Phylum Arthropoda http://i.livescience.com/images/080125-horseshoe-crab-02.jpg http://www.andrill.org/iceberg/blogs/julian/images/pc030012sea-spider.jpg http://thedailydish.files.wordpress.com/2009/02/lobster.jpg

External jointed skeleton (exoskeleton) with 2 layers: Known for metamerism (body divided into segments)- each body region = tagmata External jointed skeleton (exoskeleton) with 2 layers: Epicuticle= Outermost waxy layer Procuticle= Inner layer made of chitin which partially hardens Exoskeleton molts (endysis) periodically so that arthropod can grow. Internal cavity (hemocoel) with open circulatory system and internal organs Metamorphosis (change in body form/physiology) often present; this reduces competition between larva and adult stages

Subphylum Chelicerata Known for 2 tagmata: Prosoma/cephalothorax = 1st body region which is a sensory, feeding, and locomotor tagmata. ***This region also includes legs (appendages). 1st pair of appendages are called chelicerae (used for feeding); 2nd pair are called pedipalps (used for used in feeding, locomotion, or reproduction) Opisthosoma = 2nd body region which contains digestive, reproductive, excretory, and respiratory organs Mostly carnivores No antennae

Class Merostomata Horseshoe crabs (only 4 species living) Mostly in Atlantic Ocean and Gulf of Mexico Scavenge for annelids, molluscs, and other invertebrates Last pair of appendages have leaflike plates for locomotion and digging Opisthosoma contains book gills (gases exchange between blood and water) Dioecious (female lays eggs which are fertilized by male)

Class Arachnida Malpighian tubules for excreting waste Book lungs (similar to book gills) Open circulatory system Many sensory structures (sensilla) on body Dioecious (often by spermatophore) Most are oviparous (female lays eggs that develop outside body) Others may be ovoviviparous (development internal with a yolky egg for nourishment) or viviparous (eggs that are nourished directly by female mother, live young are born) Many care/tend to eggs and young Digestion may be partially external as well as internal

http://insects.ucr.edu/ebeling/figures/fig035.jpg

Class Arachnida (cont.) Order Scorpionida Scorpions Dancing-like courtship that is followed by ovoviparous or viviparous fetilization (young stay with mother on her back until 1st molt) Order Araneae Largest order: Spiders Prosoma with poison glands and fangs Pedipalps modified for sperm transfer 6-8 eyes (some species have well developed eyes for catching prey)

World’s Most Venomous Scorpions… *In general, scorpions with slim and narrow pincers are equipped with more toxic venom. Powerful venom compensates for the scorpion’s weaker pincers and lack of brawny strength. DEATH STALKER SCORPION http://1.bp.blogspot.com/_6EdUefA9bik/RsDNm0QzzfI/AAAAAAAAA7o/O2b4TnAa9ZE/s400/death-stalker-scorpion.jpg http://www.orovalleyhomes4sale.com/images/ScorpionsInDark.jpg Scorpions glow under UV light (black light) http://www.dkimages.com/discover/previews/797/931243.JPG

Opisthosoma has spinnerets associated with silk glands (there are several types of silk produced) Silk may also be used by young spiders for dispersal (called ballooning) Female may attract male with pheromones or male may attract female by plucking on her web Sperm given to female with pedipalps, female lays up to 3,000 eggs in silk case Order Opiliones Harvestmen or daddy longlegs Prosoma and opisthosoma are joined (making body look oval/ovoid) Many are omnivores (feed on plants and animals) Sperm transfer is direct by penis like structure

World’s Most Venomous Spiders… http://farm3.static.flickr.com/2173/2158857410_d57efe2160.jpg http://www.spiderzrule.com/spider307/PICT0645.JPG The Brazilian Wandering Spider (Guinness World Records 2007) http://www.spiderzrule.com/spiders063/Picture%20029.jpg

Australian Funnel-web Spider http://mentalfloss.cachefly.net/wp-content/uploads/2008/11/440atraxspider.jpg http://abcnews.go.com/images/GMA/nm_SydneyFunnelWebSpider_090608_mn.jpg http://australianmuseum.net.au/Uploads/Images/9618/dang_29_big.jpg

Order Acarina Class Pycnogonida Mites and Ticks (mostly “ectoparasites”) Prosoma and opisthisoma are fused Capitulum projects from anterior carrying mouthparts Chelicerae and pedipalps modified for piercing, biting, anchoring, and sucking. Do not permanently attach to host (parasite???) Some carry diseases (Lyme Disease; Rocky Mountian Spotted Fever) Class Pycnogonida Sea spiders (marine, located on ocean floor)

Mites vs. Ticks Mite Tick http://axiom.anu.edu.au/~luke/images/mites/dust_mites_pin.jpg http://academics.hamilton.edu/biology/kbart/image/Wood%20Tick.jpg Mite Tick

http://www.lymediseaseaction.org.uk/images/i03/rostrum.jpg http://www.regionalpestmanagement.com/images/tickmaster.jpg

Subphylum Crustacea Almost all aquatic 2 pairs of antennae Biramous appendages (appendages separate into 2 parts at distal end- making “Y” shape) 5 classes (3 common)

Class Malacostrata Largest class of crustaceans Includes shrimp, crabs, lobster, crayfish, mysids, krill, isopods, and amphipods Feed on other invertebrates, plant matter, and dead/decaying animals Sensory structures = Compound eyes, simple eyes, statocysts, chemoreceptors, proprioceptors, and tactile setae. Excretory organs (green glands) are at bases of second antennae Dioecious (most young hatch as mini adults) Most larvae planktonic (with a single median photoreceptor)

Appendages (of most crustaceans): Pairs 1-2 = Antennae Pairs 3-5 = Associated with mouth 3 = Mandibles (chewing/grinding) 4-5 = Maxillae (food handling; #4 has a gill) Pairs 6-8 = Maxillipeds (sensory and food handling) #7-8 have gills Pairs 9-13 = Pereopods (mainly for walking; contains gonads) 9 = cheliped (pincher to capture food) All but last pair after perepods = Pleopods (swimmerets) Last segment (flipper)= Telson (anus) which has appendages called uropods

Class Branchiopoda Class Maxillopoda Fairy shrimp, brine shrimp, water fleas resistant embryos are found in this group because they usually live in temporary ponds, salty environment, or need to survive over winter Class Maxillopoda 2 common groups: copepods and barnacles Most copepods planktonic with median ocellus and very important to marine food webs Most barnacles are monoecious Barnacles attach to a variety of substrates (sometimes by a stalk) and some are modified parasites

Subphylum Myriapoda “Myriad” = ten thousand 2 tagmata (head and trunk) 4 classes (2 common) Class Diplopoda = millipedes 11-100 trunk segments Round in cross section Food = decaying plant matter Roll into a ball or release hydrogen cyanide when threatened 2 pairs of legs per segment

Class Chilopoda = centipedes Nocturnal Flat in cross section Carnivores (arthropodss, worms, snails, frogs) Poison claws to kill/immobilize prey One pair of legs/segment http://shimmyshewobble.com/wp-content/uploads/2009/05/giant_centipede.jpg http://www.life.illinois.edu/ib/109/Insect%20rearing/photos/millipede.jpg

Subphylum Hexapoda “Hexa” = six (3 pairs of legs?) Mouthparts project from head Most have wings capable of flight Most have 1 pair of antennae 3 tagmata: head, thorax, and abdomen Brain = ganglion (some capable of learning/memory) Compound eyes (as well as other sensory structures) Molting with metamorphosis Tracheal system for gas exchange Blood is not used for gas transport! Complex mating behaviors= high reproductive potential Some insects are social