Examples of Allopatric Speciation in Nature

📚 Quick Study Guide

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• Allopatric Speciation Definition: The evolution of new species due to geographic isolation.
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• Geographic Barrier: A physical barrier (mountain range, river, ocean) prevents gene flow between populations.
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• Genetic Divergence: Isolated populations experience different mutations, genetic drift, and natural selection.
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• Reproductive Isolation: Over time, the genetic differences become so significant that the populations can no longer interbreed, even if the barrier is removed.
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• Examples: Darwin's Finches (different beak shapes on different islands) and Shrimp in the Isthmus of Panama.

🧪 Practice Quiz

1. Which of the following is the primary cause of allopatric speciation?
   1. A) Behavioral differences
   2. B) Geographic isolation
   3. C) Similar environmental conditions
   4. D) Random mating
2. A population of squirrels is divided by a large river. Over time, the two groups evolve into distinct species. This is an example of:
   1. A) Sympatric speciation
   2. B) Allopatric speciation
   3. C) Hybridization
   4. D) Genetic drift
3. Darwin's finches on the Galapagos Islands are a classic example of allopatric speciation. What was the main isolating mechanism?
   1. A) Differences in mating rituals
   2. B) Geographic separation by islands
   3. C) Competition for resources on the same island
   4. D) Sudden changes in climate
4. Which of the following is NOT a geographic barrier that can lead to allopatric speciation?
   1. A) Mountain range
   2. B) Large lake
   3. C) Open field
   4. D) Desert
5. What happens to gene flow during allopatric speciation?
   1. A) Gene flow increases
   2. B) Gene flow decreases or stops
   3. C) Gene flow remains constant
   4. D) Gene flow becomes more random
6. Two populations of birds live on separate islands. They were once the same species, but now they cannot interbreed. What has occurred?
   1. A) Sympatric speciation
   2. B) Allopatric speciation
   3. C) Convergent evolution
   4. D) Parallel evolution
7. The Isthmus of Panama separated populations of marine organisms. This is an example of allopatric speciation due to:
   1. A) Behavioral isolation
   2. B) Temporal isolation
   3. C) Geographic isolation
   4. D) Reproductive isolation