1. Phylum Arthopoda (Greek for “jointed foot”)
Taylor Myers, Stephanie Gillespie, Tony Bent

2. Drill Have you ever seen a: Spider Lobster Crab Insect
Describe these animals and what makes them unique.

3. Vocabulary
Appendage-Projecting part of an organism, with a distinct appearance or function.
Chitlin- A substance made of polysaccharides that forms the majority of an exoskeleton.
Spiracle- An external respiratory opening.
Exoskelton- A rigid external covering for the body.

4. Characteristics More than 83% of all animal species are arthropods.
All arthropods have exoskeletons made of chitlin.
Classified by habitat, body structure, diet.
Have an open circulatory system.

5. Characteristics continued…
More evolved than their ancestors:
-Bilateral symmetry(left-right)
-Segmented body
-Hard exoskeleton
-Jointed legs
-Many pairs of legs
NO backbone

6. Crustaceans Two pairs of antennae Branched appendages
Legs attached to abdomen
30,000 species
Lobsters
Crayfish
Crabs
Barnacles
Shrimp
Most members of this class are marine animals.
Breathe through gills
Shrimp, crayfish and lobster have specialized swimming structures

7. Chelicerata Ancient group-includes extinct animals. Eight legs
Pinchers and fangs
No mandible (jawbone)
No antennae
Haemocoelic cavity(part of circulatory system)
Horseshoe crabs
Scorpions
Spiders
Mites

8. Uniramians One pair of antennae Bilaterally symmetrical
Segmented and jointed legs
Tracheal system(series of tubes that carry oxygen to cells in an insect’s body)
Most live on land
Butterflies
Beetles
Millipedes/centipedes

9. Evolution Arrived on Earth during the Cambrian period.
Invaded new geographic areas and habitats over time as they evolved (new niches).
Still evolving after 500 million years.
Over 2 million types in the world.

10. Evolution continued…
Theoretically evolved from annelids(segmented worms).
Related to the trilobites-died out 248 million years ago, almost extinct today.
Most successful animal Phylum on the planet (population, size, species diversity).

11. Molting
A process in which animals shed their exoskeleton and inflate their body before the new skeleton hardens.
Occurs periodically.
The animal must shed (molt), and animals must then rapidly grow and produce a new, larger exoskeleton to grow into.

12. Molting continued… During molts, animals are extremely vulnerable.
Arthropods must molt to grow.

13. Wrap-up
What have you learned about arthropods?