Start of phanerozoic/paleozoic/cambrian

539mya

end of paleozoic/start of mesozoic/start of triassic

252mya

triassic/jurassic boundary

201mya

jurassic/cretaceous boundary

143mya

end of mesozoic/end of cretaceous, start of cenozoic/paleogene

66mya

initially formed horizontal, any movement happened later. Cake was baked horizontally no matter how it looks later

principle of original horizontality

order of formation is bottom to top depending on what it looked like when horizontal. You need to put the bottom on the cake before middle and top

principle of superposition

if something intrudes into layers it is cutting through layers, which means it has to be younger than layer it cuts through. The cut is younger than the cake

principle of cross-cutting relationships

flat layers on top of folded layers

angular unconformity

layers of different rock types, ex; igneous and sedimentary

disconformity

horizontal layers on horizontal layers

nonconformity

around when did the earliest metazoans (multicellular organisms) show up?

600mya

what important type of creature evolved in the cambrian that led to the beginning of real diversity of life?

bony fish

what are the two groups of bony fish?

ray fin and lobe fin

what evolved from lobe finned fish?

tetrapods

what do tetrapods need to reproduce

water

what group split off from tetrapods?

amniotes

what does an amniote have that a tetrapod doesn't?

membrane around egg

when did amniotes evolve

carboniferous

what are the three groups of amniotes?

anapsid, synapsid, diapsid

what kind of amniote are mammals

synapsids

what kind of amniotes are dinos?

diapsids

when did mammals evolve?

late triassic

what groups did diapsids split into

lepidosaurs and archosaurs

are dinos more closely related to lepidosaurs or archosaurs

archosaurs

what two groups did archosaurs split into?

crocodilians and ornithodira

what groups did ornithodira split into?

pterosaurs and dinosauria

when did pterosaurs show up?

late triassic

what are the two groups of dinos?

ornithischians and saurischians

pubis points towards tail, all herbivores

ornithischians

pubis points towards head, some towards tail, both herbivores and carnivores

saurischians

saurischians split into...

saurischian dinosaurs and aves

when did flowering plants show up?

late cretaceous