Fossil Records

The fossil record is a collection of all known fossils and the layers of rock in which they are found.

Fossils form when dead organisms are quickly buried under sediment, such as mud or sand, which protects their remains from decay.

Over long periods, minerals seep into the remains, turning them into rock and preserving shapes like bones, shells, or plant impressions.

Fossils are typically found in sedimentary rock layers, with the oldest layers at the bottom and the newest ones on top.

This layering helps scientists arrange fossils in chronological order, showing which life forms appeared first and which came later.

They also use radiometric dating, which measures how certain radioactive materials in the rocks break down over time.

For example, radiometric dating has shown that dinosaurs went extinct about 66 million years ago, while early humans appeared only about 2.5 million years ago.

Fossils also show how Earth’s surface has changed through earthquakes, volcanoes, and shifting continents.

The fossil record is a timeline of life, showing how some organisms are related through common ancestors.