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Chapter 3
MARINE BIOLOGY
I. Early life
A. Miller-Urey experiment: Stanley Miller, a student of Harold Urey, showed that organic
compounds, amino acids in particular, could be created from inorganic molecules present
on the early earth; the chemicals needed electricity or UV light to stimulate the reactions;
this experiment showed the basis for early life on earth
B. the first primitive bacteria appeared around 3.5 billion years ago in the oceans
C. all phyla contain species that live in the ocean
II. Types of Marine Life
A. pleuston (pelagic, ex: man-of-war): organisms that float on the surface of the water; wind
has a large effect on their movement
B. neuston (pelagic): organisms that live in the surface layer of water
C. plankton (pelagic): organisms that drift with ocean currents and usually can’t move on
their own; individual organism is a plankter; plankton account for 98% of the biomass in
the oceans; small plankton float best because they have a high surface-area-to-volume
ratio; in Greek, planktos = something drifting
1. trophic classifications
a. phytoplankton: autotrophic plankters, such as algae
b. zooplankton: heterotrophic plankters, such as animals or protozoans; mostly small
shrimp-like crustaceans, such as copepods and euphausiids
c. bacterioplankton: drifting bacteria; can be zooplankton or phytoplankton
2. size classifications
a. megaplankton (20+ cm): jellyfish
b. macroplankton (2-20 cm): jellyfish
c. mesoplankton (0.2 mm-20 mm): copepods
d. microplankton (20-200 µm): protists
e. nanoplanton (2-20 µm): protists
f. picoplankton (0.2-2 µm): bacteria
g. femtoplankton (< 0.2 µm): viruses
3. life classification
a. holoplankton: spend their entire lives as plankton
b. meroplankton: only spend part of their lives as plankton; may swim or sink to
benthic environment as adults
D. nekton (pelagic): organisms (mostly animals) capable of swimming independently, such
as fish, squid, and marine mammals
1. nektobenthos [demersal organisms] (ex: stingray): nekton that swim just above the
ocean bottom
E. benthos (benthic): organisms that live on or in the ocean bottom [benthic environment];
98% of marine species are benthic
1. infauna: buried in sediment
a. meiofauna: intermediate size classification (between micro and macro); most of
these benthic invertebrates live between grains of sand, so they are called
interstitial fauna
2. epifauna: live attached to the sea floor or move over its surface
III. Organisms’ Adaptations to Marine Environment
A. osmoregulation: physiological mechanisms designed to control internal salinity
1. marine fish (hypotonic) drink large quantities of ocean water because lots of water is
lost due to osmosis; secrete salt from chloride cells in the gills by active transport
2. marine reptiles and birds excrete salt through specialized salt glands
3. freshwater fish (hypertonic) don’t drink much water but excrete lots of water because
lots of water comes into their bodies by osmosis
B. streamlining: because the ocean water has a high viscosity (internal resistance to flow),
organisms must decrease their drag so that they can swim more efficiently through the
water; drag is the force of a fluid pushing back on an object as it passes through the fluid
due to friction
C. camouflage [cryptic coloration]
1. countershading: a form of camouflage; the bottom side of the organism is light to
match sky and the top is dark to match deep sea
D.
E.
F.
G.
H.
I.
