Name _______________________________ Class __________________ Date __________________
Quick Lab
Ch. 9 Geologic Time Scale MATERIALS
• blank piece of 8.5” x 11” paper • pencil
• scissors • colored pencils
• metric ruler
PROCEDURE
1. Complete the table below by using the scale 1 mm is equal to 10 million years. ERA
PERIOD
Precambrian
LENGTH OF TIME (years)
SCALE LENGTH (mm)
4,058,000,000
Paleozoic
291,000,000 Cambrian
54,000,000
Ordovician
44,000,000
Silurian
28,000,000
Devonian
57,000,000
Carboniferous
60,000,000
Permian
48,000,000
Mesozoic
185,500,000 Triassic
51,000,000
Jurassic
54,000,000
Cretaceous
80,500,000
Cenozoic
65,500,000 (to present) Tertiary
63,700,000
Quarternary
1,800,000
2. Cut a blank white piece of paper length wise and tape the short ends together to make one long strip. You will be using this to scale 4.6 billion years down to 46 cm. 3. Use a metric ruler and a pencil to mark off the beginning and end of Precambrian time according to the time scale you calculated. Do the same for the other three eras and all their respective periods. Clearly label each time division era and period, and color each a different color with colored pencils.
Original content Copyright © Holt McDougal. All rights reserved. Additions and changes to the original content are the responsibility of the instructor.
Holt McDougal Earth Science
1
A View of Earth's Past
Name _______________________________ Class __________________ Date __________________
4. Using the same scale that was used in step 2, calculate the scale length for each of the 11 periods of geological time listed in Table 1 on p. 231 in your textbook next to the four eras. Start with the Quarternary period working your way to the Cambrian. Some periods will be very close together, so make sure to label them clearly. Mark the boundaries of each period listed. Mark the boundaries of each period on the paper strip, and label the periods on your scale. 5. Decorate your strip by adding names/ drawings of the major organisms that lived in each division of time. ANALYSIS
1. When did humans appear? What is the scale length from that time to the present? _______________________________________________________________ _______________________________________________________________ 2. Add the lengths of the Paleozoic, Mesozoic, and Cenozoic Eras. What percentage of the geologic time scale do these combined eras represent? What percentage of the geologic time scale does Precambrian time represent? _______________________________________________________________ _______________________________________________________________
Original content Copyright © Holt McDougal. All rights reserved. Additions and changes to the original content are the responsibility of the instructor.
Holt McDougal Earth Science
2
A View of Earth's Past
