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Viruses were identified as non-bacterial toxic agents by many researchers beginning with Louis Pasteur in the 1870's, Charles Chamberland in 1884, and Dimitri Ivanovsky in 1892. Viruses were different because they could penetrate filters that stopped bacteria. Martinus Beijerinck defined the virus as an extremely small nucleotide particle rather than a fluid in 1898. It was not until 1935 that Wendell Stanley was able to crystallize viral particles, and they were imaged for the first time using an electron microscope in 1939.
Wiki User
∙ 10y ago
Wiki User
∙ 14y agoThere are only hypotheses from scientists about this since viruses do not leave a fossil record. They have been around since the first one celled organisms evolved. The three major theories are:
# Regressive Hypothesis = they may have been small cells that lived as parasites in larger cells and then evolved to eliminate the cell structures and genes that they no longer needed. (Also called the Degeneracy hypothesis.) # Cellular origin Hypothesis = they may have evolved from escaped bits of DNA or RNA that were leaked from the genes of larger organisms. (Also called Vagrancy hypothesis and Jumping Genes.) # Coevolution Hypothesis= they may have evolved from protein and nucleic acid molecules at the same time that cells first developed on Earth. If that is what happened, they would have lived in that state dependent on the cells for millions of years.
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Anonymous
1942
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Why were viruses discovered later than other types of microorganisms?
why were viruses discovered later than other types of microorganisms.
Which form of virus was discovered first Computer Viruses or Biological Viruses?
Biological.
How many new viruses are discovered every day?
Over 200 hundred are discovered each month!
What year was HPV discovered and by whom?
HPV, discovered in 1956, is a group of viruses that affect the skin and mucous membranes of humansHPV was discovered in 1993.
How viruses like hijackers?
Many viruses hide in (or 'hijack') a healthy cell - so as not to be discovered by the body's immune system.
What did Peyton Rous discover?
Francis Peyton Rouse discovered viruses
Why weren't viruses discovered until about 1935?
The very small size of virus particles was a major limiting factor of the discovery of viruses.
Why they are telling that virus is made up of cell?
They are confused of what are viruses (or they discovered something we don't know), but importantly viruses are not made out of cells or a cell
Ras genes were first discovered in viruses that cause tumors known as sarcomas in rats?
true
How many viruses exist in the world?
The exact number of how many viruses exist in the world is not known because there have been some that have yet to be discovered. Also, many known viruses are also able to mutate into brand new viruses. This makes it next to impossible to get an exact count.
Is bronchiolitis contagious?
Usually, yes. The most common causes are respiratory synsythial virus (RSV), parainfluenza viruses, influenza viruses. Metapneumovirus, human bocavirus, and a number of other recently discovered viruses are implicated as well.
Dr Esau discovered that plant viruses and sugars can be transported through plant tissues via?
Phloem (Sieve tubes)
