Lesson Outline

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Lesson Outline
I. Protozoans
II. Porifera
III. Cnidarians
IV. Ctenophores
V. Worm Phyla
VI. Mollusks
VII. Bryzoans
VIII. Arthropods
IX. Echinoderms
X. Chordates
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Taxonomic Hierarchy

• The animal kingdom is divided into major groups
  called phyla.

Each phylum is divided into smaller groups called
classes, and so on down to the smallest groupings
called genus and species
Kingdom Phylum Class Order Family G
enus Species
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Animal Kingdom Tree
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Phylum Protozoa
The protozoa (first animals) are single-celled
animal plankton called zooplankton.
Two important marine protozoa are

• Foramanifera

• Radiolaria

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Noctiluca
Noctiluca feeds on plankton, such as diatoms and
dinoflagellates, and can grow up to 1 mm in
length.
Noctiluca is bioluminescent, capable of producing
its own light. They cause the sea to glow when
the water is disturbed, perhaps confusing
would-be predators with eyes adapted to the
dark.
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Niches

• A niche is an ecological term used to describe
  the functional role an organism plays in its
  environment and, in particular, where it lies in
  the food chain.

For example, a foraminiferan is a single celled
animal that feeds on diatoms and dinoflagellates
in the plankton.
The term zooplankton is also used to describe its
niche. A zooplankton organism lives in the
plankton and consumes other plankton, both plant
and animal.
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Foraminifera
Foraminifera are single-celled animals that feed
on phytoplankton.
Forams have porous shells of calcium carbonate
called tests.
Spines and cytoplasmic extensions from the test
trap small particles of food.
Upon death, the tests fall to the ocean floor
where they may comprise an important fraction of
the sediments that accumulate on the deep sea
bottom.
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Radiolaria
Radiolaria form porous, symmetrical, glass-like
shells made of silica.
Like forams, radiolarians have spines to ensnare
food. They also have pseudopods for capturing
prey.
They are most abundant in warm equatorial waters.
The bottom sediments in these regions are
dominated by radiolarian ooze.
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Porifera
The Porifera are the sponges, or the
pore-bearing animals.
Approximately 5000 species of sponges are known,
of which more than 95 are marine.
Sponges are benthic animals, found in nearly all
marine regions from the intertidal to the
deep-sea.
Generally, sponges are sessile, though it has
been shown that some are able to move slowly (up
to 4 mm per day) within aquaria.
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Filter Feeders
Sponges are benthic filter feeders.
Water is drawn in through small pores in the
outer walls by the beating of internal,
flagellated cells.
These cells filter particles from the water as
the water is pumped through the internal canals
and chambers, then out other larger openings.
The flow of water through the sponge is
unidirectional, driven by the beating of the
flagella of the internal cells.
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Cnidaria (Coelenterata)
The name Cnidaria comes from the Greek word
cnidos, which means stinging nettle.
The cnidarians include jellyfish, anemones,
corals, and hydras.
The members of this phylum are characterized by a
gelatinous bodies, tentacles, and stinging cells
called cnidoblasts.
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The Structure of a Cnidoblast.
The stinging cells, cnidoblasts, contain small,
sometimes toxic darts coiled up in a capsule.
When the trigger is touched, the stinging cell
releases the coiled, barbed thread, which wraps
around or injects a paralyzing toxin into the
prey.
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Cnidarians
There are three major classes within the phylum
Cnidaria

• Hydrozoa

• Scyphozoa

• Anthozoa

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Class Hydrozoa
Many hydrozoans are colonial, existing as large
colonies of individual members. The most
well-known hydrozoans are the fire-coral and the
Portuguese Man-OWar.
Fire corals often cover other structures
including corals, but they are not a true coral.
They are usually tan-colored with whitish tips.
Fire coral is a sessile benthic predator that
kills its prey with a powerful sting.
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Portuguese Man OWar
The Portuguese Man OWar is also a colonial form
of hydrozoa.
The float is a gas-filled member of the colony.
Other members hang downward from the lower
surface of the float some of these have stinging
cells.
These organisms are able to kill sizable fish
with their tentacles.
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Class Scyphozoa
Scyphozoans include most of the jellyfish
familiar to beach-goers and divers.
Some jellyfish are pelagic, free-swimming forms
of the open ocean.
Most species are planktonic, and one order, the
Stauromedusae, are sessile on the ocean floor.
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Jellyfish
Jellyfish range in size 12 mm to more than 2 m
across.
Their life cycle involves an alternation between
sessile polyp stage and a free-swimming medusa
stage, though the medusa stage, shown here,
usually predominates.
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Class Anthozoa
This class consists of the true corals, the sea
fans, and the sea anenomes.
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Coral
Anthozoans live exclusively as polyps.
While they retain their stinging cells and may
feed on prey or particulate food, some anthozoans
supplement their diet by growing symbiotic algae
in their tissues.
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Coral Reefs
Most hermatypic (reef-building) corals of the
tropics have symbiotic algae, called
zooxanthellae, living inside their tissues.
For this reason, reef-building corals are
exclusively shallow-water dwellers without light
they cannot survive (although solitary corals and
anemones may inhabit much cooler and deeper
waters).
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Sea Anemones
Sea anemones are soft-bodied anthozoans that
usually attach to rocks or coral.
They have a central mouth surrounded by tentacles
with stinging cells.
Anemones are found in coastal areas all over the
world, especially in warmer waters.
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Phylum Ctenophora

