Fossils (OCR GCSE Biology A (Gateway Science Suite)): Flashcards

What are fossils?

Preserved remains or traces of organisms from millions of years ago

3 ways fossils can form

1. Preservation without decay 2. Mineral replacement 3. Preserved traces

Conditions that prevent decay in fossil formation

Absence of oxygen or moisture

In mineral replacement, what replaces bones/teeth/shells?

Minerals

Examples of preserved traces in fossils

Footprints, burrows, rootlets (plant roots)

How do fossils provide evidence of evolution?

Show how anatomy of organisms changed over time

What are evolutionary trees?

Diagrams mapping relationships between species

Why are early life fossils rare?

Early life forms were soft-bodied and decayed completely

Geological processes that destroy fossils

Erosion, volcanic activity, tectonic movements

Where are fossils typically found?

Embedded in rock layers