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Week 32 - Fossil Evidence and Geological Time

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Book: Week 32 - Fossil Evidence and Geological Time
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Week 32 - Fossil Evidence and Geological Time

Table of contents

Exercise 4.1


Lesson 4.1: Tracing Evidence of Geological Change Using Fossils


Activity A: Fossils and Time



Required Readings

Science in Action 7
pages 410 to 414
or
Science Focus 7
pages 418 - 422



People have always been interested in the Earth's early history. The people who study this type of history are called paleontologists. Fossils, whether they be plant or animal remains, give an indication what the environment was like a long time ago. Fossils also can indicate what the earth can expect in the future.



Fossils are traces of once living things that are preserved in rock. Because of how they are deposited in the sediment they can help date the layers of rock.

Make sure you are reading your textbook pages listed on the side before you attempt to answer the questions below.

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Exercise 4.1: Fossils and Time



Copyright © 2001, the Crown in Right of Alberta, as represented by the Minister of Learning, Alberta Learning, 11160 Jasper Avenue, Edmonton, Alberta T5K 0L2

Exercise 4.2


Lesson 4.2: Method Used to Interpret Fossils

ACTIVITY A: Interpreting Fossils


Required Readings

Science in Action 7
pages 415 to 418
or
Science Focus 7
pages 418 to 427
There are several methods used to interpret fossils such as absolute dating, relative dating and fossil records. These methods are important because they give us an idea what and where creatures lived on the earth. Also fossils provide information on environmental changes that have occurred in the past. This information is important since history has a tendency to repeat itself. For example in the past glacial ages occurred which would possibly indicate that similar changes might occur in the future.

ABSOLUTE DATING

Absolute dating is a method used to tell how old an item or fossil is in years. The amounts of certain elements in the rock can tell scientist how old something is. The method employed to find something's age is called radiocarbon dating. Over billions of years some elements can change into others. Such as uranium in rock with change into lead after a period of 4.5 billion years. The time for this element to change 50% of its material is called its half life. Different elements will take different amounts of time to undergo these changes. From knowing how long the elements take to decompose into the daughter material and measuring samples, absolute dating can occur.




RELATIVE DATING

Relative dating is a relationship of the age of the fossils to the age of the strata, or layer of rock, that they are found in. For the most part the further you dig down into sedimentary rock the further you go back in time. Therefore the principal of superposition applies. This principal states that in undisturbed layers of rock, the oldest layers will be on the bottom and the youngest layers will be on the top. Using this concept, we can assume that fossils found in layers of lower layers of rock will be older than those found above it.


FOSSIL RECORDS

Index fossils are fossils which where only on the earth of a short and set period of time. From knowing when these organisms lived and died they can be used to determine the age of the material they were found in. By looking at the layers and the fossils found in them, the time can be determined when certain life forms lived on this Earth.
If you have never
been to
Drumheller's
Tyrrell Museum Website, click here

Radiometric Dating from New Zealand.
Exercise 4.2: Interpreting Fossils


Exercise 4.3


Lesson 4.3: Geological Time

ACTIVITY A: Geological Time
© 2000-2002 www.arttoday.com

Required Readings

Science in Action 7
pages 419 to 424
or
Science Focus 7
pages 425 to 426


Geological time intervals are useful since the eras give an indication to our past environment. The examination of fossils throughout the world give scientists a better idea about the type of flora and fauna available through time. The various changes in bygone eras indicate that there at times nature has been hindered by catastrophic events. An example of such an event was the mass extermination of the dinosaurs. By examining the past intervals scientists do get an insight into what to expect in the future.

 

 

 

 © 2000-2002 www.arttoday.comClick on the image for "Stories from the Fossil Record"
© 2000-2002 www.arttoday.com
Click on the image for "Understanding Geologic Time"
Click on the image for "Geologic Time Scale"
Exercise 4.3: Geological Time

Section 4 Notes

You have two options for your Section 4 Quiz - a multiple choice quiz or a written response quiz. You may choose to write the multiple choice or the written response. You only need to write one of them, so the choice is up to you! You are allowed to try both quizzes if you want, but it is not required.

The quiz attempt with the highest grade will be the one that is recorded on your report card.

The multiple choice quiz has 10 multiple choice, matching, and true/false questions. You have 15 minutes to complete it. As soon as the quiz submitted it will be auto-graded and you will receive a grade immediately.

Click the image above to start your quiz

The written response quiz has 5 short answer questions. Your responses must give a complete and detailed answer to the question. You have 20 minutes to complete the quiz. This quiz needs to be manually marked by your teacher, so you may have to wait a few days to get feedback and a grade.

Click the image above to start your quiz