What role do viruses play in the process of speciation?
362581
Yes and no. While many viruses inject DNA into the host cell, only retroviruses (retroviridae), and, perhaps, some of the viruses most closely related to such, add DNA to the genome. Further, once a cell is infected by a virus, that cell will typically be lysed before it can reproduce.\nEven when this is not the case, the DNA added interrupts the normal sequence of DNA in the cell, usually producing introns (non-coding regions). Then, in the case of multicellular life, unless it happens in a germ cell rather than a somatic cell, it will not be passed on to future generations of organisms.\n\nIn spite of all these obstacles, it does happen, and nearly all life on earth has endogenous retroviruses in their genomes, as well as other indications of contributions by viruses to genetic variability. \n\nFor more information, I suggest you start by looking up "endogenous retroviruses". You may not find much about speciation, as the likelihood of identifiable contributions to speciation by viruses is negligable, but you'll find information about how viruses have added genetic variability (mostly in the form of 'junk' dna which then gets mutated and selected)
192805
No.  Viruses depend on a number of components of the host cell for basic functions like replicating DNA and producing proteins because they do not have these systems themselves.  Since they don't have these systems, they can't preform the necessary functions for another virus.\n\nWhen a virus infects a cell, it injects its viral DNA into the genome of the host cell, and the cell replicates and transcribes the viral DNA along with its own.  If a virus were to inject its DNA into another virus, that other virus wouldn't have the ability to replicate the DNA, so nothing would happen.  Also, viruses don't really have membranes (they just have protein), so it probably wouln't be able to inject its DNA in the first place.
403247
Essentially the first question is right, but human viruses are very clever in that several coat layers are used. for example HPV, HSV (herpes).  Viruses are just proteins and DNA, nothing more.  They don't contain organelles, they don't reproduce independantly, they don't fulfill many life functions.
293644
It is possible that viruses may have been among the original forms of life on this planet, however that is hotly contested.  It is even contested as to whether or not viruses are actually living.\n\nVirology is an entire field of it's own.  Their development, and how they mutate is quite a complicated subject.  I would recommend getting started with a basic biology text book and reading the sections on molecular biology, and viruses.  I think it would help you quite a lot in understanding what viruses are, and how it is that they function... and that not all are bad.  In fact there is evidence that some viruses have actually inserted themselves in the human genome and now serve a functional role in our development.
755009
Viruses - what you might catch this flu season is not the same as the "parent virus" - it evolved.
1022872
New animal species observed:\n\nDrosophila paulistorum (1971)  Cultured fruit fly species that in 1958 was able to produce fertile hybrids when crossed with strains from other regions.  By 1963 though, those same crosses produced only sterile males.\n\nNumerous other speciation events have occurred or been produced in the lab between different Drosophila strains over the years.\n\nApple maggot fly (Rhagoletis pomonella) has already been mentioned, a fly whose normal host was the hawthorn tree, but during the nineteenth century some of the population switched to apples.  This may well represent a sympatric speciation event or adaptive radiation in a wild species observed occurring in real time.\n\nA similar adaptation to new hosts may be driving speciation among different strains of the gall former fly (Eurosta solidaginis) as well.\n\nAssortive mating on the basis of size has been induced in laboratory strains of flour beetle (Tribolium castaneum), which could lead to different species of this beetle.\n\nOne of my favourites is the 'lab rat worm', Nereis acuminata.  Back in 1964, a small collection of Nereis worms were collected in the wild, and mated with each other to produce thousands of individuals used in a variety of environmental toxicology studies across North America.  In the 1990s, when new wild populations were collected from the same regions as the original collections, they were not fertile with the laboratory worms.  Lab worms crossed with lab worms were fertile, and wild populations were more or less successful when crossed with other wild populations, but the lab worms could no longer interbreed with the wild worms.  This is a speciation event that has taken place in the last forty years.\n\nThe presence of different species of symbiotic gut bacteria in different populations of the mosquito Culex pipiens (the mosquito which is also the primary vector of West Nile virus) has resulted in reproductive isolation of different strains of the the mosquito.  Those who possess one species of gut flora cannot interbreed with individuals who possess the other species of gut flora.  This isolation could lead to speciation very quickly.\n\nSo those are just some of the new animal species observed in the past 50 years.\n\nOther observed speciations in the past ten to six thousand years could include many of our domestic animal species, such as cow, goat, sheep, dog, cat, chicken, turkey, guinea pig, llama, alpaca, and horse.  Many of these species are no longer able to interbreed with their wild counterparts.
