1. 30.5 Arthropods

3. Overview Phylum Arthropoda +1 million species
Are protostomes and coelomates

4. Body Structure Freely movable jointed appendages
Exoskeleton made of chitin
Protection, muscle
attachment, locomotion,
prevention of dessication

5. Molting: shedding of exoskeleton Body secretes new/larger exoskeleton
Starts off soft/wrinkled, then hardens
Segmented, but some fused into regions
Head, thorax, cephalothorax, abdomen
Appendages specialized for function
Reproduction, eating, sensory reception

7. Nervous System Well-developed nervous system Sense organs
Brain and ventral solid nerve cord
Sense organs
Antennae
2 types of eyes (simple and compound)

9. Compound Eye
Made of several visual units (operate independently)
Focuses image --> results in eye sight that's good for tracking movement

10. Crustaceans

11. Habitat Marine Barnacles, shrimps, crabs, lobsters Freshwater Crayfish
Terrestrial
Sow bug (roly poly bug)

13. Body Structure Exoskeleton
Head generally has 1 pair of compound eyes and 5 pairs of appendages
Antennae – 1st two pairs, sensory functions
Other 3 pairs are mouthparts, used for feeding
2 body regions: cephalothorax and abdomen

15. Crayfish Thorax has 5 pairs of walking legs Gills above walking legs
1st – pinching claw
Gills above walking legs
Cephalothorax covered by carapace
Abdominal segments
Swimmerets
Final 2 segments – uropods and telson

17. Feeding and digestion
Divided stomach – one end grinds, the other filters
Green glands on head region excrete metabolic wastes
Coelom reduced to space around reproductive system

18. Circulatory system Heart in pericardial cavity
Blood carries respiratory pigment hemocyanin
pumped to hemocoel (made of sinuses)
Hemolymph flows into organs
Open circulatory system

20. Nervous system Crayfish similar to earthworm
Brain and ventral nerve cord
Ganglia with paired lateral nerves

22. Reproduction Separate sexes Males Gonads ventral to pericardial cavity
Coiled sperm duct at base of fifth walking leg
Sperm transfer completed by first 2 pairs of swimmerets

23. Females
Ovaries open at bases of 3rd walking legs
Seminal receptacle between fourth and fifth walking legs
Eggs attach to swimmerets of female

24. Insects

26. Body Structure Head, thorax, abdomen
Head has pair of sensory antennae, pair of compound eyes, several simple eyes
Mouthparts adapted to lifestyle

28. Abdomen holds most internal organs
Thorax has 3 pairs of legs and wings (1 or 2 pairs, or none)
Exoskeleton lighter and contains less chitin

29. Grasshopper 3rd pair of legs for jumping 2 pairs of wings
Forewings tough/leathery
Broad, thin hindwings
(Lateral surface) 1st abdominal segment has tympanum for sound waves

30. Posterior region has 2 pairs of projections
Female
Posterior region has 2 pairs of projections
Form ovipositor, which digs hole where eggs are laid

32. Feeding and Digestive System
System suited for herbivorous diet
Mouth chews food --> temporary storage in crop --> passed to gastric mill (finely ground) --> nutrients absorbed into hemocoel --> stomach --> intestine --> rectum --> anus

34. Excretory System
Malpighian Tubules: extend into hemocoel and collect nitrogenous wastes
Forms solid nitrogenous waste (Uric acid), conserving water

36. Respiratory System Spiracles: openings in exoskeleton
Air enters trachae
Branch until they end intracellularly
Air pumped by alternating contraction/relaxation of body wall through bladder-like structures (attached to trachae near spiracles)
Air enters anterior 4 spiracles and exits posterior 6 spiracles

37. Circulatory system
Slender, tubular heart (lies against dorsal wall of abdominal exoskeleton)
Pumps hemolymph into aorta, leading to hemocoel
Circulates then returns to heart

39. Reproduction Male has penis
Sperm passed to female and stored in seminal receptacle
Internal fertilization prevents gametes/zygotes from drying out
Fertilized eggs deposited in ground with ovipositor

40. Metamorphosis: change in form/physiology occurring as larvae (immature stage) becomes an adult
Gradual Metamorphosis: gradual change in form as they mature
Immature insect called a nymph

42. Complete Metamorphosis: drastic changes in form
Begins a worm-like larva (caterpillar), then a case (cocoon), and finally becomes an adult
Larvae and adults have different food sources

44. Comparison to crayfish

45. Crayfish
Gills
Oxygen carrying pigment in blood
Excretes liquid nitrogenous waste (ammonia)
Use uropods when swimming
Grasshopper
Trachae
No pigment
Excretes soild nitrogenous waste (Uric acid)
Tympanum
Penis that passes sperm
Legs for hopping
Wings for flying

46. Terrestrial spiders, scorpions, ticks, and mites
Arachnids
Terrestrial spiders, scorpions, ticks, and mites

47. Body structure Cephalothorax has 6 pairs of appendages
Chelicerae
Pedipalps
4 pairs of walking legs
Thorax contains internal organs

49. Scorpions Oldest terrestrial Arthropods
Live in tropics, subtropics, and temperate regions
Nocturnal
Pedipalps are long pincers, long abdomen ends with stinger

51. Ticks and Mites Parasites Suck blood of hosts
Spread diseases like spotted fever or lyme disease

52. Spiders Narrow waist separates cephalothorax and abdomen
Chelicerae have a fang that delivers venom
Pedipalps assist in sensing or holding prey
Digestive juices liquefy tissues, gets sucked into stomach
Silk threads using for nesting and catching prey

54. Inner body wall form lamellae – known as book lungs
Malpighian tubes work with rectal glands to reabsorb ions and water (prior to Uric acid excretion)
Inner body wall form lamellae – known as book lungs
Air flows into one side of lamellae and exchange gases with blood flowing in opposite direction