2. disruptive coloration (ex: tropical fish): bold, contrasting color patterns that break up
the organism’s outline, but do not match the background
echolocation: using sounds instead of light to see and locate things; sound is a better form
of communication and sensing in water because light penetration is limited by turbidity
1. a sperm whale can detect objects 400 m away using echolocation
photophore: light-producing organ with photocytes responsible for bioluminescence, the
capability of some of organisms to glow, which can be useful for a lure, as it is for the
anglerfish; commonly found in animals in the mesopelagic zone; may contain bacteria
that produce light for them or luciferin, a compound that produces light when stimulated
1. phosphorescence: energy is absorbed and slowly released as light
2. fluorescence: the absorption, then re-emittance of light with a longer wavelength
halophyte: a plant that thrives in saltwater or salty environments
chromatophore: cell containing pigments that reflect light; results in skin having color,
which allows an animal to camouflage itself
counter-current heat/gas exchange: this is a method of exchanging gases or heat between
blood and gills, another body part, or the environment that maximizes efficiency by
flowing the fluids in opposite directions past each other
gas containers (ex: swim bladder): allow animals to float with neutral buoyancy (at a
constant depth); contained in fish and molluscs such as the nautilus, cuttlefish, and deepsea squid
J. hemoglobin: red blood protein that carries oxygen in vertebrates; it has an iron atom in
the middle holding together 4 polypeptides
K. hemocyanin: blue respiratory pigment that carries oxygen in some invertebrates and is
made of copper, but is less efficient that hemoglobin
IV. Miscellaneous Vocabulary and Concepts
A. general terms describing an organism and its niche
1. sessile: immobile; attached to a substrate; includes sponges and plants
2. motile: organism is capable of moving independently
3. respiration: the breakdown of glucose to release energy for the cell
a. aerobic: organism uses oxygen in cellular respiration; cannot live in hypoxic or
anoxic waters
b. anaerobic: organism does not use oxygen in cellular respiration
4. environmental condition variation
a. euryhaline organism: can tolerate a wide range of salinity conditions
b. stenohaline organism: tolerates only small salinity changes; usually inhabits open
ocean
c. eurythermal organism: can tolerate a wide range of temperatures; found in surface
waters and coastal waters where temperatures vary more greatly
d. stenothermal organism: tolerates only very small temperature changes; usually
inhabits open ocean where temperatures don’t vary much
e. eurybathic organism: inhabits a wide depth range
f. stenobathic organism: restricted to a narrow depth range because it can’t tolerate
much pressure change (this could require it to stay deep, shallow, etc.)
5. endotherm [homeotherm]: “warm-blooded”; maintains constant internal body
temperature
6. ectotherm [poikilotherm]: “cold-blooded”; uses environment to change body
temperature
7. autotrophs: make their own food by photosynthesis or chemosynthesis
a. chemosynthesis: autotrophic process of using inorganic chemical compounds
(hydrogen sulfide, methane) to provide energy; common in organisms around
hydrothermal vents
b. photosynthesis: the use of light to make energy available for cells
i. H2O + CO2 + light  glucose + O2
8. heterotrophs: feed off of other organisms for energy
B. radial symmetry: symmetrical around the center (ex. starfish=pentaradial)
C. bilateral symmetry: symmetrical over a single axis
D. cephalization: concentration of sensory organs in the head
E. bioaccumulation: the concentration of poisons in an organism’s tissue
F. biomagnification: the increase in concentration of poisons in organisms higher up in the
food chain because top carnivores consume large amounts of prey with the poison
G. lophophore: ring of ciliated tentacles used for feeding by brachiopods and bryozoans
H. myoglobin: red protein in muscles that binds to oxygen and makes it available for
respiration in muscles; red muscle is best for endurance because it has lots of myoglobin;
white muscle is best for small bursts, but not prolonged use
I. body sections
1. anterior: leading end or head
J.
K.
L.
M.
N.
O.
P.
Q.
R.
