Geologic Time, Fossils, and Archaeology: Content Knowledge for Teachers

For scientists of the natural and cultural world, clues to the past come in the form of fossils, bones, and artifacts. Whether created naturally or by humans, these “clues” provide a glimpse into what life was like long ago. They are undeniably engaging. Who hasn’t been intrigued by a fossil, a dinosaur skeleton, or an arrowhead? Even what seem to be simple objects point to a wealth of information and scientific concepts: geologic time, plate tectonics, rocks and minerals, and so on. Like every other region on earth, the Arctic and Antarctica are home to these types of clues. Glossopteris fossils, found in Antarctica (and all southern continents), inspired Alfred Wegner to first propose the concept of Pangaea and continental drift. Cultural artifacts found in Alaska suggest an ancient migration across the Bering land bridge. Recently discovered dinosaur fossils in both polar regions raise interesting questions about past climate as well as adaptations.

While the polar regions provide an engaging hook – Did you know that there are plant and animal fossils in Antarctica? – most elementary curricula deal with the basics: the types of fossils, the process of fossilization, and what scientists can learn from fossils. We’ve chosen to highlight resources that will develop your own personal knowledge of geologic time and fossil basics. We’ve also included a few sites that discuss polar fossils and Arctic archaeology, which can be used in conjunction with our featured lessons and activities (What’s the Difference? Activities to Teach Paleontology and Archaeology) in the Across the Curriculum department. Finally, we’ve referenced the National Science Education Standards that are met by teaching these topics.


Geologic Time

Earth history spans approximately 4.5 billion years. This history has been divided by geologists into smaller periods: eons, eras, and epochs based on climatic events and the presence of various forms of life.

Geologic Time: Eons, Eras, and Epochs: Background Information for Teachers
This resource guide from the Middle School Portal 2: Math and Science Pathways project includes links to texts, graphics, interactive presentations, online courses for teachers, common student misconceptions, information about the geologic time scale, and fossils.

Smithsonian Geologic Time Interactive
At this site, the Smithsonian Department of Paleobiology invites users to explore the eons, eras, periods, and epochs of Earth’s history through an interactive timeline. Each segment on the timeline contains an overview with defining and secondary characteristics as well as links to more detailed information.

The History of Life in a Single Year
The concept of geologic time can be overwhelming for teachers and students alike. One popular analogy is to compare geologic time to a single year. This page provides corresponding dates and explanations for major events throughout geologic time.


Fossils

There are many different types of fossils. Body fossils, though rare, include bones, teeth, or entire organisms preserved by freezing or being trapped in wax, asphalt (tar), or amber. This is the only method for preservation of soft tissue.

Impression fossils show outlines of plants, feathers, or fish that die in sediment. As they decay, they leave a carbon deposit that shows as a dark print of the organism. Tracks, tail marks, burrows, teeth marks, and body outlines are considered impression fossils. These impressions form in soft sediment and are covered before they can be washed away or destroyed.

Mold and cast fossils are also impression fossils. A mold is formed when an organism is buried in sediment and decays, leaving a hole (the mold) in its place. If this mold is later filled with sediment, it produces a three-dimensional model (the cast) that resembles the organism.

Mineral replacement fossils are formed when an organism is buried in sediment. Water seeping into the bone dissolves the bone, which is replaced by minerals. Petrified wood is also an example of a mineral replacement (or permineralization) fossil.

Fossils: Window to the Past
This page addresses the overarching question “What is a fossil?” by discussing the types of fossils, fossilization, finding and dating fossils, and what we can learn from fossils.

Fossils
This page, from the Oxford Museum of Natural History, includes links to information about fossils, geologic time, and identifying invertebrates. This site may also be useful for upper-elementary students.


Polar Fossils

Many types of fossils have been found in the Arctic and Antarctica. Both regions include rich deposits of plant and marine animal remains, as evidenced by the presence of oil fields in the Arctic and coal deposits in Antarctic mountains. Fossils of trees and other plants indicate that both regions once were much more temperate in climate than today. Dinosaurs have been found in both locations.

Near-Polar Finds Offer New Look at Dinosaurs
This 2002 article from the New York Times archive provides an overview of polar dinosaurs and their prehistoric environment.

Arctic Redwood Fossils Are Clues to Ancient Climates
This 2002 article from National Geographic Today discusses the redwood-type fossils found in the Arctic region.

Fossil Forests
This article from Science News for Kids discusses the fossilized trees found in the Arctic region.


Archaeology and Culture (Arctic region)

People have lived in the Arctic for thousands of years. All Arctic people can trace their heritage to a common ancestor in central Asia. It is believed that people migrated from Eurasia into Alaska via the Bering land bridge about 11,000 years ago. From Alaska, migrations continued, with eventual settlements across northern Canada and Greenland. These cultural groups shared an ability to survive in the harsh environments of the Arctic and relied heavily on resources from the sea and land.

Peoples under the Arctic Sky
Learn about the indigenous peoples of the Arctic in this article written by the program director of GoNorth!, an adventure learning series focused on the circumpolar Arctic.

Archaeology in Arctic North America
This multipaged site includes a brief overview of the Arctic environment, a discussion of the challenges of Arctic archaeology, and archaeological site descriptions. Most useful is the cultural history of the Arctic, which provides an overview of the traditions of Arctic people.

Native Americans: Arctic Culture: Inupiaq, Yup’ik and Kalaalit (Inuit)
This page discusses the indigenous Arctic cultural groups found in North America.


National Science Education Standards

Teaching about fossils meets the following content standards:

Science as Inquiry (Content Standard A):

As a result of their activities in grades K-4, all students should develop understandings necessary to do scientific inquiry and understandings about scientific inquiry.

  • Ask questions about objects, organisms, and events in the environment.
  • Employ simple equipment and tools to gather data and extend the senses.
  • Use data to construct a reasonable explanation.
  • Communicate investigations and explanations.

As a result of their activities in grades 5-8, all students should develop understandings necessary to do scientific inquiry and understandings about scientific inquiry.

  • Use appropriate tools and techniques to gather, analyze, and interpret data.
  • Develop descriptions, explanations, predictions, and models using evidence.
  • Think critically and logically to make the relationships between evidence and explanations.
  • Recognize and analyze alternative explanations and predictions.
  • Communicate scientific procedures and explanations.

Earth and Space Science (Content Standard D):

As a result of their activities in grades K-4, all students should develop an understanding of properties of earth materials, objects in the sky, and changes in earth and sky.

  • Fossils provide evidence about the plants and animals that lived long ago and the nature of the environment at the time.

As a result of their activities in grades 5-8, all students should develop an understanding of structure of the earth system, earth’s history, and earth in the solar system.

  • Fossils provide important evidence of how life and environmental conditions have changed.

Read the entire National Science Education Standards online for free or register to download the free PDF. The content standards are found in Chapter 6.


This article was written by Jessica Fries-Gaither. For more information, see the Contributors page. Email Jessica at beyondpenguins@msteacher.org .

Copyright April 2008 – The Ohio State University. This material is based upon work supported by the National Science Foundation under Grant No. 0733024. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. This work is licensed under an Attribution-ShareAlike 3.0 Unported Creative Commons license.

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