In virology, to what does the term viral species refer?

• A. A group of viruses that share a common evolutionary lineage and occupy a particular ecological niche
• B. All viruses that infect the same host species
• C. A set of viruses that are identical in genome sequence and morphology
• D. Any single virus particle (virion) capable of infecting a cell

Answer: (A)

Verified step by step guidance

1. Understand that in virology, the concept of 'viral species' differs from the traditional biological species concept used for cellular organisms.
2. Recognize that viral species are defined based on evolutionary relationships rather than strict reproductive isolation, since viruses do not reproduce sexually.
3. Identify that a viral species groups viruses that share a common evolutionary lineage, meaning they have descended from a common ancestor and have genetic similarities.
4. Consider that viral species also occupy a particular ecological niche, which includes the specific host range and environmental conditions where the viruses thrive.
5. Conclude that the correct definition of a viral species is a group of viruses sharing a common evolutionary lineage and occupying a particular ecological niche, rather than simply infecting the same host or being identical in genome sequence.