223756
Allopatric speciation - Speciation in different area due separation population by big mountains, oceans etc \n\nsympatric speciation - speciation in same  area due to gamete incompatibility, different times when they are active etc
746000
Speciation is the evolutionary process by which new biological species arise. There are four modes of natural speciation, based on the extent to which speciating populations are geographically isolated from one another: allopatric, peripatric, parapatric, and sympatric. Speciation may also be induced artificially, through animal husbandry or laboratory experiments.\n\nThere are many means for an organism to split into two species.  When this happens, it doesn't mean that one organism ceases to exist.  For example, when nectarines were bred using peach stock, it doesn't mean that peaches no longer exist.\n\n\nDuring allopatric speciation, a population splits into two geographically isolated allopatric populations (for example, by habitat fragmentation due to geographical change such as mountain building or social change such as emigration). The isolated populations then undergo genotypic and/or phenotypic divergence as they (a) become subjected to dissimilar selective pressures or (b) they independently undergo genetic drift. When the populations come back into contact, they have evolved such that they are reproductively isolated and are no longer capable of exchanging genes.
888659
the difference is how they make the cells produce the new genetic material for the viruses. RNA viruses does not require the cells' DNA to reproduce.
591012
well...\nu could talk about how little we know about whether organisms like bacteria and viruses have consicousness and a probable effect that might happen if we change their genomes . we dont really know whether those kind of organisms have an "individuality" or anything, so thats where i would start off from.\nhope this helped
218892
1.\n\n\n\n\n\n\n2. Viruses are neither unicellular nor multicellular organisms; they are somewhere between being living and non-living. Viruses have genes and show inheritance, but are reliant on host cells to produce new generations of viruses. Many viruses have similarities to complex molecules. Because viruses are dependent on host cells for their replication they are generally not classified as "living". Whether they are "alive", they are obligate parasites, and have no form which can reproduce independently of their host. Like most parasites, they have a specific host range, sometimes specific to one species (or even limited cell types of one species) and sometimes more general.\n\n3. protozoa and algae. I don't know why\n\n4. The protozoa are mostly single-celled, motile, and feed by phagocytosis, though there are numerous exceptions. They are usually only 0.01-0.5 mm in size, generally too small to be seen without a microscope. They are ubiquitous throughout aqueous environments and the soil, commonly surviving dry periods as cysts or spores, and include several important parasites. Based on locomotion, protozoa are grouped into:\n\nFlagellates with long flagella  -like Euglena\nAmoeboids with transient pseudopodia   -like Amoeba\nCiliates with multiple, short cilia    -Paramecium\nSporozoa non-motile parasites; form spores like Plasmodium.\n\n\n\n5. The algae gather light energy through photosynthesis. They include many single-celled creatures that are also considered protozoa, such as Euglena and Paramecium bursaria, which have acquired chloroplasts through secondary endosymbiosis. Others are non-motile, and some are truly multicellular, including some members of the following groups:\nChlorophytes green algae, related to higher plants  -like Ulva\nRhodophytes red algae  -like Porphyra\nHeterokontophytes brown algae, diatoms, etc.  -like Macrocystis\n\nThe green and red algae, along with a small group called the glaucophytes, appear to be close relatives of other plants, and so some authors treat them as Plantae despite their simple organization. Most other types of algae, however, developed separately. They include the haptophytes, cryptomonads, dinoflagellates, euglenids, and chlorarachniophytes, all of which have also been considered protozoans.\n\n\n6.\n\n\n\n\n\n\n7.\n\n\n\n\n\n\n8. hyphae is any of the threadlike filaments forming the mycelium of a fungus. Hyphae is a long, branching filament that, with other hyphae, forms the feeding thallus of a fungus called the mycelium. Hyphae are also found enveloping the gonidia in lichens, making up a large part of their structure. A typical hypha consists of a tubular wall, usually made of chitin, which surrounds, supports, and protects the cells that compose a hypha. For most fungi, a cell within a hyphal filament is separated from other cells by internal cross-walls called septa (singular septum).\n\nSome forms of parasitic fungi have a portion of their hyphae modified to form haustoria that are able to penetrate the tissues of a host organism. Similar, yet mutualistic forms of penetrating hyphae are called mycorrhizae and are important in assisting nutrient and water absorption by plants.\n\n\n\n9. \n\n\n\n\n\n\n\n\n10. Lichen is a fungus, usually of the class Ascomycetes, that grows symbiotically with algae, resulting in a composite organism that characteristically forms a crustlike or branching growth on rocks or tree trunks.
