12.05 Life in Phanerozoic Flashcards
1
Q
How much Oxygen is in the sedimentary crust?
A
35x present day atmosphere?
2
Q
Which has been proposed as a trigger for the Cambrian Explosion?
A
- Evolution of body patterning HOX genes.
- Evolution of large-bodied predators.
- Increase in atmospheric O2 concentration.
3
Q
End-Ordovician Extinction
A
- Drying up of seas due to Glacier formation.
4
Q
Permian mass Extinction
A
- Sea level fall.
- CO2 perturbation due to volcanism.
5
Q
How did Amphibians appear?
A
Crawling fish?
Lobe-finned Fishopods turn into Reptillian Amphibians.
6
Q
How did Reptiles and Mammals appear?
A
Hole in the head of Reptile lineages turn into mammals.
Diapsids Reptiles turn into predator alligator style.
7
Q
Triassic
A
First dinosaurs.
