Invasion of the Arthropods
Phylum Arthropoda is considered to be the most successful phylum, as it is estimated that there are between 5-10 million species of arthropods. Animals in this phylum are characterized by an exoskeleton of chitin, a head with jointed appendages, specialized body segments, sensory systems, and bilateral symmetry. Arthropods also have digestive, excretory, and open circulatory systems.
There are four main subphyla of Phylum Arthropoda. The subphylum Chelicerata includes horseshoe crabs (class Merostomata) and spiders, ticks, and scorpions (class Arachnida). Chelicerates have two main body segments, while most arthropods have three (head, thorax, and abdomen). They also have pincers which most use to feed. The second subphylum is named Crustacea and includes crabs, shrimp, lobster, and barnacles. These have two-parted limbs. Next, insects are in the subphylum Hexapoda. Insects have three pairs of jointed legs, three body parts, antennae, and compound eyes. Insects are extremely diverse, representing more than half of all known living organisms and over 1 million species. Bees, butterflies, ants, flies, termites, beetles, and ladybugs are all insects. Finally, centipedes and millipedes are in the subphylum Myriapoda. These animals live on land and can have up to 750 legs (most arthropods have 6 or 8 legs).
There are four main subphyla of Phylum Arthropoda. The subphylum Chelicerata includes horseshoe crabs (class Merostomata) and spiders, ticks, and scorpions (class Arachnida). Chelicerates have two main body segments, while most arthropods have three (head, thorax, and abdomen). They also have pincers which most use to feed. The second subphylum is named Crustacea and includes crabs, shrimp, lobster, and barnacles. These have two-parted limbs. Next, insects are in the subphylum Hexapoda. Insects have three pairs of jointed legs, three body parts, antennae, and compound eyes. Insects are extremely diverse, representing more than half of all known living organisms and over 1 million species. Bees, butterflies, ants, flies, termites, beetles, and ladybugs are all insects. Finally, centipedes and millipedes are in the subphylum Myriapoda. These animals live on land and can have up to 750 legs (most arthropods have 6 or 8 legs).
What is NOT characteristic of all arthropods? (Correct answer will launch you to the next page)