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Classification of Living Organisms
Author: Michael Colebrook

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The following classification of living organisms is based on a division into five Kingdoms used by Lynn Margulis and Karlene Schwartz in their book Five Kingdoms, An Illustrated Guide to the Phyla of Life on Earth (W.H.Freeman & Co., 1998). The listing only includes the highest ranks of classification, the Kingdoms and the Phyla. There are no objective definitions of either of these terms, but the Kingdom is essentially a top-down category representing the division of living things into reasonably self-evident categories, animals, plants, bacteria etc. The Phylum (pl. Phyla) is more of a bottom-up category and represents a group of organisms which appear to be similar to each other in terms of one or more substantial and significant features, such as the possession of a back-bone or its precursor. Each Phylum is also considered to represent a coherent group in terms of evolutionary history. Where possible, an everyday language name of the group or of a typical representative or some other simple description is included for each Phylum.

Current on-going work involving genetic finger-printing has provoked controversy about some of the traditional ideas about the relationships between organisms at the level considered in this presentation. See, for example: http://www.wellcome.ac.uk/News/2006/Features/WTX034649.htm
A good place to look for more detailed information is the  Diversity of Life Web Index



Subkingdom ARCHAEA
Phylum l Euryarchaeota – methane producers and salt lovers
Phylum 2 Crenarchaeota – hot-acid lovers
Phylum 3 Proteobacteria – purple bacteria
Phylum 4 Spirochaetae – spirochetes (corkscrew bacteria with internal flagella)
Phylum 5 Cyanobacteria – oxygenic photosynthesizers
Phylum 6 Saprospirae – fermenting gliders
Phylum 7 Chloroflexa – green nonsulphur phototrophs
Phylum 8 Chlorobia – green sulphur phototrophs
Phylum 9 Aphragmabacteria – wall-less bacteria
Phylum 10 Endospora – bacilli and related formers of internal spores
Phylum 11 Pirellulae – stalked, protein-walled bacteria
Phylum12 Actinobacteria – fungus-like bacteria
Phylum 13 Deinococci – radioresistent, tiny spheroidal bacteria
Phylum 14 Thermotogae – thermophilic fermenters



Phylum 1 Archaeprotista – flagellate amoebas
Phylum 2 Microspora – microsporans
Phylum 3 Rhizopoda – amoebas without flagellae
Phylum 4 Granuloreticulosa – foraminifera and relatives
Phylum 5 Xenophyophora – large deep-sea benthic protoctists
Phylum 6 Myxomycota – plasmodia1 slime molds
Phylum 7 Dinomastigota – dinoflagellates
Phylum 8 Ciliophora – ciliates
Phylum 9 Apicomplexa – symbiotrophs with apical complex
Phylum l0 Haptomonada – Coccoliths and other yellow-brown planktonic unicells
Phylum 11 Cryptomonada – flattened asymmetric unicells, usually photosynthetic and motile
Phylum 12 Discomitochondria –euglenoids
Phylum 13 Chrysomonada –golden brown algae
Phylum 14 Xanthophyta – yellow green algae
Phylum 15 Eustigmatophyta – green eyespot flagellate algae
Phylum 16 Diatoms –photosynthetic algae with silica shells
Phylum 17 Phaeophyta – brown algae
Phylum 18 Labyrinthulata – slime nets
Phylum 19 Plasmodiophora – symbiotrophs with multinudeate protoplasts
Phylum 20 Oomycota – egg moulds; zoosporic conjugators
Phylum 21 Hyphochytriomycota –fresh water osmotrophs with single anteriorly directed undulipodium
Phylum 22 Haplospora – – unicells in tissues of marine animals
Phylum 23 Paramyxa – nesting cells in tissues of marine animals
Phylum 24 Myxospora –in tissues of fish, sipuculans, and annelids
Phylum 25 Rhodophyta – red algae
Phylum 26 Gamophyta –conjugating green algae
Phylum 27 Actinopoda – sun animalcules
Phylum 28 Chlorophyta – green algae (plant ancestors)
Phylum 29 Chytridiomycota – chytrid water molds (fungal ancestors)
Phylum 30 Zoomastigota – zoomastigotes, opalinids, choanomonads (animal ancestors)


