Species separated by geographical barriers are called :-

Options

A. Allopatric
B. Sympatric
C. Sibling
D. Endemic

Answer

To solve the question "Species separated by geographical barriers are called:", we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Types of Speciation**:
- There are three main types of speciation: allopatric, parapatric, and sympatric. Each type describes how new species arise.

2. **Define Allopatric Speciation**:
- Allopatric speciation occurs when a population is divided by a geographical barrier (like mountains, rivers, etc.), leading to isolation. This isolation prevents gene flow between the groups, allowing them to evolve independently.

3. **Identify the Characteristics of Allopatric Speciation**:
- In allopatric speciation, after a long period of isolation, the separated populations may evolve into distinct species due to different selective pressures and mutations.

4. **Consider Other Types of Speciation**:
- **Parapatric Speciation**: This occurs when populations are adjacent to each other but do not interbreed, often due to differing environments.
- **Sympatric Speciation**: This occurs within the same geographical area, where new species arise from a common ancestor without physical barriers.

5. **Analyze the Options**:
- The question specifically asks for species separated by geographical barriers, which directly corresponds to allopatric speciation.
- Other options like parapatric, sympatric, sibling, and endemic do not describe species separated by geographical barriers.

6. **Conclude with the Correct Answer**:
- Based on the definitions and characteristics discussed, the correct answer is **allopatric**.

### Final Answer:
Species separated by geographical barriers are called **allopatric** species.

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