The Silurian PortalIntroductionSelected article on the Silurian world and its legaciesVirus particles (known as virions) consist of two or three parts: i) the genetic material made from either DNA or RNA, long molecules that carry genetic information; ii) a proteincoat that protects these genes; and in some cases iii) an envelope of lipids that surrounds the protein coat when they are outside a cell. The shapes of viruses range from simplehelical and icosahedral forms to more complex structures. The average virus is about one one-hundredth the size of the average bacterium. The origins of viruses in the evolutionary history of life are unclear: some may have evolved from plasmids—pieces of DNA that can move between cells—while others may have evolved from bacteria. Viruses are considered by some to be a life form, because they carry genetic material, reproduce, and evolve through natural selection. However they lack key characteristics (such as cell structure) that are generally considered necessary to count as life, so whether or not viruses are truly alive is controversial. (see more...) Selected article on the Silurian in human science, culture and economicsSelected image
Did you know?
Need help?Do you have a question about Abyssal/Portal:Silurian that you can't find the answer to? Consider asking it at the Wikipedia reference desk. GeochronologyEpochs - Llandovery - Wenlock - Ludlow - Pridoli Plants - Lycopods - Rhyniophytes - Vascular plants Fossil sites - Yea Flora Fossil Site Researchers - Increase A. Lapham - Roderick Murchison Quality ContentFeatured Silurian articles - Fungus SubcategoriesRelated contentAssociated WikimediaThe following Wikimedia Foundation sister projects provide more on this subject:
|