2. posterior: tail end
3. dorsal: back side
4. ventral: belly side
5. aboral: side opposite of the mouth
schooling: socially-organized groups of fish, squid, and crustaceans; fish at the rear lead
the school and other fish know where to go by using their lateral lines to detect vibrations
1. bait ball: school of fish swimming in close formation to protect from predators
2. advantages of schooling
a. protection from predators
b. ensures fertilization during spawning
migration: movement of some pelagic species (cetaceans, sea turtles, fish) in order to find
food or meet needs of young; gray whale makes the longest migration each year (22,000
km) of any animal; whales may use magnetic fields to navigate long distances
1. catadromous fish (ex. Atlantic eel): spawn in the ocean, then spend their adult lives in
freshwater rivers, and return back to the ocean to lay eggs
2. anadromous fish (ex. salmon): spawn in freshwater rivers, then spend their adult lives
in the ocean, and return to rivers to lay eggs
feeding
1. filter/suspension feeder: an organism that takes in water and filters out plankton;
examples are sponges, corals, and baleen whales
a. active: uses energy to pump water through a filtering structure
b. passive: lets a current carry food over a feeding structure
2. piscivore: carnivore that eats only fish
3. deposit feeder [grazer]: feeds on organic deposits or biofilms, which are mats or
layers of microorganisms
a. detritus feeder: eats detritus, dead and decaying organic matter including waste
Reproduction
1. hermaphrodite: species with the ability to change sex or has sexual organs of both
sexes; more common in invertebrates than in vertebrates
2. oviparous: lay enormous amounts of eggs (because many are eaten by predators) that
hatch in the open water
3. ovoviviparous (sea horse): eggs are kept in the reproductive tract and incubated; birth
is given to live young
a. sea horse deposits the eggs in a pouch in the male
4. viviparous (mammals, some sharks and rays): birth is given to live young; nutrients
are supplied by the placenta
5. parthenogenesis: growth and development of an egg without being fertilized
6. fecundity: the amount of offspring produced by an organism
7. spawning: laying large quantities of eggs in the water
protoplasm: substance of all living matter; 80% is water on average
photoinhibition: decrease in photosynthesis at high light intensities
marine snow: macroscopic aggregates of amorphous material from living organisms; can
come from tunicates’ mucus tunics
diel events occur over a 24-hour period; diurnal events occur in the daytime
diapause: energy-saving state in which an animal does not feed and its metabolism slows;
occurs in cold, unproductive waters
S. bioturbation: disturbance and movement of soft sediments due activities of benthic
organisms, such as sea cucumbers and worms; this can result in sediment sorting
V. Plants: require nutrients and light to do photosynthesis
A. iron hypothesis (John Martin - 1987): we can “seed” the ocean with iron to boost
productivity, fix carbon, and reduce global climate change; initially done around the
Galapagos Islands
B. coastal grasses
1. eelgrass [wrack] (Zostera): temperate coastal
2. surf grass (Phyllospadix): temperate coastal
3. turtle grass (Thalassia): tropical coastal
4. marsh grass (Spartina): salt marshes
5. cordgrass: dominant low marsh plant in North America
VI. Reptiles
A. nest temperature determines the sex ratio of turtle hatchlings
B. carapace: the shell on the back of an organism such as a turtle
C. sea snakes: are extremely poisonous and have flat tails for swimming; all are found in the
Indian ocean and Pacific ocean
D. sea turtles: migrate long distances between nesting areas and foraging areas; mostly
found in tropical areas; most eat jellyfish
1. largest sea turtles
a. leatherback - largest
b. green sea turtle: eats sea grasses
c. loggerhead
d. hawksbill
2. most endangered sea turtle: Kemp’s ridley turtle
VII. Cnidarians
A. hermatypic coral: has a mutualistic relationship with zooxanthellae, a dinoflagellate
algae which helps provide the coral with nourishment (by doing photosynthesis) and
helps it precipitate carbonate for the reef; all reef-building corals are hermatypic
B. ahermatypic coral: has no mutualistic relationship with zooxanthellae and doesn’t build
reefs
C. octocorals = soft corals, sea pens, sea fans; hexacorals = hard corals, sea anemones
D. basal plate: part of a coral that attaches to a substrate
E. coenosarc: the common soft tissue that unites individual hydroids to form a colony
F. planula: small, free-living, larval stage of many cnidarian species
G. acrorhagi: a sea anemone’s tentacles with many nematocysts
H. gorgonians (sea whips, sea fans): branching coral with horny skeletons sometimes made
of gorgonin protein
I. mesoglea: clear, jelly-like material in the bodies of cnidarians and ctenophores
J. multiple life stage: polyps (asexual stage, usually sessile) and medusae (sexual stage,
