Phylum Arthropoda - Subphylum Crustacea
crabs, shrimp, lobsters, brine shrimp, isopods, barnacles

Phylum Arthropoda - Subphylum Crustacea

•	38,000 species - crabs, shrimp, lobsters, brine shrimp, isopods, barnacles
•	Mostly marine - crustaceans dominate the sea the way insects dominate the land
•	Biramous appendages

•	Legs on both abdomen and thorax
•	First two pair of appendages modified as antennae

•	Third pair of appendages are mandibles, for tough biting and chewing (other arthropods have mandibles)

•	All crustaceans share a common larval form, the nauplius larva

•	Order Isopoda - one of the few successful terrestrial crustaceans (plus a few crabs)
•	Very common, abundant

•	Curl up in a spiral to protect themselves

•	Feed on decaying vegetation (detritivores)

Phylum Arthropoda - Subphylum Myriapoda
centipedes, millipedes

•	Centipedes and millipedes form the subphylum Myriapoda (lots and lots of legs)
>	Class Chilopoda - centipedes
>	Class Diplopoda – millipedes

Subphylum Myriapoda - Class Chilopoda – centipedes

•	2,800 species, centi = 100, but they don’t really have 100 legs
•	One pair of legs per segment
•	Uniramous appendages

•	Carnivorous, eat mostly insects
•	Poison fangs, very painful bite, a dangerous creature!!

Subphylum Myriapoda -Class Diplopoda - millipedes

•	11,000 species, milli = 1,000, but they don’t really have 1,000 legs
•	Mostly herbivorous, feed on decaying vegetation (detritivore = feed on detritus)

•	Two pair of legs per segment (fusion)
•	Curl up in a spiral to protect themselves, secrete a defensive fluid (cyanide gas)

Phylum Arthropoda - Subphylum Hexapoda - Class Insecta – insects

•	Over 925,000 named species, maybe up to 30 million species undiscovered
•	Insects evolved about 200 mya, cockroaches and dragonflies were the first to appear
•	We live in the Age of Insects

•	Body consists of head, thorax, abdomen
•	Uniramous appendages
•	3 pair of walking legs (= 6 legs)

•	Communicate by scent and sound (pheromones)
•	Compound eyes

•	Terrestrial forms breathe via openings along the abdomen called spiracles
•	Spiracles open into a network of tiny tubes called trachea
•	Lose water vapor through trachea, many insects have valves to close spiracles

•	Excrete by means of malphigian tubules, projections of the digestive tract

•	Only invertebrates that fly
•	One or two pair of wings (usually two)
•	Extremely elaborate mouthparts, highly modified for chewing, sucking, or piercing

•	Insects undergo metamorphosis – simple or complete
•	Simple metamorphosis (hemimetabolous) - about 10%
•	No resting stage, juvenile looks like tiny adult (ex. grasshopper)

•	Complete metamorphosis (holometabolous) - about 90%
•	Resting stage (pupa), adults look different, live in different places, eat different things (ex. butterfly)
Orders of Insects

>	Hymenoptera - ants, bees, wasps
>	Coleoptera - beetles
>	Lepidoptera - butterflies and moths
>	Diptera - flies, mosquitoes
>	Orthoptera - grasshoppers, crickets, roaches
>	Isoptera - termites