Taxonomists relegate all animals in the brute kingdom , from single prison cell animals to humans , into category , called phylum . Each phylum is further subdivide into course of instruction , decree , home , genus and species . Since the mid seventies , wanderer classification underwent change , especially in the genus and coinage categories , harmonize to Jonathan Coddington , curator at the Smithonian National Museum of Natural History , Washington , D.C. taxonomist employ scientific gens to sort out all organisms , so that an organism can be identified all over the Earth in spite of local names and unlike voice communication .
Step 1
Spiders belong to to the phylum Athropoda . All animals with an outer skeleton ( exoskeleton ) , made of a horny substance , called chitin , are in this phylum . The animal in this phylum have segment body and jointed leg and appendages . They also have at least three twain of leg . Phylum Arthropoda include insect , crabs , shrimp , lobster , milliped and centipedes and spider .
Class Arachnida
The phylum Arthropoda is further subdivide into classes . wanderer belong to the class Arachnida . The members of this class are called arachnids . This socio-economic class include all arthropods that have four brace of leg , but no antennae or wing . The dead body of the arthropod in this class is segmented or fused into one part . The class Arachnida include spider , scorpions , harvestmen , pinch and ticks . spider differ from the other members in this class by having two trenchant physical structure parts , an venter and a front part , call the cephalothorax . The eyes and all legs are tie to the cephalothorax .
Step 2
Order Araneae
Classes are divided into orders . Spiders belong to the ordering Araneae . It is one of 11 fiat in the course Arachnida . spider in this order take issue from the animals in the other orders by how the abdomen is attach to the cephalothorax , the lack of segment in the abdomen , and by possessing a hind organ , the spinneret , for produce silk . In spiders , the connection between the abdomen and cephalothorax is very thin , while scorpions , harvestman , and mites have a broad connexion . spider with different characteristics are further subdivide into several suborders .
Families, Genus and Species
The order and suborder for spiders are further subdivide into about 110 families , 3,600 genus and 39,000 species , according to Jonathan Coddington . The categorization of some spiders into these groups is still subject to change . Taxonomists have not yet identified all subsist spider and have placed some into incompatible categories . These category relegate spiders by their lineages , anatomical characteristic and use . The unwashed house spider is an case of a well characterized spider ; it belongs to the family Theridiidae and the genus and species Achaearanea tepidariorum .
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