Animal taxonomy is an ancient discipline, an important branch of zoology. Single because of the variety of animals, because some groups still lack in-depth research and understanding, so until now the classification of animals around the world has not a relatively perfect classification system. The reason for the difference is that some scholars will have a number of differences in the outline has been promoted to the door, such as the original body cavity in the animal's rotifers, abdominal hair, kissing, linear, nematode and other animals, some scholars will be promoted to the door.
In addition, there are some new groups of classes found in the original all the doors are not appropriate, simply new to a separate door, such as the comb jellyfish animal door, that is because of the discovery of the comb jellyfish animals. For the Study of medicinal animals, early as "medicinal Herbs" 1960, will be divided into 10 doors, later, "The Chinese Medicine Appraisal" 1977, etc. are also used, still divide the animal kingdom into 10 doors.
According to the characteristics of the cell is still: differentiation, the formation of germ layer, the body cavity, the form of symmetry, the division of the section, the nature of the bones, the characteristics of the appendages, and other organ system of occurrence and development, and reference to the geological classification of strata and other information.
In addition, there are other methods of animal classification.
1.
Primitive Animal Doors: all single-celled animals, the most primitive animals, such as eye worms, paramecium, etc.
2.
Rhombus Gate: Simple structure of the parasitic animals, there are few records;
3.
Direct swimming insect door: animals resembling rhombic worms;
4.
Porous Animal Doors: Also known as sponge animal doors, sponges are primitive multicellular animals;
5.
Flat panel animal Door: So far, this door has been silk worm an animal monopoly;
6.
Ancient Cup animal door: As the name implies, "ancient" means that such animals have been extinct, "cups" means they look like cups;
7.
Coelenterate doors: Including Hydra, jellyfish, sea anemones and coral;
8.
The door of the comb jellyfish animal: Some people also put this door into the coelenterate door, as the guide of the comb jellyfish;
9.
Platyhelminthes Doors: There are vortices, worms, tapeworm and other parasites;
10.
Urechis unicinctus Insect Animal door: Marine benthic animals, the body is columnar or long capsule shape;
11.
Tongue-shaped animal door: All is "sucking blood does not blink" parasites, classification status is still difficult to determine;
12.
Micro-jaw Animal doors: The newly discovered species of animals in the 1994 are poorly known to humans;
13.
New Zealand-shaped animal doors: similar animals that are slightly higher than platyhelminthes;
14.
Jaw stomach animal door: small body shape, living in shallow sand, people know not much;
15.
Nematode animal door: a large family, including worms, etc.
16.
Abdominal hair animal door: a kind of animal with cilia in the body's abdomen;
17.
Worm Gate: Very small, similar to native animals;
18.
Spething Gate: A class of animals resembling nematode animals;
19.
Gill-Towing Animal doors: Marine benthic fauna living in cold water near the poles, with very few documented species;
20.
Kissing animal Doors: Similar to the gill-dragging animal;
21.
Spike worm door: a kind of animal with kisses on the front end of the body;
22.
Armor Animal Door: A new door found in 1983, no precise classification;
23.
Inner anus Animal Door: moss-like small animals;
24.
Link animal doors: including earthworms, leech, sand silkworm, etc.
25.
Ring-mouth Animal door: a newly discovered species of animals;
26.
Sipunculus nudus Animal Door: Similar to urechis unicinctus insect animals;
27.
Mollusks Door: Package contains a large number of common animals such as snail, snails, oysters, octopus and so on;
28.
Soft tongue spiral animal door: extinct;
29.
Leaf foot animal door: including the Cambrian shrimp and so on;
30.
Slowly animal door: a very strong category of animals, can endure high temperature, absolute zero, high radiation vacuum and high-pressure;
31.
Claw Animal Door: The body is worm-shaped, the foot is cylindrical, the end has claws, near extinction;
32.
Arthropod doors: Animal species accounted for more than two-thirds percent of animals, insects, spiders, crabs and so on belong to the door;
33.
Brachiopods Animal Doors: Sometimes you'll see some fossils like shells on the streets of these animals.
34.
Outer ANUS Animal Door: once with the inner anus animal for the same door collectively known as moss Animals, is now separated;
35.
Broom Animal Door: a small door with only 10 of several animals, all marine benthic animals;
36.
Ancient insect animal Doors: 530 million years ago in the outbreak of the life of the long extinct, in recent years only found;
37.
Echinoderms doors: including starfish, sea urchins, sea cucumber and lily, etc.
38.
The door of the wrist: no parasitic animal with mouth and digestive tract, and living in deep-sea, classified status is controversial;
39.
The abnormal vortex: only 2 species, distributed around the Baltic Sea, have been considered platyhelminthes and molluscs;
40.
The fur jaw door: Only about 50 species, or marine animals;
41.
Semi-cord animal door: The body is worm-shaped, and someone will be classified into the chordates door;
42.
Chordates doors: including tail-cord animals, head-rigging animals, vertebrate three sub doors, man is the door.