What is a species ?

Options

A. A basic unit in the phylogenic history of living organisms
B. A group of related populations from evolutionary point of view.
C. A basic category containing most of the taxonomic information
D. A population of similar characteristics which forms evolutionary basis of variation

Answer

### Step-by-Step Solution:

1. **Definition of Species**: A species is defined as a group of organisms that share similar characteristics and can interbreed to produce fertile offspring. This definition emphasizes the biological aspect of species, focusing on reproductive isolation and genetic continuity.

2. **Characteristics of Species**: Members of a species typically exhibit similar morphology (physical structure) and behavior. This similarity allows them to be classified together within the biological classification system.

3. **Evolutionary Perspective**: From an evolutionary standpoint, a species represents a group of related populations that have diverged from a common ancestor. This evolutionary relationship is crucial for understanding biodiversity and the process of natural selection.

4. **Taxonomic Information**: While species are a fundamental category in taxonomy, they do not contain the most comprehensive taxonomic information. Instead, they form a basic unit that can be further classified into higher taxonomic categories (like genus, family, etc.).

5. **Variation Among Species**: It is important to note that while individuals within a species share similar characteristics, there can be variations within the species itself. However, these variations do not define the species but rather contribute to the evolutionary dynamics within it.

6. **Conclusion**: Based on the definitions and characteristics discussed, the correct understanding of a species aligns with the idea of a group of related populations that can interbreed and produce fertile offspring. Therefore, the most accurate option regarding the definition of a species is that it is a group of related populations from an evolutionary point of view.