Final flashcards

Question 1

historical earth formation/creation views

Answer 1

• pre 19th century based on religious views
• james hutton seen as father of geology - concept of uniformitarism
• 1700s noahs arc questioned
• james usher based on biblical calculations said it was since 4004B.C

Question 2

correlation

def and methods

Answer 2

stratiagraphy - how rock layers are stacked on top of eachother to determine history of an era

methods:
1. physical continuity
2. similarity between rock types
3. correlation with fossils (index fossils and fossil assemblage)

Question 3

Geologic time scale: key periods

Answer 3

• earth, 4.6by (human lifespan only 0.000002% of this)
• precambrian, 544my-
• paleozoic, 251my-
• mesozoic, 65my-
• cenozoic, present

Question 4

Isotopic dating methods

Answer 4

1. Radiocarbon dating (ratio of carbon12 to carbon14, for less than 44,000y)
2. Comogenic isotope dating (neutron radiation bombardment, surface exposure dating)
3. Fission track dating (large nuclei (uranium) split into small nuclei, analyse damage trails - purpose to investigate thermal history)

Question 5

Geologic time scale with subdivisions

Answer 5

1. Eons - Hadean (4.6-4by), Archean (4-2.5by), Proterozoic (2.5by-541my), Phanerozoic (541my-present)
2. Eras - Paleozoic, Mesozoic, Cenozoic
3. Periods - P( Cambrian, Ordovician, Silurian, Devonian, Missisipian, Pennslyvanian, Permian), M( Triassic, Jurassic, Cretaceous), C( Paleogene, Neogene, Quarternary)
4. Epochs of Cenozoic era - P( Paleocene, Eocene, Oligocene), N( Milocene, Pliocene), Q( Pliestocene, Holocene (current) )

Missisipian and Pennslyvanian reffered to as Carboniferous outside US

Question 6

Influential evolution figures

Answer 6

1. Buffon 1707-1788 - first to support evolution, adaptation and inheritance (didnt work as he though earth was only 75,000y)
2. Erasmus Darwin 1731-1802 - small generational changes in breeding & environmental adaptations, relationship between environment and heredity (couldn’t explain it)
3. Lamarack 1744-1829 - inheritance of aquired charaterisitics, giraffe example, laws 1. traits from evolution preserved by heredity 2. organs grow stronger with use
4. Charles Darwin - 1859 published “On the Origin of Species by means of Natural selection”, vast species diversity & competition for food, high offspring mortality rate, survival favouring best adapted, natural selection (poorly adapted dont reproduce), ex galapagos finches (14 species adapted to fit their environment) - incomplete theory (didnt explain how traits arose and heredity)

Question 7

Evidence for evolution

Answer 7

1. Branching organisation of life (ex. humans -> primates -> mammals -> invertebrates -> animals), anatomical comparison (98% similar to chimpanzees)
2. Homology - organs with different functions share same structures
3. Vestigal structures - remnants of unused structres organs eg. tailbone
4. Embryonic history - ex. gills (suggest shared ancestory)
5. Biogeography and evolution - unique regional species, ecological convergence (different species adapt the same way in the same environments), modern evidence (bacteria withstanding pesticides and antibiotics)

Question 8

Heredity discovery

Answer 8

Gregor Mendel 1822-1844
laws of heredity with famous pea plant experiment

Question 9

DNA Discovery

Answer 9

1944

Question 10

Modern evolutionary concepts

Answer 10

1. Fossil record - patterns of divergence and adaptive radiation (ex after dinosaurs went extinct, mammals diversified to fill niches)
2. Phyletic gradulism - slow changes
3. Punctuated equilibrium - rapid changes followed by static

Horse evolution: initially thought it was gradual, now know there is a bushy family tree with co-existing species & punctuated equilibrium

Question 11

Hadean

Answer 11

First 500my
* molten surface, few cooling fragments forming early microcontinents
* intense meteorite bombardment
* moon 2x closer to earth
* atmosphere lacked oxygen, N2, methane, ammonia, CO2, water vapour