Subkingdom PARAZOA
Phyluml Placozoa – trichoplaxes
Phylum 2 Porifera – sponges
Subkingdom EUMETAZOA
Phylum 3 Cnidaria – hydroids, medusas and jellyfish
Phylum 4 Ctenophora – comb jellies
Phylum 5 Platyhelminthes – flatworms
Phylum 6 Gnathostomulida – jaw worms
Phylum 7 Rhombozoa – dicyemids and heterocyemids
Phylum 8 Orthonectida – orthonectids
Phylum 9 Nemertina – ribbon worms
Phylum10 Nematoda –thread worms, round worms
Phylum11 Nematomorpha –Gordian worms, horsehair worms
Phylum 12 Acanthocephala – thorny-headed worms
Phylum 13 Rotifera – rotifers
Phylum 14 Kinorhyncha – kinorhynchs
Phylum 15 Priapulida – priapulids
Phylum 16 Gastrotricha – gastrotrichs
Phylum 17 Loricifera – loriciferans
Phylum 18 Entoprocta – entoprocts
Phylum 19 Chelicerata – horseshoe crabs, spiders, and sea spiders
Phylum20 Mandibulata – insects, centipedes, and millipedes
Phylum 21 Crustacea – crustaceans and pentastomes
Phylum 22 Annelida – annelid worms
Phylum 23 Sipuncula – peanut worms
Phylum24 Echiura – spoon– worms
Phylum 25 Pogonophora – beard worms, tube worms
Phylum 26 Mollusca – snails, bivalves, slugs, squid and octopuses
Phylum27 Tardigrada –waterbears
Phylum 28 Onychophora – velvet worms, peripatuses
Phylum 29 Bryozoa – moss animals
Phylum 30 Brachiopoda –lampshells
Phylum 31 Phoronida – phoronids
Phylum 32 Chaetognatha – arrow worms
Phylum33 Hemichordata – acorn worms
Phylum34 Echinodermat – sea urchins, sea stars, or starfish, and sea cucumbers
Phylum35 Urochordata – sea squirts, larvaceans and salps, doliolids, and chain tunicates
Phylum 36 Cephalochordata – lancelets
Phylum37 Craniata – fishes, reptiles, amphibians, mammals, and birds

Kingdom FUNGI
Phylum 1 Zygomycota – molds
Phylum 2 Basidiomycota – mushrooms, puffballs, rusts, smuts, and jelly fungi
Phylum 3 Ascomycota – molds, yeasts, and lichens

Phylum 1 Bryophyta – mosses
Phylum 2 Hepatophyta – liverworts
Phylum 3 Anthocerophyta – hornworts thorned liverworts
Phylum 4 Lycophyta – club mosses, and spike mosses
Phylum 5 Psilophyta – whisk ferns,
Phylum 6 Sphenophyta – horsetails
Phylum 7 Filicinophyta – ferns
Phylum 8 Cycadophyta – cycads
Phylum 9 Ginkgophyta – maidenhair tree
Phylum 10 Coniferophyta – conifers
Phylum11 Gnetophyta –jointfir, ephedra, and Welwitschia
Phylum 12 Anthophyta – flowering plants

The following diagram places the five kingdoms in the context of time. It emphasises the long period during which the only living organisms were bacteria and the longer period when the only organisms were bacteria and protoctista.

The following diagram and Text are taken from: Carl Zimmer. Evolution (William Heinemann, 2002), p. 102 and reflects the most up to date (but incomplete) information about the divergence of DNA within the kingdoms of living organisms.

This evolutionary tree encompasses all living species on Earth. The common ancestor (the base of the tree) gave rise to three great branches: bacteria, microbes known as archaea, and eukaryotes (a group of species that includes us). The lengths of the branches reflect how much the DNA of each lineage has diverged from their common ancestor. They demonstrate that most of life's genetic diversity turns out to be microbial; the entire animal kingdom (shown at the upper right) are just a few twigs at one end of the tree.