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Darwins Finches

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					                                    Darwin’s Finches

Even on a single island the adaptations to different niches led to reproductive isolation
and speciation

The Galapagos are geographically isolated. The nearest continent is S America some
1000 miles away

The adaptation to these niches meant that these finches now differed from the ancestral
ones on the mainland

This single ancestral species found few competitors and so flourished

Some finches made the improbable journey from the mainland to the Galapagos

Some finches found their way to other islands despite these were geographically isolated
from each other

Mutations arose, leading to natural selection favouring those individuals that were better
suited to some of the ecological niches. Changes to the shape of the beak meant they
could exploit different food sources

The new arrivals flourished because there was no competition

Due to the geographic isolation of the islands the birds were also reproductively isolated
and so became separate species

Mutations arose leading to increased variety and natural selection acted upon these
changes so some birds could use new sources and varieties of food

				
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