Biology unit 2 topic 6

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Origins of stuff
It is believed that earth formed around 4500 million years ago, and that life began around 3500 million years ago.
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Extinction can be caused by a number of factors:
A new disease, the environment changes, new predator may evolve or be introduced, new competitor, single catastrophic may occur. Climate change could make too hot/cold or wet/dry for a species or its food supply
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Isolation of species
New species can arise from existing species if a group becomes isolated from the rest
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Geographical isolation
- if an island separates from the mainland or a new river separates two areas, or a mountain range or old craters can separate organisms.
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The isolated organisms may be exposed to different environmental conditions:
food availability or predators.Natural selection will occur in both areas but different characteristics will be beneficial.If the two populations are brought back together&cannot interbreed,they are now two different species.this is called speciation
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Other cards in this set

Card 2

Front

A new disease, the environment changes, new predator may evolve or be introduced, new competitor, single catastrophic may occur. Climate change could make too hot/cold or wet/dry for a species or its food supply

Back

Extinction can be caused by a number of factors:

Card 3

Front

New species can arise from existing species if a group becomes isolated from the rest

Back

Preview of the back of card 3

Card 4

Front

- if an island separates from the mainland or a new river separates two areas, or a mountain range or old craters can separate organisms.

Back

Preview of the back of card 4

Card 5

Front

food availability or predators.Natural selection will occur in both areas but different characteristics will be beneficial.If the two populations are brought back together&cannot interbreed,they are now two different species.this is called speciation

Back

Preview of the back of card 5

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