Often, we do not notice the presence of those animals with bodies of strange shapes and varied colors that live around us, fly over our heads or those that move near our feet. Most of these beings are formed by arthropod animals.
This group includes animals such as spider, fly, crab, centipede, snake louse, shrimp, scorpion, bee, among many others. The arthropod group is so well adapted to different environments that it currently represents over 70% of known animal species.
Arthropod general characteristics
The main characteristic that differentiates astropods from other invertebrates is the articulated paws. It was this characteristic that gave the group its name, since the expression articulated paws comes from the Greek: artro, which means "articulation", and pods, "paws".
The articulated paws allow the animal to perform many different movements, many of them well-defined and elaborate. In addition to very efficient locomotion, the articulated paws have other advantages for the animal, as they help in its defense and food capture. In everyday life, it is easy to observe in ants, for example, the activity that these paws allow.
In addition to the articulated paws, another important feature of arthropods is the presence of an external reinforcement: the exoskeleton. It is resistant, waterproof and consists of salts of chitin, which is a type of "sugar".
The exoskeleton coats and protects their bodies from many external dangers and also prevents them from losing water. It is an important adaptation to the terrestrial environment.
Insect coming out of its ancient exoskeleton
Although it offers protection, the exoskeleton limits the size of the animal as it does not keep up with body growth. When this exoskeleton becomes small, molting occurs. In this phenomenon, the old exoskeleton detaches from the animal's body and is replaced by the new one, which is already formed.
Until they become adults, arthropods can make this switch several times. So we can find arthropod exoskeletons that are loose in trees.
The various groups of arthropods
Arthropods are subdivided into classes according to some criteria, such as the body split it's the number of appendices displayed (eg number of paws, antennas, etc.).
Among the arthropod classes, we can mention: crustaceans, arachnids, kilopods, diplomats and insects.
Next, let's get to know each one better.