Which one of the following systems of classification assumes that organisms belonging to the same taxa have a common ancestor ?

Options

A. Earliest system
B. Artificial system
C. Natural system
D. Phylogenetic system

Answer

To answer the question "Which one of the following systems of classification assumes that organisms belonging to the same taxa have a common ancestor?", we need to analyze the four systems of classification provided: the earliest system, the artificial system, the natural system, and the phylogenetic system.

### Step-by-Step Solution:

1. **Understand the Question**: The question asks which classification system assumes a common ancestor for organisms within the same taxa.

2. **Examine the Earliest System**:
- The earliest system of classification was proposed by Aristotle.
- It was based on the observation of physical characteristics of animals.
- This system does not consider evolutionary relationships or common ancestry.
- **Conclusion**: This option is incorrect.

3. **Examine the Artificial System**:
- The artificial system was developed by Carl Linnaeus, known as the father of taxonomy.
- It classifies organisms based on arbitrary characteristics such as the number of stamens.
- This system does not take into account evolutionary relationships or common ancestry.
- **Conclusion**: This option is also incorrect.

4. **Examine the Natural System**:
- The natural system was proposed by Bentham and Hooker.
- It is based on personal studies of actual specimens and their characteristics.
- While it is more systematic than the previous two, it still does not explicitly assume common ancestry.
- **Conclusion**: This option is incorrect as well.

5. **Examine the Phylogenetic System**:
- The phylogenetic system was introduced by Charles Darwin in his work "The Origin of Species."
- This system classifies organisms based on their evolutionary relationships and assumes that organisms within the same taxa share a common ancestor.
- **Conclusion**: This is the correct option.

6. **Final Answer**: The system of classification that assumes organisms belonging to the same taxa have a common ancestor is the **phylogenetic system**.