bell-shaped, motile, tentacles downward); coral only exists in the polyp stage
K. nematocysts: harpoon-like projectiles located in cnidocytes/cnidoblasts (specialized
cells in cnidarians) used to poison and retrieve prey
L. siphonophores (ex. Portuguese man-of-war, Physalia): cnidarians with air-filled sacs that
allow them to float on the water and drift with the winds; the pneumatophores are the
floating gas-filled chambers; these organisms are sometimes considered a colony of
polyps
M. ocelli: light-sensitive organs on the bell of some jellyfish
N. otocysts/statocysts: gravity-sensitive organs on the bell of some jellyfish that aid in
orientation
O. some jellyfish can have tentacles up to 60 m long; tentacles are used to capture prey
because all jellyfish are carnivorous
P. lion’s mane jellyfish: largest cnidarian; can reach a diameter of 2 m
VIII. Ctenophores (comb-jellies): carnivores
A. contain rows of cilia that allow them to swim and eat, which is why the are called “combbearers”
B. colloblasts: cells on tentacles that release sticky threads that catch prey on contact with
them; ctenophores do not have nematocysts or cnidocytes
IX. Sponges (porifera): most primitive multicellular animals
A. spicules: small calcareous or siliceous structures that provide support to the sponge and
fit together to form the sponge’s skeleton
B. spongin: flexible protein that holds together the hard parts of the sponge’s skeleton
C. spongocoel: cavity in the middle of a sponge
D. choanocytes [collar cells]: cells with flagella used for filter feeding
X. Fish (osteicthyes, chondricthyes, agnatha)
A. agnatha: primitive jawless fish with elongated bodies; lampreys and hagfish; have mouths
surrounded with many small teeth
1. hagfish: scavenger; eats dead whales that sink to the sea floor
2. lamprey: parasites that attach to other fish and cut into their flesh
B. chondrichthyes: fish with cartilaginous skeletons and no scales; sharks, skates, and rays;
some sharks and rays are fertilized internally and are ovoviviparous, but skates lay eggs
in protective pouches attached to a substrate; have oil-filled livers for buoyancy
1. whale shark: largest fish; eats plankton with special filters in gills
2. basking shark: second largest fish; eats plankton with special filters in gills
3. manta rays: eat plankton; have very large wing spans
4. bull shark: can live in saltwater and freshwater
C. osteichthyes: bony fish; most successful group with many species
1. teleostii: subgroup of bony fish; largest fish group; most evolutionarily-advanced
2. barracuda: predatory fish with large mouth and teeth
3. anglerfish: has a modified dorsal fin with a bioluminescent lure to attract fish
4. grunion: small silvery fish that spawns on the California coast in large numbers; the
only fish that come ashore to spawn
5. remora: warm-water fish that has a suction disk to attach itself to other fish, usually
sharks, for locomotive purposes, not to suck the host’s blood
6. mahi mahi: dolphin fish
7. some mesopelagic fish can unhinge their jaws and have expandable organs to eat
large prey; they typically have many sharp teeth and are sometimes bioluminescent
8. elver: a young eel
9. archerfish: spits a stream of water at insects to get them to fall into the water
10. stonefish: highly camouflaged fish that has spines containing venom
11. stout infantfish: lightest fish in the world; 7-8 mm long, weighs 1 mg
12. cusk eel: deepest recorded fish at 8400 m
D. anatomy
1. Ampullae of Lorenzini: electrical sensory organ in the heads of sharks and rays that
allows the animal to detect temperature changes and electric fields
2. gills: respiratory organs that exchange gases directly with the seawater; capillaries are
the small blood vessels in gills that exchange gases
3. lateral line: detects underwater vibrations and is capable of determining the direction
of their source
a. neuromasts: receptors in the lateral line of a fish that contain groups of hair cells
4. operculum: bony plates above the gills that allow bony fish to force water past the
gills without swimming; cartilaginous fish, including sharks, must force water past
the gills by swimming, which is called ram ventilation
5. swim bladder: a membrane-bound air-filled sac found in some slow-moving bony fish
that allows the fish to achieve neutral buoyancy (remains at constant depth)
a. pneumatic duct: tube that allows some fish to quickly take gas in or out of the
swim bladder by exchanging it through the esophagus
E. other
1. fish oil comes from fishes’ livers and is a common ingredient in vitamin supplements
and paint
2. surimi: a fish protein extracted from Alaskan pollocks that is used in artificial crab
meat
3. caviar: sturgeon eggs harvested for food; international trade of caviar is now banned
4. fugu: Japanese delicacy made from pufferfish; dish must be prepared carefully
because the fish have poison in their skin and organs
5. prey-capture methods
a. lunging: wait for prey to pass by, then jump quickly to capture them
b. cruising: swim quickly in pursuit of prey
