Phylum Arthropoda

1.Arthropoda – “jointed legs” A. Segmented bodies, jointed appendages, and a tough exoskeleton made of chitin. 1). 3 layers a) Outer – waxy, repels water. b) Middle – Hardened by tough additional calcium. c) Inner – Muscle attachment, flexible at joints, chitin.

2. Feeding A. Very Diverse – filter feeders, detritus feeders, carnivores, herbivores, blood suckers 3. Antennae – feelers 4. Compound Eyes – multiple lens

5. Respiration A. Aquatic species breathe through gills B. Horseshoe crabs breathe through book gills C. Spiders breathe through book lungs D. Terrestrial arthropods breathe through tracheal tubes 6. Open circulatory system 7. Well developed nervous system and sense organs

8. Molting – a process induced by hormones A. Shedding its skin and manufacturing a larger one, multiple times so it may grow larger. B. New skin is soft and animal is vulnerable and hides until it hardens. 9. Metamorphosis allows the arthropod to change shape and form.

10. 4 Subphyla A. Trilobita- all extinct

B. Crustacea – known as crusteceans includes crayfish, shrimp, lobster, crab, and more. C. Chelicerata – includes spiders, mites, ticks, scorpions, and horseshoe crabs. D. Uniramia – includes centipedes and millipedes and insects.

9. Subphylum Crustacea A. Examples – crab, lobster, shrimp, crayfish, type if plankton, barnacles (sessile existence) rolly pollies. B. Nauplius – Free swimming larvae B. Two pairs of antennae C. Several pairs of mouthparts D. Appendages with 2 branches E. Mandibles are specialized pair of mouthparts

10. Anatomy of a crayfish A. External 1. Cephalothorax 2. Abdomen - tail A). Telson – 7 th segment, flat paddle posterior end. B). Uropod – 6 th seg. Helps propel crayfish in a tail flip. (backwards movement) 3. Antennules- Feelers, touch, taste, equilibrium. 4. Antennae – feelers, touch and taste.

5. Maxillae – manipulate food, respiration. 6. Maxillipeds – 3 pairs, manipulate food. 7. Chelipeds – large claws, food and defense 8. Walking legs – 4 pairs 9. Swimmerets – appendages attach to abdomen used to hold eggs during reproduction

11. Crayfish systems A. Digestion – stomach contains small teeth to grind food that enters. B. Respiration – Gills that extend from the base of the walking legs. Water is circulated as it walks pushing it over the gills. C. Circulation – Open system, heart pumps hemolymph.

D. Excretion – Green glands found at the base of the antennae release excess water. E. Nervous system – pair of ganglia F. Statocysts – Cells that contain particle of calcium that move when the crayfishes body is upside down, The movement of these particle alerts crayfish to flip itself back right side up.

8. Subphylum Chelicerata- A. Examples – spiders, mites, scorpions, horseshoe crabs B. Body is divided into 2 parts: cephalothorax and abdomen, 4 pairs of legs. C. Chelicerae are specialized mouthpart D. Pedipalps are the second specialized mouthpart, holding food, chewing. E. Class Arachnida Ex. Spiders, mites, ticks, and scorpions

1. Anatomy of a spider A. Cephalothorax B. Abdomen C. Chelicerae – modified fangs D. 8 simple eyes E. Spinnerets – web weaving organ 1) webs, homes, capture food, store food 2) Ballooning – young use silk to fly away from nest to relocate.

F. Book lungs- paired sac with folds that increases surface area for respiration. G. Trachea – some spiders have this tube that carries oxygen directly to tissues. H. Spiracles – Holes in abdomen that attach to trachea that allow oxygen to enter. I. Malpighian tubules – excretory organs J. Coxal Gland – another excretory gland in some spiders.

10. Class Chilopoda A. Centipedes 1). One pair of leg per segment 2). Flattened body 3). Pair of poisonous claw-like appendages that inject venom into prey. 4). Nocturnal 5). Carnivore

11. Class Diplopoda A. Millipede 1) Two pairs of legs per segment. 2) Rounded body 3) Herbivores 4) Eat during the day time 5) Fairly harmless, secrete a toxin from skin pores when threatened.