Materials Included In Kit

Additional Materials Required

Prelab Preparation

1. The rubber-tip widgets should be assembled before class by the instructor.
2. Place one small dot of super glue on the pointed end of the supplied wood dowel stick (see Figure 2).
   {12758_Preparation_Figure_2}
3. Place one piece of rubber leg onto the super glue on the wood dowel stick (see Figure 3).
   {12758_Preparation_Figure_3}
4. Allow to dry.

Safety Precautions

Although the materials in this kit are considered relatively nonhazardous, please follow all normal laboratory safety guidelines. Remind students to wash their hands thoroughly with soap and water before leaving the laboratory.

Disposal

Please consult your current Flinn Scientific Catalog/Reference Manual for general guidelines and specific procedures, and review all federal, state and local regulations that may apply, before proceeding. The microfossils may be saved for future use or disposed of according to Flinn Suggested Disposal Method #26a.

Lab Hints

• Enough materials are provided in this kit for 30 students working in pairs. This laboratory activity can reasonably be completed in one 50-minute class period.
• The Microfossil Worksheet should be copied and supplied to the students for multiple microfossil drawings and classifications.
• The microfossil samples may be dispensed (using the microfossil spoon) by the instructor if desired.
• Extra filter paper has been given for additional microfossil sorting.
• 20X magnification works best for the viewing of microfossils.
• The filter paper is used under the microfossil sorting dish to provide a white background for easy microfossil viewing. It may be removed if desired.
• The included microfossil CD contains a wealth of pictures and information about the different types of microfossils that have been isolated from the specific collection site. It is a great student reference and teaching tool for this activity.

Teacher Tips

• After viewing, fossils may be securely sealed and stored within commercial or custom-made well slides, such as deep-well projection slides.

Further Extensions

• Have students write brief essays describing the biotic environment in which the microfossils found in this activity lived during the Devonian Period.
• Have students research the types of microfossils found in your state and if they can be readily found. If so, have students list the microfossil locations and geological periods.

Sample Data

Category of Microfossil: ___Snail___

Sketches

Answers to Questions

1. What key features (e.g., size, shape, markings, textures) of this microfossil provides key evidence as to its identity?

   Coiled shell, smooth surface, etc.

2. What structure of the organism formed the microfossil?

   This was the shell of the organism.

3. Do you think this organism lived in a group or individually?

   This microfossil most likely lived individually.

4. Do you think this was a free-moving organism?

   This was a free-moving organism.

5. Do any related marine species still exist today? Which ones?

   This organism is related to the common snails of today.

6. What is the likely mineral or chemical composition of this microfossil?

   Limestone.

Post-Lab Questions

1. Which categories of microfossils were most commonly found by your group? What about the class?

   Student answers will vary.

2. Give possible reasons why microfossils in some categories may be more abundant than others.

   Student answers will vary. Location gathered, depth of the sample, conditions when organisms were fossilized, etc.

3. List similarities and differences between the identified microfossil specimens.

   Student answers will vary.

4. Besides the categories of organisms represented in the Checklist and Photos of Microfossil Categories in Sievings, what other marine organisms (invertebrate or vertebrate) were also abundant during the Devonian Period, as evidenced from fossil specimens collected worldwide?

   The vegetation of the early Devonian consisted primarily of small plants, the tallest being only a meter tall. By the end of Devonian, ferns, horsetails and seed plants had also appeared, producing the first trees and the first forests. Also during the Devonian, two major animal groups colonized the land. The first tetrapods, or land-living vertebrates, appeared during the Devonian as did the first terrestrial arthropods, including wingless insects and the earliest arachnids. In the oceans, brachiopods flourished. Crinoids and other echinoderms, tabulate and rugose corals and ammonites were also common. Many new kinds of fish appeared.

5. Find reference information showing continent positions during the Devonian Period (about 400 MYA). Describe the global location/position of the underwater land mass.

   During the Devonian Period, there were three major continental masses. North America and Europe sat together near the equator with much of their current land underneath the sea. A portion of modern Siberia lay to the north. A composite continent of South America, Africa, Antarctica, India and Australia dominated the southern hemisphere.

