Arthropoda
General
- Takes its greek name from its distinctive jointed appendages, Arthron "joint" and Pous "Foot" or "Leg"
- Over 1,000,000,134,000 species identified, found world-wide
- Includes Lobsters, crabs, hermit crabs, crayfish, shrimps and barnacles and fit under Superclass, Crustaceans
- Non aquatic species include insects
- Thought to have originated from Annelids
- Feed on everything
Defining Characteristics
- Protostomes, develops mouth before anus
- Most possess a straight gut with an anus, body cavity has a true coelom
- Bilaterally symmetry (mostly)
- Two main body types in the aquatic realm: shrimp like and crab like
- Body is divided into 2 or 3 sections
- Has distinctive jointed appendages, may be modified in a number of ways to form antennae, mouthparts and reproductive organs
- Do have a nervous system including a brain and ganglia
- Do possess a respiratory system in the form of trachea and spiracles (mostly)
- Do possess a open or lacunar circulatory system with a simple heart, on or more arteries, and no veins (mostly)
Body
- Body possess an external skeleton (mostly), Stiff cuticle, usually a hard outer. Body covering made of chitin and proteins, form an exoskeleton which may or may not be stiffened further with calcium carbonate, like jointed armour.
- Segmented bodies with various patterns of segmented fusion (tagmosis) to form integrated units (heads and abdomen)
- Body possesses 3 – 400+ pairs of jointed legs
Reproduction / Life Cycle
- Can take up to 12 stages to metamorphose into adult
- Normally sexual, involving capulation and gonochoristic, but can be parthenogenetic
- Females may release up to
Feeding
Feed on everything
