Terms to Know:
Animalia
vertebrate
invertebrate
sponges
Phylum Porifera
spicules
choanocytes
porocytes
porocytes
osculum
symmetry
filter feeder
spongin
larvae
symmetry
radial symmetry bilateral symmetry
Phylum Cnidaria oral surface
aboral surface
polyp
medusae
nematocysts
Class Hydrozoa Siphonophore
Portuguese Man O' War
Class Scyphozoa
Class Anthozoa Class Cubomedusae
jellyfish
sea anemone
coral
Stony Coral
Australian Box Jellyfish nerve net
Phylum Ctenophora Comb Jellies
colloblass
dorsal
ventral
lateral
anterior
posterior
Flatworm
Phylum Platyhelminthes
Class Turbellaria Class Trematoda
Class Cestoda
fluke
tapeworm
endoderm
mesoderm
ectoderm
parasite
Phylum Nemertea ribbon worm
Phylum Nematoda roundworm
Phylum Annelida
segmented worm Class Polychaeta
Class Oligochaeta setae
parapodia
Nereis
Class Hirudinea Phylum Mollusca
Class Gastropoda Class Bivalvia
Class Cephalopoda mantle
gill
Open circulatory system
radula
Calcium carbonate chitin
siphon
Nudibranchs
Seaslug
ink sac
octopus
squid
nautilus
cuttlefish
Cone shell
architeuthis
Kraken
Australian Blue Spotted Octopus
sessile
exoskeleton
Phylum Arthropoda Class Decapoda
Class Amphipoda Class Isopoda
Subphylum Crustacea antennae
Barnacles
Krill
shrimp
Crab
cephalothorax
abdomen
Hermit Crab
cheliped
swimmerets
maxillipeds
Cirri
compound eyes Horseshoe Crab
Class Merostoma Phylum Echinodermata
endoskeleton
Water Vascular system tube feet
ampullae
madreporite
pedicellariae
radial canal
lateral canal
Class Asteroidea Class Ophiurodea
Class Echinoidea Class Holothuoidea
Class Crinoidea
Sea Stars
Brittle Stars
Sea Urchins
Sea Cucumbers
feather Stars
Sea Lilies
Sand Dollar
Aristotle's Lantern Phylum Hemichordata
Phylum Chordata Dorsal Nerve cord
Pharyngeal Gill slits notochord
Protochordate
Subphylum Urochordata Class Ascidiacea
Sea Squirts
Class Thaliacea Salps
tadpole larvae
Subphylum Cephalochordata
Lancelets
Outline of Chapter :
I. General
A. Chapter is largely a list of marine
animals without backbones and their characteristics
1. all
lack a true backbone
2. invertebrates
show a huge range of complexity
3. may
have no, radial or bilateral symmetry
II. . Phylum Porifera - Sponges
A. Characteristics
1. have no true tissues
2. have specialized cells
a. choanocyte - moves water via a flagella
b. porocytes provides water channels
3. have no symmetry
4. have defensive spicules embedded in body
5. openings to outside for water discharge are called osculum
6. all filter feeders
7. sexual and asexual 9 reproduce by cloning or amphiblastula larvae
III.. Phylum Cnidaria - stinging cell animals (Jelly fish, sea
anemones, corals, hydrozoans)
A. Characteristics
1. body consists of only 2 tissue layers
a. each cell can directly exchange materials and waste with their environment
b. no specialized organs
c. loose net of nerve cells coordinate weak muscle cell contractions of
bell or body
2. all have specialized stinging cells - nematocysts
a. nematocysts consist of a trigger, water filled cell and a capped hair
like stinger
1. fire automatically upon touch
b. can still fire and sting on a dead animal
c. all cnidarians are carnivores
d. many are adapted as filter feeding organisms, catching small prey from
the water
e. anemones and corals directly compete for space by stinging one another
f. some stings can be dangerous to humans
1. Portuguese Man O' War
2. Australian Box Jellyfish and other Cubomedusae
3. has a blind, one way digestive cavity
a. oral surface
b. aboral surface
4. mouth surrounded by stinging tentacles
B. Taxonomy
5. Class Scyphozoa are jellyfish
a. have a medusae dominant body form
6. Class Hydrozoa are hydroids and colonial forms
a. have alternating generations
1. medusae are sexual forms, give rise to polyp generation which is clonal
2. some have only polyp generations
3. Portuguese Man O' War was our example of a dangerous , colonial Siphonophore
7. Class Anthozoa - Flower animals
