1. Chapter 28 Arthropods and Echinoderms

2. Arthropods “organism with a tough exoskeleton, jointed appendages and a segmented body”

3. Learning Targets 28.1 • Identify the defining features of arthropods. • Describe the important trends in arthropod evolution. • Explain growth and development of arthropods

4. Exoskeleton • Exoskeleton made of chitin (a carbohydrate) • Can be tough and hard or soft and leathery

5. Tick Tough Exoskeleton

6. Spiny Lobster Tough Exoskeleton

7. Emperor gum mouth Catepillar Flexible, leathery exoskeleton

8. Some have dozens of segments while others have only 3 • Tough exoskeleton requires joints between segments and appendages to move

9. Feeding • Display all types • Mouthparts are modified to fit feeding behavior

10. Praying Mantis Carnivore

11. Lubber Grasshopper Herbivore

12. Respiration • Aquatic arthropods use gills • Horseshoe crabs use book gills • Spiders use book lungs • Terrestrial arthropods use tracheal tubes (supplies O2 by diffusion-muscles contract tube)

13. Book Gills/Lungs • Several sheets of tissue are layered like pages in a book (increases SA)

14. Internal Transport • Open circulatory system • Blood travels through heart to arteries to smaller vessels to sinuses and back to heart

15. Excretion • Terrestrial - excrete N waste through malpighian tubes (remove waste from blood and add to feces) • Aquatic - N waste removed by diffusion across gill surfaces • Some have glands near antenna

16. Diamond Beetle uses Malpighian tubes

17. Hermit Crab uses gills

18. Response • Well developed nervous system (All arthropods have a brain) • Large compound eyes (may have more that 2000 separate lenses!) • Some smell w/ antennae and use hair on legs to taste • Well developed hearing (ears in strange places like behind leg)

19. Compound eye Horsefly

20. Harlequin beetle long antennae as feelers

21. Stick grasshopper camoflauge Hoverfly Mimics bee Caterpillar markings as trick

22. Movement • Use well developed muscular system that is controlled by its nervous system which pulls and pushes against exoskeleton

24. Reproduction • Terrestrial arthropods have internal fertilization • Some Aquatic arthropods have external fertilization

25. Growth and Development • Tough exoskeleton protects but does not grow and must be shed (suit of armor) • Molting – arthropod sheds entire exoskeleton and produces larger one • (most molting involves metamorphosis which uses molting hormone) • Digests and eats/new skeleton is soft for up to a day

27. 2 Types of Development • Complete • Incomplete

29. Complete Metamorphosis • 4 stages – egg, larva, pupa and adult • Involves interaction b/t molting hormone and juvenile hormone

30. Incomplete metamorphosis • Young look like adults without wings or sex organs • Gain these through gradual molts

31. 28-2 A tour of Arthropods “Trilobites, Chelicerates, Crustaceans and Uniramians”

32. Learning Targets 28.2 • Explain how arthropods are classified • Identify the distinguishing features of the three subphyla of arthropods.

33. Trilobites • Chelicerae • Class Merostomata • Horseshoe Crabs • Class Arachnida • Spiders • Mites and Ticks • Scorpions • Crustacea • Uniramians • Centipedes • Millipedes • Insects

34. I. Trilobites • Now extinct • Hundreds of lenses in eye • Divided into many segments each with a walking leg.

35. II. Chelicerates • Chelicerates have mouthparts called chelicerae and two body sections and nearly all have four pairs of legs. • Ex) Horseshoe crabs, spiders, ticks and scorpions

36. 2 part body • 1) Cephalothorax (contains legs, brain, mouth, eyes) • 2) abdomen (most of internal organs) • Specialized mouth parts = chelicerates and pedipalps • No antennae found in other arthropods

37. Used to grab prey Contain fangs which are used to stab and paralyze prey

38. Class MeristomataI. Horseshoe crab (Not so much a crab at all!) • Not dangerous • Tail for plowing through sand • Lysate in blood is used to test purity of medicines

39. B. Class Arachnida • Spiders, mites, ticks, scorpions, and daddy long legs • 4 pair of walking legs on cephalothorax • In addition they have chelicerae (sucking and biting) and pedipalps (holding prey)

40. 1. Spiders • All are carnivores • Capture prey by pouncing or spinning webs with spinnerets (on abdomen) • Usually feed on insects (chelicerae-paralyzing venom-enzymes digest-suck) • Produce protein - silk

41. Interesting facts about spiders webs: • Whether or not they spin webs they produce silk • Spider silk is stronger than steel. • Web spinning spiders can spin webs almost as soon as they hatch!

44. Sydney funnel web spider

45. The Brown recluse “The culprit”

46. “The effects” Day 3

47. Day 4

48. Day 5

49. Day 6

50. Day 9