1. Arthropods Blue print for Success

2. Arthropod Characteristics Includes crayfish, lobsters, spiders, mites, scorpions, and insects Metamerism modified by the specialization of body regions for specific functions (tagmatization) Chitinous exoskeleton, support and protection Paired jointed appendages, ventral nervous system Growth accompanied by molting, metamorphosis open circulatory system, complete digestive tract

3. Exoskeleton Major reason for Arthropod success Provides structural support, protection, impermeable surfaces to prevent water loss, and a system of levers for attachment of muscles and movement Exoskeleton made of two layers -outer of waxy lipoprotein, prevents dehydration and impermeable to microorganisms -Inner of chitin, tough polysaccharide and protein Hardens by deposition of calcium carbonate Joints had to be incorporated with flexible membrane

4. Exoskeleton

7. Molting is necessary to permit growth, 4 steps -Enzymes secreted to separate exoskeleton from procuticle -New procuticle is secreted -Animal swells by air or water intake, old exoskeleton is split along ecdysal lines New exoskeleton hardens by addition on calcium carbonate, takes few hours to days and animal is vulnerable, remains hidden

8. Molting

10. molting

11. Exoskeleton

12. Arthropod Anatomy Hemocoel serves as a cavity for the open circulatory system, the rigid exoskeleton means the coelom is no longer a hydrostatic skeleton Internal organs are bathed in body fluids to exchange nutrients, wastes and sometimes gases Metamorphosis- radical change in body form from larva to adult, eliminates competition between larval and adult stages for food

13. Subphylum Trilobitomorpha Trilobite body has three longitudinal sections thus the name Dominant life form in the cambrian period 600 million years ago to 345 million years ago Body was oval, flattened and could roll into a ball for protection Appendages had two lobes Biramous, inner for walking and outer had spikes for digging

14. Trilobite

16. Trilobites

17. Subphylum Chelicerata Spiders, mites, ticks, horseshoe crabs and sea spiders Two Tagmata: cephalothorax- contains sensory, feeding and locomotion structures Opisthosoma- contains digestive, reproductive, excretory and respiratory organs First pair of appendages are pincerlike or chelate (claws) or specialized hollow fangs Pedipalps- second pair appendages, sensory or feeding, locomotion Third pair appendages walking legs

18. Class Arachnida Majority of spiders mites ticks and scorpions are harmless or beneficial to humans Sea scorpions dated to 425 million years ago and other arachnids date to 345 million years ago Most are carnivores, either pour or inject enzymes over prey and digested tissue is eaten or sucked in The front portion of the gut is modified into a pumping stomach, mid gut and hind gut complete digestion

19. Arachnid Anatomy Nitrogenous wastes are collected with coxal glands or malpighian tubules, both collect nitrogenous wastes from blood Coxal exit at bottom of posterior appendages Malpighian tubles deposit excretory wastes into gut tract and exit with digestive wastes Book lungs exchange gases thru lamella that air passes thru from ventral slit on abdomen Trachea are tubules which deliver air directly to body tissues exit thru side of abdomen

20. Order Araneae Spiders- largest order of Arachnids Chelicerae with poison glands and fangs Six to eight eyes Spinnerets- conical projections associated with silk glands Silk is a protein, different types produced for different sections of web Stronger than Kevlar (steel) Elastic Safety Line, Ballooning, wrap eggs

21. Spider Multiple Eyes, Setae

22. Spider

23. Order Acarina Mites and Ticks, many are ectoparasites, some free living terrestrial and aquatic Chelicerae and pedipalps are modified for piercing, biting, anchoring and sucking 4 pairs of walking legs (adults) Chiggers larva break down and suck host skin Dust mites (allergen), scabies tunnel under human skin Ticks transmit rocky mount. Spotted fever, lyme disease

24. Mite

25. Mite Infestations

26. Tick

27. Removing a tick

28. Ticks on wild Rabbit

29. Horseshoe Crab

30. Sea Spiders

31. Sea Spider

32. Sea Spiders

33. Order Scorpionida Range tropical to warm temperate areas Nocturnal and secretive Hide under logs, stones during day Chelicera- Jaws Chelate pedipalps- Claws Stinger at base of postabdomen (tail) Only a few toxic to humans in north Africa Mexico and southwest U.S., most sting like a wasp

34. Scorpion

35. Scorpion with Babies

36. Subphylum Crustacea Crayfish, shrimp, Lobster, crabs, copepods, cladocerans, fairy shrimp, isopods, amphipods and barnacles Two pairs of antennae and Biramous appendages Basal segment- endopodite medial ramus exopodite lateral ramus

37. Class Malacostraca Crabs, Lobster, Crayfish, shrimp, mysids, Krill, isopods and amphipods Class Decapoda crab, lobster shrimp Shrimp muscular abdomen for swimming Lobster, Crabs crawl on bottom Abdomen of crabs greatly reduced Cephalothorax- fusion of head and thorax, shield like Carapace

38. Maine Lobster

39. Florida Lobster

40. Ghost Crabs

42. King Crab

43. Crab Larva Zoea

44. Crayfish Anatomy

45. Appendages – 1 first Antennae, shorter 2 second antennae, longer Appendages 3 mandibles for chewing 4 maxillae food handling 5 maxillae food handling, small gill, blade called gill bailer for circulating water over gills Appendages 6-8 Maxillipeds sensory and food handling Appendages 9-13 peropods walking legs