Earth Science Exam 2 (Ch. 11,12,13) – Flashcards
Unlock all answers in this set
Unlock answersquestion
The oceans cover approximately ________ percent of Earth's surface.
A.40
B.50
C.60
D.70
answer
D. 70
question
Which one of the following is not part of the continental margin?
A.continental shelf
B.continental slope
C.continental rise
D.continental trench
answer
D.continental trench
question
Using the line below, which of the following places the order of events in correct chronological sequence?
A.A=prokaryotic life, B=Multicellular animal life, C=Extinction of dinosaurs, D=origin of humans.
B.B.A=prokaryotic life, B=Multicellular animal life, C=origin of humans, D= Extinction of dinosaurs.
C.C.A=Multicellular animal life, B= prokaryotic life, C=Extinction of dinosaurs, D=origin of humans.
D.D.A=Multicellular animal life, B= prokaryotic life, C=origin of humans, D= Extinction of dinosaurs.
answer
A.A=prokaryotic life, B=Multicellular animal life, C=Extinction of dinosaurs, D=origin of humans.
question
The Great Oxygen Event marks the time, approximately 2.5 billion years ago, when ________.
A.there was enough oxygen in the atmosphere to support a major burst of life on Earth
B.there was a massive volcanic eruption that lead to a very rapid increase in oxygen levels on Earth
C.there was a cataclysmic weather event that absorbed most of the oxygen in the atmosphere and locked it into iron deposits in the oceans
D.there was significant oxygen in the atmosphere
answer
D.there was significant oxygen in the atmosphere
question
Banded Iron Formations are interbedded iron oxides and chert that formed on the sea floor between 3.5 and 2 billion years ago because ________.
A.precipitated iron was very abundant in the early earth prior to oxygen production
B.iron was precipitating out of ocean water when binding with the oxygen produced by bacteria
C.iron was a common ocean deposit created by weathering of continental crust
D.photosynthesis had not yet started to generate oxygen so iron precipitated out of the ocean water and was deposited on the sea floor
E.outgassing produced iron oxide that settled on the sea floor
answer
B.iron was precipitating out of ocean water when binding with the oxygen produced by bacteria
question
Endosymbiosis is an evolutionary theory that explains the origin of eukaryotes and suggests a specific order in which this might have occurred. Ancestral cells engulfed and then began to use the metabolic processes of the smaller cells. Based on shared core processes and features, which statement most accurately describes the order, the theory and the evolutionary implications for all organisms within domain Eukarya?
A.Ancestral heterotrophic eukaryotes most likely engulfed both a heterotrophic and an autotrophic prokaryote, whereas ancestral photosynthetic eukaryotes probably provided the host cell for the first mitochondria. Over time, natural selection favored these relationships and these cells became ancestors of all eukaryotes.
B.As Earth was becoming more anaerobic (oxygen poor), natural selection would have favored organisms that acquired a photosynthetic prokaryote to convert carbon dioxide into sugars. These would have likely been the first eukaryotic cells. At which point, these ancestral cells engulfed mitochondria-like prokaryotes that would have provided an even greater advantage for cells in this environment.
C.All ancestral eukaryotes would have most likely consumed a nucleus-like prokaryote that eventually became the eukaryotic nucleus. These new eukaryotic cells would have had an advantage over prokaryotic cells by acquiring a nuclear command center for regulating cellular activities.
D.As Earth was becoming more aerobic (oxygen rich), mitochondria would have provided an advantage to host cells by converting "toxic" oxygen into energy for heterotrophic cells. Since mitochondria are found in all eukaryotes, these combinations likely evolved first. Photosynthetic eukaryotes probably acquired an autotrophic prokaryote, which developed an advantageous symbiotic relationship with the host cell.
answer
D.As Earth was becoming more aerobic (oxygen rich), mitochondria would have provided an advantage to host cells by converting "toxic" oxygen into energy for heterotrophic cells. Since mitochondria are found in all eukaryotes, these combinations likely evolved first. Photosynthetic eukaryotes probably acquired an autotrophic prokaryote, which developed an advantageous symbiotic relationship with the host cell.
question
According to geologist the earth formed approximately ________ years ago.