References

Special thanks to the late Dr. Charlie Drewes, IA, for presenting this activity to Flinn Scientific.

Boardman, R. S. et al. (1987) Fossil Invertebrates, Blackwell Scientific, Palo Alto, 713 pp.

Clarkson, E. N. K. (1998) Invertebrate Palaeontology and Evolution, 4th Ed., Blackwell Science, Oxford, 452 pp.

Lehmann, U. & G. Hillmer (1980) Fossil Invertebrates, Cambridge University Press, Cambridge, 350 pp.

Levin, H. L. (1999) Ancient Invertebrates and Their Living Relatives, Upper Saddle River, NJ, Prentice Hall, 358 pp.

Thompson, I. (1999) National Audobon Society Field Guide to North American Fossils, Knopf Publishing, 848 pp.

Introduction

Explore and classify thousands of actual microfossils that are over 375 million years old!

Concepts

• Fossils

• Classification
• Biostratigraphy

Background

Microfossils are small, fossilized remains of organisms (animal, plant or protozoa) that require magnification for study. They usually derive from the hard parts of organisms (e.g., skeletons, shells, jaws, teeth, seed coverings). Microfossils may be imbedded in rock or exist as loose particles within soft substrate. The smallest microfossils may be only 0.001 mm (= 1 micron) and the largest up to 1–2 mm in size. Fossils larger than 2 mm are generally referred to as macrofossils.

From the standpoint of research, microfossils are relied on heavily for research advances in fields such as biostratigraphy (the recognition of fossils and the relative position of their occurrences over space and time), paleoenvironmental reconstruction (recon-structing past environments) and paleooceanography (the study of the oceans over time). Research studies of microfossils provide insights into ecological and evolutionary relationships among plant and animal communities that existed on Earth hundreds of millions of years ago. Microfossils also provide excellent hands-on material for science classroom education in general biology, evolution and earth science.

The microfossil specimens in this activity are from the Devonian Period (approximately 375 to 400 million years ago!). They were isolated from soft deposits of shale and shaley limestone in Iowa. The microfossils were carefully sieved to select for particle sizes between 0.3 and 1.0 mm. The sievings were washed to remove the fine silt and then dried. Microfossils are very abundant in the given samples and careful microscopic examination of even small quantities should yield a rich diversity of specimens. A table of the various microfossils found in the given sievings is listed in the Checklist and Photos of Microfossil Categories in Sievings.

Experiment Overview

In this activity, microfossils will be identified and characterized to gain a greater appreciation of the richness of marine biodiversity from the Devonian Period.

Materials

Safety Precautions

Although the materials in this kit are considered relatively nonhazardous, please follow all normal laboratory safety guidelines. Wash hands thoroughly with soap and water before leaving the laboratory

Procedure

1. Obtain a Petri dish bottom. Using a Beral pipet, fill the bottom of the dish with water until it is covered.
2. Use the microfossil spoon to carefully transfer 3 small spoonfuls of microfossil sievings from the stock microfossil tube into the sorting dish (see Figure 1).
   {12758_Procedure_Figure_1_Tip of a widget is used to move microfossils in the water-filled dish}
3. Place a piece of filter paper on the stage of a stereoscope. Place the sorting dish on top of the filter paper on the stereoscope. Adjust the above stage illumination for the best light intensity for the sievings.
4. Obtain a rubber-tipped widget (see Figure 1).
5. Hold the widget as if it was a pencil and use the rubber tip to move the microfossils in the Petri dish. Use the other hand to focus the microscope on the granules and shake the Petri dish slightly if needed.
6. Carefully scan the granules in the sorting dish, looking for shapes and textures that are characteristic of microfossils.
7. Select microfossils may be moved to the lid of the Petri dish and studied further if so desired.
8. Proceed with further sorting and observation of isolated microfossils.
9. Locate and draw an isolated microfossil on the Microfossils Worksheet.
10. Answer the classification questions on the Microfossils Worksheet.
11. Obtain additional Microfossils Data Sheets and repeat steps 10 and 11 for additional microfossils if time allows.
12. Consult your instructor for appropriate disposal procedures.

Student Worksheet PDF

12758_Student1.pdf