Arthropods Phylum Arthropoda

Phylum Arthropoda Over 900,000 Species “Jointed Legs” External Skeleton made of Chitin - strong flexible polysaccharide - Molting to grow Compound Eyes: many individual light detectors each with their own lens Includes: crayfish, lobster, centipedes, millipedes, shrimp, spiders, insects

Ancient Arthropods Trilobites

Subphylum Crustacea Copepods Daphnia Barnacles Isopods = Sow Bugs, Pill Bugs Japanese Spider Crab Crayfish, Lobster, Crabs, Shrimp

Subphylum Chelicerata Spiders Scorpions Mites, Ticks Sea Spiders Horseshoe Crabs

Subphylum Myriapoda Millipedes Centipedes

Class Insecta 3 body segments: Head, Thorax, Abdomen Study of = Entomology Insect Development - Incomplete Metamorphosis: a nymph hatches from an egg and slowly develops into an adult; nymph looks like miniature adult without wings Complete Metamorphosis: insect undergoes two stages of development between egg & adult

Classification Common Name: Crayfish Scientific Name: Cambarus acanthura Phylum: Arthropoda Class: Crustacea Other: Order: Decapoda “Crawfish”, “Crawdad”

Major Characteristics Body Plan: Cephalothorax (fused head and thorax), Abdomen Body Cavity: Coelom Symmetry: Bilateral Cell Specialization: Organs Other: Appendage specialization

Life Support Processes Absorption: Intestine Feeding: Detritus feeders, Mandibles = mouthparts Digestion: Stomach lined with teeth, Digestive glands near the stomach Respiration: Feather-like Gills, as it walks the legs circulate water over them Circulation: Heart - Open Circulation - Sinuses; Hemolymph = fluid

Life Support Processes Excretion: Anus, Green Glands - eliminate excess water, Gills Secretion: Digestive Glands Response: Brain, Nerve cord, Ganglia, Sensory hairs in antenna & antennules (taste, touch, balance), Compound eye Movement: Walking Legs, Swimmerets, Uropod, Telson Reproduction: Male uses swimmerets to deposit sperm on the females telson

Life Support Processes Support: Exoskeleton - Molts in order to grow in size - very vulnerable

Ecological Relationships Aquatic Terrestrial Detritus Feeders

Body Systems Compared With Humans Specialized Appendages Movable Mouth Parts

Advancements Over The Previous Phylum Gills Appendages Nervous System

Awesome Arthropods! The largest Lobster species is the North Atlantic lobster (Homarus americanus). The largest ever caught weighed 44 lb. 6 oz. And measured 3 ft. 6 in. ! (Mmmmm, yummy!) The largest of all crustaceans is the Giant Spider Crab. It’s body can reach a size of 12-14 in. and have a claw span of 8-9 ft. !

Goliath Spider Orb Weaver Spider - largest web18 ft. circumference