GRADE 3 SCIENCE INSTRUCTIONAL TASK
Fossil Records
Science Grade-Level Expectation
The exercises in this instructional task address content related to the following science grade-level expectation:
(ESS-E-A7) Identify characteristics of selected fossils and explain how fossil records are used to learn
about the past. (GLE 52)
Objectives
Task
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Interpret and analyze models to form conclusions
Cite evidence to support conclusions
Predict environments for fossilized organisms
Explain how fossil records are used to learn about the
past
Sample Student Exemplar Response
Implementation Tips:
 This task is intended to be integrated into a larger unit that contains hands-on science opportunities,
student-led investigations, non-fiction reading, and a variety of other instructional strategies.
 Teachers may choose to use or modify the task as part of an instructional lesson or as a formative or
summative assessment.
 Strategic instructional decisions will need to be determined prior to implementation such as:
o Should the provided text be read aloud to students or read independently by students?
o Will students work collaboratively or individually to complete the task?
o What content knowledge and skills will students need to have prior to attempting the task?
o Does the task need to be modified based on the needs of the students at the time of
implementation?
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Read “Green River Formation Fossils.”
Read “A Huge Fossil Find” in Time for Kids.
Analyze the historical timeline below.
Task Part 1: Based on the fossils found in the layers on the time-line, predict the type of environment that
existed during each time period. Provide evidence to support your conclusions.
Task Part 2: Using specific examples, describe how fossils help scientists learn about the past?
Sample Student Exemplar Response:
Part 1
The environment during the Paleozoic era included oceans and swamps. This is evident because fish, shell fish,
reptiles, amphibians, and jellyfish are shown. The environment was warm and moist, and included wetlands and
marine habitats.
During the Mesozoic period, dinosaurs, alligators and ferns are shown. This indicates a land environment which
may include forests, grasslands, jungles, and swamps. The environment was warm, supporting cold-blooded
reptiles such as dinosaurs and reptiles. Ferns require water to thrive so either the air was very humid or it often
rained.
The Cenozoic era shows only land animals. Large and small animals and humans are shown. For these animals to
thrive, there must have also been an abundance of plants to be used for food. The environment may have
included grasslands, swamps, forests, and jungles. There had to have also been sources of freshwater such as
lakes, rivers, and streams for these animals to inhabit the area.
Part 2
Scientists use fossils in many ways to learn about the past. Fossils are deposited in many layers of land with the
oldest layers being buried the deepest. Fossils present in each layer of earth can be used to tell us what life was
like on Earth during different time periods. Scientists look at the order of layers of rock in which fossils are found
to determine the order in which life appeared on Earth.
In addition to the type of fossils present, scientists can determine what Earth’s surface was like and the rock
composition of each layer surrounding the fossil to determine the environments present at that time. The fossils
and skeletons of animals and the fossils of plants also give clues to the environment and what must have been
present for the animal or plant to survive.
Scientists compare the fossils of the past to forms of life on Earth today to see if there is any relationship
between today’s life forms and those found in the past. Using skeletal fossils, scientists determine the body
structure of the organism that left the skeleton. These can be compared to today’s animals using tools such as xrays. Since we can’t go back in time, fossils are our biggest clue to past life and the changes in Earth’s
environment.