“jointed foot” Insects, centipedes, millipedes, spiders, and crustaceans

1. “jointed foot” Insects, centipedes, millipedes, spiders, and crustaceans

2. Most extensive phyla

4. Population density • 1x1019 individuals (insect) • = 10 quintillion individuals • =10 million millionmillion

5. Arthropod Diversity • 1,004,898 described species as of 2009 • (Footit & Adler) • True estimates most likely 5 million species (Erwin 1982) • 1 million described • 4 million undescribed

6. Why have arthropods achieved such great diversity and abundance? • Small size • Less energy requirement • Habitats/ niches • Flight (some individuals) • Escape/dispersal • Cuticle • Protective/ efficient attachment for muscles • (more muscle mass per unit body mass) • Highly organized/ effective sensory neuro-motor system • Recognize integrate and respond to external and internal signals • High reproductive capacity • Differentiated stages • Larva vs adult

7. General Characteristics • Jointed legs • Eucoelomate • Protostome • Exoskeleton • Chitin • Feeding • Carnivorous • Herbivorous • Omnivorous • Habitat • Air • Land • Freshwater • Marine • Parasitic (endo and exo) • Size • >0.1mm to 4 m

8. Tagma- groups of fused segments 2 Tagma Cephalothorax Opistosoma

9. Tagma- groups of fused segments 3Tagma Head Thorax Abdomen

10. Phylum Arthropoda • Subphylum Chelicerata • Class Merostomata • Class Arachnida • Subphylum Crustacea • Subphylum Uniramia • Class Chilopoda • Class Diploda • Class Insecta

11. Subphylum Chelicerata • 6 pairs of cephalothoracic appendages • Chelicerae (1 pair) • Pedipalps (1 pair) • Walking legs (4 pair) • No antenna • Two classes • Class Merostomata • Horseshoe crab • Class Arachnida • Spiders, scorpions, ticks and mites

12. Mandibulates • Characteristics • Mouthparts are mandibles • One or two pairs of antennae • 3 tagma • Head • Thorax • Abdomen • Variable leg numbers • Insects, crustaceans, and myriapods

13. Class Merostomata

14. Class Arachnida • Spiders • Scorpions • Whip scorpions • Ticks • Mites • Harvestmen

15. Araneae: Spiders • Respiration • Book lungs • Parallel air pockets extending into a blood filled chamber • Trachea • Air tubes connecting the outside directly to the blood

16. Excretion • Malphighian tubules • Uric acid

17. Sensory • Simple (poor vision movement not shapes) • Cuticular mechanoreceptors (sense vibrations/ air movements) • Sensory setae • Trichobothria • Slit sense organs

18. Web spinning • Spinnerets/ silk glands • Scleroprotein (liquid but hardens as a result of being pulled) • Strong and stretchy • Stronger than steel but will stretch 1/5 their length before breaking

19. Reproduction • Male spins web to drop sperm in, gathers it with his pedipalps and carries it to the females genital opening (lock and key) • Female lays eggs in a net (cocoon), she may carry it or attach it to a plant

20. Venom • Largely harmless to people (2 exceptions) • Black widdowLatrodectusdectes • 4 to 5 out of 1000 bites are fatal • Brown Recluse Loxoscelesskelos • 0 proven fatalities , most bite heal on their own, 10% cause tissue damage warranting medical attention. • Neurotoxin • Disrupt nerve impulses • Hemalytic toxin • Destroys blood cells and linings of capillaries

21. Mandibulates • 2 groups • Subphylum Crustacea • Subphylum Uniramia

22. Subphylum Crustacea • Characteristics • Marine, fresh water and terrestrial • Two pair of antennae • Five or more pairs of legs • Biramious (two main branches) • Gills

23. Internal Features • Hemocoel • Blood-filled body space • Muscular system • Antagonistic arrangement • Extensors- draw parts away from the body • Flexors- draw parts towards the body

24. Circulatory System • Open circulatory system • No veins • No separation of blood from intestinal fluid • Blood leaves the heart by way of the arteries, circulates through the hemocoel, and returns to venous sinuses or spaces before it reenters the heart

25. Respiratory system • Small • Gas exchange occurs over thin areas of the cuticle or the entire body • Large • Feather like gills

