16: Amniotes (Reptiles) Flashcards
When do we see reptiles form?
Carboniferous Period, 350 million years ago
What are the three major branches?
Synapsida
Anapsida
Diapsida
When did the dinosaurs go extinct?
End Cretaceous
When did turtles appear?
Mesozoic
When was the earliest reptile fossil from?
315mya
What was the earliest reptile fossil?
Tracks showing 5 fingers and scales
Can see position of legs, how they moved
Hyolonomus Iyelli
Examples of anapsids
Stem reptiles
Turtles
Tortoises
Examples of euryapsids
Ichthyosaurs
Plesiosaurs
Examples of diapsids
Crocodiles Snakes Lizards Pterosaurs Dinosaurs Birds
Examples of synapsids
Mammal-like reptiles
Mammals
What are Ichthyosaurs?
Thrived in the Mesozoic
Sea reptiles
Evolved from unknown land reptiles
Viviparous
Function of the shell
External protection
Interaction with environment
Permeable
Function of the chorion
Allows nutrients to pass between
Protection
Function of the allantois
Sac that facilitates respiration
Stores waste
As yolk sac empties, allantois fills
Fuses with chorion
Function of the amnion
Covers embryo when it forms
Fills with amniotic fluid, which protects embryo
Function of yolk sac
Nutrients for growth
Difference between fish/amphibian eggs and reptile
In fish/amphibians there is only one membrane
Called the embryonic (Vitelline) membrane
How many EXTRA skull holes do diapsids have?
2 on each side (4 in total)
How many EXTRA skull holes do anapsids have?
0, just eye holes
How many EXTRA skull holes do synapsids have?
1 on each side
What are the skull holes called?
Fenestrae (single is fenestra)
Early reptile anatomy
Larger humerus than sarcopterygians and primitive amphibians
5 digits
Longer radius and ulna
Can support own body weight
Advantages of being a reptile
Free of water
Access to different food
Avoid predators in water
Egg safety
Exaptations that reptiles needed to have before move to land
No metamorphosis- only grow
Lay eggs on land
Internal fertilisation