Download Speciation

Biology
Darwin’s Finches: Speciation at Work
Name:_____________________________________________________________ Block:________
There are 14 different species of finch on the Galapagos Islands that evolved from a
common ancestor. How did it happen?
Step 1: The Founding Fathers (or for the finches: The “Founding Feathers”)
- A few finches end up in the islands on Island A.
- Finches do not usually fly long distances over water.
Step 2: Separation
- Some finches travel to a second island, Island B.
- The two groups are separated by ocean and have achieved reproductive
isolation.
Step 3: Change
- Over time, the two populations adapt to their different environments.
- The gene pools change as a result of natural selection.
Step 4: Total Reproductive Isolation
- The birds now prefer to mate with other birds that have similar beaks.
- If some Island B birds return to Island A, the two groups will NOT interbreed.
Step 5: Reunion
- The two species of birds are reunited and one of three things will occur as a
result.
1) Coexistence: Two species must occupy different niches.
2) Extinction: Two species occupy the same niche and compete; the better fit
species will survive, the less fit species will die off.
3) Further Evolution: Enough variation between the two species can lead to one
or both species evolving further; this can lead to coexistence.
Assignment
Work with your partner (the person at your table) to make up your own example of
speciation. Make sure that you cover the same five steps listed in the example of
Chuck’s finches.
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________