Geological evidence:
* oldest zircons (4,400my)
* ocean formed from precipitation
* stratification of earth and crest (how scientists divide and organise earth and its crust)

Question 12

Archean

Answer 12

3,800-2,500my

Oldest rock formations, most underwent significant metamorphism making original formations unclear

Younger rocks (pillow like structures) indicate underwater lava flows, suggests earth largely ocean covered

Continental accreation: ancient cores formed through orogenic episodes

Greenstone belts: mafic igneous and clastic sediments
Gneiss belts: stromatolites in chert beds and fossils incdicate simple life (prokaryotes, single cell and non nucleated)

Question 13

Early earth atmosphere experiment

Answer 13

1953 lab experiment stanley miller

Question 14

Proterozoic

Answer 14

2,500-540my

rise of oxygen - BIFs (metallic iron & chert), red strata (red beds)
first eukaryotes (nuclei, subcellular structures)

multicellular life evolved 600my

Edicaran fossils - large soft bodied, replaced by animals with skeletons 550my (cambrian)

Question 15

Late precambrian

Answer 15

Varangian glaciation (600my) - near total refridgeration (mass extinction of micro organisms)

Key fossils and evolutionary milestones
oldest fossils stromatolites (3.5by formed by cyanobacteria)

Rodinia began splitting up due to rifting

Question 16

Cambrian explosion

Answer 16

rapid diversification of life including trilobites, molluscs, echinoderms and brachiopods

Question 17

Early cambrian

Answer 17

fragments surrounded by slowly sibsiding passive margins (slowly sink into the earth)

Question 18

Late cambrian

Answer 18

continents nearly submerged, marine transgression of craton

Question 19

North American (Cambrian) Craton

Answer 19

Folded strata along continental margin

Transcontinental arch - key feature

Sedimentary pattern - passive margin (thick deposit of shallow marine sediments, mostly quartz sandstone)

Interior basins (low deposition due to shallow water)

Question 20

Paleozoic Orogenies

Answer 20

Taconic (Ordovician):
* Seperation of lapetus ocean (North America and Europe)
* Collision between north america and volcanic arcs, microcontinents led to deformation
* transition of north east america from passive to active margin

Acadian (Devonian, Missisipian):
* collision of North America with microcontinent avalonia
* closure of lapetus ocean
* intercratonic orogenic fault forms due to continent-continent collision

Allehegian (Carboniferous-Permian)
* closure of pro-atlantic ocean due to collision of north west africa (part of gondwana) with north america
* formation of pangea
* thrust faults and folding elevated appalachian mountains

Question 21

Pangea formation

Answer 21

aggregation of all continents during late paleozoic

Question 22

late paleozoic

Answer 22

late paleozoic sedimentation: transgressive and regressive cycles (2my)

coal formation in pennslyvanian coastal plain swamps

permain mass extinction (95% marine species, 70% land species)
causes:
1. climactic fluctuations, greenhouse warminng, massive volcanic eruptions

Question 23

Ecological advancements

Answer 23

Ordovician

complex food webs primary producers algae and plankton

top predators gaint nautiloids (2m)

feeding levels extended below and above sea floor

Question 24

Additional mass extinctions

Answer 24

late ordovician: sea level changes, glaciation

late devonian: major marine extinction, ammonoids and other species

Question 25

First land plants

Answer 25

late ordovician, forests made of primative of vascular (plumbing system) plants 10m tall

Question 26

Vertabrates

Answer 26

fish diversified, devonian age of fishes oldest amphibian in upper devonian similar to lobe finned fish late devonian - amphibians evolved from lobe finned fish late paleozoic - amphibians like eryops reached 2m long and 130kg, diplocalus (triangle head), athrocosaurus gave rise to reptiles reptiles emerged during pennslyvanian with amniotic egg (life on land)

Question 27

Burgess shale

Answer 27

unique preservation of soft body parts in fossils stromatolites (3.5by) declined in cambrian due to grazing invertebrates

