1. BiologyUnit 25 Arthropods

2. KEY CONCEPT Arthropods are the most diverse of all animals.

3. Arthropod features are highly adapted. Arthropods are invertebrates that share several features. exoskeleton (cuticle) made of chitin jointed appendages segmented body parts

5. Chelicerates—specialized daggerlike mouthparts

6. Insects—most live on land, have six legs

7. Myriapods—long bodies and many pairs of legs

8. Arthropod exoskeletons serve a variety of functions. Joints are made of stiff and flexible cuticle to allow movement. The exoskeleton is made of many layers of chitin. hard material that protects the body must be shed in order to grow

10. Sensory organs such as antennae are made of modified cuticle.

13. body segmentation similar to annelids

14. molecular evidence suggests segmentation is analogous development

17. Crustacean appendages can take many forms. Crustacean appendages are used for a variety of functions. collecting and manipulating food attracting females protection

21. Arachnids are the largest group of chelicerates. There are three major groups of chelicerates. horseshoe crabs

23. horseshoe crabs

24. sea spiders

26. no antennae

27. four pairs of walking legs

28. one pair each of chelicerae and pedipalps

29. Arachnids are a group of chelicerates that live on land.

30. eight legs

31. fanglike pincersthat inject venom

33. waterproof cuticle

34. book lungs

35. Malpighian tubules

38. thorax head abdomen Insects are the dominant terrestrial arthropods. Insects are in nearly every ecological niche. Insects have a body with three parts. head thorax abdomen

41. There are three life stages of incomplete metamorphosis.

42. egg

43. larva

44. pupa

48. Arthropods and humans share many of the same resources. Many arthropods are herbivores that eat plants humans also depend on. Arthropods cause millions of dollars of crop damage. Insecticides have unwanted side effects.

50. arthropod-specific insecticides

51. integrated pest management (IPM)

54. Bubonic plague is caused by a bacterium carried by fleas.

55. Yellow fever is caused by a virus carried by mosquitoes.

56. Malaria is caused by a protozoan parasite carried by mosquitoes. It is the world’s most deadly disease.

57. West Nile virus is caused by a virus carried by mosquitoes.

58. African sleeping sickness carried by tsetse fly