Phylum Cnidaria .
9400 species...4 classes..
free swimming and bottom
microscopic to several
radially symmetrical with
cells arranged into
posses tentacles and
2 layer body wall with
non-living jelly-like wall containing elastic
fibers to allow movements
in between with digestive cavity
Scyphozoa, Cubozoa, and Anthozoa
2 distinct life history
phases, free swimming Medusa and sedimentary polyp.
primitive Many consist of feathery or bushy colonies of tiny polyps.
They are attached to
pilings, seaweed, shells and other surfaces. The Siphonophores are hydrozoans
in drifting colonies.
Some polyps form floats,
others form long tentacles to capture prey. Portuguese man-of-war is an
fish has digestive system is a set of radiating canals linking the central
portion to a peripheral ring. Some mesogleas can expel heavy chemical ions and
replace them with lighter ones to adjust buoyancy.
class Cubozoa, which includes box jellies and sea wasps
medusa is box-shaped and has complex eyes
Class Anthozoa Corals
and sea anemones only exist as polyps.
The sea anemones always
bear more than eight tentacles .
Some burrow in mud but
most dwell on a hard substratum, cemented there by secretions from a well
are hard corals whose polyps are encased in a rigid calcium carbonate skeleton.
Most hard corals live in colonies which are composed of vast numbers of small
polyps (about 5mm) but can be larger in solitary forms .
Most are subtropical or tropical
in distribution. In colonial forms, the polyps are interconnected laterally
forming a living sheet overlying the skeleton.
Corals exhibit a great
diversity in growth forms, ranging from delicately branching species to those
whose massive skeletal deposits form the building blocks of the reef.
On type, Meandrrina,
the polyps are arranged continuously in rows, resulting in production of a
skeleton with longitudinal fissures, a feature which accounts for its name,
There is an order related
to the hard corals without a skeleton that are anemones which can cover rock
faces. The black or thorny corals form a slender, plant-like colonies arranged
around a horny axial skeleton and possess numerous thorns
Octocorallian corals have
eight featherlike tentacles and an internal skeleton like structure. These
include the horny corals, sea whips and fans and red coral. Most of these have
ancestral rod composed of organic material around which is draped the
coenenchyme and polyps, the former containing spicules which impart a vivid
coloration and form the spines of the red coral which is used in jewelry.
To trap prey, cnidarians
normally employ stinging cells which are discharged (under nervous control?)
sometimes exposing barbs and frequently contain a toxin that can enter the body
of the prey. Some are extremely potent (sea wasps ) and have killed humans...respiratory
paralysis. Sea slugs are known to pirate Nematocysts (stinging cells) and use
them for their own protection.
Comb Jellies Phylum: Ctenophora
About 90 species ...worldwide and marine distribution.
4cm to 1m in size.
.radial symmetry with eight rows of plates..fused cilia (comb)
Fewer than 100 species have been described. They are
classified on the basis of their
1. These are a group of bi-radial
jellyfish called comb jellies because of the presence of ciliated comb plates
used in locomotion. Their
beating refract light creating a prism-like multicolor effect. Each row is a
series of small paddles and each paddle is
composed of thousands of
tiny cilia. Collectively, the cilia produce a color spectrum in much the same
way as a diffraction grating or the surface of a compact disk. Entirely marine
and mostly pelagic or planktonic...some can creep.
2. Only body cavity is
the gastrovascular cavity in the form of canals.
3. The body wall is
composed of an epidermis, layer of collenchyme, and a gastrodermis. Collenchyme
contains amoebocytes, connective tissue and true muscle cells, so
its more advanced than the mesoglea in cnidarians.
4. Most ctenophores
possess on their tentacles adhesive cells called colloblasts. The tentacles are
used for catching prey and
balancing organs (nematocysts in cnidarians and only one
5. Skeletal structures and excretory and respiratory organs
6. Varied shapes
7. Well developed
statocyst at pole and a nerve net system in epidermis
Comb jellies are
virtually all true plankton (drifters)-dwellers whose almost invisible
transparent bodies drift in the oceans trailing tentacles like fishing lines.
These are armed with
lasso cells that explode and ensnare their microscopic prey.
Class Tentaculata with
Order Lobata Mnemiopsis
Order Cestida Velamen
Class Nuda without
Order Beroida Beroe
Three phyla of marine animals, Ectoprocta, formally Bryozoa,
Brachiopdoa and Phoronida, are characterized by a lophophore, a circular or
U-shaped ridge around the mouth bearing either one or two rows of ciliated,
Because of this unusual feature, they are thought to be
related to one another.
