See A Brief History of the Kingdoms of Life | Earthling Nature|
* Eukarya - Single or multi-celled organisms with a cell nucleus.
Kingdom Bacteria - Single celled organisms prokaryotes [no nucleus]). Bacteria inhabit soil, water, and the deep portions of Earth's crust. Bacteria also live in symbiotic and parasitic relationships with plants and animals.
Kingdom Archaea - Single celled organisms (prokaryotes [no nucleus]) with distinctive cell membranes. Archaea were initially viewed as extremophiles living in harsh environments, such as hot springs and salt lakes, but they have since been found in a broad range of habitats, including soils, oceans, marshlands and the human colon and navel.
Kingdom Protoctista or Protista - e.g. Protozoa, Green Algae, Slime mold, ...
Kingdom Plantae - e.g. Mosses, grasses, flowering plants, shrubs, vegetables, fruit trees, conifers, ...
Kingdom Animalia - e.g. Sponges, jellyfish, coral, worms, oysters, fish, reptiles, insects, birds, mammals, ...
Kingdom Fungi - Mushrooms, Penicillium (from which Penicillin is derived) molds, athlete's foot, rusts, yeasts
Kingdom Chromista - Diatoms, kelps, golden algae, yellow-green algae, downy mildew
Estimates for others, invertebrates (insects, crustaceans and earthworms), algae, fungi, mosses and gymnosperms, bacteria and others vary widely from 5 to 100 million species.
|Class ||# of Species
| ||Known ||Projected
|Amphibains- frogs, toads and salamanders ||6,600
|Flowering plants ||270,000
In the 108 years from 1898 to 2006, 57 kinds of freshwater fish declined to extinction in North America. The causes include damming of rivers and streams, the draining of ponds and lakes, the filling in of springheads, and pollution, all due to human activity.
Paleontologists and biodiversity experts estimate that since the existence of modern humans (200,000 years ago) the rate of extinction is between 100 to 1,000 times higher than it was before humans.
Source: A Biologist's Manifesto for Preserving Life on Earth - E.O. Wilson | Sierra Club
Example of Human Classification: (Items in parenthesis were not part of original 7 level system):
Some of the groups come from new methods of classification (e.g. Cladistics) and would not be included in the traditional scientific classification system.
Domain - Eucarya - Multi-celled with nucleus
Kingdom - Animala or Metazoa - Can move around, specalized sense organs,...
(Subkingdom) - Metazoa or Eumetazoa - Distinguishes the rest of the animals from sponges
Note: The second classification above, K: Metazoa and SK: Eumetazoa, tends to be more popular now.
(Branches) - bilateria: coelomate: deuterostome
(Grade) - Bilateral - bilaterally symmetrical (left/right)
(sub-grade) - Coelomata - True body cavities
(SuperPhylum) - Deuterostomia - Develop (embryo) mouth second
Phylum - Chordata - Hollow nerve cord
Some places show SuperPhylum = Chordata and
Phylum = Craniata - bilateral symmetry, bone and/or cartilage
(Plants use Division instead of phylum)
(Subphylum) - Vertebrate - backbone
Euteleostomi - Bony vertebrates
(Superclass or Infraphylum) - Gnathostomata - jawed vertebrates.
Newer, cladistic, classifications include 3 other levels here:
Teleostomi (Dermal bone, fin rays)
Euteleostomi (bony vertebrates)
Tetrapoda - Four footed gnathostomes - Can live on land.
Class - Mammalia - Hair, Mammary glands for nursing young
(Subclass) - Theria - Live births.
All mammals except monotremes - egg laying e.g. platypus.
(Infraclass) - Eutheria - Placental (unborn children carried in the uterus)
(SuperOrder) - Euarchontoglires
Order - Primate - (Monkeys) - Binocular vision (forward eyes) - opposable thumbs
(Suborder) - Haplorrhini (Anthropoidea & Tarsiodea) - Simple dry nose
Rotating sholder and elbow joints allowing them to swing from their arms.
(Infraorder) - Catarrhini - Downward facing, narrow nostrils
(Parvorder) - Catarrhini
(Superfamily) - Hominoidea (Apes) Absence of tails, rounded molars, color vision.
Family - Hominidae - (Great apes) - Complex social behaviors, larger body,
Skeletal modifications for semi-upright posture, 32 teeth
(SubFamily) - Homininae (hominines) - Gorilla, Chimp, Human
(Tribe) - Hominini or hominins - canine tooth, which looks more like an incisor.
