Species X has lived in the forest for many years. One day, some individuals in...
Species X has lived in the forest for many years. One day, some individuals in the Species X forest population moved to the mountains, away from the native habitat in which they had lived for so long. A large river then developed between the mountains and the forest, separating the two environments. None of the Species X individuals in the forest could travel to the mountains and none in the mountains could come back to the forest. Gradually, over time, the individuals that had moved to the mountains became increasingly different from the animals that remained in the forest. Eventually, the Species X individuals that moved to the mountains became so different from those in the forest that they could no longer breed with one another. Which of the following best describes this type of speciation?
- A. Sympatric speciation
- B. Peripatric speciation
- C. Allopatric speciation
- D. Parapatric speciation
Correct Answer: C. Allopatric speciation
Explanation
The definition of species states that once two groups of animals are no longer able to breed with one another, they are considered members of different species. Allopatric speciation describes speciation that happens when two groups of organisms become separated by a geographic barrier that prevents interbreeding. In this question, the river is the geographic barrier separating the organisms in the mountains from those in the forest. Over time, these two groups of organisms acquire differences. Once these differences are enough to prevent the members of these two groups from being able to mate with one another, they are considered different species and allopatric speciation has occurred.