It is important to recognize relationships amongst species. One of the most common in our area is the White-tailed Deer (Odocoileus virginianus). When identifying its full taxonomic classification, we must remember Dear King Phillip Came Over For Good Spaghetti which is a pneumonic device to remember Domain (the broadest taxonomic group, often left off the list), Kingdom, Phylum, Class, Order, Family, Genus, and Species. Genus and species then make up the organisms scientific name or "binomial nomenclature" if you if you want to impress others with your terms. This name represents the genus with the first letter capitalized and the species completely lowercase, both words are italicized such as Homo sapiens for humans.
Wikipedia, surprisingly, is one of the best ways to find the full classification of a species, often including additional categories such as "subs" like subfamilies. When researching white-tailed deer, Wikipedia informed me that it is in the same genus as two other species (Mule Deer and Yucatan Brown Brocket), however, after searching further in scholarly articles I determined that the Yucatan Brown Brocket was not in the same genus, but found with other brockets in the genus Mazama.
The White-tailed Deer and the Mule deer do share many similarities in appearance, however, their ranges, antlers, ears and tails show differences. Please see the presentation below.