Grades 2 to 3

Fossils are parts of animals or plants that have been saved in the Earth’s crust. Fossils can also be things like animal footprints or even animal waste! Some fossils are the actual animal or plant parts, like bones or seeds. Some fossils are animal or plant shapes. Fossils reveal important facts about how the animal behaved long ago and what it ate.

Most fossils are created when an animal or plant dies. If a dead animal or plant is covered with mud, clay or minerals, its shape can be saved. This is like taking play-dough and covering up a toy. When you remove the toy, the play-dough has the same shape as the toy. Over time, the shape can fill with minerals. These form rocks that look like the animal or plant. Many of the fossils we find were once in water. Over time, the water drained away and left the hard fossils. Animal fossils can be found in bogs, quicksand, amber, volcanic ash and tar pits.

You can see a variety of plant and animal fossils. Just take a tour of the virtual fossil museum by clicking on this link:

The fossil record
The scientists who study fossils are called paleontologists (pay-lee-un-tall-o-gists). They have made a fossil record. The fossil record shows where they found fossils and what kind of rocks or minerals were present. They discovered in the early 1800s that the same kind of fossils were found in similar rocks all over the earth. They also found the fossils in the same order.

Show students how sediment forms fossils.

Fossils can come in many forms. Upper left: The limestone rock has the shape of a trilobite, a small sea creature that made an impression that was filled in with minerals when the rocks was formed. Upper right: Teeth are coated with enamel that helps preserve them. This rhinoceros tooth helps scientists know what kinds of foods were eaten and how old the animal was when it died. Bottom: This leg bone from a mastodon helps scientists determine how large the animal was when it died.