A.5,000
B.4,600,000,000
C.13,700,000,000
D.33,200,000,000,000
answer
B.4,600,000,000
question
The basic concept of Uniformitarianism is ________.
A.nothing has changed since the earth was formed
B.geology has not changed since the earth was formed but other things do change
C.geology changes constantly but the rules that control those transformations do not change
D.none of the above are correct
answer
C.geology changes constantly but the rules that control those transformations do not change
question
If you observe a disconformity, you would infer that the region had experienced ________.
A.deposition in shallow water, uplift or lowering of sea level enough to expose the rocks to erosion and non-deposition for a period of time, and subsequent resubmergence of the remaining sedimentary units where they experience new deposition
B.uplift and tilting of sedimentary units that exposes them to erosion over a period of time with subsequent renewed deposition
C.intrusion of igneous rocks into a depositional setting, forcing the sedimentary layers upward and possibly deforming them, followed by subsidence of the remaining sedimentary layers and renewed deposition
D.deposition of sedimentary layers on crystalline igneous or metamorphic rocks that are exposed at the surface of the earth.
answer
A.deposition in shallow water, uplift or lowering of sea level enough to expose the rocks to erosion and non-deposition for a period of time, and subsequent resubmergence of the remaining sedimentary units where they experience new deposition
question
A worm would stand a poor chance of being fossilized because ________.
A.worms have been rare during the geologic past
B.worms have no hard parts
C.worms contain no carbon-14
D.all of these
answer
B.worms have no hard parts
question
How many protons does a carbon molecule have if it has seven neutrons and an atomic mass of 14?
A.2
B.4
C.5
D.6
E.7
answer
E.7
question
Carbon 14 has a radiometric half-life of approximately 5000 years. If you find a fossil that has only 1/4 of its original carbon 14 parent element remaining, then what is the approximate age of the fossil you found?
A.5,000 years old
B.10,000 years old
C.15,000 years old
D.20,000 years old
answer
B.10,000 years old
question
The surface area of Earth is composed of ____ percent ocean and _____ percent landmass.
answer
71; 29
question
Which of the following oceans is the largest and deepest on Earth?
answer
the Pacific Ocean
question
The three main provinces of the ocean floor as we go from the shore towards the middle of the ocean are ___________________.
answer
continental margin, deep-ocean basin, mid-ocean ridge
question
Which of the following statements regarding active and passive continental margins is true?
answer
Active continental margins are associated with plate boundaries, whereas passive margins are not associated with plate boundaries.
question
Which of the two following features compose a passive continental margin?
answer
shelf and slope
question
What type of plate boundary is associated with deep-ocean trenches?
answer
subduction zone
question
Why are mid-ocean ridges elevated?
answer
Lithosphere created at the ridge is hot.
question
Ocean sediment composed of former diatoms is an example of _________ sediment
answer
biogenous
question
Which sea floor resource-based industry is second in economic value only to the petroleum industry?
answer
sand and gravel
question
Gas hydrates mostly contain ________
answer
methane
question
How is Earth unique from other planets?
answer
-Earth's atmosphere supports varied forms of life.
-Earth's distance from the Sun produces surface temperatures that support varied forms of life.
-Earth's core creates a magnetic field that is just strong enough to protect the surface from the solar wind.
question
What is the relationship between planetesimals and protoplanets?
answer
-Planetesimals are smaller than protoplanets.