Toe bone improved for moving bipedally.
Genus - Homo "man" - Larger brain
Species - Homo Sapien "wise" - Language, more sophisticated tools.
Sub-species (breed, race 3 , strain)
Form or cultivar (plants)
Although there are 7 main taxa in the original model, we see above a total of 22 taxa from sub-divisions added over time to further distinguish different branches.
Homo Sapien Lineage at Taxonomy Browser at the National Center for Biotechnology Information (NCBI) at the National Institutes of Health (NIH).
Domain: Eukaryota; Kingdom: Metazoa; Eumetazoa; Bilateria; Coelomata; Deuterostomia; Phylum: Chordata; subphylum: Craniata; Vertebrata; superclass:Gnathostomata; Teleostomi; Euteleostomi (bony vertebrates); Sarcopterygii; Tetrapoda; Amniota (amniotes); Class: Mammalia; Theria; Eutheria (placentals); SuperOrder: Euarchontoglires; Order: Primates; Suborder: Haplorrhini; Infraorder: Simiiformes; Parvorder: Catarrhini; Superfamily: Hominoidea; Family: Hominidae; Homo/Pan/Gorilla group; Genus: Homo; Species: Homo sapiens;
Evolution of classifications
The Binomial Nomenclature (Genus, Species) introduced by Swedish Naturalist Carolus Linnaeus (Karl von Linné), the father of modern taxonomy, in the mid-1700's lasted for 200 years.
Taxonomy has changed technologically as the field of biology has progressed.
The classifications of living organisms has evolved from two kingdoms (animal and vegitable) to six kingdoms to the current (2004) system of three Domains. As recently as 2000 35 new species were defined just for primates. See History below.
Historically, classification has been by comparison of anatomy
since 1960, use of molecular tools has allowed classification based on differences in DNA (and proteins) to identify common ancestries (a shared genetic heritage).
See history below.
Major redesigns of the classification system, using PhyloCodes, are being proposed based on Systematics & Cladistics. See Phylogenetic Tree and Cladistic classification at the evolution page.
Unfortunatly Zoologists and Botanists have different views on how things should be classified.
The following has the most common Phylums but it is not complete. There is little consistency in the reference books and web pages in this area. The following it an attempt to list the most common classification as of 2006, but it seems to be a moving target.
There are currently proposals to replace the Linnean System with a new PhyloCode.
Note: Viruses are made up of genetic material not complete cells, so are not considered living organisms.
|Domain ||Kingdom ||Phylum ||
|Proteobacteria ||Nitrogen-fixing bacteria, such as rhizobium, in the root nodules of legumes, as well as enteric bacteria that live in the intestinal tract of animals (including E. Coli). Includes both Chemoautotrophic (free living) and Chemoheterotrophic (parasitic), like Salmonella.
|Cyanobacteria ||Includes most bacterial photosynthesizers. Originally they were called blue-green algae because of their ability to photosynthesize, but were reclassified when it was found that they are more similar to bacteria, existing as prokaryotic cells. Produced the oxygen in early Earth.|
|Gram-Positive Eubacteria ||Display unique staining patterns when exposed to certain gram stains. Includes species of streptococci that causes strep throat.|
| Spirochetes ||Helical bacteria that all are chemoheterotrophs (parasitic). Includes Treponema pallidum, which causes syphilis.|
|Chlamydiae||Intracellular parasites that get vitamins, amino acids, ATP, and other vital cellular molecules from their host cell. Some cause venereal disease others a type of pneumonia.
|ARCHAEA ||CRENARCHAEOTA ||Pyrodictium, Thermoproteus ||A new group of micro-organisms were discovered in the Open Sea in 1970 and assigned their own domain in 1994.
They live in extremes of heat/cold, salinity and acidity.
