Fossils & Extinction
This lesson covers:
- What fossils are, and the three main ways they're formed
- What fossils can tell us about extinct species
- How species can go extinct
are the remains of organisms from millions of years ago, which are found in rocks.
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Why are fossils used to as evidence for evolution?
Fossils show us how species have changed over millions of years
Fossils can form from animal or plants
Fossils can be made in many ways
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Why is the fossil record incomplete?
(Select all that apply)
There are different types of fossils
Some fossils formed long ago may have been destroyed since
Some organisms are soft-bodied so do not fossilise well
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Three main ways fossils can form
footprints / bones / sediment / decay / amber / minerals / casts
- Hard body parts, such as and shells, which very slowly, are gradually replaced by , forming rock-like substances.
- Animals can leave impressions or , such as or burrows. These become covered by layers of , which eventually become rock.
- Some parts of organisms may not decay at all. For example, dead animals and plants can be preserved in , peat bogs, tar pits, or in ice.
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Why might a dead animal be preserved in a tar pit, rather than decay?
Not enough oxygen for decay to take place
Too cold for decay to take place
Too acidic for decay to take place
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What does it mean for a species to become extinct?
The species is affect by a new disease
There are no remaining individuals of a species still alive.
The species undergoes a genetic change
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Suggest three ways a species may become extinct.
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