a. polyp form is dominant
1, anemones, corals
2. body is like an inverted jellyfish
3. Stony Corals produce skeletons of calcium carbonate
4. only the out surface of stony corals is alive
a. new growth accumulates on top of old skeleton
5. Polyps exist inside of pockets of secreted mineral
a. Great Barrier Reef of Western Australia is the largest Biological structure
on earth
8. Class Cubomedusae
a. based on extreme toxicity and anatomy, Box Jellies are in a class of
their own
IV. Phylum Ctenophora - Comb Jellies
A. Characteristics
1. All similar to jellyfish
a. radial symmetry
b. mostly water
2. No stinging cells
a. have sticky colloblasts instead
b. all carnivorous
3. only two tentacles , when present
4. two tissue layers in body
5. one opening to digestive cavity
6. Key feature is the presence of 8 rows of cilia by which jellies swim
7. many exhibit bioluminescence
V. Phylum Platyhelminthes - Flat Worms
A. Characteristics
1. Bilaterally symmetrical
a. have dorsal, ventral, lateral, anterior and posterior directions and
surfaces
2. body consists of 3 true tissue layers
a. endoderm, mesoderm and ectoderm
3. have distinct nerve cords - central nervous system
a. have distinct ganglia an sensory organs
b. primitive eyes
4. digestive cavity has only 1 opening
a. may be predatory, herbivorous or parasitic
1. parasitic forms have lost many anatomical features of free living forms
5. small - no circulatory system
B. Taxonomy
1. Class Turbellaria
a. marine flatworms
b. small - free living
c. intensely colorful if aposematic forms
d. maybe cryptic in coloration
2. Class Trematoda
a. flukes
b. parasites
c. have complex life cycles involving an invertebrate and a vertebrate
hosts
d. Blood and Liver flukes were examples
e. many are found embedded in muscle of fish
3. Class Cestoda
a. tapeworms
b. reduced to a head(scolex) and reproductive proglottids
c. intestinal parasites
1. 50 feet long in one species which infects sperm whales
2. most with complex life cycles involving multiple host species
VI. Phylum Nemertea - Ribbon worms
A. Characteristics
1. have a true circulatory system
2. two opening, complete digestive tract
3. distinct proboscis used to entangle prey
4. shallow water, bottom dwellers
5. small in diameter, but one species reaches 100 feet in length
VII. Phylum Nematoda - Roundworms
A. Characteristics
1. Three tissue layers
2. hydrostatic skeleton
3. complete digestive system
4. typically very small, exist in large numbers
5. function largely as decomposers in marine environments
6. some species are adapted as intestinal parasites
a. Anisakis in seals and dolphin
VIII. Phylum Annelida - Segmented worms
A. Characteristics
1. 3 tissue layers as all animals from here on do
2. body has a segmented plan
a. allows specialization of segments
b. each segment has a hydrostatic skeleton
c. central nervous system with branches to each segment
d. head segment highly specialized in some
1. sensory structures -eye, antennae
2. feeding apparatus - proboscis, jaws
3. tentacles
3. complete , closed circulatory system
4. complete digestive system
5. some with gills
6. true body cavity called a coelom
7. many different life histories
a. predators
b. filter feeders
c. deposit feeders
d. all of the above may be benthic burrowers
e. many free swimming and planktonic forms
B. Taxonomy
1. Class Polychaeta
a. comprise most all marine annelids
b. have parapodia
c. have numerous setae (bristles) on each segment
1. may be heavily adapted to various applications
2. ex: filter feeding structures of Christmas tree worms
d. have gills
e. have a proboscis with teeth
1. some mildly venomous
f. have a trochophore larvae
g. examples include: Nereis, Platynereis, Christmas Tree and Feather Duster
worms.
2. Class Oligochaeta
a. earthworms and related forms
b. no highly developed head and segment structures
c. only a few setae per segment of body
e. inconspicuous mud and sand dwellers.
