Studied by 16 people
What is science?
discovery, world is understandable through observations
belief knowledge
knowledge unique to each person
research knowledge
universal knowledge, observable and measurable
good science
doubt, recognize biases, several theories may be raised to explain one observation
observation
facts that should be repeatable from one person to the next
interpretation
hypotheses invented to explain observations
pseudoscience
reference to authority rather than observation, use science to promote a message even though its not based on science
plate tectonics theory
outer portion of the earth is broken into plates
What is a rock?
An aggregate of minerals and mineraloids
What is a mineral?
Naturally occurring
inorganic solid
orderly internal structure (crystal lattice)
definite chemical composition
whole earth composition
iron 32%
oxygen 30%
silicon 15%
magnesium 14%
sulfur 3%
most common silicate materials
quarts and feldspar
example: granite
earth’s core
solid inner iron core
less dense matter began to flow up from the core to make up the surface
deeper into the core, temps rise and pressure increases
accretion (solids form large objects-planets) , differentiation (melting, separates materials, heavier sink-core and lighter rise-crust), contraction (shrinkage from cooling)
crust composition
Oxygen 47% (O)
Silicon 28% (Si)
Aluminum 8% (Al)
Iron 5% (Fe)
Calcium 4% (Cl)
Sodium 3% (Na)
Potassium 2.5% (K)
Magnesium 2% (Mg)
common non-silicate minerals
carbonates, oxides, halides (salts), sulfates, sulfides, minerals composed of one element (gold, copper, sulfur)
coal
mineraloid NOT a mineral, made from plants- organic matter
3 types of rocks
igneous, sedimentary, metamorphic
igneous rocks
a melted rock that cools and hardens
What is the difference between magma and lava?
Magma: molten rock beneath the surface
pluton- glob of magma
sill- magma travelling horizontally
dike- magma traveling vertically
Lava: molten rock erupted onto the surface
two kinds of igneous rocks
intrusive - cool slowly beneath earth surface
extrusive, cool quickly on earth surface
sedimentary rocks
made of disaggregated bits of other rock
form at the earth’s surface
sedimentary rock process
weathering attacks preexisting rocks and produces sediment
sediment transported by either water, wind, or ice and pile up
deposited- delivered and stops moving
once in rest needs to be buried to become a rock
clastic sedimentary rocks
made from grains (pieces) that came from weathering
defined by grain size
sediment: gravel, sand, silt, clay
after burial: conglomerate, sandstone, siltstone, shale
chemical sedimentary rocks
made from chemicals that came from weathering of rocks
chemicals from fluids, and if concentration is high enough, becomes minerals
ex: carbonates- limestone
metamorphic rocks
heat and pressure cause preexisting rocks to change
occurs in solid NOT melted state
protolith (og rock)>> heat and pressure>> metamorphic rock
rock processes
uplift and weathering
burial and cementation and compaction
heat and pressure
melting
cooling and crystallization
plate tectonics theory
outer portion of earth is broken into plates
plates move and interact
3 kinds of plate boundaries
divergent, convergent, transform
divergent boundary
plates pull apart resulting in the formation of new crust from magma
passive margin (no effects)
where?
ocean, rising magma is cooled by water
convergent boundaries
when plates collide, plates smash together
types of convergent boundaries
Ocean Crust vs. Continental Crust
Oceanic crust will always subduct because it is more dense(volcanos arise from subducting crust)
Continental Crust vs. Continental Crust
They collide resulting in the build up of mountains, produce earthquakes
Oceanic Crust vs. Oceanic Crust
older plate will give up and be subducted under the younger plate, formation of volcanic islands
transform boundary
plates slide past each other, earthquake!
plate tectonics evidence: divergent
mid ocean ridges, age of ocean crust
plate tectonics evidence: convergent
earthquakes, volcanoes
general plate tectonics evidence
hot spots and magnetic strips
importance of plate tectonics
control rock cycle
environment
set of conditions that exist today in a particular location
controls sorting of sediment
energy of env controls grain size
Sorting of sediment
Windblown sand: very well sorted
Beach sand: well sorted
River sand: moderately sorted
Glacial sediments: very poorly sorted
terrestrial environment
on land NOT in the ocean
coastal environment
shallow marine environments, lots of fossils come from here
marine environment
deep sea
paleoenvironments
ancient environments
high energy environment
moves large sediment pieces
gravel>> conglomerate
intermediate energy environment
movement, but not too much, can move sediment
sand>> sandstone
low energy environment
can’t really move sediment pieces
fine grained sediment
silt-clay>> siltstone-shale
sedimentary structures
physical features formed during sediment transport/ deposition
flat laminations
ripples
dunes
mud cracks
raindrop impressions
Flat laminations
grains fall out of suspension
low energy/ quiet water
asymmetric ripples
flow in one direction
cross strata dip in direction of flow
sediment will be coarser
not flat or parallel
medium energy
symmetric ripples
back and forth flow
tuning fork
medium energy
dunes
asymmetrical
constrained by depth of flow (air), so can get huge!
subaerial (windblown)
high energy
mud cracks
environment dried out!
