Rana's Characteristics of Viruses Argumentation

Virus Argumentation - Should a virus be classified as a living thing?

Viruses should not be classified as living things.  In order for anything to be considered living it must have all of 7 characteristics.  All living things are composed of cells, have different levels of organization, use energy, respond to stimuli, grow, reproduce, and adapt to their environment.  Viruses however, only contain few of those characteristics.  They have biomolecules, can reproduce, and have genetic material.  This is not sufficient enough for them to be classified as living. Table 1 shows many different objects and their characteristics.  Only the living things contain at least one of every characteristic in the table, while the non living things are missing at least one of the characteristics.  Some of the living things in this table are, sponges, elodea, plasmodium, e. coli, tube worms, and dogs.  Each of them have an energy source of either the sun, organic compounds, or inorganic compounds.  They all have a carbon source of either carbohydrates, or carbon dioxide.  They all have a waste production, respond to external stimuli, have all 4 biomolecules, a form of reproduction, genetic material, and they grow.  All of these that they contain are necessary for any organism to be labelled as living.  

Viruses may enter cells, infect cells, and reproduce inside cells, but in no way are cells.  Viruses are tiny bundles of genetic material, either DNA or RNA, and are carried in protein shells called capsids.  Genetic material is the molecule that plays the fundamental role in determining the nature and structure of an organism or cell.  All living things contain genetic material, viruses as well, but the genetic material would lie within the cells and viruses do not have and are not cells.  Also, the genetic material inside the virus is not activated until the virus is inside a cell.  Once a virus enters a cell, the cell itself will create more copies of the virus.  Which also shows that viruses cannot reproduce.  Living things reproduce in order for their species to survive, but they only reproduce either asexually or sexually.  Asexual reproduction is to produce offspring without the use of gametes, while sexual reproduction is producing offspring by joining sex cells.  As seen in table 1, viruses such as the influenza virus and the adenovirus only replicate, and require a host in order to do so.  Furthermore, the use of energy is important in all living things, it is used for maintenance and growth.  According to table 1, viruses such as the influenza virus and the adenovirus do not contain any energy source, meaning that they do not produce or use energy.  Living organisms also respond to their stimuli by making changes in response to their environment.  Both the influenza and the adenovirus do not respond to their external stimuli.  In order to be living they also should grow through cell division.  However, since viruses do not contain cells and are not cells, they can not grow either.

Unlike viruses, the sponges, elodea, plasmodium, e. coli, tube worms, and dogs are all living things that contain the necessary characteristics of life.  They all have an energy source for maintenance and growth.  The energy is used for internal processes such as photosynthesis.  Also, they all have a carbon source, which is to gain carbon because it is an essential atom used in the formation of molecules such as the 4 biomolecules: nucleic acids, proteins, lipids, and carbohydrates.  The nucleic acids make up the genetic material contained in all living organisms, both DNA and RNA.  In order to maintain homeostasis, they each all have a form of waste production, and in order to adapt and change according to their environment they each have the ability to respond to external stimuli. Lastly, they all have either sexual, asexual, or both as their form of reproduction in order for their species to survive.   

Even though an object may contain some characteristics that may classify it as living, if it does not have all of the characteristics, it is not living.  Similarly, a computer, which is also in table 1, does have an energy source, waste production, and responds to external stimuli.  However, it is obviously known that it is also not living, but it still contains some of the same characteristics as other living things.  Likewise, viruses are not living things though they may contain biomolecules, a form of reproduction, and genetic material.  Since viruses do not have an energy source, a carbon source, waste production, response to stimuli, or growth, they are not living.