Reptiles Flashcards
There are 4 classes in the reptile clade. What are they?
Class Reptilia - snakes, lizards and tuataras
Class Chelonia - turtles and tortoises
Class Eusuchia - crocodiles and alligators
Class Aves - birds
What is the largest tortoise or land turtle?
Galapagos giant tortoise (or Madagascar?)
What is the largest living turtle?
Leatherback turtle
What kinds of environments are the members of class chelonia adapted to?
Turtles are adapted to marin, freshwater and terrestrial habitats
What are the pieces of a turtle shell?
Dorsal carapace and Ventral plastron
- skeleton fused with inner shell
- pieces connected with a bridge
What are Scutes?
scales with keratin underlain with bone
- reinforced scales
How many bones compose the carapace of the shell? What is it derived from?
59-61 bones
likely derived from and fused with ribs and vertebrae
What is the Plastron derived from?
bones of the shoulder girdle and abdominal ribs
- some species have a hinged or movable plastron
What do turtles and tortoises have in place of teeth?
horny ridges
What is the reproductive method of class chelonia?
Oviparous - egg laying
- internal fertilization
What kind of environment do turtles lay their eggs?
terrestrial
How do you tell lizards from amphibians?
all lizards have scales and most have claws
- Geckos have adhesive toe pads
How do you differentiate legless lizards from snakes?
Lizards have moveable eyelids and external ear openings
What are 2 kinds of legless lizards?
Glass lizards
Amphisbaenians - worm lizards
What are Amphisbaenians?
Legless worm lizards
What are the reproductive modes of Class Reptilia?
Most are oviparous
- some are ovoviviparous
- viviparous
What is parthenogenesis with respect to parthenogenic lizards? What is the advantage?
Asexual reproduction (no egg fertilization) - advantage for colonization
What is caudal autonomy?
ability to drop tail to distract a predator
What are 2 typical threats to BC reptiles?
Habitat Loss and Road Kill
All lizards are terrestrial except?
Marine iguana endemic to the galapagos
What do marine iguanas eat?
only herbivorous lizard that eats green algae
How does an ectomorph reptile such as the marine iguana maintain body temperatures while diving?
Bask in sun and restrict peripheral circulation in the cold ocean
What is in the order Squamata?
Suborder serpentes (ophidia)(snakes)
What are 6 characteristics of snakes?
Legless Scales, dry skin No movable eyelids No external ears - deaf Highly sensitive to tactile and chemical receptors Highly kinetic skull
What are 6 features that make the rattlesnake a highly evolved predator?
Venom fangs (hollow, immobilize prey)
Pit organs detect infrared (heat sensing)
Eyes for daytime vision
Rattle for warning
Cryptic (camoflage) and aposematic (recognizable warning to predators) colouration
Body that detects vibrations
What is the function of the Jacobson’s organ?
Detects large molecules like pheromones
What 4 organs are part of the pheromone/molecule sensing of a snake?
Brain, nerves, jacobson’s organ, forked tongue
What role does the forked tongue play in sensing with the Jacobson’s organ?
Forked tongue flickers and collects molecules, forked tongue fits into place with the jacobson’s organ and transfers molecules
How do snakes eat prey much larger than it appears their mouths/bodies can fit if they don’t chew?
Slow intake of prey possible because of mandibular liberation
What is mandibular liberation?
mandibles of lower jaw expand to accomodate large prey
they bottom jaw is not fused and each side can move independently
connected with ligaments
quadrate and mandibular joint also play a role
What kind of fertilization do snakes have?
internal - adapted to terrestrial life
What is a hemipenis in snakes?
2 that are remnants of a bilateral body plan
Which 4 BC snakes are oviparous?
great basin gopher snake
night snake
western yellow-bellied racer
sharp-tailed snake (endemic)
Are there any BC snakes that are viviparous?
No
- boa constrictors and green anacondas do though but not local species
What are 2 BC snakes that are ovoviviparous?
all 3 species of garter snakes
rubber boa
What are 3 characteristics of Tuataras and where are they found?
Between bird and reptile clade
Superficially look like lizards
Third eye on top of head that likely only sees light and dark (no shapes) and is covered/protected by scales
What is Class Eusuchia?
Crocodiles and alligators
formerly Crocodylia
How do you tell Crocodiles and Alligators apart?
Head shape of alligator is broad and crocodile comes to a knobby point
The 4th tooth of the lower jaw of a crocodile sticks out and upwards
Do reptiles exhibit parental care?
Most don’t but crocodillians do
Reptiles, turtles, crocs and birds have epidermal scales composed of what material?
Keratin
How do the scales of reptiles differ from fish?
Reptile scales are not separate
- continuous sheet
What happens when reptiles grow and produce new skin?
They shed
- snakes shed in a continuous sheath
What is different about the amniotic eggs of reptiles and birds?
they are surrounded by a leathery or calcarous shell
What are 4 extraembryonic membranes?
Amnion
Allantois
Chorion
Yolk sac
What is the function of the amnion?
protects embryo within aquatic environment
What is the function of the yolk sac?
provides nutrients
What is the function of the allantois?
stores metabolic wastes
-fuses with chorion for gas exchange
What is the function of the chorion?
functions in gas exchange between extraembryonic membranes and the rest of the amniotic egg
What is the albumin?
egg white
What are 3 reproductive characteristics of reptiles and turtles?
internal fertilization
special insemination organs for males
some females can store sperm
What might be one reason for ovovivipary in cold climates?
eggs are retained for thermoregulation
What is an advantage of having an amnoitic egg?
No longer bound to aquatic environment
What adaptation to shelled eggs do hatching reptiles, snakes, lizards and even birds possess?
Egg tooth to aid in hatching
Most animals have their sex determined genetically. What is different about crocodiles, tuataras, and many turtles and lizards in this respect?
environmental sex determination such as ambient temperature
- protein or enzyme dependent on temp that is responsible for estrogen/testosterone production
- food for thought:effects of climate change?
What are 4 methods that aquatic turtles use to respire?
lungs (no gills)
skin
lining of the throat
bursae (vascular sacs in cloaca)
How is blood in reptiles oxygenated?
lungs (not gills)
How many chambers are in the heart of a reptile or turtle?
3
oxygenated and deoxygenated blood intermingle
How many chambers are in the heart of crocodilians?
4
like birds and mammals
separation of ventricles
more efficient adaptation
How many chambers are in the heart of fish?
2
oxygenated blood doesn’t get pumped through heart?
What are 2 adaptations for water conservation?
kidneys excrete uric acid (as nitrogenous waste - less water than urea)
glands that excrete salt near nose or eyes
- crocodile tears!
Describe uric acid
a semi-solid paste that is largely insoluble in water and results in little water loss
Where do turtles crocodiles and marine birds excrete salt?
orbital glands near eyes
Where do sea snakes excrete excess salt?
sublingual glands under tongue
Where do lizards excrete excess salt?
nasal glands
Define Ectothermic
use of environmental temperature to regulate body temperature
Why are reptiles the best thermoregulators?
reptiles use environment and therefore don’t need to eat as much for metabolism
fish are limited by areas of low spatial thermal heterogeneity
- geography limited, swim long distances to reach different temps
Amphibians are limited by vulnerability to dessication
- warm usually = dry and would suffocate
Birds and mammals use behavioral thermoregulation to stay within an ambient temp range w/in which they can maintain body temp
Where do alot of invasive reptiles originate?
as released pets