Plants & Animals
mes for the protists
Some divide the kingdom into subkingdoms then
phila; some into classes.
|Chlorophyta ||Green Algae
|dinoflagellates (Red tides)
|Kingdom ||Division ||
|Zygomycota ||tube fungi, including some rusts, bread molds, water molds and others|
|Ascomycota ||sac fungi including yeasts, powdery mildews, cup fungi, blue and green molds, some bread molds and others|
|Basidiomycota ||club fungi, including most mushrooms, toadstools, bracket fungi, shelf fungi, puffballs, smuts and rusts.|
| ||lichens are not a single organism, but rather a symbiotic association between a fungus and an alga.|
|Deuteromycota || A miscellaneous junk category for forms of uncertain affinity, including those fungi in which sexual reproduction is unknown. It is not treated formally in more recent systems, although it is still used widely by plant pathologists.|
|CHROMISTA ||Phaeophyta ||kelp|
|Bacillariophyta || Diatoms|
|Haptomonada || haptophytes|
||rusts and mildews
|| Bryophyta ||nonvascular (no roots, stems, or leaves) e.g. mosses and liverworts|
| Pterophyta ||ferns and relatives|
| Coniferophyta ||cone-forming seed plants, conifers (gymnosperms)|
| Anthophyta ||fruit-forming seed plants - flowering plants (angiosperms), trees, Maple, Oak, Roses, tulips, sunflower, water lilie|
1. There are two Cordata sub-phylums which are not vertebrates:
|Domain||Kingdom ||Sub- |
|Superphylum ||Phylum ||Sub-Phylum
Plants & Animals
||Parazoa || ||Porifera (sponges )
|Chordata 1 (with a nerve cord) (fish, reptiles, birds, amphibians, mammals) ||VERTE-
|Hemichordata (Acorn worms, graptolites)
|Echinodermata (starfish, sea urchins, sand dollars, sea cucumbers, etc. ) ||
|Arthropoda (Insects, Spiders, lobster, crab, shrimp, scorpions )
Cephaloryncha (radialian worm )
Nematoda (roundworms )
Nematomorpha (gordian horsehair worms )
Onychophora (velvet worms )
(worms, molluscs, & lophophorates)
|mollusca (oysters, snails, slugs, scallop, octopus, squid and clams )
Annelida (Segmented worms, leeches )
Brachiopoda (lamp shells )
Bryozoa ("moss animals")
| ||Cnidaria (jellyfish, coral and sea anemones, and hydra. )
|Platyzoa ||Platyhelminthes (flatworms )
|Vendian Animals || (the First animals )
Urchordata - Sea squirts
Cephalochordata - Jawless Fish - Lamprey, Hagfish, Lancelets
2. Deuterostome means "mouth second"; which refers to early embryo development. The other major group of bilateria animals, protostomia, develops the mouth first. See below.
See Eukarya for a 9 Kingdom model and list of 33 Phylums for Animalia.
There are estimated to be a total of 5-9 million species.
A team including Dr Derek Tittensor, who is based at the UN Environment Programme's World Conservation Monitoring Centre (Unep-WCMC) and Microsoft Research in Cambridge, UK, and peers from Dalhousie University in Canada and the University of Hawaii placed the number at 8.7 million from studying relationships between the branches and leaves of the "family tree of life".
The figure excludes bacteria and some other types of micro-organism.
About 1.2 million species have been formally described.
[ ] - Number of Species
* DOMAIN BACTERIA (Eubacteria) (formerly Monera or Prokaryota See history.) [4,800 known, est. up to 5 Million]
Any organism, including the bacteria and cyanobacteria; characterized by the lack of a defined nucleus, and the possession of a single double-stranded DNA molecule and a very small range of organelles; almost all such organisms are unicellular and have a true cell wall containing peptidoglycan.
Very few bacteria species have been given a scientific name. One Norwegian study found between 4000 and 5000 bacterial species in a single gram of soil.
Blue-green algae, which accounted for most of the oxygen created in the early earth 2.5 milliion years ago, are now classified as bacteria (cyanobacteria) because they have no nucleus.
- Heterotrophic Bacteria
Green Nonsulfur Bacteria
Green Sulfur Bacteria
Spirochaetes (yphilis and Lyme disease are caused by these)
* DOMAIN ARCHAEA (Archaebacteria)
In 1970 a new group of microorganisms were discovered in the Open Sea. Since then, they had been found mostly in extreme environments such as high-temperature volcanic vents on the ocean floor, continental hot springs and fumeroles, and highly salty or acidic waters.
Archaea is sometimes classed as a Kindom.
In the early 1990's Carl Woese proposed they be assigned a new high level classification, Archaea. See history below
Archaea at: trishul.sci.gu.edu.au, John Kimball's site and UCMP - Univ. of California Museum of Paleontology.
