Most numerous the invertebrate animal trains the animal group.
The invertebrates lack spine and articulated internal skeleton. Majority of invertebrates have protectionexternal, as if outside an armor, like the escarabajos, but are invertebrates that do not have any type of protection, like the pulpy one. The invertebrates classify themselves in several groups:• The arthropods
• The worms
• The equinodermos
• The jellyfish
• The sponges
The arthropods are characterized because they have his bodyand its legs articulated, that is to say, divided in pieces that move.
The most important groups are:
• The insects
• The arachnids
• The crustaceans.
• The miriápodos
The insects are the abundant arthropods but. They have the following characteristics:
• Its body this divided in head, thorax and abdomen.
• They have two antennas in the head, andsix legs in the thorax.
• They are terrestrial and they breathe by tracheas that are tubes located in the abdomen by which they pick up the air.
The arachnids have thefollowing characteristics:
• Its body is divided in cefalotórax and abdomen.
• Cefalotórax is a unique piece that includes the head and the thorax.
• They lack antennas. In the mouth they owntweezers that serve to them to eat, and in cefalotórax they have eight legs.
• They are terrestrial and they breathe by tracheas.
The crustaceans have the followingcharacteristics:
• Its body is divided in cefalotórax and abdomen.-
• They own two antennas in the head and the majority has ten legs in cefalotórax some crustaceans, like the crab, have the frontlegs transformed into tweezers.
• The majority is aquatic and breathes by gills.
The miriápodos have the characteristics:
• Its body is divided in head and trunk....