What are some key features of arthropods?

Answer 1

An arthropod is an invertebrate animal having an exoskeleton (external skeleton), a segmented body, and jointed appendages. Arthropods are members of the phylumArthropoda(from Greek ἄρθρον arthron, "joint", and ποδός podos"foot", which together mean "jointed feet"), and include the insects, arachnids, crustaceans, and others. Arthropods are characterized by their jointed limbs and cuticles, which are mainly made of α-chitin; the cuticles of crustaceans are also biomineralized with calcium carbonate. The rigid cuticle inhibits growth, so arthropods replace it periodically by molting. The arthropodbody plan consists of repeated segments, each with a pair of appendages. It is so versatile that they have been compared to Swiss Army knives, and it has enabled them to become the most species-rich members of all ecological guilds in most environments. They have over a million described species, making up more than 80% of all described living animal species, and are one of only two animal groups that are very successful in dry environments - the other being the amniotes. They range in size from microscopic planktonup to forms a few meters long.

Answer 2

Arthropods are characterized by segmented bodies, an exoskeleton made from chitin, and joint appendages. They have an internal body cavity (hemocoel) and an open circulatory system which employs hemolymph, a fluid that does not distinguish between interstitial fluid like lymph and oxygen carrying fluid like blood as in most vertebrates. They use a copper-based oxygen carrier molecule instead of the iron-based hemoglobin, which floats freely around in the hemolymph and is not bound to blood cell proteins. They do not have a dedicated and separate branch of their circulatory system just to oxygenate; internal organs (and cells) are simply bathed in this fluid. Their nervous system is 'ladder-like' on their ventral surface, and their brains formed around the esophagus from fused segment nerve ganglia.

Answer 3

Jointed appendages , chitinous exoskeleton . tagmatization and metamerization .