Question 28

True corals

Answer 28

not evolved yet during cambrian, ecological niche occupied by archeocyathids (sponge like organisms formed from earlier rifts) 2 more groups: brachiopods - spiral/coral shape molluscs - shell shape

Question 29

Initial breakup of a super continent

Answer 29

heating, doming, block faulting, basaltic dikes, volcanic eruption, non-marine sedimentation (land, freshwater), initial sea floor spreading and marine sedimentation (evaporites), marine passive margins including reefs

Question 30

Triassic

Answer 30

initial breakup of pangea, north africa and europe still attatched to north america non marine sedimentation uncertainty about cordilerra terrane (west north margin of north america) Geological highlight: pallasides sills (NY) collumnar join basalt cliff, igneous intrusions forced between triassic layers forms western bank of hudson river (visible from jersey city, hoboken)

Question 31

Jurassic

Answer 31

Early: Initial sea-floor spreading and marine sedimentation North Africa moving away, but Europe still attached Evaporites deposited in the newly opened Gulf of Mexico Late: First major transgression of the western craton since Permian Africa moves far enough to allow normal marine circulation in Atlantic Basin, possibly forming a barrier reef Cordillera Orogenic Belt: Collage tectonics: Terranes (old arcs, ocean ridges, microcontinents) accreted to western North America

Question 32

Cretaceous

Answer 32

Western North American Margin: Plate tectonic hypothesis: Antler and Sonoma orogenies from arc collisions followed by reversal of subduction Andean-like arc formed at the continent's edge through eastward subduction Geological Features: Modern Andes Analogy: Subducted slab melts produced volcanoes and magma chambers (later forming batholiths) Major granitic batholiths lined up to form a volcanic arc, later shifted by Cenozoic faulting

Question 33

Sea level changes

Answer 33

Rapid sea-floor spreading in the Atlantic during the Cretaceous created high mid-ocean ridges Displacement of water from ocean basins led to a massive continental transgression, forming thick sequences of shale and chalk

Question 34

Cordilleran Mountain Belt:

Answer 34

Complex stacking of thrust faults in the Canadian Rockies Rise intensified during the Cretaceous, ending in the Eocene with uplift and volcanic activity Result of subduction and terrane collisions

Question 35

Mesozoic Life

Answer 35

Marine Life: Post-Permian extinction: profound changes in marine ecosystems Appearance of shell-crushing predators (crabs, lobsters, reptiles, fish) Dominance of bivalves, gastropods, and echinoids Key Fossils: Ammonoids: Widespread and common, ideal as Mesozoic index fossils Belemnites: Squid-like organisms, prevalent during the Mesozoic Land Vertebrates: Triassic Reptiles: Primitive Archosaurs dominated, including crocodiles, dinosaurs, and birds Dinosaur Evolution: Late Triassic: Primitive Archosaurs replaced by dinosaurs Two major groups: Saurischians (lizard-hipped): Gigantic sauropods, carnivorous dinosaurs Ornithischians (bird-hipped): Herbivorous dinosaurs

Question 36

Mammals:

Answer 36

First mammals appeared in the Late Cretaceous (mouse-sized, later cat-sized) Evolved from synapsids, with larger brains and complex reproductive behaviors

Question 37

Plants:

Answer 37

Flowering plants (angiosperms) emerged during the Mid-Cretaceous

Question 38

Mass Extinction at the End of the Cretaceous

Answer 38

Impacts: Wiped out dinosaurs, ammonites, marine reptiles, and invertebrates Hypothesis: Asteroid impact - high iridium levels (abundant in meteorites) foung at k-pg boundary sites globally Volcanic eruption - massive eruptions (india) released as into atmosphere inducing global cooling Regression - sea-level regression contributin to environmental stress Complex; suggests more than just 1 meteorite causing extinction

Question 39

Cenozoic Tectonics

Answer 39

Cordilleran Mountain Belt (Western North America): Experienced continental tectonism during the Cenozoic. Laramide Orogeny: Late Cretaceous to middle Eocene. Rocky Mountains formed by flexure and faulting of basement rocks. Sierran Arc: Ceased eruption likely due to shallow subduction of the Pacific margin. Middle Eocene to early Miocene: Volcanism returned in central Oregon, suggesting steeper subduction resumed. From Early Miocene to Present: Complex tectonic forces impacted the Cordilleran region. Coastal California transitioned from a subduction zone to a transform margin with the origin of the San Andreas Fault.

