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Scientific classification
Kingdom: Animalia
Phylum: Arthropoda

Arthropods (phylum or superphylum Arthropoda) are a large group of invertebrates, which means they do not have backbones (vertebrae). Insects, spiders, crabs, shrimp, millipedes, and centipedes are all arthropods. Arthropods have jointed feet, a segmented body, and an exoskeleton, a cuticle on the outside of their body.

Arthropods have by far the greatest number of species of any animal group, at around 900,000 species. One single order of insects – the beetles – outnumber all others.

"Insects are the most diverse organisms in the history of life".[1]

The other notable fact is that the arthropods are mostly terrestrial in their habitat. They are the only invertebrate phylum of which this is true.[2] Helping them in this respect is their hard exoskeleton, which reduces the loss of water (dessication). They are also notable as the first phylum to develop genuine flight.

Arthropods are made up of four groups of living animals and one group of extinct animals. The four groups are insects, arachnids, crustaceans, and myriapods. The trilobites are extinct, and they are the second most famous type of fossils, after the dinosaurs.

Arthropods are a source of food for many animals, including humans.

Images[change | change source]

References[change | change source]

  1. Grimaldi D. and Engel M.S. 2005. Evolution of the insects. Cambridge University Press, p1. ISBN 0-521-82149-5
  2. Even so, two classes, the trilobites and the crustacea, are mainly or wholly aquatic.