GCSE Biology - What Are Fossils? What Fossils Tell Us About Extinct Species #78

The video tutorial explains fossils as remnants of long-dead organisms, highlighting their role in understanding extinct species and evolution. It describes three main fossil formation processes: gradual mineral replacement, casts and impressions, and preservation. The tutorial also discusses the incomplete fossil record and various causes of species extinction, such as environmental changes, new predators, diseases, and catastrophic events.

Why are fossils crucial for understanding extinct organisms?

• They are used to predict future climate changes.

• They offer insights into organisms that no longer exist.

• They help us understand the diet of ancient humans.

• They provide direct evidence of current species.

What is the most common way fossils form?

• Through immediate preservation in peat bogs.

• By being trapped in volcanic ash.

• By gradual replacement by minerals.

• Through rapid freezing in glaciers.

How do casts and impressions differ in fossil formation?

• Casts are formed in glaciers, impressions in tar pits.

• Casts involve mineral replacement, impressions involve clay hardening.

• Casts leave a gap, impressions leave a mark.

• Casts are only of bones, impressions are only of footprints.

What is a reason for the incomplete fossil record?

• All fossils have been discovered.

• Soft-bodied organisms decayed quickly.

• Fossils are only found in deserts.

• Fossils are destroyed by human activity.

Which event is an example of a catastrophic cause of extinction?

• A species outcompeting another for food.

• A new disease spreading slowly.

• A predator gradually hunting a species.

• An asteroid impact wiping out dinosaurs.