Question

Define arthropods?????​

Answer 1

An “arthropod” is an invertebrate animal that has an exoskeleton, a segmented body, and jointed appendages. The following families of organisms are all examples of arthropods:

Insects such as ants, dragonflies, and bees

Arachnids such as spiders and scorpions

Myriapods (a term which means “many feet”) such as centipedes and milipedes

Crustaceans such as crabs, lobsters, and shrimp

It may help to remember that the term “arthropod” comes from the Greek words for “jointed foot.” If the organism has an exoskeleton with joints between its feet and its body, it is probably an arthropod!

Arthropods are a lineage of life that developed skeletons on the outside – their hard shells, made of a material called “chitin” – instead of on the inside for structural support.

Arthropods’ bodies also have other important differences from those of vertebrates like ourselves – their organ systems are simpler and less efficient, which limits the size arthropods can attain.

An ant the size of a human, for example, would not be able to pump oxygen through its blood to feed all its tissues, since the arthropod circulatory system is simpler and less efficient than a humans’.

All arthropods are thought to have evolved from a single common ancestor, though scientists are not sure what this common ancestor looked like, or exactly when it lived.

Arthropod Characteristics

Characteristics shared by all arthropods include:

Exoskeletons made of chitin

Highly developed sense organs

Jointed limbs (the limbs must be jointed like the joints in a suit of armor, since the exoskeleton is rigid and cannot bend to allow movement)

Segmented bodies

Ventral nervous system. “Ventral” means “in front,” so this means that arthropods’ nervous systems run along the front of their bodies, near their stomachs, instead of along their backs like the spinal cords of animals.

Bilateral symmetry. This means that the left and right sides of an arthropod are the same – it will have the same number and arrangement of legs, eyes, etc. on the right side of its body as on the left.