Explain the significance of the following people in the history of microbiology: hooke, van leeuwenhoek, virchow, pasteur, koch, lister, gram, petri, ehrlich, fleming, jenner, linnaeus watson and crick.

Robert Hooke. He discovered cavities in  a cork sheet at the microscope and named that structures as cells.Anton van Leewenhoek. He is known as the father of microbiology because he was the first to make observations  in a microscope improved by himself. He observed protozoans, spermatozoans, wood sheets, etc.Rudolph Virchow. He was one of the proposers of the cell theory. He postulated that all cells are originated by preexiting cells.Louis Pasteur. He made experiments to demostrate that the spontaneous generation theory was wrong and developed a theory to explain that many diseases are caused by microorganisms. He also developed vaccines for anthrax and avian cholera.Robert Koch. He proposed postulates to check if an organism is the caused of a disease (Koch postulates) and discovered the Tuberculosis bacillus.Joseph Lister. He developed by heating methods to prevent the injuries infection.Hans Christian Gram. He developed a staining method for bacteria and could classified them as Gram- possitives and Gram-negatives.Julius Richard Petri. He invented the Petri dishes to grow microorganisms with different media.Paul Ehrlich. He proposed a theory to explain immunological specificity: The cell receptors recognize toxins and produce antitoxins (antibodies).Alexander Fleming. He discovered the antibiotic activity of Penicilin from a fungi (Penicillium chrysogenum) in a bacterial culture.Edward Jenner. He discovered the smallpox vaccine by inoculation of pus from blisters  from dairy infected by cows with smallpox.Carl Linnaeus. He was the creator of the classification of living being or taxonomy. He developed the binnomial nomenclature where the first name is the genus and the second name is specific os the specie. He groupped genus in families, those in classes, classes in phyla and those in kingdoms.James Watsin and Francis Crick. They proposed that the DNA in the cells was a double-helix and the chains of the helix are antiparallels. They also proposed that the nucleotides of one chain of the helix are complemented to those in the other chain (Adenine=Timine and Guanine= Cytosine).

Size and shape of continents