F. fins
1. pelvic & pectoral fins: paired fins used to turn, brake, and balance
2. dorsal & anal fins: used to stabilize the fish
3. caudal fin: used to propel the fish forward
a. heterocercal (ex: shark): fin that provides lift and is asymmetrical
b. homocercal: symmetrical
i. lunate (ex: swordfish): used for steady propulsion
ii. truncate
iii. rounded
iv. forked
XI. Sea birds
A. feeding techniques
1. active pursuit: penguins, cormorants, murres, puffins
2. skimming: skimmers, gulls, petrels
3. plunging: pelicans, terns, gannets
B. auks: group of arctic marine birds that can’t fly well; includes puffins
1. great auk: driven to extinction by overhunting in the 1840s; found on North Atlantic
islands
C. albatross: a large seabird that spends long periods of time above deep water hunting for
food; has the largest wingspan of any extant bird
D. booby: have elaborate courtship rituals and nest in large colonies in rocky areas; called
dumb because they are tame and don’t avoid capture
E. egret: usually white, long-legged, long-necked heron found in temperate regions
F. penguins: only found in Antarctica and the Galapagos Islands, where water is cooled by
the Peru current
1. emperor penguins, the largest, can dive to more than 250 m, the deepest of any bird
2. king penguin: has an unusual 18-month breeding cycle
XII. Marine Mammals
A. cetaceans (whales, porpoises, dolphins)
1. hunting of whales has yielded: lamp oil, meat, and baleen for stiffening women’s
clothing
2. lek: gathering of male whales to make competitive mating displays
3. International Whaling Commission (IWC): regulates conservation of whales; created
moratorium on commercial whaling in 1986
4. features and adaptations
a. blubber: thick layer of insulating fat
b. melon: oil-filled organ in a whale’s head that changes shape to focus sound
c. apnea [apneustic breathing]: taking several short breaths at the surface, then
holding one’s breath; allows cetaceans to conserve oxygen while diving
d. bradycardia: slowing of the heart rate to conserve oxygen while diving
e. fluke: the horizontal tail fin with no bones, unlike whales’ pectoral fins
f. alveoli: sacs in the lungs where gas exchange occurs with capillaries
g. falcate: describes the sickle shape of a dolphin’s dorsal fin
h. bubble-net feeding: humpback whales release bubbles around schools of fish,
acting as nets, making the fish easier to catch
B.
C.
D.
E.
F.
5. odontoceti: toothed whales; includes sperm whales, killer whales [orcas], dolphins,
and porpoises; generally smaller than baleen whales; sperm whales is the largest
toothed whale; make higher-frequency sounds than baleen whales
a. ambergris: waxy substance found in the digestive system of sperm whales to
protect their tracts from the hard beaks of squid; sometimes found floating in
ocean
b. spermaceti: the waxy substance in a sperm whale’s forehead which allows it to
dive to different depths because it changes density at different temperatures
(regulated by blood flow)
c. sperm whales dive up to 2800+ m deep to find squid (record for marine mammal
dives); it is also the most vocal whale
d. museau du singe (French=monkey’s muzzle): structure in sperm whales that
makes clicking noises
e. blowhole: generates sound in toothed whales other than sperm whales
f. in the only recorded fight between a killer whale and great white shark, the killer
whale won
g. killer whales [orcas] are called the “wolves of the sea” due to their group hunting
habits
h. pod: social group of toothed whales
6. mysticeti: baleen whales; larger than toothed whales; the largest is the blue whale,
then the finback whale; also includes the humpback whale and right whale; make
low-frequency sounds with their tracheas
a. baleen: sieve-like plates made of the protein keratin; collect plankton in a whale’s
mouth; baleen whales feed on krill and other plankton
b. right whale is threatened by extinction due to over-hunting; it got its name
because it’s the “right” whale to hunt since it floats; it has experienced the
greatest net percent population decline of any whale
c. gray whale was endangered, but then its population bounced back
d. suction feeding: gray whales’ method of sucking up benthic organisms, then
filtering them out with their baleen
sea otters: the only marine mammals without blubber, but have thick fur to make up for it
polar bears hunt seals by sitting on ice near holes waiting until a seal comes up for a
breath
walruses are the only marine mammals with ivory
sea cows
1. Steller’s sea cow: a manatee species that went extinct in the 1700s shortly after its
discovery due to overhunting
2. most manatee deaths are caused by collisions with boats
pinnipeds [“feather-footed”] (seals and sealions)
1. true seals [earless seals]: earless, better adapted for aquatic movement, streamlined
snout
a. Caribbean monk seal: went extinct around 1950 due to overhunting
2. sealions [eared seals]: external ears, fur seal is a sealion, better adapted for terrestrial
movement, large foreflippers
XIII.
