EXTINCTION: “THE GREAT DYING” Flashcards
When were therapsids the dominant land animals?
(Late Permian thru Middle Triassic)
Were the dominant vertebrate fauna during the Triassic period
How do stable carbon isotope ratios (13C/12C) change during the “Great Dying”
What does this signify
Major decrease
Signifies release of 13C-depleted carbon into the atmosphere
Sharp rise of CO2 in the atmosphere
How do carbon isotope ratios (13C/12C) during the PTB mass extinction differ from those of the preceding Carboniferous?
carboniferous–coal was so buried during the time: Created increase in C13/C12 ratio bc burial depleted coal/org carbon so much in atm and ocean system
PTM–release of mass amounts of CO2 into the air and quickly. raised the amount of inorganic carbon in the atm/ocean system quickly which increased ph
Great Dying “kill mechanism”
Siberian Traps (large igneous province with extrusion of massive amounts of lava)
LIPs
large igneous provinces
Exaptation: evolution of jaw bones
evolution of jaw bones into ear bones during reptile-to-mammal transition (modification of pre-existing structures to serve a new function)
Morganucodonts (Late Triassic)
(Late Triassic): earliest true mammals, diminutive shrew-sized mammals
When were dinosaurs (diapsids) the dominant land animals?
Most of the Mesozoic Era: Late Triassic thru Cretaceous)
In general, what did the earliest dinosaurs look like?
Eoraptor: earliest and most primitive dinosaur
A lot of them were bipeda
How are dinosaurs distinguished from other reptiles?
Advanced mesotarsal joint- the main foot hinge is positioned between the first and second row of ankle bones
Ankle bones are fused to the shin
Astragalus larger than calcanem
Pterosaurs
ankle bones, advanced mesotarsal joint => first appear during Triassic Period
Evolution of Flight
convergent evolution in wings of pterosaurs, bats, and birds- super long pinky finger (4th digit) in Pterosaur wings
