Reptiles Flashcards
(18 cards)
Amniotes
reptiles and mammals, develop an amnionic egg
Embryonic membranes
Amnion - protects embryo
Amnionic fluid - keeps embryo wet
Yolk sac - provides nutrients
Allantus - Waste storage
Albumen - Protein
Amniote innovations
keratinised scales for water conservation so no more skin breathing
rib breathing, more expansion so more o2
Reptile characteristics
body with horny epidermal scales
pair limbs, usually 5 toes
bony, ossified skeleton
no gills
3 chambered heart
ectotherms
internal fertilisation
Crocidylia
crocodiles
aquatic predators
inflate their lung using their liver
Testudines
turtles and tortoises
ossified plate on chest and carapace on top which ribs are fused to, makes breathing hard
Squamata
snakes
developed from lizards
lost legs, breathe through a trachea
non-fused skull to absorb large prey
Role of venom
block acetylcholine receptors and prevents neural signal transmission
causes tissue necrosis (pre-digesting tissue)
Sphenodonta
tuatara
- 2 bony arches on back of skull
- teeth fused to jaw
- no external earhole
- well developed parietal organ
Capturing air: Salamander
simple air sac, still gets oxygen from skin
Capturing air: lizards
intercostal muscles in between ribs expand, negative pressure
breathing through nose to reduce water loss
Capturing air: tortoise
ribs fused to carapace so hard to breathe, leg muscles while walking pump the lungs
Capturing air: Crocodile
use liver to relax and contract lungs, palate that seals trachea when underwater
Reptilian circulation
double circulation with a partial septum, so some mixing of blood
Nitrogen waste products
Ammonia, Urea and Uric acid
lots of water to little amount of water
Ammonia
produced by aquatic animals, highly toxis, highly soluble
Urea
produced by aquatic and terrestrial
non-toxic
more costly
Uric acid
produced by animals with limited access to water
non-toxic
low solubility
