8 - Reptiles 2 Flashcards
(25 cards)
Important themes
Water conservation
Support and mobility on land against gravity
Dealing with temperature extremes and fluctuation
Reptile temperatures
- ectotherms (similar body temp to environment)
- deal using behaviours
Skin
- thick, dry, keratinized
- no respiratory function
- scales modified for different functions (ex: locomotion with traction for snakes)
- Epidermal layers shed through ecdysis
Ecdysis
shedding skin
Cryptic colouration
colour patterns resemble their surroundings
Aposematic colouration
sharply contrasting or bright colours that advertise that animals are dangerous/distasteful to predators
Mimicry
species resembles another species and gains protection from the resemblance
Colour and colour change
Sex recognition and thermoregulation
Thermoregulation
Lighter to reflect heat off and dark to absorb heat
Orient themselves the way needed to get more or less heat
Press body against warm surface
Blood flow to skin when they want to absorb heat
To avoid heat loss, blood flow in core of animal
Support and movement
skeleton highly ossified (more support for terrestrial existence)
Additional cervical vertebrae (atlas and axis) for greater freedom of movement for the head
Autotomy
tail loss
adaptation allowing lizards to escape from predator grasp
Caudal vertebrae of many lizards include vertical fracture plane to allow this
Lizard later regenerates lost portion of tail
An exception to ectothermy
brooding indian pythons use metabolic heat to raise their temperature when incubating eggs
also dinosaurs were often mesothermic
Behavioural thermoregulation
Orientation at right angles to sun’s rays
warming by conduction from warm surfaces
Cooling by seeking shade or burrows, assuming erect posture and nocturnal habits
Panting and blood flow directed to mouth
Marine iguanas
Feed on algae in cold water
Bask in sun, flood flow to skin is increased to gain heat
Hibernacula
snakes group up in one for the winter provides thermoregulatory benefit mass of bodies retain heat good for temperate climates important areas to protect
Aestivation
some reptiles in warm dry climates
prolonged torpor/dormancy of an animal during a hot dry period
Feeding
- most are carnivores other than some turtles/tortoises
Tongue types
nonprotrusible (turtles/crocodilians)
protrusible (lizards and tuatara)
Feeding adaptations of snakes
- bones of skull/upper jaw = moveable
- ligaments loosely join the halves anteriorly
- posterior pointing teeth
- glottis opens far forward in mouth s o snake can breathe while swallowing prey
- hinged maxillary bone in vipers
- venom glands in some (modified salivary glands)
Snake venom
- some are neurotoxins that attach nerve centers and cause respiratory paralysis
- some are hemotoxins. break up blood cells and attack blood vessel linings
Median/parietal eye
3rd eye/ pineal eye
sense light and darkness levels
plays role in circadian and cirannual rhythms
also used in orientation to the sun
Pit organs
- heat sensitive organs on side of face in pit vipers like rattlesnakes
- used to detect objects with temperatures that are different than surroundings
- helps locate warm-blooded prey at night
Magnetic compass sense
sea turtles and several other migratory species can detect earth’s magnetic field
particles of magnetite have been found in brains of species with the ability
Parthenogenesis
Development of an embryo from an unfertilized egg cell. Females only
