In this Grade 3 lesson from Science: A Closer Look, Chapter 3, students learn what fossils are, how they form in rock layers, and what they reveal about ancient plants and animals. Students explore the concept of extinction, examining real examples like saber-toothed cats and the St. Helena Olive tree to understand how environmental changes and human activity can cause species to disappear. A hands-on modeling activity reinforces how scientists use rock layers to determine the age and order of fossils.
Section 1
Fossils Reveal Ancient Life Stories
Scientists study fossils—remains of organisms from long ago—to learn about extinct plants and animals. Fossils show an organism's size, shape, diet, and movement methods, helping us understand Earth's past.
Section 2
Environmental Changes Drive Extinction
When environments change suddenly, species can become extinct. Dinosaurs disappeared after a meteor impact, saber-toothed cats vanished when ice melted, and today's species die from hunting and habitat loss.
Section 3
Scientists Compare Modern and Ancient Animals
Researchers study living animals to understand extinct relatives. By comparing elephants to woolly mammoths or eagles to pterodactyls, scientists can deduce how ancient creatures used their body parts and behaved.
Section 4
Rock Layers Tell Time Stories
The depth of fossils reveals their age—deeper means older. Scientists examine fossil layers to understand how Earth changed, like finding fish fossils on land showing areas once covered by water.
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Section 1
Fossils Reveal Ancient Life Stories
Scientists study fossils—remains of organisms from long ago—to learn about extinct plants and animals. Fossils show an organism's size, shape, diet, and movement methods, helping us understand Earth's past.
Section 2
Environmental Changes Drive Extinction
When environments change suddenly, species can become extinct. Dinosaurs disappeared after a meteor impact, saber-toothed cats vanished when ice melted, and today's species die from hunting and habitat loss.
Section 3
Scientists Compare Modern and Ancient Animals
Researchers study living animals to understand extinct relatives. By comparing elephants to woolly mammoths or eagles to pterodactyls, scientists can deduce how ancient creatures used their body parts and behaved.
Section 4
Rock Layers Tell Time Stories
The depth of fossils reveals their age—deeper means older. Scientists examine fossil layers to understand how Earth changed, like finding fish fossils on land showing areas once covered by water.
Book overview
Jump across lessons in the current chapter without opening the full course modal.
Continue this chapter