- KINGDOM (or Phylum) CRENARCHAEOTA
- KINGDOM (or Phylum) EURYARCHAEOTA
- KINGDOM (or Phylum) KORARCHAEOTA
- Methanogens (Live in anaerobic environments such the muck of swamps and marshes, the rumen of cattle, sludge)
- Halophiles (These are found in extremely saline environments such as the Great Salt Lake in the U.S. and the Dead Sea.)
- Thermoacidophiles (Like acid and hot environments. Live in acidic sulfur springs (e.g., in Yellowstone National Park) and undersea vents ("black smokers").
- Others: Methanococci, Methanopyri, Archeoglobi, Thermococci
- KINGDOM (or Phylum) NANOARCHAEOTA
* DOMAIN EUCARYA (Eukaryota) - (Plants and Animals)
See Eukaryota at UCMP, John Kimball
- KINGDOM PROTISTA [est. 250,000]
- KINGDOM FUNGI [69,000 known] - molds, fungi, yeasts, mushrooms, Lichens
- Protozoa - Divisions Sarcodina/Rhizopoda (e.g. amoebas), Sporozoa/Apicomplexa (e.g.Plasmodium vivax, which causes malaria), Mastigophora/Zoomastigophora (e.g. Trypanosoma gambiense, which causes African sleeping sickness), Ciliophora (fresh water organisms and use cilia to move)
- Algae - Divisions Rhodophyta (red algae), Phaeophyta (brown algae, kelp) and Chlorophyta (green algae, spirogyra), Chrysophyta (golden algae, Diatoms), Pyrophyta (Dioflagellates),
- Fungus-like Protists - Division Myxomycota (slime molds)
SEE: UCMP, Kimball's pages.
- KINGDOM PLANTAE [270,000 known] --
See Plant Classifications (annual/perenial, Deciduous/Evergreen etc.) at ND State Univ.
- Division Bryophyta-- nonvascular (no roots, stems, or leaves) e.g. mosses and liverworts
- Division Pterophyta--ferns and relatives
- Division Coniferophyta-- cone-forming seed plants conifers (gymnosperms)
- Division Anthophyta-- fruit-forming seed plants - flowering plants (angiosperms)
- Class Dicotyledonae- plants with one seed leaf e.g., geranium, carrot, maple
- Class Monocotyledonae- plants with two seed leaves e.g., lily, grass, bamboo, palm
- KINGDOM ANIMALIA/METAZOA [est. >6-7 Million]
Animals are also classified into grades/sub-kingdoms as follows:
"Parazoa" [subkingdom] - No true tissue or loose tissue organization. (sponges)
"Eumetazoa" [subkingdom] - True tissue
"Radiata" [grade] - Only top and bottom - Jellyfish, corals
"Bilateria" [grade] - Bilaterally symmetrical (left/right)
"Acoelomata" [sub-grade] - Flat worms
"Pseudocoelomata" [sub-grade] - Round worms
"Coelomata" [sub-grade] - True fluid filled body cavities
"Protostomia" - Develop mouth first - Earthworms, Molluscs, Anthropods, ...
"Deuterostomia" - Develop anus first - Chordata (Vertibrates,..),
Echinodermata (star fish, urchins, ...)
- Sub-Phylum: Invertebrata. [est. >6 Million 95-99% of all animal species]
- Phylum Chordata (animals with a nerve chord) [45,820]
- Sub-Phylum: Vertebrata [52,000 ?]
Vertebrates also differ from all the other animals by having quadrupled their HOX gene cluster; that is, vertebrates have 4 clusters of HOX genes located on 4 different chromosomes.
Tetrapods (terrestrial vertebrates)
- Fish [21,723]
- Class Agnatha - Jawless fish/lamprey
- Class Chondrichthyes - Sharks, skates, rays
- Class Osteichthyes - bony fishes: bass, tuna, salmon
- Class Amphibia Amphibians [4,334] - frogs, toads and salamanders
- Class Aves Avians[>9,000] - Birds
- Class Reptilia Reptiles[6,778] - snakes, crocodiles and alligators
subclass Archosauria - Dinosars
- Class Synapsida - (extinct) Early (300 mya) predecessor to mammals (looked like reptiles)
Order: Therapsida - Therapsids became the dominant land animals during
the Middle Permian. Mammals evolved from them.
- Class Mammalia Mammals [5,400]
- Sub-Class - Eutheria (Placentals: Mammals in which the young develop in a placenta inside the uterus.)
