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Unit 2 Biology (Higher) > Fossils > Flashcards

Flashcards in Fossils Deck (6)
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What is a fossil?

The remains of organisms found in rocks.


Name three ways fossils form.

Gradual replacement by minerals, from casts and impressions and preservation where decay doesn't occur.


What is gradual replacement?

Where things like teeth, bones and shells are replaced by minerals that leave a rock-like substance, creating a fossil.


How do casts and impressions create fossils?

When an organism is buried in a soft material like clay, the clay hardens as the organism decays and leaves a cast/impression of the organism.


How does preservation create fossils?

Areas or materials, like glaciers where it's too cold for decay microbes to work, stop organisms from decaying.


What do fossils show?

How organisms have evolved over time.