1. Introduction to Arthropods
The Arthropods
Introduction to Arthropods

2. Introduction over one million species
most abundant of all visible animals
live virtually everywhere
can destroy crops and transmit diseases
can produce valuable things like wax, honey, drugs, and silk
help maintain crops by assisting in cross-fertilization
control numbers of harmful arthropods
engineers have improved machines by studying their design

3. Characteristics exoskeleton (protection and support)
triple layer secreted by epidermis
outer layer of proteins repels water and prevents water loss
middle layer consists of protein and chitin
inner layer similar to middle but provides more flexibility at the joints
molts
jointed appendages
means of defense, sensory reception, chewing food, sexual reproduction

4. Characteristics
body segmentation
head
thorax
abdomen
cephalothorax

5. Characteristics open circulatory system (depends on gravity)
dorsal heart
ventral nervous system
antennae
sensory bristles
eyes
compound (common)
simple

6. Classification 4 Subphylum Trilobita (extinct) Crustacea Chelicerata
Uniramia
20 Classes
primary characteristics that separate the groups are
body division
number and kinds of appendages
means of respiration

7. Subphylum Crustacea
lobsters, crayfish, shrimp, crabs, pill bugs, barnacles

8. Life Processes
of the crayfish

9. Life Processes: Crayfish
movement
muscles
legs
swimmerets
flipper-like appendages
four pairs of walking legs

10. Life Processes: Crayfish
scavengers
nutrition
ingestion
digestion
esophagus, anterior portion of stomach
gastric mill
posterior portion of stomach
digestive glands
intestine, anus

11. Life Processes: Crayfish
respiratory
two sets of feathery gills
gills allowed for flow of oxygenated water
can store water for walking on land
circulation
open system
pericardial sinus (stores blood, surrounds heart)
dorsal heart
sternal sinus (passes blood to gills)
excretion
green glands filter out waste
fluid excreted through a pore anterior to the mouth

12. Life Processes: Crayfish
heart
pericardial sinus
sternal sinus

13. Life Processes: Crayfish
green gland

14. Life Processes: Crayfish
response
ventral nervous system
sensory organs
compound eyes
antennae & antennules
tiny bristles
statocyst (organ of balance)

15. Life Processes: Crayfish
reproduction
regeneration for repair only
sexual with separate sexes
mate in the fall, female stores sperm until spring when she lays eggs
“in berry”
molting (seven times during the 1st year)

16. Subphylum Chelicerata
“claw”

17. Subphylum Chelicerata
Class Arachnida
spiders, scorpions, ticks, mites

18. Class Arachnida (most recognized)
Characteristics that distinguish them from the insects
four pairs of walking legs
two body parts
cephalothorax
abdomen
no antennae or mandibles

19. Class Arachnida respiration through book lungs
usually four pairs of simple eyes
book lungs

20. Spiders largest and most familiar group in the class
six pairs of appendages (no antennae)
chelicerae
poisonous fangs
pedipalps
sensory reception
transfer of sperm in male

21. Spiders silk production spinnerets uses capturing food
reproductive purposes

22. Spiders separate sexes female often larger
male transfers sperm to ventral surface of female
some type of “courtship” like offering of food
some females eat male after mating

23. Spiders black widow brown recluse tarantulas other arachnids scorpion
mites
ticks

24. The word root “-poda” means
head.
foot.
flat.
pore.
BJU PressArt, biology textbook, pp. 369

25. The exoskeleton of the arthropods is made up of
cellulose.
chitin.
bone.
lime.
BJU PressArt, biology textbook, pp. 369

26. The single exoskeletal plate that protects the cephalothorax is the
carapace.
mantle.
mandible.
gastric mill.

27. Chitinous teeth line the stomach of the crayfish and help to grind up food.
true
false

28. The respiratory organs of the crayfish are the
green glands.
gills.
lungs.
epidermis.

29. Although crayfish have an open circulatory system, some arthropods have a closed system.
true
false

30. The cavity that surrounds the heart of the crayfish is the
sternal sinus.
cardiac cavity.
pericardial sinus.
dorsal cavity.

31. The excretory organs of the crayfish that remove soluble wastes from the blood are the
green glands.
intestines.
kidneys.
anus.

32. A sac that helps the crayfish keep its balance is the
ganglion.
brain.
antennule.
statocyst.

33. The crayfish can reproduce asexually.
true
false