Describe the key features of the Triassic:
-A great radiation of reptiles began -Its end was marked by a mass extinction event due to the impact of a meteorite -O2 levels drop to 15%
Describe the key features of the Jurassic period:
-Pangea become fully divided into Laurasia and Gondwana -Dinosaurs become the dominant large vertebrates -High levels of CO2 and O2 drops even more (11%)
Describe the key features of the cretaceous:
-Laurasia and Gondwana break apart into smaller continents. -Radiation of flowering plants
What are the terrestrial causes of extinction?
-Ecosystem can be really fragile due to their connectivness -Changing in the geology of the habitat -Biochemical properties of the atmosphere
What are the possible extra-terrestrial causes of mass extinction?
-Bolides -Transit through Spiral Arms/Gamma Burst
What are the two main cause of the PT extinction?
-Eruption of two bigs volcano -Breaking up of Pangea.
What are the three different types of skull?
-Anapsid -Synapsid -Diapsid
Describe the anapsid skull:
It has no fenestration at all.
Describe the synapsid skull:
A single lateral opening, no temporal opening behind the orbit.
Describe the diapsid skull:
Has two temporal openings.
What are the four components of an amniotic egg?
1) Amnion 2) Allantois 3) Chorion 4) Yolk sac
What are the features that distingush archosauromorpha?
-The presence of an antiorbital fenestra (in front of the eye). -4th trochanter on the femur
What are the features that distinguish crocodilians from other archosaurs?
-Development of a secondary palate -They have nostrils on the tips of the snout. -They have a septum in their heart.
What are the characteristics of lepidosauromorpha?
The skull has a dorsal temporal opening but lacks a lower temporal fenestra.
What are the characteristics of non-avian reptiles?
-Waterproof outer layer to protect from the dry environment. -They mute their skin -Developed new kind of kinetic jaws connected by elastic ligament -New sensory systems (thermal sensors).
What are the similarities between birds and therapods?
1) They have a S-shaped neck. 2) Hollow, pneumatic bones.