Amniotes Flashcards
Adaptations of Amniotes
Amniotic egg*
Thicker, waterproof skin
Rib ventilation of lungs
Stronger jaws
High-pressure cardiovascular system
Water-conserving nitrogen excretion
Expanded brain and sensory organs
Earliest members of clade, first to have amniotic eggs
Clade Reptilia
Amniotic eggs have extraembryonic membranes to:
Protect embryo against desiccation (hard or leathery shell)
Cushion embryo (albumin)
Promote gas transfer
Store waste materials
Rib Ventilation
in Amniotes
Amniotes draw air into lungs via expansion of thoracic cavity using rib muscles
Tongue types in Amniotes
Non-protrusible (turtles and crocodiles)
Sticky tongues (some lizards and tuataras)
Protrusible tongues (chameleons)
CV System
of Amniotes
High-pressure CV System
Based on amphibian plan, but higher pressure:
Two atria; incompletely divided ventricle
Sinus venosus reduced pacemaker
T/F
All amniotes have brain with relatively large cerebrum and cerebellum
Reptiles have brains similar to other vertebrates
True
T/F Hearing is dominant sense in most reptiles
False; Vision is dominant sense in most reptiles
Expanded Brain and Sensory Functions
Some reptiles have median (parietal) eye
Have Jacobson’s organs (vomeronasal organs) ; olfactory
Rattlesnakes and other pit vipers have heat-sensitive pit organs
How Ectotherms Achieve Temperature Independence
Physiological thermoregulation
Panting, torpor
Behavioural thermoregulation
Allows regulation of body temperature with considerable precision
what are the 4 orders of The Reptilian Groups are extant
Order Testudines or Chelonia (turtles)
Order Squamata (lizards and snakes)
Order Sphenodontida (tuataras)
Order Crocodylia
Characteristics of Order Testudines or Chelonia
Bony shell
Limbs articulating internally to ribs
Keratinized beak instead of teeth
Dorsal part of shell =
Ventral part of shell =
Dorsal part of shell = carapace
Ventral part of shell = plastron
How do turtles allow their head to be drawn into shell
Turtles have 8 cervical vertebrae that can be articulated into S-shape
Turtle Reproduction
Long life spans
Oviparous; no parental care; temperature-dependent sex determination
Order Squamata types:
Lacertilia (the lizards)
Geckos, iguanas, chameleons, gila monster
Serpentes (the snakes)
differences between lizards and snakes
Eye focusing mechanism and retinal morphology
Snakes have reduced or absent left lung and displacement of gall bladder, right kidney, gonads
How the skulls of squamates are modified from ancestral diapsid
Loss of bone ventral and posterior to lower temporal fenestra
Allowed for evolution of kinetic skull
Reproduction and Development
All male reptiles have intromittent organ
Females may store sperm in seminal receptacle
Amniotic eggs require large energy expenditure by parents
Courtship behaviours of the Reptilian
Head bobbing and displaying of colourful patches of skin on throat
In snakes tail-waiving displays, chin rubbing, entwining – very tactile
Sex pheromones also used
What is Lateral undulation in movement of snakes
Typical S-shaped movement
Lateral push against rough ground and surface irregularities
What is Concertina movement in movement of snakes
Enables climbing and movement into narrow passages
Extension of body using S-shaped loops to brace against sides of the surface
Rectilinear movement
slow but effective way of moving inconspicuously
stalking and straight movement towards prey
2 to 3 sections of the body rest on the ground; intervening sections lift up and pull forward using rib muscles
Sidewinding
Allows desert vipers to move quickly across loose sandy surface with minimal contact
Works by throwing its body forward in loops while keeping the body at 60 degree angle in the direction of travel
Order Sphenodontia
Two rows of teeth in upper jaw; one row in lower jaw
Where did Dinosaurs and crocodiles derived from
Dinosaurs and crocodiles derived from archosaurs
T/F Living crocodilians include alligators, crocodiles, gavials and caimans
True
Describe Order Crocodylia
-Powerful laterally compressed tail - swimming, offensive and defensive maneuvers
-All have elongate, heavy skull with robust jaw musculature
-Thecodont teeth – set in sockets
Reproduction and Parental Care in Order Crocodylia
-Oviparous, females lay 20 to 90 eggs in nest of dead vegetation or buried in sand and guards nest
-Crocodilians show some level of parental care
