1. Squid swimming
Various cephalopods

2. Class Polyphacophora (Fig. 7.14)
Greek “many plate-bearer”
ex. chitons
shells of 8 overlapping plates
grazers using radula

3. Marine Invertebrates
Part II

4. Two remaining Phyla: P. Arthropoda (G. jointed feet)
P. Echinodermata (G. spiny skin)
Plus one group of the Phylum Chordata
Subphylum Urochordata (G. string tail)

5. Phylum Arthropoda
The largest animal phylum, containing 75% of all animal species.
Contain terrestrial, freshwater, and marine forms.
Most familiar marine examples include
shrimps
lobsters
crabs
barnacles
krill
copepods

6. General characteristics:
Bilaterally - highly cephalized.
Segmented, with tagmata (functional regions) such as head, thorax and abdomen or cephalothorax and abdomen.

7. General characteristics:
Jointed appendages (unique among invertebrates)
1 pair per segment
modified depending on lifestyle for:
sensory function
feeding
locomotion
reproduction
respiration
Includes antennae, mouthparts (maxillipeds), claws (chelipeds), walking and swimming legs

8. General characteristics:
Exoskeleton (cuticle) of chitin (polysacchride) and proteins
Grow by molting – soft shell crabs

10. Subphylum Chelicerata (G. claw)
Possess chelicerae for feeding
(terrestrial - spiders and scorpions)
marine members:
horseshoe crab Limulus (common on east coast of U.S., west coast of Asia) (Fig. 7.24) mating
sea spiders (pycnogonids - G. all leg)

11. Male vs female?

12. “chewing”

13. Subphylum Crustacea L. a crust
Class Malocostraca (G. soft shell)
Order Decapoda (G. 10 feet) (Fig. 7.22)
Most crabs, shrimp, lobsters
Actually 5 prs. of thoracic appendages
Abdominal appendages (when present) often adapted for swimming or reproduction

16. Male Female

18. Order Euphausiacea (ū fow’ zē ā sē ah) (Fig.7.19b)
possess 8 prs. of thoracic appendages
includes the common krill
important in food chains for many animals, including large mammals such as whales
biomass in Arctic waters alone equals current world harvest of all other marine animals combined.
Many bioluminescent
may decrease in size at molts (adaptation to starvation conditions during arctic winter decreased production?)

19. Class Copepoda (G. oar feet) Ex. Copepods (Fig. 7.21a)
bullet-shaped
move by using antennules
extremely important as 1o consumers of phytoplankton

20. Class Cirripedia (L. hairy feet) Ex. Barnacles (Fig. 7.23)
stand on heads in “house” of calcium carbonate - attached to substrate
wave legs out to catch floating debris for food Barnacles feeding

22. Phylum Echinodermata (G. spiny skin)
Exclusively marine and estuarine animals
Ex. Sea stars, sand dollars, sea urchins, sea cucumbers, sea lillies, feather stars

23. General characteristics:
Pentaradial symmetry into star, cylinder or globe shape
no cephalization
oral and aboral surfaces
calcareous endoskeleton with spines that project through overlying epidermis
many have impressive powers of regeneration (sea stars, cucumbers)

24. General characteristics:
water vascular system - takes on role of many “typical” organ systems found in other animals
system of tubes and canals that circulate water thoughout the body
exploit the flow for locomotion (tube feet), respiration and excretion (diffusion across walls of tube feet); circulation.
locomotion

25. Ex. Sea stars, serpent (brittle) stars
usually predatory
often extrude one stomach to digest prey (corals, oyster beds, etc.)
may autotomize (drop limbs) to escape predators

27. Ex. Sea urchins, sand dollars
Many grazers - scrape surfaces with jaw apparatus (Aristotle’s lantern) of over 100 parts.
May burrow beneath sand/mud eating sediment (sand dollars)

28. Ex. Sea cucumbers
modified tube feet as “tentacles” to capture debris from water or substrate and transfer to mouth. (feeding)

29. Sea lillies
ancient group, stalked, common in deep water

30. Phylum Chordata Subphylum Urochordata (G. tail string) Fig. 7.26
Ex. Sea squirts, larvaceans, salps
possess dorsal hollow nerve cord, stiff notochord, and gill slits as larvae only
“tadpole” larvae - hence the name

32. Also known as “tunicates” - case of cellulose-like polysaccharide.
All filter feeders
Important 1o consumers of nano- and micro-producers
anterior siphon (incurrent) and dorsal siphon (excurrent)
Cases add to detritus mesh