1. The Cambrian Explosion

2. The Phylum Arthropoda The most successful animal group on earth
HOW DO THEY DO THAT?
1. Hard exoskeleton composed of chiton
2. Segmented body and specialized jointed appendages
3. Complex nervous & sensory system
4. Variety of respiratory organs
5. Complex innate and learned behaviors
6. Complex life cycle with metamorphosis

3. Segments of Arthropod Body Partitioned into Two or Three Tagmata
cephalothorax
abdomen
cephalothorax
head
thorax
abdomen

4. Arthropod Muscular System

5. Arthropod Respiratory Systems

6. Subphylum Trilobita Once abundant in ancient oceans
Extinct for over 200 million years

7. Subphylum Chelicerata
1. Two tagmata (cephalothorax and abdomen)
2. 6 pairs of appendages: chelicerae, pedipalps, 4 pairs walking legs (no antennae, no mandibles)
3. Respiration via book gills or book lungs

8. Class Merostomata: Horseshoe Crabs
1. cephalothorax completely covered with a large carapace
Long, spine-like telson
Book gills

9. Class Pycnogonida: Sea Spiders
1. Four pairs of long, thin walking legs (some males have one pair modified for carrying eggs = ovigers)
2. Proboscis for sucking juices from hydroids
3. Abdomen reduced or absent

10. spiders, scorpions, mites, ticks
Class Arachnida
spiders, scorpions, mites, ticks
1. cephalothorax partially or completely covered with a carapace-like shield
2. Abdominal appendages (if present) modified into spinnerets (spiders) or pectines (scorpions)

11. Class Arachnida Order Araneae - Spiders
Cephalothorax and abdomen joined by narrow pedicel
Chelicera function as fangs and connect to poison glands
Breathe using book lungs and/or tracheae
Have 8 pairs of simple eyes
Have silk glands and spinnerets

12. Class Arachnida Order Araneae - Spiders
Cephalothorax and abdomen joined by narrow pedicel
Chelicera function as fangs and connect to poison glands
Breathe using book lungs and/or tracheae
Have 8 pairs of simple eyes
Have silk glands and spinnerets

13. Brown Recluse Spider

14. Class Arachnida Order Araneae - Spiders
Cephalothorax and abdomen joined by narrow pedicel
Chelicera function as fangs and connect to poison glands
Breathe using book lungs and/or tracheae
Have 8 pairs of simple eyes
Have silk glands and spinnerets

15. Multiple Pairs of Eyes
Spinnerets

16. Class Arachnida Order Scorpionida - Scorpions
Modified abdominal appendage (pectine)
Order Opiliones - Harvestmen
Chelicera modified into pincer-like appendages
Order Acari - Ticks and Mites
Mouthparts on anterior projection (capitulum)
Transmit a wide variety of diseases

17. Subphylum Myriapoda (millipedes, centipedes)
Uniramous (unbranched) appendages
Paired appendages on most/all segments
Body of two tagmata (head & trunk)
One pair of antennae, mandibles, maxillae
Respiration via tracheae and spiracles

18. Class Chilopoda: Centipedes
one pair legs per segment
appendages of 1st body segment modified to form poisonous fangs
predatory

19. Class Diplopoda: Millipedes
two pair legs per segment
hatch with 3 pairs of legs
herbivores or scavengers
unique defensive behavior

20. Subphylum Crustacea Mostly marine, some freshwater
Three tagmata (head, thorax, abdomen)
2 pr antennae, 1 pr mandibles, 2 pr maxillae
Biramous, highly specialized appendages
Respiration via gills

21. Biramous Specialized Appendages

22. Stalked Compound Eye

23. Simple vs. Compound Eye Compound Eye Simple Eye Camera Eye
Concave Mirror Eye
Pinhole Eye
1. Light enters transparent cuticle
2. Crystalline cone
3. Light sensitive cells stimulated
4. Nerve impulses fired off to brain
Compound Eye

24. Ecdysis Have to molt to grow Under hormonal control
1. Epidermis secretes new cuticle under old cuticle
2. Dissolves and resorbs calcium to weaken the old cuticle
3. Splits old cuticle and discards
4. Absorbs water to swell body
5. Hardens new shell
6. Reestablishes osmotic balance

25. Crustacean Reproduction
Aquatic larval stages: nauplius and zoea
Molt through many intermediate larval stages
Separate sexes with sexual dimorphism

26. Oligostraca bivalve carapace completely encloses body
Ostracoda, Branchiura, Pentastomida
bivalve carapace completely encloses body

27. Pentastomida parasite of carnivorous vertebrates
Four claw-like appendages
Chitinous cuticle
Extensive parasitic modifications make phylogeny difficult

28. Branchiopoda, Copepoda, Thecostraca, Malacostraca
Vericrustacea
Branchiopoda, Copepoda, Thecostraca, Malacostraca

29. Branchiopoda
Diplostraca (cladocerans), Anostraca (fairy shrimp), Notostraca (tadpole shrimp)
bivalved carapace or no carapace
no abdominal appendages

30. Malacostraca isopods, amphipods, euphausids, decapods
All thoracic and most abdominal segments bear specialized appendages
Gills occur along the bases of thoracic appendages

31. Kiwa hirsuta

32. Subphylum Hexapoda (entognatha, insects)
Uniramous (unbranched) appendages
Body of three tagmata
One pair of antennae, mandibles, maxillae
Respiration via tracheae and spiracles

33. Class Insecta: Insects
Body composed of three tagmata
(head, thorax, abdomen)
One pair of large compound eyes and multiple ocelli
One pair of antennae
Three pairs of walking legs
Two pairs of wings one may be reduced = halteres

34. Wingless insects Winged insects some species lack tracheae
direct development
all have tracheae
metamorphic development

35. Insect Respiratory System
Tracheoles
Air sacs
Tracheae
Spiracles

36. Insect Excretory System

37. Insect Flight direct muscle system indirect muscle system
muscles to raise wings
muscles to lower wings
direct muscle system
longitudinal muscles
dorsoventral muscles
indirect muscle system

38. Complete metamorphosis
egg 
larva
pupa
adult

39. Modifications of Mouthparts
mouthparts modified for piercing/sucking
mouthparts modified for chewing plant material
mouthparts modified for grabbing
mouthparts modified into a long proboscis

40. Complex Behaviors
nocturnal swarming

41. Social Systems
queen worker drone

42. 1. Subphylum Trilobitomorpha
2. Subphylum Chelicerata
a. Class Merostomata - horseshoe crabs
b. Class Pycnogonida - sea spiders
c. Class Arachnida – spiders, scorpions, ticks, mites
3. Subphylum Crustacea
Class Branchiopoda - cladocerans, brine shrimp
Class Maxillopoda - ostracods, copepods, barnacles
c. Class Malacostraca - isopods, shrimps, crabs, lobsters
4. Uniramia Subphylum Myriopoda
a. Class Diplopoda - millipedes
b. Class Chilopoda - centipedes
5. Uniramia Subphylum Hexapoda
Class Insecta – insects
Class Entognatha – spring tails, bristletails, proturans