1. small, numerous and important to sediments in some areas
3. Class Hirudinea
a. leeches
b. bodies similar to oligchaeta but with a sucker on both ends
c. mostly fresh water but a few are predatory on marine fish and invertebrates
IX. Worm odds and ends
A. Phylum Sipuncula - peanut worms
B. Phylum Pogoniphora - Beard worms
1. vestmentiferan tube worms* - deep hydrothermal vent communities
C. Phylum Chaetognatha- Arrow worms
X. Phylum Mollusca - Snails, clams, octopus, squid, etc.
A. Characteristics
1. all have a mantle tissue
a. secretes calcium carbonate shell in many
b. in octopus and squid, mantle has become a water cavity
1. can contract to force water over the gills
2, can contract to pump a jet of water out of the siphon for swimming
2. in , squid, and cuttlefish, shell is reduced and internal, absent
in octopus
3. Most have a well developed head with sensory structures
4. body is unsegmented and has a muscular foot
a. bilateral
b. paired gills
c. open circulatory system in all but cephalopods
d. two opening, complete digestive system
5. many have a radula
a. made of chitin
b. barb or file like feeding structure
6. Life histories
a. predatory - example: Welks, Cone Shells, Octopus
b. burrowing filter feeders - example: Clams
c. free swimming filter feeders - example: Scallops
d. sessile, attached filter feeders - example: Oysters
e. free grazing herbivores - example : Sea Hare
B. Taxonomy
1. Class Gastropoda - Snail like forms
a. single shell
1. many can retract body into shell
2. shell may be coiled, straight, tubular
b. shell may be absent as in sea slugs (Nudibranchs)
c. well developed head
1.eyes
2. sensory tentacles
3. radula
d. well developed muscular foot
e. Examples: Welks, Conchs, Cones, Olive Shells,
f. Cones are active predators which use toxins delivered by a proboscis
stinger
2. Class Bivalvia - clam like species
a. two shells
1. hinged shells are closed by muscle
2. some have eyes
a. scallops
3. no well developed head
a. no radula
4. mantle is developed into siphons for directing water into mantle cavity
5. gills are expanded and serve to filter food particles from water as
well as for respiration
6. Examples: Clams, oysters, Coquinas, Scallops,Mussels
3. Class Cephalopoda - Octopus, squid, cuttlefish, nautilus - most highly
developed invertebrates
a. well developed heads
1. mouth ringed by tentacles with suction cup grips
2. parrot like beak
3. some with venom glands - Australian Blue Spot Octopus
4. well developed eyes
5. well developed nervous system and brain
a. complex behavior
b. intelligent
c. communicate with color and behavior
d. complete, closed circulatory system
6. most are able to control color and patterning of skin to an extreme
degree
a. use contractile chromatophores
b. many exhibit bioluminescence
c. many can alter shape to mimic surroundings
7. Mantle is developed into a muscular cavity
a. pumps water over the gills
b. can jet water through a muscular siphon tube for swimming
8. Shell
a. is absent in Octopus
b. reduced and internal in squid and cuttlefish
c. elaborate, coiled floatation device in nautilus
9. all have ink sacs for defense
10. Octopus
a. 8 tentacles
b. examples:
1. Australian Blue Spot - extremely venomous bite
2. Pacific Giant Red Octopus - 30 feet across
11. Squid
a. elongate body
b. efficient swimmers
c. 10 tentacles
1. 2 of them are highly retractable and modified for hunting
d. shell is internal and reduce to a "pen" of chitin only
e. Example : Architeuthis - giant squid
1. maybe the origin of the "Kraken" myth
2. largest specimen is 66 feet long
a. some report much larger sightings
3. no live specimen has been obtained or filmed
a. some obtained from Sperm whale stomachs
b. decomposing specimens have washed ashore
4. apparently extremely deep water species
5. tentacles have cutting teeth in the suckers
4. Other molluscs
a. Class Polyplacophora - chitons
b. Class Scaphopoda - tusk shells
c. Class Monoplacophora - Limpets
XI. Phylum Arthropoda - animals with a jointed exoskeleton
A. characteristics
1. Body plan is segmented
