Download Conclusions: Geologic Time Scale

Conclusion Questions: Geologic Time Scale
The history of the Earth is preserved in and can be interpreted from the layers of rock that make
up the crust of the Earth. Geologists use information such as fossils, chemical composition of rocks
and the type of rock to interpret past climate, life and atmospheric conditions. With your lab
partner(s), you recently created a timeline using and illustrating the geologic time scale.
Complete the following questions regarding the Geologic Time Scale. Use a separate sheet of
paper. You do not need to use complete sentences, but each question should be answered
completely/thoroughly. You may discuss the questions with your classmates, but please use your
own mind and your own words when answering the questions. When asked for mathematical
calculations be sure to SHOW YOUR WORK. Full credit will be earned for responses that are
correct, answered fully and show all work in mathematic calculations. Please take your time and
answer the questions to the best of your ability.
1. Answer in table form – 1) mya (millions of years ago), 2) era/epoch/period, 3) cm from present
WHEN . . . . . . . .
a. did the Earth form?
b. did oxygen BEGIN to accumulate in the atmosphere?
c. did the first fish appear?
d. were the first forests formed?
e. did the atmosphere reach the current composition (or approximately)?
f. were the dinosaurs dominant (range of years)?
g. did the earliest hominids appear?
h. did modern man/civilization begin?
2. If the whole time scale were the length of a football field (100 yards) with the beginning of
Earth at one goal line, where on the field would the following be located
a. First Fish
b. Permian extinction
c. Dinosaurs (first and last)
d. Modern man
e. How much longer were the dinosaurs on Earth in relation to modern humans and
how much more distance (the difference) does this represent on the football field?
3. What was the primary event of the first 700 million years of Earth’s history?
4. The early atmosphere was dominated by CO2. Based on sea and land plant populations,
when would the first big increase in O2 have occurred? WHY?
5. In which eon, era, period and epoch do we live?
6. How does coal form (may need to do a little research)? Based on the names of the periods,
what time period would have been associated with most of the coal that we are burning
today? WHY? Where was North America at this time and what was the environment like?
How long ago was that?