no flow and indicates water depth
raindrop impressions
environment dried out but it was also raining
eolian wind environments
well sorted
major rock types; sandstone
frosted grains bc sand is hitting against it
beaches
well sorted sandstones
symmetric ripples indicating oscillatory flow
braided river
major rock types: sandstone and conglomerates
high energy
moderately to poorly sorted
asymmetric cross bedding
murky water bc fine grain is carried by water
glacial environment
major rock type: tillite
poorly sorted
high energy
rocks are faceted instead of rounded
flattened instead of like in water where its rounded
nils stensen
fossils were remains of past organisms by using the shark tooth
17th century
kinds of fossils
body, trace and chemical
body fossils
physical remains of an organism
ex: shells, bones, compressed plants, petrified wood
informs about morphology
what It could do when it was alive
trace fossils
evidence of activity
not the organism itself
ex: footprints, worm trails, coprolites (fossil poop)
informs about what the organism did and how it interacted with the environment
chemical fossils
chemical evidence of past life
ex: isotopic signatures, organic molecules attributed to life
only certain chemicals made by life or certain groups
ex: cholesterol or remains of cholesterol
informs metabolism
isotope
Element with same number of protons, different number of neutrons
life tends to prefer lighter isotopes
concentration of 12C in a rock could indicate the past presence of life, and would represent a chemical fossil
fossilization potential
bias towards hard parts rather than soft parts
bias towards low energy
bias towards ocean rather than land
taphonomy processes
occurs after the organism dies but before it becomes a fossil
organism must survive this process to become a fossil
types of taphonomy processes
Biologic attack
Ex. Borers, scavengers
Mechanical attack
Ex. High energy environments
Chemical attack
Ex. Weathering
Steno’s conclusion about geologic time
superposition and original horizontality
superposition
oldest layer at the bottom with successively younger layers above
original horizontality
Sedimentary rocks form horizontal layers \n Thus, inclined sedimentary rocks suffered subsequent disturbance (tectonics!)
crosscutting relationships
Something that cuts across or affects another layer must be younger than the material that’s being affected
stratigraphic columns
Environmental description of each layer
fossil succession
George Cuvier- 1800s
fossils occur in an order
some appeared in a layer and then never appeared again
extinction!
William Smith- 1800s
rock types change from place to place
young with young fossil and old with old fossil, always!
index fossils
widespread
short lived
can subdivide geologic time into smaller units
relative time, no date, just sequence of events
geologic time scale
a record of geologic events and life forms in Earth’s history
relative
Eon
Phanerozoic
era
in order from youngest to oldest
Cenozoic (age of mammals)
Mesozoic (age of dinosaurs)
Paleozoic (age of tribolites)
Paleozoic periods
in order from youngest to oldest
Permian
Carboniferous
Devonian
Silurian
Ordovician
Cambrian
Mesozoic periods
in order from youngest to oldest
Cretaceous
Jurassic
Triassic
Cenozoic periods
in order from youngest to oldest
Neogene
Paleogene
relative time
The sequence in which events took place
Chronostratigraphic
absolute time
the actual time (usually measured in years) as determined by radiometric age dating
Chronometric
What rocks can be radiometrically dated?
Igneous and Metamorphic
time vs rock
time is continuous but abstract and rock is discontinuous but tangible
meteorites
leftover bits from the formation of solar system
sedimentary record
sediment accumulation rate varies from place to place
gives snapshots versus continuous record
taxonomy
the science of classifying organisms
looks for differences
phylogeny
the study of the (evolutionary) relationships between groups of organisms
looks for similarities
species
Basic unit of taxonomy and phylogeny
Biologic definition
A population of organism capable of interbreeding and producing fertile offspring
Genetic definition (better)
Based on the similarity of DNA in a population
% of similarity
morphological species concept
based on similarity of appearance
morphology = shape
DNA encodes for shape
Genes control shape, genes control morphology, so both concepts linked
cladistics
based on parsimony
simplest is the best
branching, things don’t directly change, different branches to create more diversity
cladistics vs parsimony
min steps are the best, fewer assumptions
step 1: define characters of taxa
find characteristic that is either exclusive or common
step 2: construct character matrix
quantitively assign characteristics to the taxa
step 3: construct tree using parsimony
how closely taxa are related to each other based on how many characteristics they share
parsimony tree
clade- include the common ancestor and ALL its descendants
paraphyletic
does not include all descedants
poyphyletic
does not contain the most recent common ancestor
DNA
deoxyribonucleic acid
the blueprint for life
polymer of nucleotides
central dogma of biology
DNA>> RNA>> Protein
who discovered dna?
Rosalind Franklin, James Watson and Francis Crick
code of DNA
pairs of 4 nucleotides
Sequence of dna catalogs the order of adenine, thymine, guanine, cytosine (nucleotides)
A+t and g+c, only!
Replication of DNA
DNA Polymerase copies DNA very accurately
Transcription of DNA
RNA Polymerase converts DNA to mRNA
Genes are transcribed into mRNA
Translation of DNA
Ribosomes translate mRNA into proteins
Note 
Flashcard (78)