-Planetesimals combine to form protoplanets
question
How was free oxygen introduced in Earth's amosphere?
answer
Bacteria released free oxygen as a by-product of photosynthesis.
question
What is the age of the oldest rock found on Earth?
answer
4 billion years old
question
Which era marks the formation of the Basin and Range Province?
answer
Cenozoic era
question
When did the supercontinent Pangaea form?
answer
250 million years ago
question
Which of the following statements regarding prokaryotes is true?
answer
Prokaryotes did not have nuclei.
question
What was the "Cambrian Explosion"?
answer
a sudden large increase in life forms, during which all major groups of invertebrates came into being
question
When did dinosaurs go extinct?
answer
65 million years ago, at the Cretaceous-Paleogene boundary
question
How did the mass extinction at the end of the Cretaceous time period influence evolution?
answer
The demise of the dinosaurs led to diversification of mammals.
question
The fundamental principle of geology put forth by James Hutton is called _______.
answer
the principle of uniformitarianism
question
Which of the following principles are key to relative dating?
answer
-law of superposition
-principle of cross-cutting relationships
-principle of original horizontality
question
Which of the following terms are types of unconformities?
answer
-disconformity
-angular unconformity
-nonconformity
question
What is the difference between a mold and a cast?
answer
Molds reflect the shape of an organism; casts fill in the molds.
question
What two special conditions are necessary to preserve organisms as fossils?
answer
rapid burial and hard parts
question
Which of the following statements describes index fossils?
answer
Index fossils are geographically widespread and have short life spans.
question
What happens during radioactive decay?
answer
The forces binding protons and neutrons together are weak and nuclei break apart.
question
Which of the following radioactive isotopes is used to date very recent events?
answer
carbon-14
question
What subdivision of the geologic time scale represents the greatest expanse of time?
answer
eon
question
What is the primary problem in assigning numerical dates to rocks?
answer
Not all rocks can be dated by radiometric dating methods.
question
What is Catastrophism
answer
Landscape developed by catastrophes
James Ussher, mid-1600s, concluded Earth was only a few thousand years old
question
what is Uniformitarianism
answer
processes have shaped earth in the past are essentially the same as those operating today
question
Principles and Laws related to time
answer
Law of superposition
-the oldest layer must be at the bottom because it must've been there for the other layer to be laid on top of it
Principle of original horizontality
-things are laid down horizontally originally but then deformations occur later that form mountains and volcanoes...etc because of gravity
Principle of cross-cutting relationships
-if there is a fault in rocks, the fault must be younger than the rock it goes through because the rock had to be there for it to crack
question
Principle of lateral continuity
answer
-Continuous across the layer
question
Inclusions
answer
The rocks had to be there to be included in the new rock....the older rock had to be around to be included in the other rocks
question
Types of Unconformities
answer
Angular unconformity
Disconformity
Nonconformity
question
Angular unconformity
answer
tilted rocks are overlain by flat-lying rocks
question
Disconformity
answer
strata on either side are parallel
question
Nonconformity
answer
Metamorphic or igneous rocks below
Younger sedimentary rocks above
question
Fossil
answer
remains of an organism that lived in the distant past
question
Types of fossils
answer
Mold - shell or other structure is buried and then dissolved by underground water
Cast - hollow space of a mold is filled with mineral matter
Carbonization - organic matter becomes a thin residue of carbon
Impression - replica of the fossil's surface preserved in fine-grained sediment
Preservation in amber - hardened resin of ancient trees surrounds an organism
question
Indirect evidence
answer
-Tracks
-Burrows
-Coprolites - fossil dung and stomach contents
-Gastroliths - stomach stones used to grind food by some extinct reptiles
question
Index fossils
answer
Widespread geographically
Existed for a short range of geologic time
question
Mass number
answer
Neutrons+protons
question
Atomic number
answer
an element's identifying number; number of protons in the atom's nucleus
question
Half-Life
answer
the amount of time it takes 100 atoms (Parent element) of a given element to break down into 50 (the actual numbers don't matter just has to break down half in a constant amount of time)
question
Carbon-14 dating
answer
-Half-life of only 5730 years
-Used to date very recent events
-Carbon-14 produced in upper atmosphere
-Incorporated into carbon dioxide
-Absorbed by living matter
question
Radiometric dating
answer
-Half-life - the time for one-half of the radioactive nuclei to decay
-Requires a closed system
-Cross-checks are used for accuracy
-Complex procedure
-Yields numerical dates
question
Difficulties in dating the time scale
answer
-Not all rocks are datable (sedimentary ages are rarely reliable)
-Materials are often used to bracket events and arrive at ages
question
Oldest to youngest events
answer
prokaryotic life, eukaryotic life, Cambrian explosion, mammals pop up, dinosaurs disappear, humans appear
question
Cretaceous
answer
-Flowering plants appear and diversify
-Many organisms (including dinosaurs) become extinct at the end of this period
question
Ordovician
answer
-Colonization of land by plants, fungi, mammals
question
Cambrian
answer
-sudden increase in diversity
question
Ediacaran (in order oldest to youngest)
answer
-Oldest fossils cells appear
-Concentration of atmospheric oxygen begins to increase
-Oldest fossils of cells (prokaryotes) appear
question
Order of key events
answer
-origin of solar system
-prokaryotes
-oxygen
-single-celled eukaryotes
-multi-cellular eukaryotes
-Animals
-colonization of land
-Paleozoic
-Mesozoic
-Cenozoic
-Humans
question
First Life?
