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61 Cards in this Set

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how old is the Universe?
~15 BYA
how do we know the age of the Universe?
evidence the universe is expanding-- "red shift" is an increase in wavelengths of lightwaves travelling thru space
how old is Earth?
~4.6 BYA
how do we know the age of Earth?
radiometric dating-- measuring amts of parent and daughter isotopesin rock to find age in conjunction w/ their constant rates of decay
what is the basic structure of Earth?
inner/outer core, mantle. crust
why is this the basic structure of Earth?
impacts of giant bodies (mars) and decay of rad isotopes causes heat during Es accretion-- produces molten E, dense materials to center, less dense to surface
how does Earths structure influence its history?
less dense silicates floated to surface to produce magma ocean-- cooled to form feldspar rich coast-- precursor to todays oceanic crust
What is the geological tome scale?
organizes history of E into eons, eras, periods, and epochs. precambrian is rock w/o discernible fossils, cambrian is when fossils appear, fossils are boundary.
time zones: largest to smallest
eon, era, period, epoch.
what are the eras in the phanerozoic?
paleozoic- old life
mesozoic- middle life- dinos
cenozoic- modern life- mammals
dates of archean eon?
4.6-2.5 BYA
dates of proterozoic eon?
2.5 BYA-545 MYA
dates of phanerozoic?
545 MYA- current
what events separate the eons?
archean- life, rocks in Cratons, E gets structure
what was early Earth like?
*asteroids coalesced to form
*E emitted and retained gas to make own atmosphere
*volcanoes emitted: water vaopr (#1), hydrogen, HCl, carbon mono, carbon dio, N, methane, ammonia
*can't handle life- less oxygen
*oceans form from water vapor
*salts from rocks-> river-> oceans
*many meteorite impacts
*double the heat produced, lithosphere in small plates
When did life begin?
~4.2 BYA
how do we know when life began?
before 4.2 bya asteroid impacts produced to much heat for life to emerge
how does proterozoic geology differ from archean geology?
large cratons emerge late in archean-- deep water deposition and greenstone belts
large cratons persist thru proterozoic- extensive record of deposition in shallow seas; more unmetamorphosed sed rocks than archean available for study
what evidence is their for planetary snowball events?
ice cover ends land weathering
mo more CO2 drawdown
oceans become anoxic
volcanoes continue to release CO2 and levels rise
CO2 leads to Greenhouse Spring- 50C
explains post high weathering and tropical conditions
what evidence is their against snowball evens?
how did life survive?
couldve not totally frozen- keeps life
proposed duration isnt long enough
what is ediacarian fauna
the beginnings of modern life when animals burst onto scene at end of proterozoic
why is edicarian fauna important?
precursors to modern animals
why is ediacaran fauna different?
unskeletonized, no opening for mouth or anus, absorbed nutrients, preserved in mudstones
how did life change in the ediacaran and cambrian?
life emerges in proterozoic/ediacaran-- explodes in cambrian
how does cambrian fauna differ from ediacaran?
skeletonization, teeth, trilobites
origin
extinction
diversity
new species
last memeber of species dies out
# species present, #originations/extinctions
mass extinction
large % of species dies, global catastrophe-- loss of diversty, many taxa lost at once
Ordivician radiation
diversification in Ordovician
New marine species and genera originate at some of the highest rates known
Just as importantly, they don’t go extinct as quickly as Cambrian taxa
Cambrian fauna
trilobites, inarticulate brachiopods, weird stuff Mostly extinct (except the brachs)
paleozoic fauna
Articulate brachiopods (calcite, not apatite)
Bryozoans (new! Most complex colonial animals alive)Crinoids and other stalked echinoderms
Rugose and tabulate corals (extinct relatives of modern)
Some mollusks (nautiloids, primitive snails and clams)
Early fish and conodonts
mesozoic modern fauna
Much more active organisms (clams, snails, bony fish)
Paleozoic survivors often continue, but rare
how was silurian diff from ordovician
ordovician glaciation over-- warmer climates, rediversified seas for modern life
how did plants colonize land in devonian
vascular plants develop new tissue-- wood-- plants can stand on own, forests
how did plants change the world in devonian
plants cause nutrient crisis and global cooling-- leads to one of biggest mass extinctions in pahnerozoic (late devonian)
what happened to marine faunas during devonian?
fish radiate extensively before mass extinction kills of 57% of marine genera
how did late devonian extinction differ from end of ordocivian extnction
devonian caused by plants, ordovician extinction caused by glaciers and lowered sea level, cooling
how did coal start to form in carboniferous
how did climate change
cooling continues, seas recover, plants continue to dominate
first appearance of coal as massive coal swamps develop
brings down CO2
lack of greenhouse effect
more cooling
carboniferous: how did vertebrates colonize land? what enabled them to leave water?
insects most successful; first to use wings
amphibians colonize as herbivores/carnis etc; develop biting jaws
how did plate movements affect global environments in carboniferous and permian
carbo- gondwanaland heads north to collide w/ laurussia--results in alleghenian orogeny and development of pangea
perm- pangea heds north
allghenian continue--
extremely dry conditions, spread of desert belts
gondwanan glaciers shrink--warming--rising sea levels
how did enviros change from permian to triassic?
from greatest mass extintion of phanero in permian to triassic recovery and new diversification- raised sea levels, climate still warm and dry, another mass extinction at end of triassic
stresses triassic survivors had to endure
rising seas, hot and dry conditions, mass ex at end
how did ecosystems get reorganized in mesozoic
extinction in triassic, rediversification, dinos dominate
what adaptations allowed reptiles to dominate
upright stance, active, fast growing, social
how did pterosaurs adapt to take flight
developed long wings and hollow bones
how did the end-triassic extinction provide dinos with their big break
most terrestrial vertebrates killed off
what was a dino? what do we know about their lifestyle?
social animals, death assemblage, guard eggs, moved quickly, lots of activity, competition
who are the dinos closest living relatives
reptiles
what allowed plants to really diversify in the cretaceous
ascendency of flowering plants, angiosperms
evidenc of asteroid impact at end of cretaceous
wiping out of most genera, nuclear winter, global warming
10 km rock drops in mexico equivalent to
100 million megatons of TNT damage
who survives cretaceous asteroid
marine taxa that eats organic matter bc of large populations
small land animals
freshwater ecosystems (ex frogs)
omnivores
what is a mammal
enodthermic vertebrates characterized by body hair, legs positioned fully under body, sweat glands, some for milk
how did mammals adapt to life w/o dinos
cenozoic
grow larger to dominate
how did birds compete
how did they avoid competition in cenozoic
daytime v nighttime feeding with bats to avoid competition
how did sea life change in cenozoic
corals dominant again
calcerous plankton come back
vertebrates return to seas (ex whales)
evolutionary advances of plants in cenozoic
grass-- growth from bottom makes grazing ok
how does grass affect ecosystem/ grazers
rodents, snakes eat grasses

grazers must develop continuously growing teeth; grass silica wears down
major plate tectonics in cenozoic
continents continue to break up
collisions betw continents
CO2 drawdown from collisions-- massive glaciers
how did plate movement and climate affect distribution of species
cenozoic
species spread to other continents
what changes took place in apes over the last 7 million years
complex communication, use of tools, education, walk upright
how did agriculture/tools affect human lifestyle
leads to urbanization, massive populatoin rise, technology