To classify organisms, scientists use similarities and variations among species. typically these variations area unit simple to ascertain, like whether or not associate animal has fur, feathers, or scales. There area unit seven main assortment ranks: kingdom, phylum or division, class, order, family, genus, species.
In accordance with the Linnaeus method, scientists classify the animals, as they do the plants, on the basis of shared physical characteristics. They place them in a hierarchy of groupings, beginning with the kingdom animalia and proceeding through phyla, classes, orders, families, genera and species.
One theory had been that hippos were related to pigs. Yet mounting evidence suggested they are closer to whales. A new study concludes that a four-footed semi-aquatic mammal that thrived for some 40 million years was a common ancestor to both whales and hippos.
There are a number of similarities between viruses and cells. Both are too small to be seen with naked eyes and require a microscope for observation. Both contain genetic material, in the form of DNA and/or RNA. Both of them can replicate, that is, produce more organisms similar to themselves.
