Historically, viruses were discovered at a time when the conditions for a scientific investigation into the origin of life on Earth were met. Louis Pasteur had refuted the idea of continuous spontaneous generation in the 1860s and Charles Darwin had published his On the Origin of Species in 1859, which inevitably led to questions of how the first life forms had emerged. At the onset of the twentieth century, immense progress was made in organic chemistry, biochemistry, and cytology. It now seemed possible to approach a question that had remained too complex and intractable until then (Fry 2006). Very soon, two clear ideological currents emerged in the field. For some scientists, self-replication (making copies of itself) was the crucial starting point for life; for others, it was self-maintenance or, in other words, metabolism. This chicken-and-egg dichotomy has persisted since then, although formulated in different terms. In the terminology of the time, it came down to a nucleus versus cytoplasm debate. Accordingly, hypotheses on the origin of life subscribed either to nucleocentric (self-replication first) or cytoplasmic (self-maintenance first) views of life.
When viruses were discovered, they were very mysterious, and due to their small sizes and their infective capacities, many scientists explicably considered them as the simplest living entities. As a consequence, they were incorporated in the debate about the origin of life for several decades, although with various different connotations: the virus as a metaphor for the simplest form of life, the virus as a functional model (an independent existing gene), and collectively, the viruses as a phylogenetic lineage with historical continuity that could be placed between the chemical world and the first cells (Podolsky 1996). As reviewed by Podolsky (1996), the importance of viruses for models of the origin of life and of the concept of what life is has varied over time, with different successive tendencies.
First, until the mid-1930s, the idea of a virus-centered origin-of-life was on the rise. In 1914, the American psycho-physiologist Leonard Troland proposed that the first life form might have been an “enzyme or organic catalyst” (Troland 1914) although little later, he spoke of a “genetic enzyme” and identified it with nucleic acids and proteins in the nucleus (Troland 1917). Herman Muller simplified Troland’s ideas and coined the term “gene” to refer to Troland’s “genetic enzyme” (Fry 2006). In 1922, Muller drew a clear conceptual link between virus and gene, saying that “there is no distinction between genes and them [viruses]” (Muller 1922); and in 1929, he openly proposed that the first living organism was a primitive gene (Muller 1929). John B. S. Haldane, in his essay on the origin of life (Haldane 1929), extended that operational view to a more phylogenetic view, asserting that “life may have remained in the virus stage for many millions of years before a suitable assemblage of elementary units was brought together in the first cell.” Similarly, Alexander and Bridges conceived of self-copying entities such as genes and viruses as the simplest components necessary to life and divided living beings into two taxonomic categories: “Cytobiontia” (cellular organisms) and “Ultrabiontia” (viruses) (Alexander and Bridges 1928). The syllogism “smallest = virus, smallest = first, so that virus = first” (Beutner 1938) was generally accepted during those early years; the nucleocentric view of the origin of life was also virocentric.
Second, during the 1930s and subsequent years, an opposite trend gained favor, largely due to the extensive work on the origin of life by Alexander I. Oparin. Oparin conceived the origin of life from a biochemical or “colloidal chemistry” perspective (Oparin 1938). For Oparin, life was a self-regulating system of catalytic reactions; he was a cytoplasmist for whom metabolism was the primary essence of life. In addition to Oparin’s influential work, several investigators, including Robert G. Green (1932) and most notably, André Lwoff (1943; 1957) questioned the idea that because they are small and simple, viruses are primitive. Viruses could be just products of regressive evolution due to their extreme parasitic nature. This opinion was increasingly accepted, and even Haldane affirmed that “most evolutionary change has been degenerative” (Haldane 1932). Although Haldane identified life with molecular self-reproduction, he also said that in a true living system, the function of any part including genes depended on the cooperation of all other parts (Fry 2006).
Viruses and nucleocentric views of life regained credence again after DNA was shown to be the genetic material (Avery et al. 1944) and after the determination of the DNA structure, which suggested an elegant self-copying mechanism (Watson and Crick 1953). It was also shown that the nucleic acid component of viruses was the infectious component (Hershey and Chase 1952). Consequently, the association of virus–nucleic acid–gene was easy to make. Even so, the initial notion that viruses were phylogenetically the most primitive organisms on Earth was abandoned in the 1950s in favor of an operational view according to which viruses were seen as metaphors for “living genes” (Podolsky 1996).
