Test 1 Flashcards
(163 cards)
cladistics
uses relatedness to form phylogenetic trees
taxonomy
system of nomenclature that classifies some groups not based on monophyly or group size
ostracoderms
paraphyletic group - extinct, sister of jawed vertebrates
symplesiomorphy
shared ancestral trait among extant spp (condition of common ancestor, not reversal)
apomorphy
derived form of the ancestral trait - gives us synapomorphy when this develops in one ancestor for a branch of the tree
homoplasy
convergent evolution leads to same trait (not common ancestral, ie. wings)
autapomorphy
derived trait in a single lineage
eusthenopteron
fish with tetrapod characteristics but no limbs
when do vertebrates appear
phanerazoic eon
fossil time division hierarchy
eons > eras > periods
Periods in the paleozoic era
Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian
Periods in the mesozoic era
Triassic, Jurassic, Cretaceous
Periods in the Cenozoic era
Tertiary, Quaternary
Cambrian Period
541-485 mya. Explosion of diversifying multicellular life
Ordovician Period
485-444 mya, diversification of marine orgs
Silurian Period
444-419 mya, plants and arthropods move onto land
Devonian period
419-359 mya, age of fishes, tetrapods move to land!!
Carboniferous Period
359-299 mya, amniotes and big swamps (carbon deposits)
Permian Period
299-252 mya.. diversification of ancestral mammals and reptiles,, until the extinction. bad. 96% of spp extinct. due to big big volcanoes and global cooling and sea level change
Triassic Period
252-201 mya. diversification of reptiles to dinos, and the first actual mammals
Jurassic Period
201-145 mya. dinosaurs, 1st pterosaurs, lizards
Cretaceous Period
145-66 mya, most of the big dinos, snakes are invented. then… extinction sad face
K-T boundary
the meteorite… in Yucatan peninsula. Killed 76% of spp, mostly large ones.
Tertiary Period
66-2.6 mya, modern terrestrial verts start up