GEO 102: EXAM TWO
78 Cards in this Set
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Eon
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unit of time equal to 1 billion years
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era
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a subdivision of an eon
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period
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a length or portion of time
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(etymology)
Phanerozoic
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"age of animals"
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(etymology)
Precambrian
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the age before animals
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(etymology)
Cenozoic
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recent animals
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(etymology)
Mesozoic
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middle animals
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(etymology)
Paleozoic
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ancient animals
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(etymology)
Proterozoic
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earlier life
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(etymology)
Archean
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beginning or origin (land/oceans/life)
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(etymology)
Hadean
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named after Hades, due to Hellish conditions on Earth at the time
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geologic map
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shows the geologic age of surface rocks
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'Strata'
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layers of sedimentary rock or soil with internally consistent characteristics that distinguish it from other layers
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Stratigraphy
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the branch of geology that studies the composition, origin, age, relationships, and geographic extent of strata
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Principle of Horizontality
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(STENO, 1669)
layers of sediment are originally deposited horizontally under the actions of gravity
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Superposition
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(STENO)
sedimentary layers are deposited in a time sequence, with the oldest on the bottom and youngest on the top
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Uniformitarianism
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(HUTTON)
believed in a weathering pattern of rocks, also in sedimentation rate
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Uniformitarianism
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(LYELL)
believed in a gradual change-slow process of erosion, proposed idea of rock cycle in 1880's
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lithostratigraphy
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using different types of rocks
(absolute age)
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chronostratigraphy
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using the different ages of rocks
(relative age)
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biostratigraphy
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using different fossil assemblages from rocks
(relative age)
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lithostratigraphy (definition)
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rocks defined and organized by their observable physical features
can be sedimentary, igneous or metamorphic rock
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chronostratigraphy
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studies the absolute age of rock strata
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radio active decay (radiometric)
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changing of atomic mass (weight) of radioactive elements over a certain period of time
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paleomagnetism (paleomag)
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the study of the earth's record of the earth'a magnetic field in igneous, and some sedimentary rock
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Radioactivity
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changing in atomic mass
radioactive elements have high atomic #'s
half life, is the duration of the decay
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Paleomag
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polar wondering- paleomag of ancient rocks shows orientations different from present magnetic field
magnetic record in rocks through time
sources of iron bearing minerals
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Arthur Holmes
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(1890-1965) pioneer of geochronology; first established Uranium-Lead dating
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Harry H. Hess
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(1906-1969)
pioneer of paleomagnetism
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paleontology
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the study of creatures/organisms/life in the past
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what do paleontologists study?
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fossils
rocks
living organisms
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fossil
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any remains of an organism from the past
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'fossus'
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latin, meaning dug up
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body fossils
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shells, skeletons, bomes, skins, feathers, eggs, etc.
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trace fossils
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nests, burrows, trackways, coprolites
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Why is paleontology important?
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origins of life
evolution
extinction
age of rocks & earth
paleoecology
fossilization
energy sources
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ammonites
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are the extinct group of cephalopods in mollusks; very common in the mesozoic
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ammonites
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the study of the process of living things into fossils
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William 'Strata' Smith
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(1769-1839)
established the ideas of biostratigraphy through faunal succession
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faunal succession
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rocks characterized by a unique set of fossil taxa
a group of fossils (fauna) representing diversity in time
the occurrence of many fossils, possibly restricted in the rock unit
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biostratigraphy
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the study and categorization of rock strata based on their fossil content and distribution
defined by first and last appearance of index fossils & fossil assemblages
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index fossils
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very common
geographically widespread
easily preserved
diagnosable for species
found in multiple environments
short species duration
(ammonites)
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evolution
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'change through time'
a process of change in a certain direction
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Thomas Malthus
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(1766-1834) first coined the term evolution
studied how a population changed over time
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biological evolution
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descent with modification
branching of speciation
change with genetic inheritance
(fossil fish species show descent w modification)
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morphology
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changes in the forms and structures, including internal and external body ( head, legs, skeleton, skull, tissues, cells, molecules, DNA)
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Microevolution
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changes on a small scales within a single population
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macro evolution
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groups larger than an individual species
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gradualism
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changing consistently through time
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stasis
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changes not evident or very weak through time
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Lamarck's theory of evolution
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(1744-1829) the theory of inheritance of acquired characteristics "use vs. disuse"
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"Evolution is a fact but not a theory"
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Origin of species
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(DARWIN)
1859, 1872
variation (among individuals)
blending inheritance of traits
geographical isolation (of populations)
earth's age & fossils
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Natural Selection
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Variation in traits
Differential reporduction
Heredity
End Result
VARIATION + DIFFERENTIAL REPRODUCTION + HEREDITY = NATURAL SELECTION
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Neo-Darwinism
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Mutations
Gene flow
Sex
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Precambrian shield
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large tracts of exposed metamorphic rocks in the continental interiors, some of the oldest crustal rocks
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Platforms
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more shield buried under sedimentary rocks
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Cratons
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collective body of platfoms and shields
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What can precambrian shields tell us?
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the origin of the continents
origin of the oceans
the early earth's atmosphere
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Hadean Eon
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(4.6-4.0 BYA)
Meteors
Differentiation
First crust formed
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Archean Eon
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(4.0-2.5 BYA)
Little volcanic islands smashed together along subduction zones making protocontinents
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Archean Eon
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layers of chert and oxidized-iron rich minerals, indicating large presence of oxygen in earth's atmosphere
2.5-2.0 BYA
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orogeny
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the formation of mountains, usually accompanied by igneous activity, metamorphism, and crustal thickening
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"Rodinia"
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first super-continent
1.3-1.0 BYA
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what constitutes life?
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chemically distinct entity that interacts with its surroundings to derive energy, and is capable of self replication
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life
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has cells, which come from preexisting cells capable of adaptation, reproduction and death
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what are the conditions necessary for life?
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liquid water
chemical elements
sources of energy
sustainable environmental conditions
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what are the conditions necessary for life?
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prokaryotic cell, no nucleus membrane, simple structure
produced the major component of the earth's oxygen during the precambrian
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stromatolites
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most common fossils (2.0-.75 BYA)
a mounded structure built up over long periods of time by layers of cyanobacteria that trapped sediments
photosynthetic organism producing O2
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eukaryotic cell
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membrane for nucleus
multiple organelles
complex
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prokaryotic cell
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no membrane for nucleus
small
simple structure, no organelles
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metazoans (animals)
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multicellular
heterotrophic
terrestrial and aquatic
mostly sexual
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Ediacaran biota
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assemblage of first multicellular organisms
fossils that exhibit only molds (impressions) of body parts or tracks, but no actual body remains
600-542 MYA
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Ediacaran fauna
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early definitive animals
large (huge) body size
no hard tissues/skeleton
no direct link to living and cambrian animals
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Geologic map
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shows the age of surface rocks
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Precambrian is an
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eon
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Stratigraphy
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study of rock types, age of rocks, rock distribution
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da Vinci
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earliest interpretor of fossils
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GEO 102: EXAM TWO