The debate about whether viruses are alive or not, has been in progress since the distinguishing of the three domains of life. Viruses share some characteristics with bacteria while some with eukarya.
Based on the complexities of their structure, life cycle and much more, most biologists do not consider them alive. This is based on some of the following criteria:
- Living things have the ability to maintain homeostasis: In the case of viruses, they are made up on genes and some organelles surrounded in an envelope and unable to resist extreme environmental changes
- Living things have different levels of organization: Viruses do have some organelles including a capsid, nucleic acids and capsomeres and thus display some levels of organization
- Living things reproduce: Viruses are only able to reproduce in the presence of a host, therefore they are able to reproduce but rely on the cellular mechanisms of another living organism to do so.
- Living things can grow: Viruses make use of host energy that they are residing in to create more virions but themselves do not change in size or complexity
- Living thing use energy: They make us of hsot energy and utilize the byproducts of metabolism
- Living things respond to stimuli: Viruses do not respond to immediate stimuli such as light, touch or sound but there is a lack of research in terms of other factors.
- Living things adapt to their environment: They are able to adapt to their surroundings via replicating through either the lytic or the lysogenic cycle, thus adapting and becoming active accordingly.
Now, more than ever, viruses are under study due to the global pandemic and their evolution is being well researched. Whether they are alive or dead is still up for debate as they demonstrate some characteristics of living things and some of dead. Viruses evolve through recombination of their DNA with other viruses and random mutations. To communicate this to the general public, it is important for them to understand why they are such complex organisms and the risk factors that come with mutations and exposure.
Koonin, E. V., & Starokadomskyy, P. (2016). Are viruses alive? The replicator paradigm sheds decisive light on an old but misguided question. Studies in history and philosophy of biological and biomedical sciences, 59, 125–134. https://doi.org/10.1016/j.shpsc.2016.02.016
Applied Plant Ecology Winter 2020 