Fossils and Extinction 3-LS4-1

Grade 3 - NGSS - CA

A fossil formed when dissolved minerals fill a mold and harden

Cast

A fossil formed when dissolved minerals fill a mold and harden. Cast. A cast is a rock copy of a once-living thing.

The preserved traces and remains of an organism that lived long ago

Fossil

The preserved traces and remains of an organism that lived long ago. Fossils are like nature's way of showing us what plants and animals looked like a long time ago.

The history of life recorded by all the fossils we have collected

Fossil record

The history of life recorded by all the fossils we have collected. Fossil record. The fossil record is like nature's photo album that shows us what animals and plants looked like a long time ago.

A fossil from an organism that existed for a short time, it is used to determine the age of other fossils

Index fossil

A fossil from an organism that existed for a short time, it is used to determine the age of other fossils. Index fossil. An index fossil helps scientists figure out how old different rocks and other fossils are.

A rock fossil created when a buried organism dissolves

Mold

A rock fossil created when a buried organism dissolves. Mold. Mold is a hollow space in the shape of a once-living thing.

A fossil formed in soft sedimentary rock, like a footprint

Trace fossil

A fossil formed in soft sedimentary rock, like a footprint. Trace fossil. A trace fossil is a mark or track left behind by animals, showing their activities like walking or burrowing.