Spiders (order Araneae) are air-breathing arthropods which have eight legs, and chelicerae with fangs which inject venom. Those are the largest sized order of arachnids and rank seventh as a whole in species diversity amongst any other groups of organisms. Spiders are located worldwide on each and every continent aside from Antarctica, and have grown to be set up in virtually every habitat excluding air and sea colonization. As of 2008, roughly 40,000 spider species, and 109 families were documented by taxonomists; yet, there's been a dilemma inside the scientific community regarding how each one of these families must be categorized, as confirmed by the over 20 different classifications which have been suggested since 1900.
