Geology 106 Exam 1 - Cornell

How old is the Earth?

approximately 4.6 billion years

Earth's history has been recorded in rock units and fossils. What are the 3 rock units?

metamorphic, sedimentary, igneous

What are some geologic events?

deformation, volcanic eruptions, climate changes, and mass wasting events

What is relative dating?

dating events by putting them in order without numbering events

What is the example given for relative dating?

trash pit: items on the bottom are the oldest and items on the top are the newest

What is absolute dating?

dating by numbering the events; radioactive dating

What are the 3 Precambrian eons?

Hadean, Archean, Proterozoic

What are the 3 Phanerozoic eras?

Paleozoic, Mesozoic, Cenozoic

What is mass extinction?

large groups of species going extinct at one time

How old did the early Christian scholars date the Earth?

6,000 years

What was the "Young Earth" theory?

theory made by the early Christian scholars of ideas mainly from the bible and genealogy

Who was George Louis de Buffon?

a French zoologist; believed that the Earth cooled and hardened from a molten state

How old did George Louis de Buffon think the Earth was?

75,000 years

Who was James Hutton?

'father of modern geology'

a Scottish geologist that established the Principle of Uniformitarianism

What is the Principle of Uniformitarianism?

"the present is the key to the past" used to determine how and when rock units and geologic structures were formed

What is the Principle of superposition?

age of rock layers, sedimentary rock layers, young on top/ old on bottom

What is the Principle of original horizontality?

dealing with sedimentary rock layers, parallel to rock surface, layers can be changed due to deformation

What is the Principle of lateral continuity?

3 locations with the same composition/ fossils but are not connected; valleys between eroded

What is the Principle of cross-cutting relationships?

rock layers that cut across other rock layers; cutting across=youngest, being cut across=oldest

ex: faults

What is the Principle of inclusions?

chunks of rock completely surrounded by other rock, older than surroundings

What is the Principle of fossil succession?

use fossil records to track change in geologic time/ region

What are unconformities?

contact between two rock layers when they deposit changes

What is a hiatus?

time gap that is not recorded in the rock record

What is a disconformity?

deposition of sedimentary rock layers, then more rock layers are above and below

What is an angular unconformity?

shows lifting and deformation of rock layers; erosion occurs during and after then layers build up horizontally

What is a nonconformity?

magma intrudes into rocks and cools causing igneous/ metamorphic erosion and then more settles on top

What is relative dating correlation?

matching geology of one location to another

What are key beds?

certain materials in each bed, most recent layers are not present; have distinct layers

What are index fossils?

lived a short time and preserve easily; fossils that are wide spread over geologic areas

Stratigraphic correlation example:

grand canyon national park, zion national park, and bryce canyon national park all have rivers that carved them and distinct layers

What is subsurface correlation/ geophysics techniques?

use physics to tell the interior of the Earth

ex: water/oil rings release energy; core samples, well logs, and seismic data give information

What did Henri Becquerel discover?

radioactive dating

What did Ernest Rutherford discover?

half-life and age-dating of rocks

What is the atomic # of an atom?

the number of protons; this distinguishes the element

How to you determine the atomic mass?

by adding the protons and neutrons

What is radioactive decay?

loss or gain of electrons; consistent period of time

What is a half-life?

how long it takes for half a radioactive element to decay

_______ rock is cooled magma that contains radioactive isotopes that turn into minerals and then its half-life clock begins.

igneous

_________ rocks cannot be radioactively dated.

sedimentary

What is dendrochronology?

dating trees by their rings; can also determine good/bad growth seasons

What is the Geologic Time Scale Development?

evolved over time through observations, correlation, relative/ absolute dating;

Who was Charles Darwin?

theologist and naturalist that tried to prove biblical creation

What place did Darwin visit where his beliefs were changed after noticing that species could change over time?

Galapagos islands

Explain Darwin's finches.

only bird on the island, 13 different species with different beaks that looked similar to a finch in S. America

What did Darwin theorize after seeing the finches?

that a common ancestor settled, dispersed and all of them adapted to their habitats

What is evolution?

how organisms change over time making modifications from their ancestors

What was Lamarck's idea?

inheritance of acquired characteristics; new traits are passed down to the offspring

ex: giraffes short->long neck

Whats was Darwin's book "on the origin of species" about?

survival of the fittest and natural selection

What is natural selection?

organisms posses heritable variations some better than others; better traits continue to pass down

(survival of the fittest)

ex: sea turtles: 1800 eggs laid and 3 live full life span

Who was Gregor Mendel?

'father of genetics'

conducted pea plant experiments to studied dominant and recessive genes

What is a chromosome?

double-stranded molecules of DNA which are found in cells

What are sex cells?

reproductive cells that can be either asexual or sexual

Sexual cells split into two and combine from _______ ___________.

two parents

What is variation?

reshuffling of genes during sexual reproduction; will vary but only in a way that is already in a population

What is a mutation?

a change in genetic coding; can be beneficial or harmful

What causes variations?

mutagens

What are some examples of mutagens?

chemicals, x-rays, uv-rays, extreme temp. change, radioactive substances..etc

What is specification?

rise of a new species from one ancestral

What is a species?

a group of individuals that look alike can reproduce with each other, and have viable offspring

What are allopatric specification?

new species arise due to geographic isolation, mostly island creatures

What is divergent evolution?

animals that share a common ancestor

what is convergent evolution?

starting with two different species and both pass on genes, end up with groups not related at all but similar adaptation

What is parallel evolution?

have closer common ancestors, develop similarities into their characteristics

What is a phylogenetic tree?

show evolutionary relationships/ patterns of ancestor descendent relationships; branches split because of new characteristics

What is a clade?

group that shares characteristics

What is a cladogram?

depict relationships amongst a member of a clade; biological traits

What are cladistics?

biological analytics, privative/derived characteristics

What is the Linnaean system of classification?

reflection of evolution, works with everything; shared characteristics from common ancestors

What is morphology?

structure of organisms; basis of system: shared characteristics

_______ is a group of similar species and ______ is similar, interbreed that produce fertile offspring

genus, species

K-P-C-O-F-G-S stands for:

Kingdom

Phylum

Class

Order

Family

Genus

Species

What are homologous structures?

similar structure, slight variation, same origin

What are analogous structures?

develop similar but with different embryological development

What are vestigial structures?

remains of organs that were once functional

ex: wisdom teeth

What is macroevolution?

large-scale changes observed within a species

What is microevolution?

small-scale changes observed within a species

_______ are remains/ traces of plants or animals preserved in rocks.

fossils

What is paleontology?

the study of fossils

What is the fossil record?

one-celled organisms appeared before multicellular ones, plants appeared before animals

___________ ________ is the best conditions to preserve fossils; buried in sediment is best.

fossilization potential

Types of fossil preservation:

body fossils

trace fossils

molds/castings

What is the Big Bang Theory?

the universe originated about 14 billion years ago

What was before the Big Bang?

indefinitely dense point not governed by out physical laws or time; all matter/ energy contained in one point of pure energy

Evidence for Big Bang?

universe expanding, galaxies are moving at great speed, radiation after glow of Bang

List the 4 fundamental forces:

gravity

strong nuclear force

weak nuclear force

electromagnetic force

What is the Solar Nebula Theory?

collapse of material in a spiral arm of the milky way, concentrated material in center formed sun, planets formed by collisions and accretion

What is differentiation?

formation of Earth layers; most important event of early Earth

What are meteorites?

pieces of material that originate in formation of the solar system with no atmosphere to stop them

What are the 3 types of meteorites?

stones, irons, stony-irons