Arthropoda Phylogeny and Major Subphyla Characteristics

What is the origin of the Phylum Arthropoda?

Evolved from a primitive ancestor called a Protoannelid.

What are the three related phyla to Arthropoda?

Phylum Annelida, Phylum Onychophora, and Phylum Arthropoda.

What are the key features of Phylum Annelida?

Segmented body, closed circulatory system, gas exchange through the skin, simple bristles for appendages.

What are the key features of Phylum Onychophora?

Segmented body, open circulatory system, breathes with trachea, has true legs and antennae.

What are the key features of Phylum Arthropoda?

Segments fused into tagma, open circulatory system, breathes with trachea or gills, has jointed appendages and a chitinous exoskeleton.

What are the four major subphyla of Arthropoda?

Trilobita, Chelicerata, Crustacea, Uniramia.

What are the characteristics of Subphylum Trilobita?

Extinct, dominant coastal marine organisms, flat with many legs.

What are the key features of Subphylum Chelicerata?

No antennae, two tagma (Cephalothorax and Abdomen), six pairs of appendages, breathe using book lungs.

What are the examples of organisms in Subphylum Chelicerata?

Spiders, scorpions, mites, ticks, horseshoe crab.

What are the characteristics of Subphylum Crustacea?

Two pairs of antennae, minimum of five pairs of legs, two tagma (Cephalothorax and Abdomen), mostly aquatic and breathe with gills.

What are the examples of organisms in Subphylum Crustacea?

Lobster, crabs, shrimp, barnacles, isopods.

What are the characteristics of Subphylum Uniramia?

One pair of antennae, two or three tagma, uniramias appendages.

What are the major classes of Uniramia?

Diplopoda, Chilopoda, Insecta.

What are the characteristics of Class Diplopoda (Millipedes)?

Elongated and cylindrical body, two pairs of legs per body segment, detritivores, can release a noxious substance for defense.

What are the characteristics of Class Chilopoda (Centipedes)?

Elongated and flattened body, one pair of legs per body segment, predators, modified appendages for injecting venom.

What are the characteristics of Class Insecta (Insects)?

Three tagma (Head, Thorax, Abdomen), three pairs of legs attached to the thorax, only arthropods with wings.

What is the habitat of Class Insecta?

Mostly terrestrial.

How did Class Insecta evolve in relation to plants?

Evolved in close association with flowering/seed plants.