Title: Geologic Time Tape Lab
Objective: Convert geologic time into a frame of reference that is easier to understand.
Background: To make studying Earth’s history easier, scientists have organized and divided the
Earth’s past into sections of time. The boundaries represent major changes on Earth, like
appearances and extinctions of life-forms, climate changes, and rock types deposited.
Problem: How can a representation of Earth’s past be made using adding machine tape?
Hypothesis: Divisions of time and changes on Earth can be scaled down, measured, and marked on paper to
construct a physical model of Earth’s history.
The scale: 1 meter = 1 billion years. You should also know that a cm is 1/100th of a meter.
Therefore: 1 centimeter = ______yrs. Also, if a mm is a 1/10th of a cm,
then: 1 millimeter = ______yrs. (Fill in these blanks to complete the scale)
Materials: 5 meters of paper, colored pencils, meter stick.
Procedures: 1) Using the scale and the provided reference data regarding Earth’s past life and events,
(jobs) measure and mark divisions and events from earth’s past.
2) Label the divisions and events.
3) Draw any life forms and/or events that are appropriate.
4) Color to separate the divisions and for visual appeal.
Awards: Extra credit for the top 3 projects. 1st = 4 pts. each, 2nd = 3 pts. each, 3rd = 2 pts. each.
Make sure your winning project is accurate, colorful, and informative.
Data: Convert each of the events listed below into the equivalent distance in meters, cm, and mm.
Approx beginning
Major Time Spans Geologic subdivisions/events/life age (yrs. ago) Distance back in time
Hadean Eon Age of the Earth-no life; Earth cools 4.6 billion yrs 4.6 m = 4m + 60cm + 0mm
Archean Eon First O2 producing organisms (bacteria) 3.8 billion yrs. ______
Proterozoic Eon Oldest animals (jellyfish appear)(continents form) 2.5 billion yrs ______
Phanerozoic Eon Paleozoic Era (Cambrian Period)(Inverts-Trilobites) 540 million yrs ______
Ordovician Period begins (first vertebrates=fish) 490 million yrs ______
Silurian Period (first land animals-scorpions+spiders) 440 million yrs ______
Devonian Period begins (first trees & amphibians) 420 million yrs ______
Mississippian Period begins (first snails) 350 million yrs ______
Pennsylvanian Period begins (Insects first appear and 320 million yrs ______
later within, the first reptiles appear) 300 million yrs ______
Permian Period begins (Pangaea forms) 290 million yrs ______
Mesozoic Era (Triassic Period)(first dinosaurs 250 million yrs ______
and later, the first mammals appear, first conifers) 245 million yrs ______
Jurassic Period begins (great dinosaurs appear 200 million yrs ______
and later within, the first birds appear) 175 million yrs ______
Cretaceous Period begins (flowering plants, Rockies) 145 million yrs ______
Cenozoic Era (Paleocene Epoch) (large mammals) 65 million yrs 0.065m=6.5cm=6cm+5 mm
Eocene Epoch begins (rodents, primates) 55 million yrs ______
Oligocene Epoch begins and climate warms 34 million yrs ______
Miocene Epoch begins (grasses appear) 24 million yrs ______
Pliocene Epoch begins (horses appear) 5 million yrs ______
Pleistocene Epoch (glaciation happens and 2 million yrs ______
Present day earliest record of man) 2 million yrs ______
Remember: ALL Measurements are to be made starting from the “Present” line and working back.
Analysis and Conclusions:
1. Explain why you cannot mark the position of important events in history, such as the
American Revolution, or World War II, on your paper scale.
______
______
2. Would it be possible to measure a distance on the paper that could represent the length of a
person’s lifetime?
_Y / N____ Explain ______
______
3. What geologic period of time did the first reptiles appear in the record ? ______
4. What geologic period of time did the first birds appear in the record ? ______
5. What geologic period of time did the first mammals appear ? ______
Extensions:
1. What might be some reasons why we do not see the same animals and plants on Earth today that
evidence shows could be found thousands or millions of years ago?
In other words, why have there been extinctions?
______
______
2. Why do some animals and plants, whose origins go back thousands of years, still exist today
relatively unchanged ?
______
______
3. Place the types of geologic divisions of time in the proper order from biggest (a) to smallest (d).
a.______b.______c.______d.______(orange book, p. 153)
4. Name the era that means “ middle life “. ______Era. (orange book, pp. 152-154)
5. Name the era that means “ old life “. ______Era. (orange book, pp. 152-154)
6. We live in the ______Eon. (orange book, pp. 152-154)
Age
Present of
------measure back from today each time ------à Earth
zero mark 4.6 m back
Work back from here
Geologic Time
The time scales above and below show the subdivisions of geologic time. The major divisions, with brief explanations of how each was named, are shown in the scale of relative geologic time at the top left. All are arranged in chronological order from the oldest division to the youngest.
The time scale above is drawn to scale so you can compare the relative lengths of geologic time divisions.
FYI: This is a Trilobite fossil