answer
The oldest known fossils are stromatolites, rocks formed by the accumulation of sedimentary layers on bacterial mats
question
What major events took place to make the shift from prokaryotes to eukaryotes?
answer
Photosynthesis
Oxygen Revolution
question
Photosynthesis and the Oxygen Revolution
answer
-Most atmospheric oxygen (O2) is of biological origin
-O2 produced by oxygenic photosynthesis reacted with dissolved iron and precipitated out to form banded iron formations
question
How did the first eukaryotic cells form?
answer
-The endosymbiont theory proposes that mitochondria and plastids (chloroplasts and related organelles) were formerly small prokaryotes living within larger host cells
-An endosymbiont is a cell that lives within a host cell
question
support for endosymbiont theory
answer
-Inner membranes are similar to plasma membranes of prokaryotes
-Division and DNA structure is similar in these organelles and some prokaryotes
-These organelles transcribe and translate their own DNA
-Their ribosomes are more similar to prokaryotic than eukaryotic ribosomes
question
The Origin of Multicellularity
answer
-The evolution of eukaryotic cells allowed for a greater range of unicellular forms
-A second wave of diversification occurred when Multicellularity evolved and gave rise to algae, plants, fungi, and animals
question
The Cambrian Explosion
answer
The Cambrian explosion refers to the sudden appearance of fossils resembling modern animal phyla in the Cambrian period (535 to 525 million years ago)
A few animal phyla appear even earlier: sponges, cnidarians, and molluscs
The Cambrian explosion provides the first evidence of predator-prey interactions
question
The "Big Five" Mass Extinction Events
answer
In each of the five mass extinction events, 50% or more of marine species became extinct
question
How big is a mass extinction event?
answer
The Permian extinction defines the boundary between the Paleozoic and Mesozoic eras 251 million years ago
This mass extinction occurred in less than 500,000 years and caused the extinction of about 96% of marine animal species
The Cretaceous mass extinction occurred 65.5 million years ago
Organisms that went extinct include about half of all marine species and many terrestrial plants and animals, including most dinosaurs
question
What causes mass extinction events? What caused the dinosaurs to go extinct?
answer
-The presence of iridium in sedimentary rocks suggests a meteorite impact about 65 million years ago
-Dust clouds caused by the impact would have blocked sunlight and disturbed global climate
-The Chicxulub (Chicx-u-lub)crater off the coast of Mexico is evidence of a meteorite that dates to the same time
question
Adaptive Radiations
answer
-Adaptive radiation is the rapid evolution of diversely adapted species from a common ancestor
-Adaptive radiations may follow
-Mass extinctions
-The evolution of novel characteristics
-The colonization of new regions
question
Why is earth known as the blue planet?
