According to Websters Taxonomy is the "orderly classification of plants and animals according to their presumed natural relationships." Basically taxonomy is the way people try to make some since of order out of the many organisms that populate this planet.
The classifications are listed below:
Classifying organisms can be confusing as there are several sets of rules, often exceptions to those and of course they change quite regularly. Until 1969 there were generally considered to be three kingdoms. Now classification lists have between 4 and 13, though generally 5 or 6 are used. All the organisms I have included in this section are in the Animal Kingdom.
Some characteristics attributed to organisms belonging in the Animal Kingdom are that they are multicellular, motile and usually reproduce sexually, though some reproduce asexually. Animals cells have no walls, which doesn't really help you if you are just standing there looking at something and trying to figure out what it is, but most other organisms are constructed of cells with walls. There are some other things about cells specific only to animals related to how they work together through intercellular junctions. Metabolism in animals is usually through aerobic respiration but some through fermentation.
Each classification creates groups that get smaller and smaller with animals in each group getting more similar.
As with the kingdoms, there are different numbers and criteria for classification as phyla. My references suggest there are between 13 to 20 phyla in the animal kingdom.
Below is a list of classifications of animals, both the freshwater invertebrates discussed on these pages and a few other common animals to provide reference. Common names and examples are in parenthesis.