26. Excretory system • No malpighian tubules • “green glands” • Pair of tubular structures located in the ventral part of their head next to the esophagus • Excretion of nitrogenous wastes (ammonia) takes place across the cuticle

27. Nervous system • Fused ganglia (brain-ish) • Supraesophageal ganglia • Eyes and antennae • Subesophageal ganglia • Mouth and appendages • 2 ventral nerve chords • Sensory system • Eyes • Compound (ommatidia) • Tactile hairs

28. Reproduction • Dioecious • Parthenogenic • Female lays unfertilized eggs which develop into young • Metamorphosis • Ecdyis • Shedding of the cuticle • Controlled by hormomes and external conditions

29. Classes • Class Remipedia • Class Cephalocarida • Class Branchiopoda • Class Ostracoda • Class Maxillopoda • Class Malacostraca • Sowbugs- pillbugs • Sand fleas • Barnacles • Crabs, lobster, shrimp

30. Subphylum Uniramia • 2 groups • Insects • Myriapods (centipedes and millipedes) • Many foot • Mostly terrestrial • Very few aquatic (freshwater) • One pair of antennae • Appendages uniramous (one)

31. Myriapods • Many legged arthropods • All have one pair of antennae • Use trachea • Classes • Diploda • Millipedes • Chilopoda • centipedes

32. Class Chilopoda • Centipedes • Flattened bodies • 1 pair of legs per metamere (segment) • 1 spiracle per metamere • 15-177 segments • Poisonous • Viviparious – (live birth) • Carnivorous • Cockroaches & other insects • Earthworms

33. Class Diploda • Millipedes • 2 pairs of legs per metamere • 2 spiracles per metamere • 25-100 segments • Harmless • Herbivorous • Repugnatorial glands

34. Class Insecta • 3 pairs of legs • 3 tagma • Head • Thorax • Abdomen • Distribution • Every continent except Antarctica • High level of adaptability and specificity

35. External Anatomy • Sclerites- system of plates which comprise the exoskeleton

36. Movement • Walking • Triangle legs/ tripod gait • Flight • Only invertebrates that can fly • Wings composed of cuticle • Most have 2 pair • Flies 1 pair + halteres • Direct flight muscles • Attach to the wing • Indirect flight muscles • Attach to the cuticle

37. Nutrition • Digestive system • Foregut • Mouth- gizzard (proventriculus) • Cuticle lined • Midgut • Stomach and gastric ceca • Hindgut • Intestine-anus • Cuticle lined

38. Feeding • Phytophagous/ herbivorous • Feeding on plants • Saprophagous • Feeding on dead animals • Detrivorous • Feeding on dead material • Predaceous • Parasitic • Hyperparasitism • Parasitoids

39. Circulation • Open circulatory system • Hemolymph (blood) • Tubular heart • Limited oxygen transport

40. Gas exchange • Tracheal system • Extensive network of thin-walled tubes that branch to every part of the body

41. Reproduction • Dioecious • Strategies • Viviparious • Live birth • Parthenogenic • Growth and development of young without fertilization • Oviparious • Young develop from eggs laid outside the body • Ovoviparious • Young develop from eggs held within the female

42. Metamorphosis • 3 types • Holometabolous“complete” • Egg, larvae, pupae, adult • Hemimetabolous “incomplete” • Egg, nymph, adult • Ametabolous “no” • Direct development

44. Nervous system • Sense organs • Keen sense perception • Mechanoreception • Sensilla • Auditory reception • Setae/sensilla • Tympanic membrane • Chemoreception(taste or smell) • Mouthparts • Vision • 2 types of eyes • Simple (ocelli) • Compound (made of ommatidia)

45. Defense • Mimicry • Imitation of a noxious/dangerous species by coloration • Crypsis • Camouflage • Chemical defense

46. Insects and human welfare • Negative • Crop damage and loss • 75% loss pre pesticide • Disease • Malaria- kills 1.2 million people annually • Positive • Predaceous insects • Food production • Pollination • Efficient protein source

48. Insect Orders

49. Ephemeroptera • Mayflies

50. Odonata • Dragonfly • “Tooth wing”