Phylum Arthropoda
The arthropods are by far the most successful phylum of animals, both in diversity of distribution and in numbers of species and individuals. They have adapted successfully to life in water, on land and in the air.
Classes Include: Insects 3 body sections Some may fly Arachnids Crustaceans - Aquatic based class
About 80% of all known animal species belong to the Arthropoda - about 800,000 species have been described, and recent estimates put the total number of species in the phylum at about 6 million.
Arthropods are found in a greater variety of habitats than any other animal group; on top of mountains, at great depths in the ocean and in the icy wilderness of Antarctica. They can survive great extremes of temperature, toxicity, acidity and salinity.
Key features of Arthropoda Bilateral symmetry Appendages jointed Exoskeleton of cuticle shed at various intervals. Complex muscular system, with exoskeleton for attachment. Coelom reduced; most of body cavity filled with blood.