CTENOPHORES

COMB JELLIES-video

All marine 100 species Radially symmetry and gelatinous body Swim with 8 rows of CILIARY COMBS, long

cilia fused at the base that beat in waves reflecting light

In warm and cold waters COLLOBLASTS- long tentacles armed with

sticky cells

www.mwra.state.ma.us/.../graphic/ctenophore.jpg

Comb jelly

BILATERALLY SYMMETRICAL WORMS

FLATWORMS, RIBBON WORMS, NEMATODES, SEGMENTED WORMS-

VIDEO

FLATWORMS

Phylum- Platyhelminthe Dorsoventrally flat Simplest animals with tissues organized into

real organs and organ systems Have a central nervous system

Simple brain- bundle of nerve cells Several nerve cords the length of the worm Only one opening for gut/anus

Embryos have a middle layer of tissue called the MESODERM (1st animal to have it)- which gives rise to muscles, the reproductive system, and other organs

20,000 species Most common marine ones are the

TURBELLARIANS- free living carnivores

www.daviddarling.info/images/flatworm_section.jpg

Polyclad flatworm, Pseudoceros sp, Egyptian Red Sea. Photo © Mike Keggen

http://www.julianrocks.net/flatworms/PseudobicerosBedfordi.html

FENCING

Flukes or TREMATODES- largest group of flatworms; 6000 species; all parasitic

Tapeworms or CESTODES- long body with repeating units; live in intestines of vertebrates; don’t have a gut or mouth but absorb nutrients

RIBBON WORMS

Or NEMERTEAN More complex organization Complete digestive tract with gut, mouth, and

anus Circulatory system Proboscis-long fleshy tube used to entangle

prey Predators that feed on worms and

crustaceans 900 species mostly marine

http://rydberg.biology.colostate.edu/Dissections/Nemertea/Nemerteawh.JPG

Nematodes

Roundworms Found mostly in sediment or intestinal tracts;

most parasitic; small, with slender body that is pointed at one end

Gut and anus Has a hydrostatic skeleton- a system that

uses water pressure against the body wall to maintain body shape and aid in locomotion

Anywhere between 10,000 to 25,000 species Larvae found in raw or poorly cooked fish

http://www.diplectanum.dsl.pipex.com/sim/anisak.jpg

SEGMENTED WORM OR ANNELIDS About 20,000 species More complex body systems Has segmentation- identical body segments Has a coelom-body cavity found in

structurally complex animals- completely surrounded by tissue developed from the mesoderm

Classes of Annelids

1)Polychaetes- most of the marine annelids;made of body segmetnns that have a pair of flattened extensions called parapodia that have setae (sharp bristles) Have a closed circulatory system that

transports nutrients, oxygen, and carbon dioxide

Have gills on the parapodia that contain capillaries to help with the absorption of oxygen

10,000 species almost all marine Live in temporary or permanent tubes made of

mucus, protein, seaweed bits, mud, etc. Mostly carnivores but some are suspension

feeders Proboscis ensnares prey

Life history of Polychaetes Have a trochophore- a planktonic larval stage

with cilia Some such as the Tomopteris are planktonic for

entire life

http://www.esu.edu/~milewski/intro_biol_two/lab__12_annel_arthro/images/nereis.jpg

Nereis

An assemblage of polychaetes (Photo by H. Torres)

2) Pogonophorans or beard worms- Lack a mouth and gut Has food absorbing tufts 135 species Deep water Another group called the vestimentiferans

are much longer Some found at hydrothermal vents

www.nematodes.org/.../pogonophora/pogo1.gif

3)Oligochaetes- found in mud and sand; eat detritus;marine relatives of earthworms; no parapodia

http://www.mpi-bremen.de/Binaries/Binary7687/Oalg_7_RGB_small.jpg

4.) Leeches- some marine species; parasitic; sucker at one end; no parapodia

Tracy Clark 8/11/2006

La Jolla ShoresHornyhead Tubot

Pleuronichthys verticalisLeech

UnidentifiedNikon D7060mm lens

PEANUT WORMS

Phylum: Sipuncula Unsegmented bodies Burrowers; shallow water; deposit feeders All marine Long, anterior portion has a mouth a a set of

small lobes of branching tentacles 320 species

http://www.livewild.org/CostaRica/Pics/a5751.jpg

ECHIURANS- phylum Echiura

135 species all marine Look like peanut worms but with a non-

retractable, spoon-like or forked proboscis Deposit feeders Some live in U-shaped tubes in the mud

http://farm4.static.flickr.com/3089/2922855838_a3df563b1e.jpg?v=1223412990

Molluscs: The Successful Soft Body

BASIC MOLLUSK CHARACTERISTICS Most have a soft body enclosed in a calcium

carbonate shell Body covered with a mantle- a thin layer of

tissue that secretes the shell Bilaterally symmetrical Ventral, muscular foot Head with sensory organs including eyes Have a radula- ribbon-like band of teeth

made of chitin used for feeding Have paired gills

3 major classes of Mollusks

Gastropods (class Gastropoda) Bivalves (class Bivalvia) Cephlapods (class Cephlapodia) 2 minor classes of Mollusks:

Chitons Tusk shells

Gastropods “stomach footed”

Largest and most common class Snails, limpets, abalones and nudibranches 75,000 species mostly marine Has a hard dorsal shell Use radula to scrape algae from rocks Some are deposit feeders; some are

carnivores Nudibranches or sea slugs have no shell

Nudibranch

http://birdhouse.org/blog/wp-content/uploads/2008/05/nudibranch.jpg

Limpet

www.barwonbluff.com.au/.../limpet%20smooth.jpg

limpet

www.theseashore.org.uk/theseashore

coneshell

http://www.scuba-equipment-usa.com/marine/JUN05/images/Conus_textile.jpg

Violet snails

http://www.floridastateparks.org/bahiahonda/images/BAH-violet-snail.jpg

BIVALVES

Clams,mussels,oysters etc. Body is laterally compressed and enclosed in

a shell with two parts No head, no radula Gills larger and used for obtaining oxygen

and to filter food particles Inner surface of shell lined by mantle;

therefore whole body is in the mantle cavity- a large space between the two halves of the mantle

Siphons-tube-like extension through which water flows in and out of the mantle cavity in bivalves, cephlapods, and tunicates

Mussels have byssal threads to attach to submerged surfaces such as rocks etc.

http://www.japan-hopper.com/wp-content/photos/pearl_oyster.jpg

Pearl oyster

Pearl diving video

www.waterworxbali.com/.../giant-clam-diver.jpg

Giant sea clam…largest bivalve can be up to 3ft in length

Some bivalves bore into coral, rock or wood Ex: shipworm– known as a fouling organism

because they settle on the bottom

CEPHLAPODA- “head-footed”

Predators Octopuses, squids, cuttlefishes Reduced or absent shell Foot modified into arms and tentacles with suckers Round bodies- octopus Elongated bodies- squid Bodies protected by thick, muscular mantle Mantle cavity behind head contains 2-4 gills Siphon = funnel- a muscular tube from the foot