The Instigator
kcarrasco
Con (against)
Losing
0 Points
The Contender
whiteflame
Pro (for)
Winning
18 Points

Should viruses be considered alive?

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Post Voting Period
The voting period for this debate has ended.
after 4 votes the winner is...
whiteflame
Voting Style: Open Point System: 7 Point
Started: 9/22/2015 Category: Science
Updated: 1 year ago Status: Post Voting Period
Viewed: 531 times Debate No: 79970
Debate Rounds (3)
Comments (0)
Votes (4)

 

kcarrasco

Con

In order for something to be considered alive they need to have/ be able to do the following
"based on genetic code
"reproduce
"grow & develop
"obtain / use material and energy
"respond to their environment
"main a stable internal environment
"made up of cells
In my opinion, viruses are not alive. Even though viruses may have most of the seven qualities, I've listed above. They cannot reproduce on their own. They need to attach themselves to a cell host. This is the main reason why bacteria is considered alive and viruses aren"t because bacteria doesn"t depend or attach themselves to anything in order for them to replicate themselves.
whiteflame

Pro

I'd like to start by formally welcoming my opponent to the site. It's always a pleasure to see more people interested in debating join the site, and all the more so to see someone interested in microbiology and the definitions of life. Both are complex subjects, and thus worthy of such discussions.

I'd also like to thank kcarrasco for offering this debate. It's a topic that interests me greatly, as virus research is a large part of what I do, and I appreciate the opportunity offered by having a formal debate on the topic.

That being said, let's move into arguments.

Let's be clear off the bat: the scientific community is divided on this subject. You will find researchers who support each view because viruses are said to be in a sort of gray area between life and non-life. While I find that there's a lot of value to this this discussion, however, my view is that viruses are most definitely life.

There are several definitions of life, to be sure. The list of possible definitions of life are highly diverse, and a large portion of those are covered in this article.[1] To determine whether or not Pro's definition is sufficient to include all of life, let's go through the list. I'll save the important ones for last.

1. Based on genetic code

As viruses are composed of a genomic component and a protein component at a minimum, they are fundamentally based on a genetic code.

3. Grow and develop

I think it's safe to say that viruses both grow and develop. Since the genome has to be replicated, the construction of that genome within a host can be considered growth. As for development, as many viruses bud out of cells, pulling membrane components with them, they are essentially developing new surface proteins and means to avoid detection.[2] We could also look to the many ways in which viruses manage to update and upgrade their genomes and quickly evolve, I would say that their development is not in question.[3]

4. Obtain/use material energy

Like all forms of life, viruses do require energy for the replication of their genomes and production of the necessary proteins. The fact that they do so with the help of other organisms doesn't affect the fact that they achieve this result.

5. Respond to their environment

You could say that viruses are more responsive to their environment than any other organism, with the capacity to respond rapidly to a broad variety of detrimental situations, including antivirals and vaccines.[4, 5]

6. Main[tain] a stable internal environment

This doesn't require much, since the internal environment is merely within the viral capsid. Since it's a closed system that only requires stability enough to keep the viral genome intact, I would say that viruses manage this quite effectively.

2. Reproduce

This is the main point my opponent contends is not true of viruses. Firstly, while what he says is true, there's nothing inherent to this part of the definition that requires independent reproduction. Viruses clearly reproduce, at a very rapid rate. Con grants that, which means it meets the definition he initially provided, which is merely to reproduce.

Second, if he's right that viruses need to "reproduce on their own" (and I'm assuming he means without the need to parasitize another cell, as many organisms cannot asexually reproduce), then Con is excluding a large number of organisms from the definition of life. This is problematic as Con grants that bacteria are alive, yet he ignores the fact that many bacteria, including Chlamydia, Rickettsia, Coxella, and Mycobacterium species are obligate intracellular parasites just like viruses. That's not to mention the many species of protozoa and fungi that also would fail to meet this definition.[6]

Third, I don't see why independent reproduction is a necessary part of life. I'll get into this on the last point, but the only reason I can think of for why reproduction must be independent is that life should be like us. As long as reproduction occurs, I contend that that is sufficient to meet the basic, unbiased definition for life.

7. Made up of cells

This is, perhaps, the most confusing of the aspects of life Con cites, and I view it as entirely unreasonable. Life should not be defined on the basis of similarity to human beings. The idea that life must be composed of either a single or multiple cells (i.e. an entity enclosed by a membrane containing organelles and genetic material) functions entirely on the basis that we view ourselves as life, and only those things that are similar on a molecular level are also deserving of the label. Why is a protein coat insufficient? What about the many viruses surrounded by a membrane " why aren't they considered a cell? Why is the presence of organelles necessary? These are questions Con will have to answer to support this portion of the definition.

I would argue that the protein coat functions in much the same way as a membrane: it's a self-contained system. Con might argue that this isn't metabolic, but when within another host, it has a form of metabolism, producing a broad variety of enzymes that completely overtake the metabolism of much larger cells and using them for their own purposes. In fact, gigantic viruses the size of small bacteria are encapsidated with huge amounts of diverse enzymes that immediately go to work the moment they're released from the virus, turning the cell's metabolism into a viral factory. These viruses are considered to be a plausible link between viruses and cells, suggesting a continuum in life between the two.[7] I'd say this more than meets any reasonable definition of what a metabolism looks like.

Conclusion:

I've made it clear that Con's own definition for life either supports the view that viruses are living entities or simply aren't relevant to what is life. Moreover, I would argue that it's unnecessary for life to meet every single one of these. Meeting a substantial majority (at least 5) should be sufficient, as this still clearly differentiates life from non-life.

With that, I hand the debate back over to Con.

1. https://en.wikipedia.org...
2. https://en.wikipedia.org...
3. http://viralzone.expasy.org...
4. http://www.ncbi.nlm.nih.gov...
5. http://www.livescience.com...
6. https://en.wikipedia.org...
7. http://www.sciencedaily.com...
Debate Round No. 1
kcarrasco

Con

kcarrasco forfeited this round.
whiteflame

Pro

Well, that's disappointing. As I stated in my opening round, I think this is a fascinating topic with a lot of room for debate. I was hoping to have it here, but, sadly, it appears my opponent was either not able or not willing to continue it.
Debate Round No. 2
kcarrasco

Con

kcarrasco forfeited this round.
whiteflame

Pro

Well, this has been extremely disappointing.
Debate Round No. 3
No comments have been posted on this debate.
4 votes have been placed for this debate. Showing 1 through 4 records.
Vote Placed by Bennett91 1 year ago
Bennett91
kcarrascowhiteflameTied
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Total points awarded:07 
Reasons for voting decision: Win/points for FF - but what a nice structure pro had. I skipped right to reproduction and it makes sense that our definition of life would be phobic towards creatures that want to amorally consume us.
Vote Placed by Balacafa 1 year ago
Balacafa
kcarrascowhiteflameTied
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Total points awarded:04 
Reasons for voting decision: ff
Vote Placed by lannan13 1 year ago
lannan13
kcarrascowhiteflameTied
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Total points awarded:06 
Reasons for voting decision: Forfeiture
Vote Placed by tejretics 1 year ago
tejretics
kcarrascowhiteflameTied
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Total points awarded:01 
Reasons for voting decision: Con forfeits multiple times.