Allopatric speciation occurs when

Options

A. genetically related population inhabit widely separted geographical area
B. genetically unrelated populations inhabit widely separated geographical area
C. genetically related population inhabit the same geographical area
D. genetically unrelated population inhabit the same geographical area.

Explanation

### Step-by-Step Solution:

1. **Understanding Speciation**: Speciation is the process through which new species arise. It is a key concept in evolution, which is driven by natural selection, as proposed by Charles Darwin.

2. **Definition of Species**: A species is defined as a group of organisms that can interbreed and produce fertile offspring. Members of different species are reproductively isolated from one another, meaning they cannot mate and produce viable offspring.

3. **Types of Speciation**: There are different types of speciation, including allopatric speciation, which is the focus of this question.

4. **Allopatric Speciation Explained**: Allopatric speciation occurs when populations of the same species become geographically isolated from each other. This isolation can be due to physical barriers like mountains, rivers, or distances that prevent them from interacting.

5. **Impact of Geographic Isolation**: Once separated, these populations can no longer interbreed. Over time, due to different environmental pressures and genetic drift, the two populations will evolve independently. This leads to the accumulation of differences, eventually resulting in the formation of new species.

6. **Conclusion**: Therefore, allopatric speciation occurs when genetically related populations inhabit separate geographical areas, leading to reproductive isolation and divergent evolution.