Linnaean taxonomy. Most students of biology, even if just in high school, are made at least a little acquainted with its stratification of relationship between living species. Most of us know the major steps: kingdom, phylum, class, order, family, genus, and species. But far fewer people are acquainted with the numerous sub-steps that can exist among most of these, making the "family tree" of relationships between species very complicated, especially among birds.
I barely knew Linnaean taxonomy and how animals relate to each other until about four years ago when I first started researching parrot-human history. In trying to understand what I was reading, I found myself discovering the relationships between parrots; the Linnaean "family tree" came to life.
Parrots are an order of birds. Other orders include Falconiformes (raptors, birds of prey), Columbiformes (pigeons and doves), and Passeriformes (huge order that includes everything from zebra finches to sparrows to crows and beyond) to just name a few you are likely to encounter in your life.
Parrots have two families which include all the species and extinct parrot species. Psittacidae are the "true parrots" and include macaws, Amazons, parakeets, lorikeets, and lovebirds.
Cacatuidae are cockatoos. This family tends to have sub-families; the cockatoos are more complicated in their evolution than the other parrots on the Linnaean taxonomy.
Many of the true parrots we think of as "families" are actually genera (the plural for genus). Amazon parrots are genus Amazona. Most macaws belong to genus Ara. Genus Poicephalus includes the popular Senegal parrot. Genus Trichoglossus are lovebirds. Genus Psittacus has one species and two subspecies. These are the African grey parrots. Congo African greys are one sub-species and Timnehs are considered a second sub-species. My favorite of the Psittacidae are the Psittacula(genus) parakeets. With a range from Africa to across most of the warmer parts of Asia, across the south pacific, and even into Australia, these pretty rain forest parakeets are known for their sub-species.
Sharing habitat with the Psittaculas are cockatoos, family Cacatuidae, with all their sub-families and diverse genera. The best known genus among the cockatoos is Cacatua, the "white" cockatoos such as umbrella cockatoos, Moluccan cockatoo, Goffin's cockatoos, and the many species and sub-species of sulfur crested cockatoos. Cacatua should stick out in your mind for the staggering number of species that are now extinct, critically endangered, endangered, or threatened in the wild. These birds, some of the most loved in aviculture, are dying out due to illegal poaching and illegal logging across the south pacific and in Indonesia in particular. More than any other genus of animal I am aware of, these birds are most likely to exist only in zoos in a few years - unless we stop what we are doing to them!
But what about cockatiels, our most popular aviculture cockatoo? Recent DNA studies looked at the relationship between cockatiels and other cockatoos. The studies found that cockatiels are closely related to palm cockatoos and other "black" cockatoos. "The researchers (also) found that the Palm Cockatoo was the first to diverge from a common cockatoo ancestor, followed by a group including the Gang-gang, Red-tailed and the Cockatiel."
Who knew Mithril and Elendil came from such an ancient line of cockatoos?
Whatever your interest in science, I hope this quick look at Linnaean taxonomy as it applies to parrots helps you better appreciate the complexity and beauty within all nature. While my examples were all about parrots, the organization behind everything here applies to all animals, including humans.