1. Meet the Arthropods
“Jointed Feet”
Kingdom Animalia!

2. Anatomy
• External skeleton
made of calcium
carbonate (Chitin)
• Jointed appendages
• Segmented body
that is plankton-
sized to a few
meters long
• Bilateral symmetry

3. Anatomy cont.
• Open circulatory
system – internal
organs bathed in
blood
• Nerve ganglia
• Compound eyes
• Rely on chemical and
mechanical sensors
(pheromones &
antennae)

4. Reproduction
• External fertilization
• External
development –
frequently in
pouches, sacks, on
parents’ body
• Planktonic larvae

5. Phylum Arthropoda
Two Subphyla:
A) Subphylum
Chelicerata – Sea Spiders
& Horseshoe Crabs
B) Subphylum
Crustacea – Lobsters,
Crabs, Shrimp, Barnacles

6. Habitat & Distribution
• Mostly benthic
• Mostly epifauna
• Worldwide
• This phylum contains
• the most species of any on earth

7. The only “attached”
crustacean
Can you name them?

8. 1. Subphylum Chelicerata
a. Sea Spiders and b. Horseshoe Crabs
Like all Arthropods, they have no bones and
grow by molting!

9. a. Class Pycnogonida
(sea spiders-yipes!)

10. b. Class Merostomata
Horseshoe Crabs are
True Blue Blooded
Creatures
We have ____________________ to make our blood
red
Many crustaceans have hemocyanin, making their
blood blue!
http://www.youtube.com/watch?v=e8KlAmtIu1E

11. Male
Horseshoe
Crabs
Have
Modified
Front Legs
That Look
Like
Boxing
Gloves or
Baseball
Mitts to
Help Hold
onto the
Female
During
Mating

12. http://horseshoe-crabs.com/horseshoe-crabs-life-cycle-on-video/

13. 2. Subphylum – Crustacea – Lobsters,
Crabs, and Shrimp – oh my!

14. Crustacean Diversity

15. More Crustaceans:
the sea insects
Scuds, Beach Hoppers, Beach Fleas, and Skeleton Shrimp:
The Amphipods

16. Still that familiar
meroplanktonic
larvae we know and
love! Special Name:
Zoea

17. Still No Skeleton – Molting Instead

18. The Smallest, Most Abundant
Crustacean in the World’s
Oceans:
The Little Copepod
??What’s the largest planktonic
Crustacean??
Are You “CooCoo” for Copepods?

19. What’s Going On Here????
http://www.youtube.com/watch?v=yMxY4c5SeIs
http://news.nationalgeographic.com/news/2006/09/060921-krill-video.html

20. http://library.thinkquest.org/J001418/wh
at.html
Which Numbers Belong To Which
Phyla?
(Try the rest for a good review before
the unit test!)

21. References (on our class website)
• http://www.dnr.state.md.us/baygame/bbc_
molting.asp
• http://www.k12.de.us/warner/structure.htm
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