2. segments are specialized
3. covered in a rigid exoskeleton of chitin (may have mineral embedded
into shell)
a. support
b. armor
c. jointed, specialized legs
1, many have highly modified legs associated with the mouth and feeding
structures
4. open circulatory system
5. well developed nervous systems
6. well developed heads
a. sensory structures - eyes, antennae
7. Must shed rigid shell in order to grow = molt
B. Taxonomy
1. Subphylum Uniramia - Insects NO marine insects
2. Subphylum Chelicerata
a. Class Pycnogonida - sea spiders
b. Class Merostomata - horseshoe crabs
3. Subphylum - Crustacea
a. exoskeletons are hardened with calcium carbonate
b. have two pair of sensory antennae
c. specialized legs
d. segments are variously fused in differing groups
4. Small Crustaceans
a. Class Copepoda - Copepods - abundant species in plankton community
1. filter feeders
2. use antennae to swim
3. some are parasitic
b. Class Cirripedia - barnacles
1. Bodies covered with an exoskeleton that secretes calcium carbonate shell
2. lead a sessile , attached life
3. filter feeders - legs modified into cirripedia filtering apparatus
4. fouling organisms attach to any surface - even whales
c. Class Amphipoda - amphipods - beach hoppers
d. Class Isopoda - isopods - sand fleas
5. Large Crustaceans - Class Decapoda - 10 walking legs
a. crab, shrimp, lobster ,krill
b. chitin shell contains calcium carbonate
c. forward segments are fused into a cephalothorax
d. abdomen consists of numerous muscular segments
1. fused , reduced and folded under in crabs
2. lobster, shrimp and krill have swimmerets
e. three pair of maxillipeds associated with the mouth
f. first pair of walking legs are modified to Cheliped (claws) in some
g. have compound eyes
h. Most have larvae which spend time in the plankton community before metamorphosing
1. zoea and megalopa stages of crabs
h. examples:
1. North Atlantic Lobster - max 3.3 feet 42 lbs
2. Japanese Spider Crab - max 13 feet - 40 lbs
3. Atlantic Blue Crab - Callinectes sapidus
4. Pink shrimp - Paneus species
5. Krill ( Order Euphausiacea) - school in billions in polar waters - food
source for whales,
sea birds, penguins, etc.
XII Phylum Echinodermata - Spiny Skins (starfish, sea urchins, sand
dollars , sea cucumbers and crinoids)
A characteristics
1. Radial symmetry
2. complete digestive tract
a. Starfish extrude stomach
3. water vascular system and tube feet
a. ampullae squeeze water into tube foot from radial canals
b. water enters system via a sieve plate - madreporite
c. tube feet extend along ambulacral groove
4. internal skeleton of bony plates embedded in skin
5. considered to be the invertebrates most closely related to vertebrates
B. Taxonomy
1. Class Asteroidea - sea stars
a. pentaradial
b. usually 5 arms, but may be 50
c. extrude stomach
d. reduced spines into pedicelliarae - pincher feet
e. skeleton consists of hinged , semi flexible plates
e. predators on molluscs
2. Class Ophiuroidea - Brittle Stars
a. Similar to sea stars
b. central body is sharply distinct from the 5 arms
c. arms are long, slender and flexible
d. feed mostly on detritus picked up from the bottom by tube feet
3. Class Echinoidea - Sea Urchins
a. internal skeleton forms a round central chamber called a test
b. test is covered in movable spines in jointed sockets
c. most feed on algae and encrusting animals
d. have elaborate mouth and jaws\ Aristotle's Lantern
e. species that burrow are sand dollars and heart urchins
1. flattened
2. reduced spines
4. Class Holothuroidea - sea cucumbers
a. most are detrtus feeders/burrowers
b. body is like an elongate sea urchin (top to bottom)
1. worm like
2. skeleton is reduced to small spicules embedded into skin
c. novel form of defense is to eviscerate themselves
5. Class Crinoidea - sea lilies
a. sessile , attached life as filter feeders
b. central body attaching to substrate by pincher feet
c. numerous arms radiate from central body as a filter (up to 200)
d. food particles passed to mouth by tube feet in ambulacrul groove
XIII . Hemichordates - study along with the next chapter