Land of the lost
Purpose: Students can examine and identify real fossils.
Procedural overview: Students can identify fossils using hand magnifiers or stereo microscopes, determine which era each fossil is from and how the fossils formed over time.
Approximate class time: One class period.
Notes to the teacher: This guide is written for 15 fossils: an ancient reptile tooth, dinosaur bone, dinosaur eggshell, an insect, a fossil fish, a trilobite, an ammonite, amber, a mammoth tusk, petrified wood, fern leaves, a gastropod, a pelecypod, a brachiopod and a shark tooth. Additional notes on each fossil are provided at the bottom of this Activity Guide. You can adapt this activity based on what materials you are able to buy or borrow. Museums are sometimes willing to loan specimens for educational purposes. It may be worth checking with a local museum. Ammonites, trilobites and small dinosaur fossils are inexpensive to buy.
Materials:
- Fossils (depending on what you have or can obtain)
- Gloves (if the samples are sharp or messy)
- 10–30x stereo dissection microscopes with top illumination
- Hand magnifiers
- Activity Guide for Students: Land of the Lost
- Books or websites to help students identify the samples (see suggested resources below)
Sample identification resources:
- For concise identification guides for rocks, minerals and fossils, as well as other related activities, see Pages 12–14 and 20–22 of the MIT Lincoln Laboratory Mini Science Kit guide
- For a more extensive identification guide to fossils, see: Rhodes, Zim, & Shaffer, Fossils (St. Martin’s Press Golden Guide, 2001) or Cyril Walker & David Ward, Fossils (DK, 2002)
- For a guide to meteorites, see: Norton and Chitwood, Field Guide to Meteors and Meteorites (Springer, 2008)
Sample fossil resources:
- For a variety of fossils at a relatively low price, see Two Guys Fossils 2
- For other fossil possibilities, American Science & Surplus
Microscope suggestion:
- For good-quality stereo dissection microscopes at a decent price, go to Home Science Tools
Directions:
- Set up several lab stations with microscopes and/or hand magnifiers.
- Have students describe the stepwise technique that they will use to observe and analyze each of their fossils.
- Distribute the fossils. If you only have one or two of each type, you can ask the students to swap samples as they finish with each one.
- Provide students with any helpful resources, including identification sheets, books or websites mentioned above.
- Have the students study and identify each sample provided and write down their findings as outlined in the Activity Guide for Students. For each fossil, students should fill out the following form:
Fossil #
What is it?
Write your observations of the fossil.
What era(s) could it be from?
How was the fossil formed?
What is the closest living relative?
Notes on 15 fossils:
Fossil 1
What is it? Dinosaur or Mesozoic reptile tooth. There are a variety of Mesozoic teeth on the fossil market, but two of the most common are: (1) Spinosaurus tooth (2) mosasaur (not a dinosaur, but still a very large, Mesozoic reptile).
Write your observations of the fossil. (1) A Spinosaurus tooth is long, narrow, with a slightly rounded tip; it is clearly carnivorous (2) A mosasaur tooth, triangular and somewhat curved, very sharp and clearly carnivorous.
What era(s) could it be from? Mesozoic
How was the fossil formed? Buried and partially or completely replaced by minerals
What is its closest living relative? Birds
Fossil 2
What is it? Dinosaur bone
Write your observations of the fossil. Porous but mineralized, unlike petrified wood. It will likely appear to be a piece of a much larger bone.
What era(s) could it be from? Mesozoic
How was the fossil formed? Buried and replaced by minerals
What is its closest living relative? Birds
Fossil 3
What is it? Dinosaur eggshell
Write your observations of the fossil. Looks like pieces of chicken egg, but with more texture
What era(s) could it be from? Mesozoic
How was the fossil formed? Buried and replaced by minerals
What is its closest living relative? Birds
Fossil 4
What is it? Insect. There are a wide variety of fossil insects on the fossil market. Most of those sold in the United States came from Cenozoic shale deposits in Wyoming or Colorado, and tend to look like flies, gnats, mosquitoes or ants.
Write your observations of the fossil. Observations will vary by insect, but students should observe, for example, six legs, the number of wings, the number of body segments.
