Biol010/Geo003 Midterm 1

Paleontology

study of ancient fossils through the fossil record

Fossil

any preserved remains, impression, or evidence of behavior (trackway or nest or coprolite) of any once-living organism

Science

the pursuit and application of knowledge and understanding of the natural and social world following a systematic methodology based on evidence

Method

Make observation

Form question: collect data

Hypothesis: "educated guess"

Experiment: test hypothesis: collect more data

Analyze data: draw conclusions (starting point for new hypothesis)

radioactive decay

gives off heat which causes mantle convection and upwelling which pushes the lithosphere around on top of asthenosphere

"clocks in the rocks"

Decay is predictable but spontaneous- think gambling, popcorn, penny tossing

divergent boundary

plates move away from each other (e.g. Mid-Ocean Ridges)

convergent boundary

plates collide (e.g. subduction zones)

transform boundary

plates sliding past one another (e.g. San Andreas Fault)

Subduction Zones (convergent boundery)

"Where oceanic crust is destroyed"

-dense oceanic crust subsides beneath Continental Crust

Continent-Continent collison (convergent boundary)

equal density continental crust collides and "stick" together

-neither is destroyed

igneous rock

rock formed from cooled molten rock (magma or lava) (Box springs, Sierras)

Sedimentary rock

Rock formed from hardened sediment (Laguna, Newport)

Metamorphic rock

Rock that has been altered by heat, pressure, or chemical reactions

Silicilastic (Formation of Sedimentary Rocks)

sediment is weathered and eroded from highlands, then transported and deposited in lowlands

Carbonates (Formation of Sedimentary Rocks)

made of carbonate minerals (Calcite and dolomite)

Steno's Law of Original Horizontality

strata are horizontal when laid down

Steno's Law of Lateral Continuity

sediments form continuous layers

Steno's Law of Superposition

oldest strata at the bottom and youngest at the top

Isotope

an atom of an element with different number of neutrons

Half-life

time needed for 1/2 of parent to decay

Relative dating

ordering and geological time scale

Absolute Dating

measure of time

Taphonomy

what happens between death and discovery

Biostratinomy

before burial (biological destruction)

Diagenisis

after burial and before discovery (chemical destruction)

Biostratinomic

Surficial processes, scavenging, breakage, transport, etc

Mechanical destruction

Biological destruction

Diagentic

Post burial processes, deformation, compaction, erosion, etc

Chemical destruction

hard parts

organisms with mineralized skeletons dominate the fossil record

soft parts

organisms without mineralized skeletons are rare in the fossil record

Rapid Burial/ seclusion from environment

need to prevent physical damage, scavenging, and microbial decay

obrution

rapid burial

(Relatively Altered Soft Body Tissues are Rare)

Stagnation

anoxia (no oxygen)

(Relatively Altered Soft Body Tissues are Rare)

Rapid Mineralization

Carbonization, Pyritization

(Relatively Altered Soft Body Tissues are Rare)

Body Fossils (2 types of fossils)

represents piece of the actual organism, either the remains or the molted skeleton

Trace fossils (2 types of fossils)

evidence of animal behavior but DO NOT REPRESENT the animal's death

Concentration Deposits (Lagerstatten)

high diversity with decent preservation

Conservation Deposits (Lagerstatten)

exquisite preservation whole organism preservation, soft body preservation

depositional environment

where sediments are deposited, ultimately producing sedimentary rocks

Non-Marine Environments (Erosional environments)

Largely erosional; Cover only about 30% of Earth's surface; Not as good a record as marine (swamps, glacial deposits, rivers, lakes)

marine environment (Erosional environments)

overwhelmingly majority of depositional environments; about 70% of Earth's surface; best fossil record (beaches, reefs, intertidal, delta)

Sediments

Solid fragments of rock that come from the weathering of rocks and are carried and deposited by wind, water, or ice

earth age

4.5 billion years

Amniotic egg

345 million years ago (this expanded the success of vertebrates on land)

Permo-Triassic Mass Extinction

250 million years ago (96% of marine species go extinct unknown cause)

Parsimony

The simplest LOGICAL explanation is the best.

Mechanical Layers of earth

Lithosphere: Rigid/Brittle

Crust & Upper Mantle (made up of plates)

Asthenosphere: Plastic/Ductile Upper Mantle (slushy)

Cross-stratified

wind or water currents exerting force on a sediment

-Symmetrical formed by water moving back and forth-

-Asymmetrical formed by currents moving in one direction

Erosional environments

geological process in which earthen materials (i.e., soil, rocks, sediments) are worn away and transported over time by natural forces such as water or wind

Lagerstatten

fossil bonanza for soft bodied organisms

(sites of extrodinary fossil presevation they are almost "snapshot" in time)

Mechanical destruction (Biostratinomic)

wind, freeze-thaw, currents, waves, post-mortem transport, etc.

Biological destruction (Biostratinomic)

scavenging, rot, boring, etc.

Chemical destruction (Diagenetic)

Tissue destroyed by applying silver nitrate to the area