This lifeform is found east of the Continental Divide in North America. This lifeform is common in suitable environments.
Spiders (Araneae) are a large group of animals usually with eight legs. Most spiders spin webs to catch their prey. There are about 3,000 species of spiders in the United States.
Arachnid (Class Arachnidae) consists of nine to eleven different surviving orders depending upon how one divides the Arachnid class. In total, there are about 60,000 to perhaps 75,000 species grouped in the following eleven orders:
Order Number of Species
Acarina-Mites and Ticks 30,000
Amblypygi-Tailless Whipscorpions 60
Araneae-Spiders 35,000
Palpigrada-Micro Whipscorpions 50
Ricinulei or Podogona-Ricinulids 20
Pseudoscorpionida-False Scorpions 1,000
Schizomida-Short Tailed Whipscorpions --
Scorpionida-Scorpions 2,000
Solpugida-Sun Spiders, Windscorpions 1,000
Phalangida-Daddy Long Legs 2,200
Uropygi-Whipscorpions 70
The old order, Pedipalpida (Whipscorpions), has been divided into the following orders:
Uropygi (Whipscorpions)
Ambylypygi (Tailless Whipscorpions
Schizomida (Short Tailed Whipscorpions))
Jointed Legged Animals (Phylum Arthropoda) make up the largest phylum. There are probably more than one million different species of arthropods known to science. It is also the most successful animal phylum in terms of the total number of living organisms.
Butterflies, beetles, grasshoppers, various insects, spiders, and crabs are well-known arthropods.
The phylum is usually broken into the following five main classes:
Arachnida: Spiders and Scorpions
Crustacea: Crabs and Crayfish
Chilopoda: Centipedes
Diplopoda: Millipedes
Insecta: Insects
There are several other "rare" classes in the arthropods that should be mentioned. A more formal list is as follows:
Sub Phylum Chelicerata
C. Arachnida: Spiders and scorpions
C. Pycnogonida: Sea spiders (500 species)
C. Merostomata: Mostly fossil species
Sub Phylum Mandibulata
C. Crustacea: Crabs and crayfish
Myriapod Group
C. Chilopoda: Centipedes
C. Diplopoda: Millipedes
C. Pauropoda: Tiny millipede-like
C. Symphyla: Garden centipedes
Insect Group
C. Insecta: Insects
The above list does not include some extinct classes of Arthropods such as the Trilobites.
Animal Kingdom contains numerous organisms that feed on other animals or plants. Included in the animal kingdom are the lower marine invertebrates such as sponges and corals, the jointed legged animals such as insects and spiders, and the backboned animals such as fish, amphibians, reptiles, birds, and mammals.