REPTILES Flashcards
(25 cards)
important clades of interest within Tetrapoda
- reptiliomorpha
- amniota
Define monophyletic
monophyletic group, or clade, is a group of organisms that consists of all the descendants of a common ancestor
Define polyphyletic
derived from more than one common evolutionary ancestor or ancestral group and therefore not suitable for placing in the same taxon.
Define paraphyletic
(of a group of organisms) descended from a common evolutionary ancestor or ancestral group, but NOT INCLUDING all the descendant groups.
Describe the 3 layers of the amniotic egg
- chorion
- amnion
- allantolis
Amniotes bypass the ___ stage and therefore don’t have to lay eggs directly in ____
larval
water
3 different types of skull fenestration
1) ANAPSID - no hole in skull
2) SYNAPSID - single hole behind eye
3) DIAPSIS - 2 holes in skull
Sauropsida inclues the ____ and ___.
anapsids
diapsids
Why is terrestrial life hard?
- conflict between locomotion and breathing
- high O2 consumption requires efficient gas exchange structures
- high metabolism produces lots of heat which is difficult to retain without insulation
- excretory systems required to remove nitrogenous waste and conserve water
How do lizards locomote?
- paired limgs
- undulations of body in short bursts
What is advantageous about bird bipedalism?
- reduces contractions on chest
Crocodile locomotion
lung ventilation aided by movement of the pelvis and GASTRALIA
3 key elements to lung ventilation in alligators using gastralia
1) pubis rotation
2) diaphragmatic muscle contracts pulling liver foward and expanding thoracic area
3) intercostal muscles contract and pull ribs and gastralia forwards with it
What are gastralia?
ventral ribs in crocodiles
The ancestral amphibian lung developed into (a) lungs with branching air sacs seen in (b) as well as the faveolar lung, which uses (c) air flow and is seen mainly in (d).
a) alveolar
b) mammals
c) faveolar
d) birds
Why is it difficult to tell what lungs dinosaurs had? Quite likely that they had ___ lungs.
- soft tissue doesn’t fossilise
- faveolar
Aim of ectotherm body plans
large surface area
Why are most endotherms big?
- costs of energy production higher so this is more expensive in smaller organisms
How did Sauropsids remove waste? Why not ammonia?
Through uric acid, allows management over water loss
- ammonia however, is soluble
Lepidosaur groups
- Sphenodon
- Lizards
- Snakes
Lizards underwent huge limb reduction into 2 ecotypes
1) short tailed burrowers
2) long tailed for dense vegetation
ARCHOSAUR groups
Crocodiles
Dinosaurs
Birds
Huge dinosaur evolutionary breakthrough?
ANKLES - allowed hind limbs behind body in an erect stance with no twisting
Suborder (a) of the Archosaurs shows giganothermy.
Sauropoda
