1. Phylum Arthropoda
Copy this organization down. Can you give the common name for each group listed?
Kingdom Animalia
Phylum Arthropoda
Subphylum Crustacea
Class Cirripedia
Class Copepoda
Class Malacostraca
Order Decapoda
Order Euphausiacea
Subphylum Chelicerata
Class Merostomata
Class Pycnogonida

2. Arthropods Largest phylum of animals
1 million species (some estimates say up to 20 million)
Includes mainly terrestrial bugs
3 out of every 4 animals are arthropods

3. General Characteristics of Arthropods
Segmented body
Bilateral Symmetry
Jointed appendages
Chitinous exoskeleton

4. Sub Phylum Crustacea
Includes:
Shrimp
Crabs
Lobsters
Barnacles

5. General Characteristics of Crustaceans
Two pairs of antennae
Mandibles for chewing
Pair of appendages on each body segment
Gills for oxygen

6. Molting
To grow, arthropods must molt their exoskeleton

7. Digestion
Smaller crustaceans are filter feeders, catching particles in bristles on their appendages
Some have specialized appendages that push food towards their mouths
Nutrients passed to an open circulatory system

8. Nervous System
Can vary from simple ladder-like to centralized nervous systems
Most have compound eyes
Keen sense of smell
Communicate with each other via body postures

9. Compound Eyes
Bundles of up to 14,000 light sensitive units grouped together

10. Reproduction Separate sexes
Mating usually takes place immediately after female molts
Some carry eggs in appendages under the body
Planktonic larvae (number of stages varies from group to group

13. Class Cirripedia Filter feeders
Cirri – feathery like appendages (actually legs) sweep water
Attached to surfaces including living ones
Calcareous plates/shells (look like mollusks)

14. Class Copepoda Abundant and important in the role of plankton
Can use their antennae to swim
“Sea Monkeys”

15. Importance of Copepods
Most numerous multi-cellular animals on Earth
Eat the tiniest plankton and are in turned eaten by fish & krill
Nutrient cycling

16. Order Decapoda “ten legs” Largest crustaceans in terms of size
Extended carapace
Shrimp, lobsters, and crabs

17. Order Decapoda
Five pairs of walking legs (pereopods) of which one is usually heavier (claws)
Carapace encloses the cephlalothorax with the rest of the body being the abdomen

18. Order Decapoda
Shrimp and lobsters can range from scavengers to parasite removers
Crabs tend to be scavengers

19. Order Euphausiacea Krill Planktonic Shrimp-like
Filter feeders (eat diatoms)
Head fused with body pieces to form a unique carapace
Major food source for larger organisms (whales, seals, penguins, etc.)
Very common in polar waters

20. Sub Phylum Chelicerata
Includes Horseshoe crabs, spiders, mites
Chelicerae are the only small appendages before the mouth
Range from small pinchers to venomous fangs

21. Class Merostomata Horseshoe Crabs
Not true crabs and have not evolved for millions of years
Six pairs of appendages
No mandible jaw
Chelicerae, Walking Legs, four pairs of Pushing Legs
Telson or tail used for steering and flipping itself right side up.

22. Class Pycnogonida Sea Spiders Have four or more pairs of legs
A large proboscis with a mouth on the tip allows it to feed on soft invertebrates
No respiratory system as gases diffuse through body
Tiny muscles consist of one cell covered with connective tissue