Lab # 5—Earth Science
Geological Time, Fossils, & Paleontology
Introduction:
This first part of this lab relates to the currently accepted geological time scale and to fossil and other evidence that relates to that scale. The study is from the Internet and it reinforces the material covered in the text and lecture notes relating to radiometric dating and relative dating as well as the time scale itself. There is some disagreement between the scientific community and certain religious groups relating to the length of Earth’s history, the fossil record, and dating techniques, but I want to emphasize that there is NO disagreement among the scientific community. As with the text and other materials for this course, the scientific viewpoint is supported by observed data and evidence.
Current data suggests that the Earth’s age is about 4.5 billion years old, and this long span of time has been broken into sections for ease of study and discussion. We do the same thing with time within our lifetime—we break it into years, then into months, then into days, then into hours, etc. The largest division is the eon of which there are four (although the earliest three are sometimes grouped together.) An eon is subdivided into a number of eras with the number of eras usually given as three. The eras are further subdivided into periods with the number of varying depending on which era. The periods are finally broken into the smallest piece called an epoch again with the number depending on which period. So, to sum that up:
Eons—–> eras—–> periods——>epochs
We currently live in Phanerozoic eon, Cenozoic era, Quaternary period, and the Holocene epoch. If you kept going, you could list your birth date as 1975 CE, March 21, 6:00 GMT. Because someone might ask, CE means the “Common Era” which is what many called AD. However, since less than half the world is Christian, CE is a better terminology than AD. GMT stands for “Greenwich Mean Time”— the Greenwich Observatory is in England and when humans started looking a different clock times around the world, Great Britain was the most powerful country, so Greenwich Observatory became the reference. In Arkansas, our time is 6 hours behind GMT. Therefore, 6:00 in the morning in Arkansas is 12:00 (noon) GMT.
The second part of the lab also uses the Internet with additional links to show you some of the features of selected eras, periods, and epochs. Paleontology is actually only the study of fossils, but we will not limit our discussion to just that narrow topic.
Procedure:
• Read the rest of the information on this exercise before starting the lab.
• Print this page to refer to while using the internet.
Part I—“Fossils, Rocks, and Time”
• Go to document “Fossils, Rocks, and Time” in the publications section of the USGS (United States Geological Survey) website by clicking on the link http://pubs.usgs.gov/gip/fossils/contents.html. Click on “Introduction” below the photograph and work your way through the presentation answering the questions below as you go. At the bottom of each page, there is an icon to take you forward or back.
• Go to the website Enchanted Learning—Dinosaur Fossils by clicking on the link http://www.enchantedlearning.com/subjects/dinosaurs/dinofossils/ . After the website’s homepage loads, click on the button that says, “How fossils form?”, and use the information to answer the next set of questions below. After completing this page, click on the button, which says “Types of Fossils”, and answer the next group of questions.
• Go to the Arkansas Geological Commission website and read about the pseudofossils Arkansas” by clicking on the link https://www.geology.arkansas.gov/geology/fossils.html
Part II—“Paleontology”
• This part of the lab focuses on the Museum of Paleontology at the University of California, Berkeley. Click on (or type in) the web site address http://www.ucmp.berkeley.edu/help/timeform.php
• We will use this outline of the Geologic Time Scale as a “home page” for the rest of this lab. As you go through the various parts of the website, answer the appropriate questions below. Remember, you can use the back button on this Internet exercise.
• Click on Hadean (eon) at the bottom of the 2nd column and read the material. When finished, use the back button to return to the Time Scale “home page.”
• Click on Archaean (eon) near the bottom of the 2nd column and read the material. When finished, use the back button to return to the Time Scale “home page.”
• Click on Proterozoic (eon) near the bottom of the 2nd column and read the material. When finished, use the back button to return to the Time Scale “home page.”
• Click on Paleozoic (era) near the middle of the 2nd column and read the material. When finished, use the back button to return to the Time Scale “home page.”
• Click on Mesozoic (era) near the middle of the 2nd column and read the material. When finished, use the back button to return to the Time Scale “home page.”
• Click on Cenozoic (era) near the top of the 2nd column and read the material. When finished, use the back button to return to the Time Scale “home page.”
• Click on Holocene (epoch) near the top of the 3rd column and read the material. This is the end of the lab.
• Remember to submit your lab report in the proper format within Canvas
Questions
(USGS)
1. What dominates the great bulk of the fossil record?
2. If two rocks from different regions of the Earth contain the same kind of fossils, what do we know?
3. What were Darwin’s four processes for “causing” evolution?
(Enchanted Learning)
4. What is permineralization and what is another name for permineralization?
5. What is an example of a trace fossil?
6. What is a coprolite? What information can they give the scientist?
(Pseudofossils)
7. What are the most common pseudofossils? What type of pseudofossil formation you would find in the Fayetteville Formation in northern Arkansas?
8. How are the ‘turtle rocks’ created?
9. How are the ‘carpet rocks’ created?
(UCMP website)
10. What was the main event of the Hadean Eon?
11. What organisms do the oldest fossils represent?
12. What major biological even took place near the end of the Proterozoic era?
13. What are two important rocks formed during the Paleozoic era?
14. What great change in plant life occurred in the Mesozoic era?
15. The Cenozoic era is usually called the Age of Mammals. What would be several other proper descriiptors?
16. What environmental event marked the beginning of the Holocene epoch?
