1. Phylum Arthropoda
The Bugs

2. Phylum Arthropoda Diversity Divided into Subphyla and Classes:
about 80% of all animals are arthropods
in virtually every habitat: marine, terrestrial, freshwater, and aerial habitats.
Divided into Subphyla and Classes:
Subphyla Trilobita (extinct)
Subphyla Chelicerata
Subphyla Uniramai
Subphyla Crustacea

3. General Characteristics
Hard exoskeleton composed of proteins (ex. Chitin)
Allows for great variation in function - biological "swiss army knives"
Must molt as they grow (Ecdysis)
Limits their size
Well developed body segments and jointed appendages
Well developed sensory organs including nervous system (brain), true eyes, and antennae
Open circulatory systems & gas exchange organs
Exhibit bilateral symmetry

4. General Characteristics
Reproduction (sexual):
Marine arthropods fertilize internally or externally
Terrestrial arthropods always fertilize internally
Pedipalps amd gonopods can be used to introduce sperm into the female
Some arthropods create a spermatophore (sac of sperm) and leave it behind for the female to collect
Some arthropods copulate in order to reproduce

5. Could this be possible?

6. Phylum Arthropoda, Subphylum Chelicerata (arachnids, horseshoe crabs & sea spiders)
3 Classes:
Class Arachnida
Class Merostomata
Class Pycnogonida

7. Subphylum Chelicerata (arachnids, horseshoe crabs & sea spiders)
Body divided into 2 regions
Abdomen
Cephalothorax (fused head & thorax)
Lack jaws
No antennae
Have 6 pairs of appendages
First appendages form chelicerae (frequently fangs)
Second pair form pedipalps
4 pairs of jointed legs

8. Subphylum Chelicerata, Class Arachnida (Spiders, Scorpions, Ticks & Mites)
Very diverse class
Most species parasitic or predatory
Many possess book lungs for gas exchange

9. Subphylum Chelicerata, Class Arachnida (Spiders, Scorpions, Ticks & Mites)
Spiders are able to produce a strong polymer – silk
Only arthropod to not have compound eyes
Chelicera (green
Pedipalps (to the side)

10. Spiders

11. More Spiders…
Tarantula
Black
Widow

12. For the true arachnophobe…
The brown recluse
and its bite wounds

13. The Camel Spider

14. Ticks & Mites

15. Ticks & Lyme Disease…

16. Common Mites
Common Mite
Dust Mite

17. Scorpions
Females keep fertilized eggs inside the body until they hatch.
The young cling to the female, but can be eaten by her as well

18. Subphylum Chelicerata, Class Picogonida (Sea Spiders)

19. Subphylum Chelicerata, Class Merostomata (Horsehoe Crab)
Changed little over 350 million years
Aquatic, mostly found on Atlantic & gulf coasts of United States
10 eyes (photoreceptors) including one on the tail

20. Subphylum Chelicerata, Class Merostomata (Horsehoe Crab)
Mates during spring and summer full and new moons, onto ocean beaches.
Females lay up to 30 thousand eggs, which males fertilize before burying them in the sand

21. Phylum Arthropoda, Subphylum Uniramai
3 Classes:
Class Insecta (Insects)
Class Chilopoda (Centipedes)
Class Diplopoda (Millipedes)

22. Subphylum Uniramai, Class Insecta (Insects)
Far & away the most diverse of animal groups
More types of insects alone than all other animal groups combined
Inhabit all terrestrial & freshwater ecosystems.
Success largely attributed to coevolution with flowering plants.

23. Insect Body Plan Insects have 6 legs or 3 pairs of legs 3 body parts
Head
Thorax
Abdomen
Most insects have wings, however in many species these are vestigial
Have advanced excretory system composed of malphygian tubules
Exchange gases through a complex tracheal system

24. Insects Vision
Have complex compound eye which is usually extremely sensitive to motion and allows 3600 vision
Most insects see well into the UV spectrum

25. Insects Vision
Consists of thousands of hexagonal tubes called ommatidia.
Each has a lens at the front and a cluster of light sensing cells at the back.
Image forms a mosaic picture
Image is not clear and detailed, but do have a much wider field of view
Many insects can see ultraviolet light
Flowers have ultraviolet markings, that are visible to pollinating insects

26. Feeding / Mouthparts
Insects usually have specialized jaws/mouthparts suited to their ecological need

27. Metamorphosis Most insects undergo a process of metamorphosis 2 Types:
Incomplete Metamorphosis – nymphs are small adults
Complete Metamorphosis – cocoon/chrysalis

28. Subphylum Uniramai, Classes Chilopoda & Diplopoda
Millipedes (Diplopoda) are segmented worm-like animals
Have 2 pairs of legs/segment
Primarily herbivores & decomposers
Centipedes (Chilopoda)
Usually terrestrial carnivores
Have 1 pair of legs/segment
Are often poisonous, using modified front claws to immobilize prey

29. Centipedes vs. Millipedes

30. Subphylum Crustacea, Class Crustacea
Includes crabs, lobsters, crayfish, shrimp, krill & barnacles
2 pairs of antennae
Appendages are often highly specialized
Gas exchange is usually through gills
Many species taste delicious in butter

31. Lobster and Crayfish
Freshwater Crayfish
Marine Lobster

32. Sexes of the Crayfish
Males – first swimmerets are modified into (1) gonopods. Gonopods transfer sperm to female.
Females – (2) seminal receptacle receives sperm while the (3) gonopore releases the fertilized eggs. The eggs attach to the swimmerets until time to hatch.

33. Krill and Shrimp
Krill
Shrimp

34. Crabs

35. Barnacles

36. Crayfish Diagram