answer
it is made mostly of water
question
Earth's water/land ratio
answer
71% of Earth's surface is represented by oceans and marginal seas
29% continents and islands
question
Hemispheres
answer
Northern Hemisphere - land hemisphere
Southern Hemisphere - water hemisphere
question
Four main ocean basins
answer
Pacific Ocean - the largest and has the greatest depth
Atlantic Ocean - about half the size of the Pacific and not quite as deep
Indian Ocean - slightly smaller than the Atlantic, largely a southern Hemisphere body
Arctic Ocean - about 7 percent the size of the Pacific
question
Bathymetry
answer
measurement of ocean depths and the charting of the shape or topography of the ocean floor
question
Echo sounder (also referred to as sonar)
answer
Invented in the 1920s
Primary instrument for measuring depth
Reflects sound from ocean floor
question
Echolocation
answer
-We now use multiple beams with echolocation
-Trail a "towfish" in the back to capture more information
-A topographic map shows elevation that can be determined by how fast the signal returns to you
-Now we use satellites
-The crest and troughs of waves can distort what we view as the elevation
question
Three major topographic units of the ocean floor
answer
-Continental margins
-Ocean basin floor
-Mid-ocean ridge
question
Passive continental margins
answer
-Found along most coastal areas that surround the Atlantic Ocean
-Not associated with plate boundaries
-Experience little volcanism and
-Few earthquakes
question
3 main pieces of a passive continental margin
answer
1: Shelf-flat top
2: Slope-dramatic drop
3: Rise
question
Passive continental margins
answer
1.Continental shelf
-Flooded extension of the continent
-Varies greatly in width
-Gently sloping
-Contains oil and important mineral deposits
2.Continental slope
-Marks the seaward edge of the continental shelf
-Relatively steep structure
-Boundary between continental crust and oceanic crust
3.Submarine canyons and turbidity currents
-Submarine canyons
-Deep, steep-sided valleys cut into the continental slope
-Some are seaward extensions of river valleys
-Most appear to have been eroded by turbidity currents
4.Continental rise
-Found in regions where trenches are absent
-Continental slope merges into a more gradual incline - the continental rise
-Thick accumulation of sediment
-At the base of the continental slope turbidity currents that follow submarine canyons deposit sediment that forms deep-sea fans
question
turbidity current
answer
a downslope movement of dense, sediment-laden water created when sand and mud on the continental shelf and slope are dislodged and thrown into suspension
question
Active continental margins
answer
-Continental slope descends abruptly into a deep-ocean trench
-Located primarily around the Pacific Ocean
-Accumulations of deformed sediment and scraps of ocean crust form accretionary wedges
-Some subduction zones have little or no accumulation of sediments
question
Active continental margins
answer
Deep-ocean trenches
-Long, relatively narrow features
-Deepest parts of ocean
-Most are located in the Pacific Ocean
-Sites where moving lithospheric plates plunge into the mantle
-Associated with volcanic activity
question
ocean basin floor
answer
Abyssal plains
-Likely the most level places on Earth
-Sites of thick accumulations of sediment
-Found in all oceans
question
Types of seafloor sediments
answer
Hydrogenous sediment
-Minerals that crystallize directly from seawater
-Most common types include
-Manganese nodules
-Calcium carbonates
-Metal sulfides
-Evaporates
question
seafloor sediments
answer
Distribution
-Coarse terrigenous deposits dominate continental margin areas
-Fine-grained terrigenous material is common in deeper areas of the ocean basin
-Hydrogenous sediment comprises only a small portion of deposits in the ocean
-There are a few places where very little sediment accumulates (mid-ocean ridges)
question
ocean basin floor
answer
Seamounts(submerged volcanoes) and guyots
-Isolated volcanic peaks
-Many form near oceanic ridges
-May emerge as an island
-May sink and form flat-topped seamounts called guyots or tablemounts
question
-2 structures that can form after volcanoes go extinct
answer
1)Seamount: below ocean surface
2)Guyout: top is exposed then eroded then submerged under water again
question
The oceanic ridge
answer
Mid-ocean ridge
-An elevated position
-Extensive faulting
-Numerous volcanic structures that have developed on newly formed crust
-Interconnected ridge system is the longest topographic feature on Earth's surface
question
Resources from sea floor
answer
Energy resources
-Oil and gas
-Gas hydrates
Other resources
-Sand and gravel
-Evaporative salts
-Manganese nodules
