1. Phylum Arthropoda
insects, spiders, scorpions, ticks, mites, centipedes, millipedes, and crustaceans
largest phylum in the animal kingdom; one million species recorded; est. > 30,000,000
mostly small; active (complex behaviors)
ecologically diverse & economically important

2. Positive Impacts food for humans pollinators decomposers
silk, wax, honey
predators & prey- integral part of the food web
bioindicators
biological control

3. Negative Impacts
competitors
pests
disease vectors
parasites
venomous

4. General Features eucoelomate, protostomes
exoskeleton - support; protective
water loss, mechanical injury, chemical injury, & UV barrier
made of chitin- polysaccharide similar to cellulose; strong & indigestible
protein, lipid, & CaCO3; water and gas impermeable
ecdysis - molting/shedding

5. Exoskeleton
epicuticle
procuticle
sclerotization
resilin

6. Metamerism
conspicuous segmentation
repetition of tissues & organs

7. Tagmatization segments fuse together into body parts: head
cephalothorax
thorax
abdomen

8. Arthropod Features (cont.)
jointed appendages: (specialization)
locomotion, sensation, & feeding
generally one pair/segment
complex muscular system
complete & complex digestive system

10. Circulation & Respiration
open circulatory system:
dorsal contractile heart
vessels
hemocoel
respiration:
body surface diffusion
trachae- respiratory exchange tubes; spiricles- external openings
gills & book lungs- folded epithelium covered by chitin

11. Nervous System nervous system: annelid-like
sensory system: well developed
compound eyes & ocelli
tympanum
tactile & chemo- receptors
statocysts

12. Excretory & Reproductive Systems
Excretion:
coxal glands- merostomata, arachnids
antennal glands-crustacea
maxillary glands-crustacea
reproduction:
dioecious
internal fertilization
oviparous, oviviparous viviparous
direct & indirect development
parthenogenesis

13. Sub-Phylum Trilobitamorpha: Class Trilobita
extinct; Paleozoic
benthic scavengers
segmented
compound eyes
biramous appendages

14. Trilobites

15. Trilobite Diversity

16. Biramous Appendages

17. Sub-phylum Chelicerata
eurypterids, horseshoe crabs, spiders, and ticks, and mites
no antennae or mandibles
chelicerae - tear food, venom injection, & secrete enzymes
(6) pair of appendages: pedipalps
predators/carnivores

18. Class Merostomata “Horseshoe Crabs”

19. Class Arachnida first terrestrial metazoans
spiders, scorpions, ticks, and mites

20. Order Aranae (spiders)
35,000 species
cephalothorax; no external segmentation;
pedipalps- appendages used to hold food; mating
silk: (prey capture, egg case, & ballooning)
book lungs, trachae or both

21. Spider Anatomy

22. Internal Structure

23. Venomous Species in North America

24. Day # 3

25. Day # 6

26. Day # 9

27. Day # 10

28. Order Scorpionida secretive; nocturnal mostly harmless
stinger on the telson
pectines
chelicera
chilipeds

29. Order Pseudoscorpiones

30. Order Acari (Acarina) mites & ticks reduced segmentation parasites
important disease vectors
Lyme Disease
Rocky Mtn. Spotted Fever
Ixodidae- hard ticks

31. Tick Hypostome

32. Parasitic Mites

33. Scabies