Phylum of Arthropoda This Phylum

¶ … Phylum of arthropoda [...] this phylum to the reader, including general characteristics of the phylum, an overview of the taxonomy within the phylum, the number of organisms within the phylum, were these organisms live, their ecological or economic importance and any interesting facts about organisms within the phylum. Arthropoda are some of the most diverse and interesting organics on our planet and just about everyone knows what they are. This phylum is made up of spiders, insects, crustaceans, scorpions, and centipedes.

A phylum is a family of organisms that are somehow related, and this phylum is made up of animals with multiple legs, like spiders, crustaceans, scorpions, and such. There are more of this family than any other on Earth, and many of them are still waiting to be discovered. Some of this diverse group helps us live by containing (eating) other insects and phylum, while other members of this group have caused some of the most devastating diseases on earth, such as the fleas that caused the Black Death (Plague) in Europe in earlier centuries (Myers).

These organisms all share some general characteristics. Arthropods have segmented bodies that are proportioned and equal. This segmentation shapes outward and internal formation. Some segments show different patterns and are joined to form specific body regions called tagmata; these sections of the body include the head, thorax (main body) and abdomen (stomach area), and this kind of joining is called tagmosis. Their bodies are covered with a hard shell or "cuticle," that is usually made up of proteins and chitin, which is a very hard, protective surface (the cuticle is called an exoskeleton). This hard outer shell protects the softer segmented bodies underneath. A good example of this type of hard outer shell is on many beetles, and crustaceans such as crabs and lobsters, who are a subspecies of this phylum (Myers and Waggoner). This chitin "body armor" is jointed so the animals can move underneath it, and this jointed body, and their jointed legs, gives the phylum its name: arthropod means "jointed feet" (Waggoner). Their muscles are joined to the shell, which helps the animals move more easily. Interestingly, the arthropoda do not have internal spines, their shell is their skeleton (exoskeleton) on the outside. This skeleton is generated (secreted) by the animal, and is replaced as the animal grows larger, because the skeleton cannot grow with the animal. So, the animal sheds the old exoskeleton, and makes a new one when it is necessary.

Internally, the arthropods have a circulatory system of blood vessels and a heart, they have a nervous system, and they have a brain, respiratory (breathing) system, and digestive system (Ramel). Their bodies are not as advanced as those of humans are, but they are more advanced than fossils that have been found of similar animals in ancient times (Ramel).

The arrangement of animals in this phylum is quite varied. These creatures are usually divided into four classes: Trilobita (trilobites, which are now extinct, but the fossils look like flat beetles or sea creatures), Chelicerata, (which include spiders and scorpions, mites and ticks, horseshoe crabs, daddy-longlegs, and other animals with eight legs), Crustacea, (which include crabs, lobsters, shrimp, and other sea creatures), and Uniramia, (which include insects, millipedes, centipedes, and insects like these). These four main classes hold literally millions of insects and members. Since there are so many diverse insects and spiders on the planet, and scientist know they have not all been discovered, many people believe there are thousands that are not yet classified, and the entire class holds many millions of animals. Estimates place arthropods at about 80% of all known animals on Earth (Tatner). Within these four classes, the animals are broken down even further into numerous sub-classes.

Probably the most interesting thing about arthropoda is how diverse they are. They can live on land, underneath the ocean, and it the hottest deserts, and some even survive in the subzero temperatures of Antarctica. Some live in trees, some live on the ground, and some live underground. Their hard outer shell helps them survive, but so do their sensory organs, like their eyes and sense of smell. Some of them, like bees and flies, do not seem to be the same as beetles and spiders, but if you look closely, even these animals have the characteristics of arthropods. They have numerous legs, they have segmented bodies, and even they are covered with an exoskeleton, even though it is not as obvious as on other animals, such as beetles, crabs, and scorpions.