A.
B.
C.
D.
E.
F.
G.
H.
I.
J.
K.
XIV.
A.
B.
C.
D.
E.
F.
G.
H.
I.
J.
K.
XV.
A.
Echinoderms (echinoderm = spiny skin): have pentaradial symmetry
tube feet: water-filled tubes that allow an echinoderm (ex. starfish) to walk and grab prey
water vascular system: circulates nutrients around body
ampulla: structure by each tube foot that puts pressure on it to fill it up
stone canals and ring canals
madreporite: opening used to filter water into the water vascular system; found on the
aboral (non-mouth) surface of sea stars and sea urchins
urchin barren: area where sea urchins have devoured kelp forests because their predators,
such as otters, have declined
crown-of-thorns starfish: eats large amounts of coral
ossicles: the calcareous plates that form the skeletons of starfish and sea urchins
pedicillariae: tiny pincers used by starfish and urchins to destroy encrusting organisms
that try to settle on them
Aristotle’s lantern: powerful feeding apparatus of sea urchins used for grazing; it has 5
grinding teeth oriented circularly around an opening
evisceration: a defensive mechanism of sea cucumbers; they shoot out their internal
organs as a decoy and grow them back later
Arthropods
zoea: first planktonic larval stage of some crustaceans, such as crabs
cypris: larval stage of barnacles that attaches to a substrate
nauplius: planktonic larval stage of barnacles and copepods
chela (pl. chelae): large pincer claw of some crustaceans, such as lobsters and fiddler
crabs (these crabs have one huge claw and one small one)
chitin: the carbohydrate polymer that is the key component of the exoskeletons of
arthropods
water fleas [Daphnia]
euphausiids [krill]: small but macroscopic crustacean zooplankton
the largest lobster was an American lobster that was 1.06 m long
copepods: microscopic shrimp-like crustaceans that are the most numerous form of
zooplankton; have a nauplius and copepodite stage
amphipods: carnivorous or scavenging crustaceans with laterally compressed bodies
red crabs migrate in massive numbers across Christmas Island to lay eggs
Molluscs (mollusc = “soft body”)
hydrostatic skeleton: body is supported by internal fluid pressure
B. veliger: planktonic larval stage of some molluscs resembling their adult form; snails and
bivalves have this stage; occurs after the trochophore stage
C. visceral mass: group of organs
D. mantle: secretes calcium carbonate to make the shell
E. pearl: calcium carbonate coating applied by a mollusk’s mantle around an irritant
F. radula (pl. radulae): elongated organ used to scrape food off rocks
G. siphons: tubes that allow burrowing bivalves to take in water and filter out plankton for
food; used by cephalopods such as squids for jet propulsion through the water
H. Sepia: genus of cuttlefish, a cephalopod, that used to be the source of a certain brand of
ink that went by the same name before alternatives were developed
I. byssal threads [bivalve beard/hairs]: strong fibers produced by mussels to attach to other
objects
1. Mussels can use these defensively against dog whelks that try to eat them. They stick
their threads to the whelk, preventing it from moving, until it dries out.