- Order: Insectivora - Insect eating - Shrews, moles
- Order: Carnivora - Meat eating - dog, cat, lion, bear, racoon, seal
- Order: Chiroptera - bat
- Order: Primates [310*]- monkeys, apes
In older classifications, the Primates were divided into two suborders: Prosimii (lemurs and tarsiers) and Anthropoidea (Anthropod - monkeys, apes, humans). See primates at Wikipedia
Sub-Order - Haplorrhini
- Infraorder Tariiformes (Tarsiers)
- Infraorder Simiiformes
- SuperFamily: Catarrhini
- SuperFamily: Hominoidea (hominoids) (Apes)
Family: Hylobatidae: Gibbons
Family: Hominidae1 (Great apes)
Subfamily: Ponginae - orangutans
Genus: Gorilla - Gorilla
Genus: Pan - chimpanzees, Bonobo (pygmy chimp)
Hominid (Tribe Hominini)
Genus: Australopithecus (extinct)
Species: H. sapiens - man/humans 3
Species: Others (all extinct) neanderthalensis, floresiensis, erectus, habilis, ...
Neanderthal's are sometimes classified as a subspecies.
Sub-Order - Strepsirrhini (lemurs, lorises, ..)
- Order: Rodentia - Rats, mice
- Order: Lagomorpha - Jackrabbit
- Order: Perissodactyla - Horse, Rhinoceros
- Order: Artiodactyla - pig, cow, sheep, deer
- Order: Cetacea - whale, dolphin, porpoise
- Order: Pinnipedia - seals, sea lions
- Order: Marsupialia - Koala, Opossum
- Order: Proboscidea - Elephant
- Order: Xenarthra - Armadillo, Two-toed Sloth
- Order: Sirenia - Manatee
- Order: Tubulidentata - Aardvark
- Order: Others: Dermoptera (Colugo), Hyracoidea (Rock Hyrax), Monotremata (Short-beaked Echidna), Pholidota (Giant Pangolin)
- Phylum Porifera - sponges [5,000 known]
- Phylum Cnidaria (Coelenterata) [9,000 known] - hydra, jellyfish, sea anemone, and the coral
- Phylum Platyhelmintes [20,000 known] - worms with flattened bodies, such as the planarian, tapeworm and liver fluke
- Phylum Nematoda [25,000 known] - roundworms such as the ascaris, pinworm, hookworm, stomach worm and the trichina or pork worm.
- Phylum Annelida [12,000 known] - worms with bodies made of segments such as the sandworm, leech and the earthworm.
- Phylum Mollusca [50,000 known] - oysters, snails, slugs, scallop, octopus and clams
- Phylum Arthropoda [est. 6 Million - 75-84% of all known animal species]
- Subphyla (or SuperClass) Hexapoda
Class Insecta [>1 Million known] --butterflies, grasshoppers, beetles, fly, mosquito, moth. 90% of anthropod species, 65-75% of all species.
(Estimates of total insect species range from 2 to 30 million.)
See aquatic insects under fly-fishing.
Non-insect (Entognatha): Collembola, Protura, and Diplura - Minute arthropods mostly found in leaf litter and soil. e.g. Springtails
- Class Crustacea [50,000] --shrimp, crayfish, crabs
- Subphyla Myriapoda [13,000]
- Subphyla Chelicerata [75,000]
Class Arachnida [75,000]--spiders, scorpions, ticks, mites
Class Merostomata --horseshoe "crab"
- Phylum Echinodermata [6,100 known] - starfish, sea urchins, sand dollars, sea cucumbers
* In June 2000 the number of recognized species of primate was increased from 275 to 310 following a meeting of primatologists, conservationists, and taxonomists in Orlando, Florida. A number of species were reclassified using molecular genetic research, behavioural observations, and anatomical evidence. Brazil has 77 species of primate, far more than any other country.
1. Until recently, most classifications included only humans in the family Hominidae; other apes were put in the family Pongidae. The evidence linking humans to gorillas and chimps has grown dramatically in the past two decades, especially with increased use of molecular techniques. It now appears that chimps, gorillas, and humans form a clade of closely related species; See Hominidae at Primates.com
The the chimpanzee/human split occurred between five and seven million years ago.
Sometimes Homo Sapiens (wise man) are divided into sub-species or race
(see below) as:
Homo Sapien Neanderthal (some classify them as their own species
Existed between 230,000 and 30,000 years ago. The average brain size
is slightly larger than that of modern humans, about 1450 cc,
but this is probably correlated with their greater bulk.