Question 40

Major Tectonic Changes

Answer 40

5 Million Years Ago: Baja California separated from mainland Mexico and began moving north. The Rocky Mountains and Colorado Plateau rose thousands of metres. Deep, narrow basins formed along faults. Modern Western US: Yellowstone hotspot migrated into Wyoming. San Andreas Transform fault dominates the Pacific Rim from San Francisco to Mexico.

Question 41

Hawaiian Hotspot Evolution

Answer 41

Hawaiian Islands formed gradually as the hotspot pierced the moving Pacific Plate.

Question 42

Alpine-Himalayan Orogeny

Answer 42

caused by collision of of Africa and Turkey with Europe causing Alps in Europe caused by collision of Arabia and India with Asia creating himalayan alps Complex folded structures formed, and the Tethys Sea closed.

Question 43

Early Climate

Answer 43

Paleocene and Eocene greenhouse climates persisted and warmed further. * Coincided with Mediterranean closure and sea level rise. Middle Eocene to middle Oligocene: Climatic deterioration began with cooling and Antarctic glaciation. Early Miocene: Warmer conditions returned briefly. Middle Miocene: Antarctic glaciers reappeared.

Question 44

Ice Ages

Answer 44

Late Pliocene (3 m.y. ago): Arctic ice caps emerged. Glaciers advanced in northern continents. Formed erratic boulders, scratched bedrock, and moraines. Lakes Formation Formed in: Closed valleys in arid areas away from glaciated regions, Ice margins. Panamanian Land Bridge Closure of the Panamanian bridge (between the Americas): * Prevented Atlantic and Pacific waters from mixing. * Warm currents moved north, increasing moisture and snow accumulation. Pleistocene Glaciation Characterised by multiple glaciation episodes: * Ice advanced/retreated every ~10,000 years. * Induced major changes in climate, sea levels, lakes, and vegetation zones.

Question 45

Hypotheses for Glaciation

Answer 45

1. changes in solar radition (hard to test) 2. Astronomical effects (earth-sun geometery) - eccentricity (ovular or circular), earths axial tilt, precession (slow wobble of earth's axis, impacts the timing of seasons) 3. terrestrial changes - (atmospheric transparency, earth surface reflectivity) 4. Heat exchange variations (affected by earths paleographic (continent stuff) changes)

Question 46

Life in the Cenozoic

Answer 46

Marine Life * Dominant Cretaceous groups (clams, snails, bony fish) persisted. * Ammonites and marine reptiles went extinct. * By the Eocene, whales evolved from land mammals to ocean predators. Age of Mammals * Surviving mammals, birds, and insects from the Cretaceous extinction underwent adaptive radiation (single specie evolves into many to fill ecological gaps) * Initial mammals were small during the Cretaceous but diversified in the Cenozoic. * Unique faunas developed due to the breakup of supercontinents during the Jurassic/Cretaceous: * - Example: Flightless birds (Ratites) evolved distinctly on each Gondwana continent. Land Bridges North and South America were once isolated, developing unique mammal species. Mid-Pliocene: Panamanian bridge rose, allowing species migration in both directions.

Question 47

Human evolution

Answer 47

1. First hominoid - Sahelanthropus (~6–7 m.y. ago in Eastern Africa) 2. First homo species - Homo habilis (1.75 m.y. ago) - Evolved two key traits: Brain size, Bipedalism. 3. Later Evolution: Homo sapiens neanderthalensis (~170,000 y. ago). Homo sapiens sapiens (~90,000 y. ago): * First modern humans appeared in Africa. * Arrived in Europe ~35,000 years ago.