Transcript Key Ideas

Roger A. Freedman • William J. Kaufmann III
Universe
Eighth Edition
CHAPTER 9
The Living Earth
HW – Read Chapter 10, 11
Online Quizzes for Chapters
9,10, and 11 due Monday 10/18
Exam 2 – Scheduled for
Monday 10/25
(will cover Chapters 7-15)
The Earth shows very little evidence of meteor
impacts because
A. plate tectonics is continuously recycling the
Earth’s crust.
B. wind and rain have continually eroded the
Earth’s surface.
C. very few meteors struck the Earth in the past.
D. vegetation has covered the craters.
E. Both A and B are correct.
Q9.11
The Earth shows very little evidence of meteor
impacts because
A. plate tectonics is continuously recycling the
Earth’s crust.
B. wind and rain have continually eroded the
Earth’s surface.
C. very few meteors struck the Earth in the past.
D. vegetation has covered the craters.
E. Both A and B are correct.
A9.11
In the greenhouse effect,
A.
B.
C.
D.
E.
Q9.4
some infrared radiation emitted by the Earth’s
surface is absorbed by the atmosphere.
some ultraviolet radiation emitted by the Earth’s
surface is absorbed by the atmosphere.
vegetation traps thermal energy near the
surface.
infrared radiation from the Sun is captured as it
enters the Earth’s atmosphere.
infrared radiation from the Sun is reflected by the
Earth’s atmosphere into space.
In the greenhouse effect,
A.
B.
C.
D.
E.
A9.4
some infrared radiation emitted by the Earth’s
surface is absorbed by the atmosphere.
some ultraviolet radiation emitted by the Earth’s
surface is absorbed by the atmosphere.
vegetation traps thermal energy near the
surface.
infrared radiation from the Sun is captured as it
enters the Earth’s atmosphere.
infrared radiation from the Sun is reflected by the
Earth’s atmosphere into space.
Which of the following is a correct statement about
seismic waves used to map the Earth’s interior
structure?
A. P waves are longitudinal and are able to travel
through solids and liquids; S waves are transverse
and can only travel through liquids.
B. P waves are transverse and are able to travel
through solids and liquids; S waves are longitudinal
and can only travel through liquids.
C. P waves are transverse and are able to travel
through solids and liquids; S waves are longitudinal
and can only travel through solids.
D. P waves are longitudinal and are able to travel
through solids and liquids; S waves are transverse
and can only travel through solids.
Q9.7
Which of the following is a correct statement about
seismic waves used to map the Earth’s interior
structure?
A. P waves are longitudinal and are able to travel
through solids and liquids; S waves are transverse
and can only travel through liquids.
B. P waves are transverse and are able to travel
through solids and liquids; S waves are longitudinal
and can only travel through liquids.
C. P waves are transverse and are able to travel
through solids and liquids; S waves are longitudinal
and can only travel through solids.
D. P waves are longitudinal and are able to travel
through solids and liquids; S waves are transverse
and can only travel through solids.
A9.7
The Earth’s magnetic field is generated by
A. electric currents in the liquid outer core; the field
has never changed direction.
B. electric currents in the liquid inner core; the field
has never changed direction.
C. electric currents in the liquid outer core; the field
has reversed many times in the past.
D. electric currents in the liquid inner core; the field
has reversed many times in the past.
E. electric currents caused by interactions with the
solar wind.
Q9.8
The Earth’s magnetic field is generated by
A. electric currents in the liquid outer core; the field
has never changed direction.
B. electric currents in the liquid inner core; the field
has never changed direction.
C. electric currents in the liquid outer core; the field
has reversed many times in the past.
D. electric currents in the liquid inner core; the field
has reversed many times in the past.
E. electric currents caused by interactions with the
solar wind.
A9.8
The oxygen in our atmosphere is chemically reactive,
combining with other elements to form compounds,
and is also being used by respiratory life. Despite
this, the amount of oxygen in our atmosphere is not
decreasing because it is being replenished by
A.
B.
C.
D.
outgassing from seawater.
volcanic eruptions.
biological activity, such as photosynthesis.
meteors and comets, which bring oxygen to the
Earth.
