|MadSci Network: General Biology|
Some time after Noah landed, some his descendants decided they should classify all living things. Many classification systems have been tried. During the 18th century, a Swede named Karl Linne (who called himself "Carolus Linnaeus" — that was when real scientists communicated in Latin) organized the system that is used today. People who classify living things call themselves "taxonomists." This is one of the few things on which they seem to agree. I am neither a protozoologist nor a taxonomist; but I am a scientist, even though I don't know much Latin. I went to my university library and did a brief search through books about Protozoa. I could soon appreciate your problem — some of the books that claimed to cover all of Protozoa did not mention sarcodines, nor the official group Sarcodina. But one did: in Lee, J. J., S. H. Hutner, and E. C. Bovee (editors), An Illustrated Guide to the Protozoa, Society of Protozoologists, Lawrence, Kansas, 1985, there was a classification scheme that included the Sarcodina. Here's how it goes — Kingdom Protista (one-celled organisms with true nuclei); Subkingdom Protozoa (protists that mostly don't have photosynthetic apparatus?); Phylum Sarcomastigophora (protozoa that have flagella, plus the "sarcodines"); Subphylum Sarcodina ("form so-called pseudopodia, of one type or another, in their trophic states," any flagella usually occur in temporary stages, may have a skeleton or "test," usually free-living [i.e., not parasitic], etc.). Subordinate classifications are Superclass, Class, Order, Family, Genus, and species; there is an endless array of these among the Sarcodina. As you probably know, pseudopodia are the little oozy projections that amoebae put out in front of them when they are trying to go somewhere. Not surprisingly, the amoebae (many varieties in several classification levels, including the genus Amoeba) are among the Sarcodina. Their "trophic state" is when they are actively moving about and engulfing stuff as food; alternately, they have a resting phase called a "cyst" that more or less hibernates when times are hard. To be classified as Sarcodina, the other, non-amoebae must form pseudopodia sometime during their lives. Some taxonomists don't think this is a valid way to classify protozoa — they might be more impressed if these organisms traveled on in-line skates. I would guess that the sarcodines are not too impressed by taxonomists, either. I hope this is most of the information you needed. At least you've learned that taxonomists are not the people who stuff dead animals.
Try the links in the MadSci Library for more information on General Biology.