Homo Sapien Sapien (Modern Man) (Average brain size of about 1350 cc.)
(150,000-120,000 years ago)
Homo sapiens (archaic) (also Homo heidelbergensis) (200,000-350,000 years ago)
(Average brain size of about 1200 cc.)
Homo erectus (1.8 mya to 300,000 years)
Homo habilis (Handy man) 2.4 - 1.5 mya)
Hominid 4 mya
See: Eukarya for another version.
Subspecies are animal groups that are related, can interbreed, and yet have characteristics that make them distinct from one another. Two basic ingredients are critical to the development of separate subspecies: isolation and time. Unlike most animals, humans are a relatively young species and we are extremely mobile, so we simply haven't evolved into different subspecies.
Evolution, Hominid Species, and A Phylogeny of Living Hominoids.
Primate Taxonomy at U. Manitoba.
Many other animal species have been around much longer or they have shorter life spans, so they've had many more opportunities to accumulate genetic variants.
Domesticated animals such as dogs also have a lot of genetic diversity, but this is mostly due to selective breeding under controlled conditions.
Many articles refer to Neanderthal as a race. I think they are using race to distinguish from the "human race" not the what we refer to as different races today.
When it comes to using "race" as a classification, race is not a scientifically-precise term. Genetically speaking, there is less than a 1% difference between negroids, caucasoids and mongoloids. Humans of different races are more than 99% alike genetically. Race is more of a political and quasi-biological term.
Source The Politics of Egyptology and the History Kemet (Egypt)
Other Animal Sites:
Animalia Kingom at North Harris College
Rennisance Animal Classification
History of Taxonomy
See A Brief History of the Kingdoms of Life
- Living Organism
- One or more biological cells.
All living organisms can replicate, and the replicator molecule is DNA. As well, all living organisms contain some means of converting the information stored in DNA into products used to build cellular machinery from fats, proteins, and carbohydrates.
- Cells without membrane bounded nuclea (bacteria)
- Organisms with cells that have nuclea
See Bacteria at John Kimball's Biology Pages
- Biological Species Concept (BSC) or Mayrian Species Concept (in honor of its principal architect, Ernst Mayr)
- States that if two creatures can produce viable offspring, they are the same species. There are many exceptions to this rule.
"The Growth of Biological Thought", Ernst Mayr
"Principles of Systematic Zoology", Ernst Mayr
Systematics and the Origin of Species, 1995, Ernst Mayr
"Full House", 1996, Steven Gould
"International Code of Zoological Nomenclature (ICZN)"
"Life Evolving", 2002, Christian de Duve
Life: The Science of Biology, by Purves et
al., from Sinauer Associates
Race in US Census
Human Race at Carleton College.
RACE - The Power of an Illusion. at pbs.org
Earth History (Geological TIme)
More Information on Taxonomy:
PALAEOS: The Trace of Life on Earth
three Domains and Phylogeny at Univ. of California Museum of Paleontology (UCMP)
Taxonomic Classifications at the Portsdown Geology site.
Tree of Life Web project
CMR Genomes Arranged by Taxonomy at the Comprehensive Microbial Resource (CMR) at The Institute for Genomic Research (TIGR)
The Taxonomicon & Systema Naturae 2000 Project - Brands, S.J. (comp.) 1989-2005. Universal Taxonomic Services, Amsterdam, The Netherlands.
Frontiers In Microbiology -> Microbes And The Three Domains
Terrestrial Vertebrates list
Bio 1003 notes at CUNY
Flora and Fauna at Google
Plant Classifications (annual/perenial, Deciduous/Evergreen etc.) at ND State Univ.
Number of Species at:
The Environmental Literacy Council
Roger Butterfield page from
Natural History Museum in London
Number of Species on Earth at CurrentResults.com/Environment-Facts
What does related mean
Invertebrates at rcn.com
Classification Lab at Sidwell Friends School
Scientific Classification at wikipedia.org
Animal, Vegetable or Mineral? by Nicholson.
Phylogentic Trees of Life: Griffith Univ., Queensland Australia
Evolution and Systematics: From Darwin to Phylogenetics at the U. of Tennessee
Systema Naturae 2000
Homo Sapiens in Taxonomy Browser and Genome Project at the National Center for Biotechnology Information (NCBI) at the National Institutes of Health.