Final answer:
Viruses have genetic material and can evolve, which aligns with traits of living organisms, but their dependency on host cells for replication and lack of cell structure, homeostasis, and metabolism lead most scientists to consider them non-living. Recent discoveries about giant viruses have challenged this view, indicating the boundary between life and non-life can be fluid. Diseases like influenza and COVID-19 exemplify the impact of viruses on living organisms.
Step-by-step explanation:
When considering whether viruses are living things, we must compare their characteristics to those of recognized living organisms. By definition, living things are capable of reproduction, maintain homeostasis, possess metabolism, react to stimuli, and are made up of cells. Viruses have genetic material and can evolve, which are traits of living organisms, but they lack other essential characteristics.
Viruses do not consist of cells, lack a plasma membrane, cytoplasm, ribosomes, and cannot reproduce or metabolize without a host. Most scientists agree that viruses should not be considered alive since they depend on a host cell's machinery to replicate. However, recent discoveries of giant viruses challenge this view, suggesting some viruses may have had the ability to reproduce independently in the past. This ongoing debate in virology demonstrates that the question of whether viruses are alive is complex and nuanced, reflecting our evolving understanding of biology.
Viruses differ from blood cells and other cellular organisms substantially. Red blood cells, for example, are complete cells that can metabolize and are integral parts of living organisms. In comparison, viruses require a host cell to carry out functions necessary for reproduction. This symbiotic relationship with the host might sometimes benefit viruses, such as the influenza virus, which avoids killing the host cell immediately to spread more effectively.
There are many diseases caused by viruses, such as the common cold, influenza, HIV/AIDS, and COVID-19. Each of these diseases demonstrates the ability of viruses to affect living organisms significantly, even though they themselves are not considered alive under the traditional definition.