I found the following, obviously reputable paper on viruses.
https://www.nature.com/scitable/topicpage/the-origins-of-viruses-14398218/
The Origins of Viruses
By: David R. Wessner, Ph.D. (Dept. of Biology, Davidson College) © 2010 Nature Education
Citation: Wessner, D. R. (2010) The Origins of Viruses. Nature Education 3(9):37
How did viruses evolve? Are they a streamlined form of something that existed long ago, or an ultimate culmination of smaller genetic elements joined together?
Figure 1
To consider this question, we need to have a good understanding of what we mean by "life." Although specific definitions may vary, biologists generally agree that all living organisms exhibit several key properties: They can grow, reproduce, maintain an internal homeostasis, respond to stimuli, and carry out various metabolic processes. In addition, populations of living organisms evolve over time.
Do viruses conform to these criteria? Yes and no. We probably all realize that viruses reproduce in some way. We can become infected with a small number of virus particles — by inhaling particles expelled when another person coughs, for instance — and then become sick several days later as the viruses replicate within our bodies. Likewise we probably all realize that viruses evolve over time. We need to get a flu vaccine every year primarily because the influenza virus changes, or evolves, from one year to the next (Nelson & Holmes 2007).
Viruses do not, however, carry out metabolic processes. Most notably, viruses differ from living organisms in that they cannot generate ATP. Viruses also do not possess the necessary machinery for translation, as mentioned above. They do not possess ribosomes and cannot independently form proteins from molecules of messenger RNA. Because of these limitations, viruses can replicate only within a living host cell. Therefore, viruses are obligate intracellular parasites. According to a stringent definition of life, they are nonliving. Not everyone, though, necessarily agrees with this conclusion. Perhaps viruses represent a different type of organism on the tree of life — the capsid-encoding organisms, or CEOs (Figure 1; Raoult & Forterre 2008).
Where Did Viruses Come From?
There is much debate among virologists about this question. Three main hypotheses have been articulated: 1. The progressive, or escape, hypothesis states that viruses arose from genetic elements that gained the ability to move between cells; 2. the regressive, or reduction, hypothesis asserts that viruses are remnants of cellular organisms; and 3. the virus-first hypothesis states that viruses predate or coevolved with their current cellular hosts.
The Progressive Hypothesis
Figure 3
Figure 2
Figure 4
The progressive and regressive hypotheses both assume that cells existed before viruses. What if viruses existed first? Recently, several investigators proposed that viruses may have been the first replicating entities. Koonin and Martin (2005) postulated that viruses existed in a precellular world as self-replicating units. Over time these units, they argue, became more organized and more complex. Eventually, enzymes for the synthesis of membranes and cell walls evolved, resulting in the formation of cells. Viruses, then, may have existed before bacteria, archaea, or eukaryotes (Figure 4; Prangishvili et al. 2006).
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more at link............................
extract:
Summary:
Contemplating the origins of life fascinates both scientists and the general public. Understanding the evolutionary history of viruses may shed some light on this interesting topic. To date, no clear explanation for the origin(s) of viruses exists. Viruses may have arisen from mobile genetic elements that gained the ability to move between cells. They may be descendants of previously free-living organisms that adapted a parasitic replication strategy. Perhaps viruses existed before, and led to the evolution of, cellular life. Continuing studies may provide us with clearer answers. Or future studies may reveal that the answer is even murkier than it now appears.
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So [as illustrated in blue highlight] the question still abounds as to whether viruses constitute life as we know it, or non life.
I have always wondered why some don't see them as life...glad that others also think the same.
While understanding that science exists on stringent definitions, are they being to pedantic in not recognising viruses as life?
https://www.nature.com/scitable/topicpage/the-origins-of-viruses-14398218/
The Origins of Viruses
By: David R. Wessner, Ph.D. (Dept. of Biology, Davidson College) © 2010 Nature Education
Citation: Wessner, D. R. (2010) The Origins of Viruses. Nature Education 3(9):37
How did viruses evolve? Are they a streamlined form of something that existed long ago, or an ultimate culmination of smaller genetic elements joined together?
Figure 1To consider this question, we need to have a good understanding of what we mean by "life." Although specific definitions may vary, biologists generally agree that all living organisms exhibit several key properties: They can grow, reproduce, maintain an internal homeostasis, respond to stimuli, and carry out various metabolic processes. In addition, populations of living organisms evolve over time.
Do viruses conform to these criteria? Yes and no. We probably all realize that viruses reproduce in some way. We can become infected with a small number of virus particles — by inhaling particles expelled when another person coughs, for instance — and then become sick several days later as the viruses replicate within our bodies. Likewise we probably all realize that viruses evolve over time. We need to get a flu vaccine every year primarily because the influenza virus changes, or evolves, from one year to the next (Nelson & Holmes 2007).
Viruses do not, however, carry out metabolic processes. Most notably, viruses differ from living organisms in that they cannot generate ATP. Viruses also do not possess the necessary machinery for translation, as mentioned above. They do not possess ribosomes and cannot independently form proteins from molecules of messenger RNA. Because of these limitations, viruses can replicate only within a living host cell. Therefore, viruses are obligate intracellular parasites. According to a stringent definition of life, they are nonliving. Not everyone, though, necessarily agrees with this conclusion. Perhaps viruses represent a different type of organism on the tree of life — the capsid-encoding organisms, or CEOs (Figure 1; Raoult & Forterre 2008).
Where Did Viruses Come From?
There is much debate among virologists about this question. Three main hypotheses have been articulated: 1. The progressive, or escape, hypothesis states that viruses arose from genetic elements that gained the ability to move between cells; 2. the regressive, or reduction, hypothesis asserts that viruses are remnants of cellular organisms; and 3. the virus-first hypothesis states that viruses predate or coevolved with their current cellular hosts.
The Progressive Hypothesis
Figure 3Figure 2Figure 4The progressive and regressive hypotheses both assume that cells existed before viruses. What if viruses existed first? Recently, several investigators proposed that viruses may have been the first replicating entities. Koonin and Martin (2005) postulated that viruses existed in a precellular world as self-replicating units. Over time these units, they argue, became more organized and more complex. Eventually, enzymes for the synthesis of membranes and cell walls evolved, resulting in the formation of cells. Viruses, then, may have existed before bacteria, archaea, or eukaryotes (Figure 4; Prangishvili et al. 2006).
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
more at link............................
extract:
Summary:
Contemplating the origins of life fascinates both scientists and the general public. Understanding the evolutionary history of viruses may shed some light on this interesting topic. To date, no clear explanation for the origin(s) of viruses exists. Viruses may have arisen from mobile genetic elements that gained the ability to move between cells. They may be descendants of previously free-living organisms that adapted a parasitic replication strategy. Perhaps viruses existed before, and led to the evolution of, cellular life. Continuing studies may provide us with clearer answers. Or future studies may reveal that the answer is even murkier than it now appears.
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
So [as illustrated in blue highlight] the question still abounds as to whether viruses constitute life as we know it, or non life.
I have always wondered why some don't see them as life...glad that others also think the same.
While understanding that science exists on stringent definitions, are they being to pedantic in not recognising viruses as life?
