1. Are arthropods good or bad
Are arthropods good or bad? Provide 4 pieces of specific evidence to support your answer

2. Subphylum Chelicerata
Kingdom Animalia
Phylum Arthropoda
Subphylum Chelicerata
Subphylum Crustacea
Lobster
Crab
Shrimp
Crayfish
Barnacles
Isopods
Class Merostomata
Horseshoe crab
Class Arachnida
spiders
Subphylum Uniramia
Class Chilopoda
centipedes
Class Hexapoda
insects
Class Diplopoda
millipedes

3. SUBPHYLUM
CHELICERATA

4. General Characteristics
Two body regions
a. Cephalothorax- sensory, feeding, locomotion, eyes
b. Abdomen- digestion, reproduction, excretion, respiration

5. 2. Paired Appendages
a. Chelicerae- first pair, pincer-like, feeding/fangs
b. Pedipalps- second pair, sensing, feeding, reproduction
3. No antennae
4. 8 walking legs

6. II. Class Merostomata Horseshoe crabs All marine
Diet- annelids, mollusks,
other inverts.
3. Horseshoe shaped body
4. Have compound eyes &
simple eyes.
5. Telson- tail; used to flip over
6. Book gills for respiration

7. 7. Dioecious- male fertilizes eggs as female sheds them into a shallow hole. No brooding occurs.

8. Compound eye
Horseshoe crab vision

9. Class Arachnida
EX: Spiders, mites, ticks, scorpions

10. Digestion/Feeding
Inject venom into prey which paralyzes & begins digesting organs of prey.
Partially digested food sucked into mouth via foregut (sucking stomach)
Food passed to
Intestine- enzyme secretion & absorption of food
Stercoral pocket- water gets reabsorbed from stored feces

11. Excretion Malpighian tubules- send waste to stercoral pocket
Water reabsorbed
Wastes excreted with digestive wastes as semisolid uric acid
** Water conservation is a major concern for many terrestrial animals. Most wastes excreted in solid form to prevent water loss.

12. Respiration
O2 and CO2 exchange in a book lung- series of folded membranes exposed to blood.

13. Circulation Open circulation
Dorsal aorta pumps blood to sinuses around organs
Blood returns to aorta thru holes in heart called ostia
Blood contains hemocyanin (blue)- does not carry oxygen as well as human blood
Hemocyanin more important for “blood clotting” when limb lost.

14. Nervous/Sensory Brain & ventral nerve cord
Setae- hair-like, can detect vibrations/motion
Chemoreceptors in exoskeleton to detect pheromones, smells in environment.

15. Nervous/Sensory 4. 6-8 Simple eyes- sense light & movement
Classified into families based on eye number & position
Hunting spiders have larger, complex eyes
Web spinning spiders have smaller, simpler eyes

16. Reproduction jumping spider dance Dioecious Spiders attract mates by:
Pheromones- chemicals given off by one to evoke a response in another.
Tactile Senses- males pluck strands of female web
Species specific “plucking”
Prevents male from becoming female’s next meal
Visual signals- “dancing”
jumping spider dance

17. Reproduction Males use enlarged pedipalp to transfer sperm to female
Females can deposit 3000 eggs in one silk sac!
Females may take care of young during & after development
Some spiderlings practice ballooning- let out silk line that acts as “parachute” to distribute young spiderling to new habitat- reduces competition among spiderlings.

18. Spider Adaptations Silk gland- produces silk (protein)
Spinnerets- spin silk which hardens when it hits the air.
Silk used to make webs, egg sacs, line a nest/retreat, ballooning.
All spiders have silk glands, not all make webs!
Have oil on feet that keep them from sticking to silk.
All spiders are venomous, only two toxic to humans

19. Dangerous Spiders of United States
a. Black widow- shiny black w/red hour glass on ventral surface of abdomen.
male
Female
Enlarged pedipalps

20. b. Brown Recluse- violin shape on cephalothorax

23. Scorpions
a. Nocturnal
b. Venom gland & stinger in tail
c. Modified pedipalps- pincers for grasping food/defense

24. d. Courtship dance where male “lays” sperm
d. Courtship dance where male “lays” sperm case and female “sits” on case to pick up sperm
e young brooded by mother on her back for about 1 month

25. Mites- 1mm or less in size
a. Many are ectoparasitic- feeding on blood or tissue
b. Some permanent (follicle mite)
c. Some temporary (chigger)

26. Ticks- up to 3cm in length
a. All ectoparasites.
b. Bodies expand as they feed.
c. Breeding occurs on host.
d. Female drops off & lays eggs.
e. Can carry disease.

27. Economic/Environmental Significance
a. Carry/cause disease
1. Rocky Mountain Spotted Fever- ticks
2. Lyme’s Disease- ticks

28. Control insect populations
Venom & silk may have medicinal value.
Mites eat dead skin cells on body.
Spider mites (& others) can kill plants/crops.

29. Brown Recluse

30. Day 1

35. Day 10

36. Myth: Daddy long legs are the most venomous
Myth: Daddy long legs are the most venomous spiders in the world but lack mouthparts to inject venom.
Truth:
Daddy longlegs (harvestmen) are not spiders.
Do not make silk & do not have venom glands.
Have “claw-like” fingers.
Produce smelly fluid when disturbed.

38. Unit 4C Journal#2 11/1
Differentiate between pleopods and periopods in a crayfish.
Please turn in Crayfish Dissection Lab if you haven’t already done so.

39. Journal Choose one of the questions below to answer:
How are hunting spiders different from web spinning spiders?
What are the main traits that all chelicerates share?