J. pteropod: winged snails that are suspension feeders; use mucus webs to catch prey
K. ctenidia: feathery external gills of nudibranchs
L. cephalopods have complex nervous systems and are among the most intelligent
invertebrates
M. siphuncle: tube connecting each chamber in a nautilus
XVI. Zooplankton: floating heterotrophic organisms
A. foraminiferans [“hole bearers”]: microscopic zooplankton with calcium carbonate tests;
use slender pseudopodia that project through the test to catch prey
B. radiolarians [“living snowflakes of the sea”]: spherical microscopic zooplankton with
spiny silica tests; they have special branched pseudopodia, called axopodia, for capturing
prey
C. dinoflagellates: can be heterotrophic, but are discussed more under “Algae”
D. tintinnids: small, abundant, ciliates that use cilia for locomotion and eating; have vaseshaped shells made of protein
E. collection: plankton nets are used to catch plankton larger than 200 micrometers; smaller
plankton are collected in sample bottles and are concentrated by filtration or centrifuging
XVII. Algae: unicellular eukaryotic photosynthesizers that can be phytoplankton, epibenthos, or
nekton (dinoflagellates); retard sinking by increasing surface-area-to-volume ratio
A. kelp: large colonies of algae
1. Macrocystis [giant kelp]: fastest growing kelp; can grow 0.5 m per day and reach
lengths of 50 m; forms kelp forests along the west coast of North America
2. otters are keystone species because they eat sea urchins, which prey on kelp
3. anatomy
a. holdfast: structure that holds kelp in place like a roots do for a plant, except a
holdfast absorbs nothing
b. stipe: equivalent to the stem of a plant
c. blades: equivalent to the leaves of a plant
d. pneumatocysts: gas-filled air sacs that support the blades and stipes of brown kelp
B. phaeophyta [brown algae]: exist in temperate or cold-water areas; brown pigment is
fucoxanthin; yellow pigments are xanthophylls; includes large kelps and seaweed; algin
is a useful product obtained from these algae
1. Sargassum: a genus of planktonic macroalgae [seaweed]
C. chlorophyta [green algae]: common in freshwater environments, but are also found in
shallow marine regions; green pigment is chlorophyll, which contains magnesium;
colonies are small
1. Ulva [sea lettuce]
D. rhodophyta [red algae]: red pigment is phycoerythrin; this is the only type of algae
found in deep water below the euphotic zone because it reflects red light and absorbs
other colors that travel deeper into ocean
1. carageenans: any gelatinous molecules from red algae
2. agar: gel used for growing bacteria and fungi in laboratories; can be used as a
preservative or for industrial jam production
E. chrysophyta [golden algae]: cold-water phytoplankton; dominant pigment is carotin (a
type of carotene), which is yellow-orange
1. silicoflagellates: have an internal skeleton composed of siliceous spicules and a
flagellum
F. pyrrophyta (dinoflagellates, in Latin = “terrible whip”): have two flagella for locomotion;
some species can cause red tides; only some species are autotrophic; adapted to lownutrient conditions
1. theca: a thick cellulose cell wall carried by some dinoflagellates
G. bacillariophyta [diatoms]: phytoplankton with silica tests [frustules], which consist of
two valves, the epitheca and hypotheca; life span is 1 week; frustules can be centric
(radially symmetrical) or pennate (elongated and bilaterally symmetrical)
1. auxospore: zygote with no frustule that forms after two gametes join in sexual
reproduction
H. coccolithophores: warm-water phytoplankton with calcium carbonate plates [coccoliths]
1. White Cliffs, Dover, England: place with lots of chalk derived from coccolithophores
I. other
1. cyst: a dormant stage of some protists, such as diatoms, or bacteria that allow them to
survive through unfavorable conditions
2. accessory pigments: transfer light energy to chlorophyll-a, the dominant pigment;
different colored pigments absorb different ranges of light wavelengths
3. epontic algae: species that live in or on ice
4. epiphytes: grow on other plants or kelp
5. coralline algae: some species of green or red algae that incorporate calcium carbonate
in their tissues; they may contribute to reefs
XVIII. Worms