918447
The variation, could be frankly anything, because it arises from mutations. It could be anything from a different shell colour for a beetle, to a different beak shape for a bird.\n\nHow does it spread? Well, through mating. Organisms mate, they produce offspring. Some will have the mutation. Others won't. The mutation will only take a hold in the population, if it gives the particular organisms that have it, an advantage. So, it doesn't so much as spread, as that it outlasts the other variations.\n\nOf course, even this description doesn't do it justice. I suggest you really, look into the below sources and remember that the Wikipedia article is open to vandalism by Creationists and IDers that don't know what they're talking about.
380054
like others have said parasites are definately living things.  I didn't know there was even a debate as to whether virus are living things, I thought it was pretty much agreed upon that they are.  I guess it depends on your definition of life, which is something that's a hotly debated issue.  I don't think there is a clear cut answer myself as far as what should be considered a life form and what shouldn't.
305803
Several modes of speciation have been suggested/observed, but they break down into two types: sympatric, in which the new species is in the same geographic location as the original species, and allopatric, in which the new species is formed in a geographically separated location. Allopatric is generally considered to be more common, but sympatric is common in some groups, for example, plants.\n\nThe rest of my answer: A sympatric example that has been observed occurred in apple maggot flies (Rhagoletes). These are host specific insects that lay their eggs on one species, which become adults, which then mate on the host tree. A mutation causes one or more flies to choose a different species of host tree (which might be right next door) and the adults mate near that tree, not encountering the non-mutant forms. Thus you have the conditions of an isolated population which will allow divergence through selection or drift, leading ultimately to a new species (this latter part has not been observed, but all the preconditions are there). There are several other modes of sympatric speciation possible.\n\nIn allopatric, the classic case would be an isolated founding population that diverges due to selection and/or drift to a point where - were the two populations brought back together - there are no viable offspring produced from intermating (=reproductive isolation). \n\nThere are many more details to both these modes which any text on evolution will outline and provide examples for.
359498
A virus (not bacteria) is made up primarily of DNA and a protein coat.  They invade the cells of a living organism and destroy the host's DNA, then inject their own DNA into the host cell.  The result is that the infected cell produces new viruses which then exit the host cell and are released to infect others.  This is done because viruses do not contain cells with the orrganells and compounds necessary to reproduce, so they must get cells from the host to do the work for them.  Of course, the host cell is no longer functional as an intact cell once the virus leaves.
627823
You probably mean "why can't we kill viruses?" Right?\n\nThe problem is that viruses tend to live inside host cells. To destroy the virus you need to destroy the cell.  Viruses also modify cell receptors so they can't properly work, which limits the ability to find something that can both penetrate the cell and kill the virus without damaging the functions of the cell.
129938
A virus is neither a plant nor an animal. It acts like a living organism when inside the body of a host, but behaves like a non living thing when outside of it! Hence viruses are able to exist for thousands of years...\nBacteria on other hand, is a living being and hence is mortal too.