Finally, virocentric ideas on the origin-of-life were largely abandoned in the 1960s and throughout the remainder of the twentieth century due to two major factors. The first had to do with the nature of viruses themselves, since advances in biochemistry and molecular biology demonstrated that viruses were strict molecular parasites. Viruses were just biological entities able, like genes, to evolve but unable to self-replicate and to self-sustain, a position still held by the ICTV (van Regenmortel 2000, 2008). The second factor had to do with the discovery of a better alternative as primitive living entity: ribozymes. Ribozymes are RNAs having catalytic activity that therefor display dual functions as informative polymers and catalysts. Furthermore, the universally conserved ribosome responsible for protein synthesis was shown to be a ribozyme. These discoveries led to the development of the “RNA world” as a powerful model of early life evolution (for a review, see Orgel 2004; Robertson and Joyce 2010). RNA replaced viruses in origin-of-life thinking: nucleocentric views on the origin of life were no longer virocentric.
They are alive
I think they are alive because how can something not living cause so much damage to something living, example, us. That also have this system in themselves where they create alternatives to the things they lack.
1. When they host a cell it becomes their own in a way.
2. They can reproduce with the help of the cell.
3. They don't react because they have an outside layer that protects them from harsh environments.
There are a few more but these are just three. Also viruses are organisms that makes them living.
Viruses are alive
Because they have the ability to reproduce which is only necessary if they are alive, a non living thing has no need to reproduce. Being able to steal energy from other living things is an adaptation, not a sign that it isn't alive. The definition of adaptation is any trait of an organism that increases it's chances of surviving and reproducing. That is what viruses do, increase their chances of surviving and reproducing.
Viruses are not alive
They do not have all of the 10 traits of life, therefore making them non living. They have living space, reproduce, respond to surroundings but that's about it. Having a "Virus trial" in class right now. On the side that says that they are not alive, so that it what I am supporting right now.
Yes! FOR SURE! I MEAN IT! DEFINITELY! Here's why:
Viruses ARE, in fact, alive. Many people think that they are not because they don't have cells, but maybe it's time to redefine the characteristics of life. Viruses reproduce, produce energy, and all of that stuff, even though they are made up of just molecules. I mean, do we really need this other characteristic to specify life? I mean, what difference does it make? A rock is still nonliving, and cells and animals are! If cells don't even have cells, then how are THEY alive? To me, we only need 6 characteristics to define life, and the seventh one just confuses people and makes them believe that certain things that things are not alive when they actually are.
Yes, they have genetic information
Though viruses are not made of cells, they are generally considered non-living. However, they have genetic information. No other non-living things have genetic information. What would a non-living thing have genetic information for? They can reproduce too, which is a characteristic of life. Maybe the science community should redefine "cell" and "life".
Viruses are alive...
According to the Webster dictionary the definition of a living organism is “an organism state characterized by capacity for metabolism, growth, reaction to stimuli, and reproduction.”
Viruses are a nucleonic acid that contains DNA concealed in a protein shell. In my opinion I think that viruses are alive. Viruses contain some characteristics of life in them such as reproduction, DNA or RNA. Some may disagree that viruses are not alive. Viruses don’t have cellular machinery it must use the host’s in order to make copies of itself. Viruses only exist to make more of themselves. There are two types of reproduction, lytic and lysogenic cycles.
Lytic cycle is when a bacteriophage (or better known as a phage) attaches itself to the host cell and injects its DNA and proteins into the cell, which then copies itself into other cells. Another cycle, lysogenic cycle, a virus injects its DNA into the host. As the host cell reproduces the DNA spreads, very rarely the DNA will separate and start a lytic cycle. Viruses exist in two states, virions (when a virus is dormant) and a virus itself after it comes in contact with a host. Viruses react and adapt to their environment during self-replication.
Yes, Nature and Biology
Nature and Biology prove that there are live viruses out there, they have the ability to adapt and feed of the energy around them. The fact that viruses can remain dominant and come back to life is another answer, because they have the ability to respond to the different changes their hosts go through.
Yes, and no
Nature and biology through research proves that there are thousands or millions of actual live viruses out there. There are also ones that are considered dormant or dead but can be brought back to life. There are some question if they are truly alive, but their constant evolution points towards the answer being yes.
Viruses are both, so yes, they are alive
Even though viruses don't have all the qualities of being officially alive, they have enough to be counted as alive in my mind. They move, grow, react to substances, and, even if they have to shoot DNA into a cell to reproduce, that's still reproducing. Viruses are made of molecules, though, but they are still able to perform as a living thing.
Life is diverse
Organisms always find a way to get what they need from their environment. They rely on material, both biotic and abiotic, to be available and adapt to that which is least restrictive, finding their niche in the world. Organisms that fail at that cease to exist. Viruses are no different. Their niche is minimalist. No need for glucose, so no need to consume or do photosynthesis. Also there is no need for water to diffuse those molecules. All that simplicity is the secret for the longevity of viruses. I feel the presence of a successful combination of DNA which is able to continually be passed along to future generations and the ability to adapt to changes in the environment are the only traits necessary to qualify as living. Remember, all the lists of traits that living things share were put together AFTER the category was created. If viruses were known back then, the list would be very different.