The coelomic cavity of them lie within the lophophore and its
tentacles and the anus is always elsewhere.
The lophophore functions in these animals as a food collection
organ and as a surface for gas exchange.
They are attached to the substratum or move slowly, using the
cilia of the lophophore to capture the plankton on which they feed.
Phylum Phoronida resemble common tube worms seen on dock
Look like polychaete worms.
They secrete a chitinous tube within which it lives out its
life and they also extend tentacles to feed and quickly withdraw them when
disturbed but that's where the resemblance to the tube worm ends.
is one of the smallest and least familiar phyla; there are about twelve or so
living species in two genera, Phoronis and Phoronopsis. However, phoronids --
or "horseshoe worms," as they are sometimes called -- may be abundant
in shallow marine sediments at certain localities.
elongated and worm- shaped, but the gut loops and ends close to the mouth,
instead of passing straight through the body as in annelids and many other
There is no straight
tube within a tube but a U-shaped gut within a sac.
Only 12 species are
known ranging in length from a few mm to 30 cm.
Some lie buried in sand
and others attach to rocks signally or in groups.
Phylum Ectoprocta (Bryozoa) look like tiny short versions of
the phoronoids ..small .5mm and colonial and called moss animals.
The new name, ectoprocta refers to the location of the anus
(proct) which is external to the lophophore.
4000 species include marine and freshwater forms..only
Most live in shallow water but some live at 18,000 feet.
Individuals secrete a tiny chitinous or limestone chamber,
ZOECIUM, attached to other members of the colony and to rocks.
Individuals communicate chemically through pores between
Their taxonomy depends on the sizes shape, and organization of
The arrangement of the zooids on the colonies is also highly
variable. Some are important as pests as they can foul up piers, pilings, buoys
and ship hulls.
PHYLUM BRACHIOPODA or
clamlike organism that are permanently attached to the substrate and possess a
complex lophophore, which consists of two spiral ciliated tentacles resembling
The LOPHOPHORE is a circular or U-shaped ridge around the
mouth bearing either one or two rows of ciliated, hollow tentacles
The lamp shells resemble clams because they have two shells
but these shells are hinged so that one shell covers the top and the other its
bottom side (dorsal and ventral whereas the clam its the left and right side.
Many species attach to rocks or sand by stalks that protrude
from within the shell, a contractile muscle called the PEDUNCLE, while others
become cemented by shell secretions to the substratum.
These shells feed on particles suspended in the water, the
cilia creating water currents sweeping food particles onto the lophophore which
lies within the shell (as opposed to others that are outside).
There are only 300 species of brachiopods existing today but
more than 30,000 species are known as fossils with the genus Lingula having
fossil records back to 500 million years.
Worms... Nematode sea worms are the most numerous of all sea
or land animals with an estimated population of 40 septillion.
The convoluta worm feeds only once in its life feeding off a
special algae and is sustained by starches made through photosynthesis by the
algae it swallowed.
modern reports say that Convoluta roscoffensis needs the algal cells (Platymonas
convoluta) to survive. The algae cells inside the worm are rounded and
hardly look like an algal cell. However when they are released into the sea
water the quickly change shape and swim to nearby flatworm eggs where they
burrow inside the eggs and grow and multiply inside the developing flatworm
embryo. Another species, Convoluta paradoxa is thought to have
photosynthetic diatoms in its tissues.
Biology of the acoel flatworm Convoluta roscoffensis
sandy beaches of the bretonic coast (near Roscoff, Carantec, Carnac, La Trinite
sur mer) are well-known habitats of the acoel flatworm Convoluta
roscoffensis (order: Acoela, phylum: Platyhelminthes) which
can be found there in summer time on a massive scale.
All photos and information kindly provided by:Arthur Hauck,
low tide, when water puddles form at sandy beaches, Convoluta roscoffensis gather
together at the surface of these warm floodlit pools to provide optimal
photosynthetic conditions to their symbiont Tetraselmis convolutae, a
green alga living inside the flatworm's body.
first glance the green coloration of sea water puddles seems to be caused by
massive accumulations of algae. However, at closer observation color is
obviously due to millions of tiny green flatworms (up to 15 mm in length)
continuously moving around.
roscoffensis up to 25.000 algae per individuum have been counted. After
entering the adult phase, crucial anatomical changes such as loss of a
functional pharynx and mouth, demonstrate that the worms now completely rely on
their endosymbionts. They have become photoautotrophic organisms consuming
sugars provided by the symbiontic algae.
relationship between Convoluta roscoffensis
and Tetraselmis convolutae shows typical
features of a true symbiosis that are
depicted on this flow scheme.
