span
• 14 or more years
• Up to 100 years
• Sexual maturity seven or eight years

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Class Reptilia

• Oviparous
• Nest contain 5 - 100 eggs
• Development lasts 4 weeks to one year
• Independent young
• Sea turtle conservation controversy

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Class Reptilia

• Order Rhynchocephalia
• Snout head
• 2 living species of Tuataras
• Burrow
• Endangered species
• Lizard-like reptiles
• Virtually unchanged from extinct members
• Tooth arrangement is the distinguishing factor

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Class Reptilia

• Oviparous
• Share underground nesting burrows with
  ground-seeking sea birds
• Venture out of the burrow at dawn and dusk for
  feeding

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Class Reptilia

• Order Squamata
• Three suborders
• Suborder Sauria - the lizards
• Suborder Serpentes - the snakes
• Suborder Amphisbaenia - worm lizards

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Class Reptilia

• Lizards
• 3,300 species
• Two pairs of limbs
• Upper and lower jaws unite
• Vary in length
• Few centimeters up to 3 m

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Class Reptilia

• Habitat
• Land Dwellers
• Burrowers
• Tree Dwellers
• Reproduction
• Most are oviparous
• Some are viviparous or ovoviviparous

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Class Reptilia

• Gecko
• Habitat
• Semitropical
• Climbers
• Adhesion disks aid
• Nocturnal
• Clicking vocalization

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Class Reptilia

• Iguana
• Thick Bodies
• Short necks
• Distinct Heads
• Marine iguana
• Flying iguana
• Can fly 30 meters

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Class Reptilia

• Chamelions - Group of Iguanas
• Characteristics
• Live in Africa and India
• Arboreal habitat
• Long, sticky tongue
• Change color
• Light
• Temperature
• Behavior

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Class Reptilia

• Gila Monster and Mexican Beaded Lizard
• Venomous lizard
• Southwestern North America
• Not fatal to humans

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Class Reptilia

• Suborder - Serpentes
• Snakes
• 2,300 Species
• 300 are venomous
• 30,000 - 40,000 humans die each year
• Most occur in Southeast Asia
• lt 100 Occur in the U.S.

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Class Reptilia

• Characteristics
• Lack limbs
• Up to 200 Vertebrae
• Skull Adaptations
• Movable upper jaw
• Each jaw moves independently

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Class Reptilia

• Adaptations
• Differences in eye focusing
• Loss of left lung
• Displacement of
• Gallbladder
• Right Kidney
• Gonads

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Class Reptilia

• Reproduction
• Oviparous
• Live birth
• Boas
• Garter snakes
• Age of snakes
• 135 million years old
• Possible relation to caecilians

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Reptilia

• Suborder Amphisbaenia
• Double walk
• Worm Lizards
• 135 Species
• Habitat
• Specialized burrowers
• Africa, South America, Caribbean, and Mideast

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Reptilia

• Characteristics
• Legless
• Wedge shaped head
• Single median tooth in upper jaw
• Can move forward or backward

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Reptilia

• Order Crocodilia
• Greek - lizard
• 21 species
• Crocodiles, alligators, gavials, and caimans
• Have existed for 170 million years

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Reptilia
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Reptilia
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Reptilia

• Snout is elongated
• Nostrils at the anterior end to help with
  breathing while mostly submerged
• Breathe and inhale water at the same time

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Reptilia

• Tail
• Muscular, elongated, and laterally compressed
• Used for swimming, attacking prey, and maneuvers

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Reptilia

• Teeth
• Laterally compressed teeth
• Thrashing motion of capture
• Swallow food whole
• Death roll
• Stomach
• Gizzard-like
• Swallow rocks and other objects

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Reptilia

• Reproduction
• Oviparous
• Parental Care resembles that of birds
• Nesting and parental care can be traced to common
  ancestor of both groups

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Reptilia

• External Structures
• Skin
• No respiratory function
• Thick, dry, and keratinized scales
• Shedding of the scales is called ecdysis
• Pheromones are secreted
• Cryptic, Aposematic, and mimicry coloration

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Reptilia

• Support
• Skeleton resembles amphibian form
• Skull is elongated
• Secondary palate
• Increase in cervical vertebrae
• Atlas and axis increase head movement
• Ribs can be highly modified
• Cobra
• Flying lizards
• Autotomy - loss of a tail

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Reptilia

• Movement
• Prehistoric Reptiles
• Many were bipedal
• Reptile
• Tetrapods
• Primitive reptiles move like salamanders
• Higher than most amphibians

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Reptilia

• Nutrition and Digestion
• Carnivores
• Tongue
• Turtles and crocodiles are nonprotrusible
• Lizards and anurans have sticky tongues
• May exceed the lizards length

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Reptilia

• Snakes
• Glottis is far forward to allow for breathing
• Vipers have hollow fangs that are hinged on the
  maxillary
• Coral, sea, and cobra snakes rigid fangs
• Some cobras can spit
• Venom glands are modified salivary glands

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Reptilia

• Body Regulation
• Gas Exchange
• Three chambered heart
• Sinous venosus is now a pacemaker

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Reptilia

• Low oxygenated blood from right atrium to
  ventricle
• High oxygenated blood from lungs to ventricle to
  left atrium

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Reptilia

• Gas exchange
• Across respiratory surfaces
• Partitioned into spongelike chambers
• Form a negative pressure mechanism for ventilation

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Reptilia

• Temperature Regulation
• Ectotherms
• Can survive (-2 to 41 oC)
• Need (25 to 37 oC) to live
• Behavior is used for temperature regulation
• Body orientation
• Nocturnal
• Panting
• Blood diversion
• Chormatophore dispersion

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Reptilia

• Nervous and Sensory Functions
• Cerebral hemisphere is larger than in Amphibians
• Improved smell
• Jacobson organ
• Snakes can smell with their tongue
• Improved vision motor coordination
• Ears detect vibrations
• Snakes have heat sensitive pit organs

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Reptilia

• Optic lobe and Cerebellum are enlarged
• Increased vision
• More refined motor coordination
• Independent eye movement
• Different fields of vision
• Dominant sense in most reptiles
• Colored vision

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Reptilia

• Excretion
• Kidneys have more nephrons or blood filtering
  units (Metanephric kidneys)
• More blood flow
• Higher pressure
• Excrete uric acid
• Insoluble in water
• Can be stored as a paste

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Reptilia

• Osmoregulation
• Reabsorption of water
• Internal respiratory surfaces
• Relatively impermeable exposed skin
• Behavior
• Nocturnal
• Avoidance of hot surfaces
• Storage of water in lymphatic spaces

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Reptilia

• Reproduction
• Eggs
• Land dwelling is possible
• Not completely independent of water

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Reptilia

• Internal Fertilization
• Egg shell forms after
• Males have an intromittent organ
• Sperm can be stored by the female
• Turtles 4 years
• Snakes 6 years

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Reptilia

• Parthenogenesis
• 6 families of lizards
• 1 family of snake
• Parental Care
• Eggs are usually abandoned
• 100 species of reptiles take care of their young
• American alligator
• Sex is temperature dependent