The phylum Arthropoda contains animals with bilateral symmetry, segmented bodies, and jointed appendages. They have an exoskeleton made of protein and chitin that protects their bodies and allows growth through molting. Arthropods live on land, in water, and everywhere in between, and eat a wide variety of foods. Their circulatory systems use hemolymph instead of blood, and respiratory organs vary between gills, book lungs, and tracheae depending on the environment. Reproduction is usually sexual, with sperm transferred to females in packets. Major subgroups include insects, chelicerates, crustaceans, and myriapods.

1. Phylum Arthropoda
By: Cecelia Lounsberry and Gabe Dwyer

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)