was pangea before or after the Mesozoic era
before
when did the continents begin to break apart
late in the mesozoic era, sea level also rose
what effect does pangea breaking have on dino evolution
formed the western interior seaway.
Pangea caused seasonality (extreme weather interior), Pangea broke apart due to extreme heat in the interior, ice capps melted causing sea levels to rise and create the western interior seaway which swallowed most of interior of Canada. This caused more maritime weather which is less extreme and more ideal for living things like dinos. With this break apart the dinos were separated, no longer mixing/evolving together and were now evolving seperatly.
what drove diversification out of the dinosaurs
- pangea breaks up- dinos no more mix cause the continents are split. Dinos and vegitation evolve seperatly (high diversity)
- pangea- dinos can mix, leading to widespread distributions of families (low diversity)
what did dinosaurs eat
ferns, horse tails )sphenopsids), gymnosperms )naked seeds), possibly angiosperms towards end of creatous era as it is found in coprlite
evolution of dinosaurs
chordates
vertebrates
tetrapods
amniotes
diapsids
archosaurs
dinosaurs
defining feature of chordates and animal
- notochord
- pikaia
defining features of vertebrates (2) and animal
- skeleton and jaw/lobes
- tiktaalik
defining features of tetrapods (2) and animal
- 4 legged & skeleton structure
- frog
defining feature of amniotes and animal
- amniotic egg- helped in surviving birthing on land
- mammals (synapsids aka. one hole in head)
defining feature in diapsids and animal
- 2 holes in head (4 total)
- snake/mosasaur
defining features (2) of archosaurs and animal
- socketed teeth (continues to replace teeth all throughout life)& antorbital fenestra for a stronger jaw
- pterosaurus
tetrapod skeleton
- four limbs
- spine
- girdles (scapula, pubis, illium, ischium
- skull with mandible
- tail
why is amniote eggs useful for evolution?
- hard like shell, can be laid on land, membrane containing embryo
- reduces dependance on water to lay eggs and resulted in stronger skeletons with less felxible vertebrae. Allowed animals to colonize interior land that is more hot and further from water
anapsids
no openings (temporal fenstra)
ex. turtles
synapsids
one opening (temporal fenstrae) (2 total, counting both sides of skull)
ex. mammals
diapsids
two openings (temporal fenstrae) (4 total)
ex. dinosaurs
what animal is a synapsid but part of the diapsids time?
dimetrodon
there was a split 300 MA where dimetrodon was born in diaspid time but was a synapsid
euryapsid
type of diaspid that split off from diaspid in the triassic
types of euryapsids
- Ichthyosaurs- triassic to mid creatous, dolphine like reptiles not a mammal
- Plesiosaurs- Early jurrasic to end of creatous
defining feature in dinosaurs and animal
advanced mesotarsal and erect stance
chicken
