Biology B2 Old and new species 6.1 - 6.4

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What is the evidence for the origins of life on earth?
Fossils are the remains of organisms from many years ago to help clarify but not explain the origins of life.
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What are fossils?
The mineralised remains of animals buried under layers of soil and mud.
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How much have organisms changed over time?
We can find this out by looking at fossil records.
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What is extinction?
Extinction is the end of a species that can be caused by new predators, new diseases or new, more successful competition.
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How does environmental change over long time scales affect living organisms?
It can cause extinction.
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What has caused mass extinction in the past?
Volcanoes and asteroid attacks.
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How do new species arise?
When two populations become isolated.
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How do populations become isolated?
When they are separated geographically.
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How does speciation take place in an isolated environment?
When in a isolated population alleles are selected that increase successful breading in the new environment when one population becomes so different that it cant mate successfully with the other it is classed as a new specie
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Other cards in this set

Card 2

Front

What are fossils?

Back

The mineralised remains of animals buried under layers of soil and mud.

Card 3

Front

How much have organisms changed over time?

Back

Preview of the front of card 3

Card 4

Front

What is extinction?

Back

Preview of the front of card 4

Card 5

Front

How does environmental change over long time scales affect living organisms?

Back

Preview of the front of card 5
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