Homework without answers Earth_s History and Geological Dating

Earth's History and dating of the Earth
Modified True/False
Indicate whether the statement is true or false. If false, change the identified word or phrase to make the statement true.
1. The geologic species scale has units based on changes in rocks and fossils. _____________
2. If all Earth’s history took place in one year starting on January 1, humans would have appeared in March.
3. If a very large asteroid impacts Earth, the dust and debris thrown into the atmosphere will act like a blanket
and trap the heat from the Sun, causing global warming. _____________
Multiple Choice
Identify the choice that best completes the statement or answers the question.
1. Geologic time is divided into units based upon types of _____.
a. sedimentary rocks
c. organisms
b. climatic changes
d. igneous rocks
2. The longest subdivision in geologic time is a(n) _____.
a. epoch
c. century
b. period
d. eon
3. A life-form in the Precambrian time was _____.
a. cyanobacteria
c. reptiles
b. humans
d. dinosaurs
4. A life-form that evolved during the _____ Era was the dinosaur.
a. Cenozoic
c. Precambrian
b. Mesozoic
d. none of the above
5. Little is known about much of Earth’s early history because _____.
a. Precambrian rocks have been deeply buried
b. Precambrian rocks have been changed by heat and pressure
c. Precambrian soft-bodied life-forms weren’t often preserved as fossils
d. all of the above
6. The division of Earth’s history into smaller units makes up the _____.
a. eras
c. periods
b. geologic time scale
d. sequence of events
7. Humans first appeared during the _____ Era.
a. Precambrian
b. Paleozoic
c. Mesozoic
d. Cenozoic
8. Geologists organized the geologic time scale based on _____.
a. superposition
c. fossils in the rock layers
b. evenly spaced time segments
d. both a and c
9. The divisions on the geologic time scale are most like which of the following?
a calendar with evenly divided weeks
sand pouring steadily through an hourglass
marking your life by the major events
marking your life by years
____ 10. Imagine all of Earth’s history taking place within 1 year, starting January 1. When did humans appear?
a. January 1
c. November 20
b. February 10
d. December 31
Complete each statement.
1. Radioactive elements decay at a _______________ rate.
2. As you move from left to right on the chart, each circle shows _______________ as many parent atoms as the
circle preceding it.
3. The geologic time scale is always drawn vertically with the _______________ rocks at the bottom.
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