Fossils, Extinction and Speciation

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What's a fossil?
Remains of dead organism (plants and animals) from many years ago which are found in rocks
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Describe the fossilisation method of Gradual replacement by minerals and Casts/Impressions
GR:Things like teeth, shells and bones don't decay easily, eventually replaced by minerals forming a rock-like substance similar to original hard part. CI:Organism buried in soft material like clay, the clay hardens and organism decay leaving a cast
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Describe the method of fossilissation of Preservation?
In Amber or Tar pits there's no moisture or oxygen so decay microbes can't survive, In Glaciers it's too cold for decay microbes to work and in Peat Bogs it's too acidic for decay microbes.
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Name the six reasons species become extinct
1) Environment changes too quickly 2) New predator 3) New disease 4) New competitor 5) Catastrophic event 6)Speciation
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What is meant by the term extinct?
Where a species no longer exists
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When does speciation occur?
When populations of the same species become so different that they can no longer breed together to produce fertile offspring
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Explain the term isolation
Where populations of a species are separated, normally by physical barriers
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Briefly describe the order of speciation
Two populations of the same species become separated by physical barriers, populations adapt to new environments, both show variation by wide range of alleles, better characteristics means better chance of survival, passed on to next generation
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Card 2

Front

Describe the fossilisation method of Gradual replacement by minerals and Casts/Impressions

Back

GR:Things like teeth, shells and bones don't decay easily, eventually replaced by minerals forming a rock-like substance similar to original hard part. CI:Organism buried in soft material like clay, the clay hardens and organism decay leaving a cast

Card 3

Front

Describe the method of fossilissation of Preservation?

Back

Preview of the front of card 3

Card 4

Front

Name the six reasons species become extinct

Back

Preview of the front of card 4

Card 5

Front

What is meant by the term extinct?

Back

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