2. General Characteristics
● Bilaterally Symmetrical
● Cells form up to the size of tissues and organs.
● Eat everything from plants to animals
● Live everywhere in land, fresh water, salt
water, and every other environment
● Largest Phyla on earth
3. Support System
● Exoskeleton-made of protein and chitin
-used for protection
-keeps joints attached
-molting- sheds exoskeleton as it grows.
● usually contain a range from 3 to 300 sets
of legs; usually have 2 pairs of antennae
● segmentation-head, thorax, abdomen
4. Digestive/Excrete System
● Eat Everything
● Food enters through the mouth and flows
into the mid-gut where food is broken down
and pushed to the hind gut.
● Nutrients and wastes are separated and
either dispersed through the body or
excreted in the form of guanine (DON'T
drink energy drinks!)
5. Circulatory System
● Open Circulatory System
body fluid enters pores to the organs and
is propelled through arteries to the body
● Body fluid-Hemolymph (NOT blood)
● Hemolymph is pumped by the heart to
sinuses called the hemocoel
● No Veins
6. Respiratory System
● Aquatic arthropods possess gills for
respiration
● Land arthropods have a tracheae and book
lungs as respiratory organs
● Air passes through the tracheae through
specialized openings in the exoskeleton
called spiracles
7. Nervous System
● Double chain of ganglia along the ventral
surface of the arthropod
● At anterior end are 3 fused pairs of dorsal
ganglia, constitutes the brain
● Much of the control of arthropod's activities
is in the central ganglia
8. Reproductive System
● Most reproduce sexually
○ However, some species reproduce through
parthenogenesis
● Sperm are usually transferred to the female
in sealed packets called spermatophores
● The paired sex organs are connected
directly to the ducts that open unto the
ventral surface of the trunk
9. Hexapoda
● Includes insects
● Mostly live on land
● 3 pairs of legs; 2 pairs of wings
● There are more species of Hexapoda than
all other forms of life combined
10. Cheliceriforms
● Includes horseshoe crabs, spiders,
scorpions, ticks and mites
● Live on land or in water
● Have chelicerae, which serve as pincers or
fangs.
● They do not have antennae
11. Crustaceans
● Live in fresh and salt water environments
● Crustacea is Latin for "Shell"
● Shell is made of calcium, protein, and chitin
● Have anywhere from 16 to 60 segments; 2-3
pairs of legs
● Advanced crustaceans have pincers
● Include: Crabs, Lobsters, Barnacle, Shrimp
12. Myriapods
● All Myriapods live on land
● Head contains 3 appendages for eating
including mandibles (jaw like structure)
● Millipedes
-less than 1000 legs (2 pairs per segment)
-herbivores
-among earliest animals on land
● Centipedes
-1 pair of legs per segment
-carnivorous (havepoison claws)