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Earth Science:
Studying Fossils
Introduction:
In this lesson, we will study fossils. Where did they come from? How
are they made? What can we learn from them? How do we identify and classify
them? These are just some of the questions we will answer in this lesson.
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Studying Fossils: Teacher Notes
Download:
Print the Fossils activity worksheets.
- For an introductory background to fossils, check the Royal Ontario
Museum Web Site: http://www.rom.on.ca/quiz/fossil/.
Review this material with the group
- Show and discuss the sample fossils provided with the lab: These
samples were purchased from WARD's Natural Science Establishment, Inc.,
Rochester NY. (Fossil Display Pack 50 E 0115) Most of the definitions
given below either are from the material provided with the samples
or were obtained from the Royal Tyrrel Museum Fossil Encyclopedia (This
site has been removed from the internet)
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A) Horn coral:
A coral found only in Paleozoic rocks and no longer exists in our present
oceans. This fossil is about 375 million years old. |
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B) Bryozoan ("moss animals"): These small aquatic animals. average less than 1 millimeter
in length but live in large colonies that are as much as 30 cm across. |
This is approximately 12 inches -- the length of a standard ruler. Modern bryozoans are found in warm shallow seas, where
they grow attached to the sea floor.
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C) Brachiopod ("lamp shells"): Brachiopods are a common type of shellfish found in marine rocks from early
in the Cambrian period onwards, and they have survived to the present today. They had two shells and lived attached to the
sea bottom. There are around 200 living species of brachiopod, and around 30,000 species of fossil brachiopods. Brachiopods
still exist today but are very rarely found as seashells on the beach. |
| D) Gastropod ("snails"): This typical snail shell has a spirally coiled, single-valved
shell. These mollusks first appeared about 550 million years ago, and exist today both on land and in water. This example
is about 100 million years old.
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E) Trilobite ("three lobed"):
Trilobites are arthropods related to the modern horseshoe crab.
They were especially abundant during the Cambrian Period and became extinct during the end of the Permian Period (225 million
years ago). A trilobite molted its exoskeleton periodically as it grew, so it is possible that one trilobite could produce
many fossil remains. From Doug DeRosear's Fossil Collection (http://burlingtonia.miningco.com/library/bltrilobite.htm)
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| F) Shark tooth: This tooth is a fossil remnant of a shark, which lived some 20 million years ago. Sharks have evolved nearly 350 million years, and
have changed little during this period. |
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G) Crinoid Stem ("sea lilies"): Crinoids live in groups. Complete crinoids are rarely preserved
as fossils since the plates that make up the animals hard parts fall apart at death. These animals are abundant and important
from the Ordovician to the Tertiary. |
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Most of them, both fossil and living species, have long stalks that anchor them to the bottom. Attached to the stalk is a cup
in which the main body organs lie. The mouth lies at the center and five or more arms channel food towards the mouth.
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