Marine Ecology


animal-like protists, over 50,000 species, 3 important ones

Protozoan 3 Groups

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Forminifera– calcium carbonate shell or test

Radiolaria– secreted shell of silica, covered with radiating spines (reduce rate of sinking for planktonic species)

Ciliates– hair like cilia used for locomotion and filterfeeding (sessile attached ot the surface of seabed or organism)


Protozoan group, tintinnids are the most abundant kind of ciliates.

-can form colonies.


-test of outer coating on a cilliate, made of sand grains glued together, covering the interior of organism containing nuclei.

Marine Animalia Vs Protista

-presence of contractile muscles

-signal-conducting neurons

-multi-cellular bodies




sponges phylum.

sponges dont have tissues/organs

-cells specialized forms and functions (not colony of identical/individual cells)

-similar to multi-cellular organisms of first forms..

-pores on sponges, allow water to enter and transport through series of canals.
Collar Cells/Choanocytes

-in sponge, sewater enters a feeding chamber lined with this.

-collar cells have flagellum which pull in water and out of sponge.

-opening at the top of the sponge
-flat cells that cover outer surface of sponge to protect it.
-elastic protein fibers to provide support and shape for sponge.

-found in sponge

-nonspecialised cells which transport food or transform into specialised if needed.

Sponge Reproduction

asexual and sexual

-sexual by amebocytes transform into sperm cells with flagellum or egg cells

-broadcast spawning -sperm release (interior fertilization though)

-parenmanchula larva-cluster/furry ball formed

Types of Sponges (4)

-Glass- lace like structure with spicules

-encrusting- covering growths on coral or rocks

-coralline- calcium carbonate skeleton

boring- oysters corals (bores through shell)


-large, diverse marine invertebrates

-jellyfish, sea anemones, corals, hydroids


Cnidarians Vs Sponges

-have specialized tissues

-radlia symmetry (body repeats around central axis)

-no head/front/back, but have:

oral surface

-aboral surface


Cnidarian Features

-bottle shaped gut- one opening (food in and waste out)

nematocysts/cnidocytes-stinging cells


-2 layers of cells

ectodermis protection, endodermis digestion

which are separated by mesoglea



Cnidaria class,

most consist of polyps arranged in coilonnies

-reproduce with planula larrva formed (football shaped) covered with cilia

drift, settle, polyps reproduce asexually by budding



-hydrozoans which form drifting colonies of polyps (CO2) formed filling floats

-Portuguese man-o-war- droplets of oil


medusa oriented

-class of Cnidarian

cubozoa-box jelly (separated from scyphozoa)


Cnidarian class

-no medusa stge, complex polyps

-gut has partitions (septa) -allow larger growth

sea anemones (solitary)


-2 sub classes, examples

Hexacorallia– stony corayls (6 tentacles)

-Black corals- hard black protein coat


-Gorgonians- secrete proteins forming branching skeletons (soft corals)

Stony corals


-smybiotic with zooxanthellae (endosymbiotic algae)

-autotrphic and heterotrophic

-asexual and sexual rep


Asexual reproduction

colony growth vs formation of new colonies

intratentacular budding (division of polyp)

extratentacular (new moutn formed between polyp)


Sexual Reproduction of Coral




gonochoric-colonies have one sex. (gamete)



phylum name, comb jellies

look like cnidarian, but unique bc:

8 rows cilliary combs

beating combs refract light

mm-2m long

carnivores, can trap with colloblasts

-can acquire nematocysts


Acoelomates and Pseduocoelomates

-animal phylums

-bilaterally symmetric, anterior cephalization)

Platyhelminthes (flatworms)

-flattened dorso-ventrally

-simple brain central nervous system

bottle gut

-largest in sperm whale at 50′


Nemertea(phylum)- ribbon worms

-look like flatworms, have probscis to catch prey

-more developed gut

neritic waters, shallow found under rocks in intertidal zone

30m longest invertebrate


Nematoda (roundworms)


found in marine mud and sedient eating detritus and bacteria

through gut

hydrostatic skeleton-muscles surround;cavity and push against incompressible fluid for movement and undulate


-in vertebrates, standard chordate is hollow nerve cord
Coelomates (2)

coelom = embryonic development, separating digestive tract from body wall

1- protostomes



segmented worms, polycheates, oligochaetes, hirundinea (leaches)

-have circulatory system

fluid filled gut, found in annelids

most species of annelids in this class

parapodia-flattened extensions

-setae– stiff bristles

-larger polycheates require gills on parapodia to absorb oxygen better.


Pogonophorans (beard worms)


-no mouth or gut

-absorb nutrients dissolved by water

-symbiotic bacteria

-vestimentiferans-found in hydrothermal vents



earthworms on terr.

-no parapodia, but segmented


-leeches, no parapodia

-sucker (anesthetic and anti-clotting agent)

ectoparasites– of fish and invertebrates

Sipuncula (peanut worms)

-soft, unsegmented worms

-anterior has mouth and tentacles

P:; Echiura

-spoon worms

-difference with peanut worms=spoon-like proboscis, which collects organic material and detritus

P:; Mollusca

-sea snails, mussels, scallops, octi, squid.

-200,000 species

calcium carbonate shells

mantle – thin tissue layer, secretes shell


-ventral, muscular foot



-on molluscans,

-its a band of small teeth used to rasp away material (encrusting algae or animal tissue)