What Fossils Reveal - 3rd Grade Science

Different organisms lived at different times. Rock layers act like a timeline, with each layer containing different species.

Its size, shape, and body parts. Preserved bones and shells reveal the physical features of extinct organisms.

A fossil that shows an organism’s activity, not its body. Examples include footprints, burrows, or bite marks left by ancient organisms.

Hard parts, such as bones, shells, or teeth. Soft parts decay quickly, while hard parts resist decay and can fossilize.

That organism’s kind has changed little over a very long time. Some species remain virtually unchanged through evolutionary time.

The organism is extinct. Extinct means the species no longer exists anywhere on Earth.

They show what organisms lived in the past and what they were like. Fossils provide direct evidence of ancient species and their characteristics.

Fossil in layer B. Lower rock layers formed first, making their fossils older.

Body fossil. Body fossils preserve actual parts of organisms like bones or shells.

They show what organisms lived, and what their environments were like. Fossils are evidence of ancient life and past environmental conditions.

Trace fossil. Trace fossils show evidence of activity, not actual body parts.

The area was once covered by water, such as a sea or lake. Fish fossils indicate ancient seas or lakes existed there.

It was likely warm and wet enough for many plants to grow. Ferns need moisture and warmth to thrive, indicating tropical conditions.

It was likely a marine (ocean) environment. Seashells form in oceans, showing the area was underwater.