Geology Reference
In-Depth Information
Perhaps the most important lesson you can learn from
physical and historical geology is that Earth is an extremely
complex, ever-changing planet. We tend to view our planet
from the perspective of a human lifetime and commonly
overlook the fact that Earth has changed markedly in the
context of geologic time and it continues to do so. Geol-
ogy, therefore, is not a static science, but one, like the dy-
namic Earth it seeks to understand, that constantly evolves
as new information and methods of investigation become
available.
Chapter Summary
Earth is a dynamic planet that has changed throughout
its 4.6-billion-year history and it continues to change.
Developing your skills as a critical thinker is one objective
of this topic and of your secondary education.
You can see examples of geologic features or processes
everywhere.
The Agricultural Revolution was a major change in
human history that allowed occupational specialization,
increased populations, and a better standard of living.
Because Earth is a dynamic planet, it produces geologic
hazards such as earthquakes, landslides, volcanic erup-
tions, and fl oods, which are threats to humans.
Some of the pressing environmental issues of today are acid
rain, ozone depletion, global warming, and rising sea level.
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Important Terms
acid rain (p. 680)
Agricultural Revolution (p. 679)
environmental geology (p. 680)
geologic agent (p. 683)
geologic hazard (p. 680)
ozone depletion (p. 681)
radon (p. 682)
Review Questions
1. Which of the following indicates that Earth is a
dynamic planet?
a. _____ volcanism;
b. _____ seismicity;
c. _____ erosion;
d. _____ none of these;
e. _____ all of these.
2. The estimated population of Earth at present is:
a. _____ 5.0 billion;
b. _____ 1.3 billion;
c. _____ 6.7 billion;
d. _____ 301 million;
e. _____ 200 billion.
3. A major change in human economy took place between
8000 and 14,000 years ago when some hunter-gatherers
developed:
a. _____ metals;
b. _____ agriculture;
c. _____ basket weaving;
d. _____ mining;
e. _____ pyramids.
4. Acid rain is defi ned as rainfall that has a pH value of:
a. _____ more than 11;
b. _____ less than 14;
c. _____ equal to 7;
d. _____ at least 5.6;
e. _____ less than 5.0.
5. Radon gas is produced:
a. _____ when sandstone weathers to clay;
b. _____ during the decay of uranium to lead;
c. _____ by weathering in a tropical environment;
d. _____ from volcanic gases;
e. _____ by the respiration of bacteria.
6. What causes acid rain and what can be done to
prevent it?
7. Why is it unlikely that volcanic eruptions have a signifi -
cant effect on ozone depletion?
8. What can we do to at least diminish the consequences
of geologic hazards?
9. What geologic processes or features can you observe in
or near your home?
10. When did the Agricultural Revolution take place and
what benefi ts did it have for humans?