E. solar radiation breaking down CO2.
Q9.14
The oxygen in our atmosphere is chemically reactive,
combining with other elements to form compounds,
and is also being used by respiratory life. Despite
this, the amount of oxygen in our atmosphere is not
decreasing because it is being replenished by
A.
B.
C.
D.
outgassing from seawater.
volcanic eruptions.
biological activity, such as photosynthesis.
meteors and comets, which bring oxygen to the
Earth.
E. solar radiation breaking down CO2.
A9.14
Key Ideas
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The Earth’s Energy Sources: All activity in the Earth’s
atmosphere, oceans, and surface is powered by three
sources of energy.
Solar energy is the energy source for the atmosphere. In
the greenhouse effect, some of this energy is trapped by
infrared absorbing gases in the atmosphere, raising the
Earth’s surface temperature.
Tidal forces from the Moon and Sun help to power the
motion of the oceans.
The internal heat of the Earth is the energy source for
geologic activity.
Key Ideas
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The Earth’s Interior: Studies of seismic waves
(vibrations produced by earthquakes) show that the
Earth has a small, solid inner core surrounded by a liquid
outer core. The outer core is surrounded by the dense
mantle, which in turn is surrounded by the thin lowdensity crust.
Seismologists deduce the Earth’s interior structure by
studying how longitudinal P waves and transverse S
waves travel through the Earth’s interior.
The Earth’s inner and outer cores are composed of
almost pure iron with some nickel mixed in. The mantle
is composed of iron rich minerals.
Both temperature and pressure steadily increase with
depth inside the Earth.
Key Ideas
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Plate Tectonics: The Earth’s crust and a small part of
its upper mantle form a rigid layer called the lithosphere.
The lithosphere is divided into huge plates that move
about over the plastic layer called the asthenosphere in
the upper mantle.
Plate tectonics, or movement of the plates, is driven by
convection within the asthenosphere. Molten material
wells up at oceanic rifts, producing seafloor spreading,
and is returned to the asthenosphere in subduction
zones. As one end of a plate is subducted back into the
asthenosphere, it helps to pull the rest of the plate along.
Key Ideas
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Plate tectonics is responsible for most of the major
features of the Earth’s surface, including mountain
ranges, volcanoes, and the shapes of the continents and
oceans.
Plate tectonics is involved in the formation of the three
major categories of rocks: igneous rocks (cooled from
molten material), sedimentary rocks (formed by the
action of wind, water, and ice), and metamorphic rocks
(altered in the solid state by extreme heat and pressure).
Key Ideas
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The Earth’s Magnetic Field and Magnetosphere: Electric
currents in the liquid outer core generate a magnetic field. This
magnetic field produces a magnetosphere that surrounds the
Earth and blocks the solar wind from hitting the atmosphere.
A bow-shaped shock wave, where the supersonic solar wind is
abruptly slowed to subsonic speeds, marks the outer boundary
of the magnetosphere.
Most of the particles of the solar wind are deflected around the
Earth by the magnetosphere.
Some charged particles from the solar wind are trapped in two
huge, doughnut-shaped rings called the Van Allen belts. An
excess of these particles can initiate an auroral display.
Key Ideas
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The Earth’s Atmosphere: The Earth’s atmosphere
differs from those of the other terrestrial planets in its
chemical composition, circulation pattern, and
temperature profile.
The Earth’s atmosphere evolved from being mostly
water vapor to being rich in carbon dioxide. A strong
greenhouse effect kept the Earth warm enough for water
to remain liquid and to permit the evolution of life.
Key Ideas
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The appearance of photosynthetic living organisms led
to our present atmospheric composition, about four-fifths
nitrogen and one-fifth oxygen.
The Earth’s atmosphere is divided into layers called the
troposphere, stratosphere, mesosphere, and
thermosphere. Ozone molecules in the stratosphere
absorb ultraviolet light.
Because of the Earth’s rapid rotation, the circulation in its
atmosphere is complex, with three circulation cells in
each hemisphere.
Key Ideas
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The Biosphere: Human activity is changing the Earth’s
biosphere, on which all living organisms depend.
Industrial chemicals released into the atmosphere have
damaged the ozone layer in the stratosphere.
Deforestation and the burning of fossil fuels are
increasing the greenhouse effect in our atmosphere and
warming the planet. This can lead to destructive changes
in the climate.