A. phylum nematoda: widespread and numerous roundworms
B. phylum nemertea [ribbon worms]: elongated worms with a proboscis that can be ejected
by hydrostatic pressure for capturing food
C. phylum hemichordata [acorn worms]: use a proboscis to capture food
D. phylum platyhelminthes: flatworms; many are free-living
E. phylum annelida: segmented worms
1. lugworm: creates a U-shaped tunnel and strengthens the walls with mucus
2. polychaetes: predators that have appendages called parapodia
a. beard worms: sessile worms that secrete tubes to live in and have a cluster of
tentacles projecting from the tube
i. giant tube worm: lives at hydrothermal vents and has a mutualistic
relationship with chemosynthetic archaebacteria, which it holds in a body sac
called the trophosome
F. chaetognaths [arrow worms]: small, streamlined carnivores; use clusters of hooks to catch
prey
G. trochophore: segmented, ciliated, larval form of organisms from several different phyla,
including mollusca, annelida, and nemertea
XIX. Other
A. tunicates live in mucus balloons called tunics; tunicates filter water through a mucus
membrane and forcibly eject the water, giving them the name “sea squirts”
XX. Classification of Life by Kingdoms: five-kingdom system was proposed by Robert
Whittaker, but is now somewhat deprecated
A. Monera: single-celled bacteria; simplest of the kingdoms; includes autotrophic and
heterotrophic bacteria
1. Prochlorococcus: bacteria responsible for at least half of the ocean's biomass
2. cyanobacteria [blue-green algae]: not really algae, but it does do photosynthesis in
tropical areas; builds stromatolites, mushroom-shaped structures, in layers; does
nitrogen fixation (N2 to NH3)
B. Protista: single-celled, eukaryotic organisms; includes autotrophs (algae) and
heterotrophs (protozoans)
C. Fungi: multi-cellular decomposers; includes molds and lichen; rare in ocean
D. Plantae: multi-cellular autotrophs; exist mostly in shallow coastal areas
E. Animalia: multi-cellular heterotrophs
XXI. Classification of Life by Domains
A. Archaea: simple prokaryotes similar to bacteria that thrive in extreme environments;
includes methanogens; close ancestors of eukaryotes
B. Bacteria: prokaryotes; many are decomposers
C. Eukarya: eukaryotes have a true nucleus in each cell
XXII. Animal Kingdom Taxonomy (subject to change in scientific community): taxonomy is
the systematic classification of life; Carolus Linnaeus developed the basis for modern
taxonomy; modern taxonomy levels are kingdom, phylum, class, order, family, genus,
species; 16% (250,000) of species live in the oceans
A. Phylum Porifera – sponges
B. Phylum Cnidaria
1. Class Scyphozoa – common jellyfish
2. Class Hydrozoa – Portuguese man-of-war (siphonophores), hydroids, hydra
3. Class Anthozoa – coral, sea anemone, sea whip, sea fan
C.
D.
E.
F.
G.
H.
I.
J.
K.
L.
4. Class Cubozoa – toxic cube jellyfish
Phylum Ctenophora – comb jellies
Phylum Platyhelminthes – flat worms
Phylum Annelida – segmented worms
Phylum Nematoda – round worms
Phylum Arthropoda
1. Subphylum Crustacea – lobster, shrimp, crayfish, barnacles, crabs
a. Order decapoda – shrimp, lobsters, crabs
2. Subphylum Pycnogonida – sea spiders
3. Class Arachnida – spiders
4. Class Insecta
Phylum Mollusca
1. Class Gastropoda – nudibranch (sea slug), snails
2. Class Bivalvia – clams, oysters, mussels
3. Class Cephalopoda – nautilus, octopus, squid, cuttlefish
4. Class Polyplacophora – chiton
Phylum Echinodermata
1. Class Echinoidea – sea urchin, sand dollar
2. Class Holothuroidea – sea cucumber
3. Class Asteroidea – starfish
4. Class Opthuroidea – brittle star
5. Class Crinoidea – feather stars, sea lilies
Phylum Bryozoa – moss animals
Phylum Brachiopoda – animals that look like bivalves
Phylum Chordata
1. Subphylum Urochordata - salps/tunicates/sea squirts
2. Subphylum Cephalochordata - lancelets
3. Subphylum Vertebrata
a. Class Agnatha (jawless fish) – hagfish [slime eel], lamprey
b. Class Chondrichthyes (cartilaginous fish) – sharks, rays, skates
c. Class Osteichthyes (bony fish)
d. Class Amphibia
e. Class Reptilia – sea turtles
f. Class Aves – birds
g. Class Mammalia
i. Order Carnivora – polar bear, sea otters
 Pinnipeds – seals, sealions, walruses
ii. Order Cetacea – whales, dolphins, porpoises
iii. Order Sirenia – manatees, dugongs [sea cows]