Activity: Exploring Fossils

Activity: Exploring Fossils

Learning Goals

• To observe and study a variety of different types of fossils
• To determine that the fossil recordis an important part of the

history of life on Earth.

• To demonstrate that fossils provide evidence of evolution, that life has changed on Earth over time.

Background Information

To understand events that occurred on Earth long ago, scientists act like detectives. Some of the most important clues to Earth’s past are fossils. A fossil is the preserved remains or traces of an organism that lived in the past. A fossil can be formed from a bone, tooth, shell, or other part of an organism. Other fossils can be traces of the organism, such as footprints, or worm borrows left in mud that later turned to stone.

During this lesson, you will have the opportunity to observe the two main categories of fossils: fossilized body parts and fossilized traces. You will be able to study a variety of different types of fossils: petrified fossils, molds and casts, preserved remains, and trace fossils. You will reflect on the important role fossils play in the study of life on Earth and learn about the job of a paleontologist as you walk around from station to station.

Materials: Collection of fossils, guide books, computer access, dissecting microscopes

What I Know: What do you already know about fossils? Have you ever seen a fossil? Where, when, and what was it? Explain.

Procedure: Rotate through the various stations and complete the indicated activity described for each station.

Station 1: Petrified Fossils

Some remains that become buried in sediments are actually changed to rock. Minerals dissolved in the water soak into the buried remains. Gradually, the minerals replace the remains, changing them into rock. Fossils that form in this way are called petrified fossils.Many of the fossils in our collection are petrified fossils. Petrified wood is an example of a petrified fossil. We also have petrified bones and shells.Observe the different fossils at this station and create a detailed drawing of any two fossil specimens and label them.

Station 2. Mold and Casts

Sometimes shells or other hard parts buried by sediments are gradually dissolved. An empty space remains in the place the part once occupied. A hollow space in sediment in the exact shape of an organism or part of an organism is called a mold.Sometimes a mold becomes filled in with hardened minerals, forming a cast. A cast is a copy of the shape of the organism that made the mold. Among our fossils is a large trilobite mold and cast.Observe the different fossils at this station and create a detailed drawing of any two fossil specimens and label them.

Station 3.Preserved Remains

Organisms can be preserved in substances other than sediments. Entire organisms, such as small ants that lived millions of years ago have been preserved in amber, a hardened sap-like substance from a tree. Observe the different fossils at this station and create a detailed drawing of any two fossil specimens and label them.

Station 4. Trace Fossils

Sometimes an ancient organism leaves evidence if its existence as a trace or imprint. These traces could be imprints, like our fern and leaf prints, dinosaur dung, nests, or footprints.

Observe the different fossils at this station and create a detailed drawing of any two fossil specimens and label them.

Station 5. Ancient Life: What did they look like?

Ammonite, orthoceras, trilobite . . . what did they look like in real life? Our collection contains a few plastic models of these organisms as they looked millions of years ago. Observe the fossils at this station and create a detailed drawing of any two fossil specimens and label them.

Station 6: Website

Go to:PaleontOLogy: The Big Dig

1. Write a definition of paleontology:

Go to: What’s the Big Idea?

1. What are fossils? Give some examples.

1. What do fossils tell us? What do they not tell us?

1. Why are fossils rare?

Station 7: Books

Look through the books about fossils at your table. Write a paragraph (at least 3

sentences) explaining something new you learned from reading the books. Include

the name of the book.

Title of Book: ______

Station 8: Video Clip

Watch the video segment from on titled: Fossils:

Windows in the Past (Segment: The Types of Fossils and How they are Formed) and answer the following questions:

a. Why do the hard parts, rather than the soft parts of organisms usually form fossils?

1. When do the soft parts of fossils sometimes become fossils?

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