What era(s) could it be from? Paleozoic through Cenozoic
How was the fossil formed? Buried in mud, image left by carbon or replacement minerals
What is its closest living relative? Lots of modern insects
Fossil 5
What is it? There are a wide variety of fossil fish on the market. Generally, just the bones fossilize, but some samples show traces of the scales as well. Most fossil fish that were found in the United States come from Green River, Wyo. Other fossil fish on the U.S. market come from China and Brazil.
Write your observations of the fossil. Observations will vary by fish, but students should observe fins, gill plates, scales and so on.
What era(s) could it be from? Paleozoic through Cenozoic
How was the fossil formed? Buried in mud, image left by carbon or replacement minerals
What is its closest living relative? Lots of modern fish
Fossil 6
What is it? Trilobite
Write your observations of the fossil. Students should observe the different characteristics of the trilobite, including number of legs and number of body segments. Students may describe the trilobite as cockroach-like. Cockroaches are probably the closest living things that students have seen. If they have seen the interior of a horseshoe crab, that resembles a trilobite much more closely.
What era(s) could it be from? Paleozoic
How was the fossil formed? Buried and replaced by minerals
What is its closest living relative? Horseshoe crab
Fossil 7
What is it? Ammonite
Write your observations of the fossil. Spiral shape
What era(s) could it be from? Paleozoic through Mesozoic
How was the fossil formed? Buried and replaced by minerals
What is its closest living relative? Nautilus or squids
Fossil 8
What is it? Amber
Write your observations of the fossil. Transparent or translucent yellow
What era(s) could it be from? Almost all amber is from the Cenozoic
How was the fossil formed? Tree resin subjected to heat and pressure while it was buried for thousands or millions of years.
What is its closest living relative? Maple sap
Fossil 9
What is it? Mammoth tusk
Write your observations of the fossil. Mammoth tusk pieces tend to be much whiter than prehistoric bone, and are usually sold as rectangular pieces that are flat or slightly curved. They resemble old piano keys, often made of animal tusk. Mammoth tusk pieces may be from glaciers in Alaska or Siberia.
What era(s) could it be from? Cenozoic
How was the fossil formed? Preserved in ice or buried in sediments
What is its closest living relative? Elephants
Fossil 10
What is it? Petrified wood. A wide variety of petrified wood is available. Look for details about the wood’s origin after buying the sample.
Make observations of the fossil. Looks like wood but is rock hard
What era(s) could it be from? Paleozoic through Cenozoic
How was the fossil formed? Buried and replaced by minerals
What is its closest living relative? Modern trees
Fossil 11
What is it? Fern leaves. Almost all fossil ferns on the market in the U.S. are Alethopteris from Pennsylvania or other states in the eastern U.S. from the Carboniferous period of the Paleozoic. Alethopteris is extinct now, but its leaves look very similar to modern fern leaves.
Write your observations of the fossil. Students should observe the different characteristics of the fern (leaf size, leaf shape, shape of branch).
What era(s) could it be from? Paleozoic through Cenozoic, but samples from Pennsylvania are Paleozoic
How was the fossil formed? Compressed until carbon formed coal and leaves left impressions
What is its closest living relative? Modern ferns or the fossilized fern may still exist. See the information guide from the source of the fossil to determine the closest living relative for the fossil you obtain.
Fossil 12
What is it? Gastropod (snail shell)
Write your observations of the fossil. Cone-shaped spiral shell
What era(s) could it be from? Paleozoic through Cenozoic
How was the fossil formed? Buried in mud and partially or completely mineralized
What is its closest living relative? Modern snails
Fossil 13
What is it? Pelecypod
Write your observations of the fossil. Two shells are alike but mirror images
What era(s) could it be from? Paleozoic through Cenozoic
How was the fossil formed? Buried in mud and partially or completely mineralized
What is its closest living relative? Clams
Fossil 14
What is it? Brachiopod
Write your observations of the fossil. Two shells are different, but each one is symmetrical
What era(s) could it be from? Paleozoic through Cenozoic, but most of the common fossils are Paleozoic
How was the fossil formed? Buried in mud and partially or completely mineralized
What is its closest living relative? Modern brachiopods, which are much less common than clams
Fossil 15
What is it? Shark tooth
Write your observations of the fossil. Small and very sharp, looks like modern shark teeth
What era(s) could it be from? Paleozoic through Cenozoic
How was the fossil formed? Buried in mud and partially or completely mineralized
What is its closest living relative? Modern sharks