Phylum Platyhelminthes...flatworms...3 layers, organs, no
anus. They are the only worm like creature without an anus, use cilia on the
bottom to glide along the surface and have muscle contraction in the body
These animals are worm like...tapeworms, planaria flukes and
There is a free-living flat worm that lives in the book lungs
of a horseshoe crab, a tapeworm in the digestive system of the whiting fish
some live on the beards or threads of mussels and one lives on the sandy
beaches in France...bright green!
Phylum Nemertea...ribbon worms...900 species..most marine.
Like flatworm but has one way digestive system and circulatory system . Usually
very highly colored and found burrowing in sand and mud on the shore or in
crevices of rocks. Some can swim and most capture their prey.
The most distinctive feature is a proboscis, a long fleshy
tube to entangle prey . Though common, some are nocturnal and not usually seen,
and others are found under rocks at low tide. They are very elastic. They are
of little economical or ecological importance.
Phylum Nematoda or round worms usually found in sediments ,
especially rich organic matter. Many can even live nicely in tissues of other
organisms. The actual number is debatable 10-15,000 but maybe more like 1/2
Phylum Annelida segmented worms 13,000 species mainly the
Polychaetes make up the marine annelids. (6,000 species) They have short
extensions or parapodia with stiff sharp bristles or setae often with gills on
them for respiration. The life cycle includes a trochophore larval feeding
stage...like other groups of invertebrates.
1900, a strange tube-dwelling worm was dredged from deep waters around Indonesia.
While somewhat resembling tube-dwelling annelids, it lacked obvious
segmentation; even more strangely, it also lacked a mouth, gut, or anus.
80 pogonophoran species are known today, with new species still being
discovered. One of the most spectacular zoological discoveries of recent years
was the finding in 1977 of giant pogonophoran worms, 1.5 meters long, growing
in heated, sulfur-rich water around warm-water vents in the Pacific Ocean, 2600
meters below the surface
do pogonophorans feed with no mouth or gut? Some nutrition is provided by
absorbing nutrients directly from the water with the tentacles. But most of a
pogonophoran's nutrition is provided by symbiotic bacteria living inside
the worm, in a specialized organ known as the trophosome that develops
from the embryonic gut.
the trophosome, these bacteria oxidize sulfur-containing compounds such as
hydrogen sulfide, which pogonophorans absorb through their tentacles -- the
bright red color of rift-dwelling pogonophoran tentacles is due to hemoglobin,
which absorbs both sulfides and oxygen for the use of the bacteria. The
bacteria derive energy from sulfur oxidation, which they use to fix carbon into
larger organic molecules, on which the pogonophoran feeds.
They include sandworms, bloodworms, fanworms or featherduster
worms, palolo worms and a variety of tube dwelling worms. These can make tubes
from mucus, protein, mudgrains, bits of seaweed, shell fragments etc..
low mounding structures that form living reefs along Floridas coast are made
by numerous tiny marine bristle worms of the family Sabellariidae (sa - bell-
AIR - id - ee). Each worm settles onto a hard, durable surface and begins to
construct a protective tube out of the surrounding sand.
Sabellariid worms attach their tubes to their neighbors tubes, forming large
colonies which grow into massive mounding reefs. These reefs are sometimes
exposed at low tide, creating tide pools and providing habitat for many marine
organisms. An outstanding example of this type of reef is found at Bathtub Reef
Park on Hutchinson Island, just 3 miles south of the Florida Oceanographic
Society, and just north of the St. Lucie Inlet
species of Sabellariid worm found in our area is called Phragmatopoma caudata.
The Adult worms are up to 2 inches long and 1/8 inch in diameter, although most
worms are closer to Ύ inch long. These worms can be found building their reefs
on limestone and coquina formations, jetties and pilings from Cape Canaveral to
the south end of Biscayne Bay.
different species of marine organisms live around these reefs. This makes them
excellent places to go snorkeling on calm days.
worms build sand hoods over their tubes to protect themselves from drying out
in the sun at low tide. Walking on a living worm reef crushes these hoods into
the tubes, sealing them, and killing the worms. People should never walk on,
scrape, or break pieces off the worm reefs.
Feeding methods relate to the locomotion and many are either
suspension feeders/deposit feeders or just plain carnivores.