• The common name for this group is the comb
  jelly. The species Mnemiopsis leidyi is found
  in local waters.

These are about the size of a fist, and have a
jelly-like body. Comb jellies are not jellyfish,
and they lack stinging cells.
Ctenophores entrap plankton and detritus with a
single pair of tentacles out the back of the
animal. Their niche is that of a plankton
predator.
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The Worm Phyla

• Three phyla contain most of the prominent marine
  species of worms.

• Platyhelminthes (Flat worms)

• Nemertea (Ribbon worms)

• Annelida (Polychaete worms)

The marine species in these groups are primarily
benthic detritus feeders, an important niche at
the base of the detritus food chain.
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Class Turbellaria (Platyhelminthyes)

• These small, nonparasitic flatworms live in the
  bottom in sand or mud, beneath rocks and shells,
  or on seaweed.

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Nemertea

• Commonly called ribbon worms, Nemerteans live in
  the bottom mud of coastal waters and are food for
  a variety of fish and invertebrate predators.

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Polychaete Worms (Annelida)

• Polychaete worms have many small projections,
  called chaetae, used to move through the bottom
  sand or mud.

These worms are commonly found inhabiting sponges
and oyster clumps from local waters.
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Chaetognaths

• The arrow worms are very abundant zooplankton
  predators.

Up to 4 cm in length, arrow worms, which are not
actually worms, have elongated transparent bodies
with fin-like appendages that give the appearance
of an arrow.
They remain almost motionless in the water, but
are capable of swift darting motions when
pursuing prey.
Arrow worms feed voraciously on smaller
zooplankton, which they capture with a cluster of
small chitinous hooks located near the mouth.
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Phylum Mollusca
Among the more than 50,000 mollusks are some of
the most familiar invertebrate marine species,
such as clams, snails, and the octopus.
Most species of mollusks are benthic, but there
are a few pelagic forms, like the nautilus and
squid.
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Physical Characteristics of Mollusks

• Three body regions a head, a visceral mass, and
  a foot.

• An extension of the body wall called the mantle,
  responsible for secreting the shell.

• A radula (tongue like feature) used to rasp away
  at food.

• Well developed body organs (nervous system,
  circulatory system, respiratory system, etc.),
  but no body segmentation.

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Mollusca Classes
There are seven classes of mollusks, five of
which contain the predominant marine species

• Placophora

• Scaphapoda

• Bivalvia (Pelecypoda)

• Gastropoda

• Cephalopoda

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Class Placophora
Members of the subclass Polyplacophora (many
plates) are more commonly called the chitons.
Chitons are benthic algae feeders that move
slowly along hard surfaces.
Chitons have an eight part shell with overlapping
plates.
Often found in the intertidal zone and on sea
walls, a chiton uses its muscular foot to attach
itself tightly to surfaces.
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Class Scaphopoda
The scaphopods, or tusk shells, are a small group
of benthic detritus feeders.
They are sedentary animals with a slender,
tubular shell open at both ends.
Scaphopods have a well-developed foot, used for
burrowing, located at the large end of the shell.
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Class Bivalvia
The bivalves (two shells) are perhaps the most
well known mollusks because they are a source of
food for humans.
Clams, mussels, oysters and scallops are all
bivalves. There are about 15,000 known species of
bivalves, about 80 of them marine.
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Bivalves

• Bivalves are common in coastal waters, but may be
  found anywhere in the ocean.

Most species of bivalves are benthic filter
feeders.
A few species are very motile, like scallops that
can swim quickly by opening and shutting their
shells. Others, like the clams, can move slowly
through the mud on a muscular foot. Still other
bivalves, like oysters and mussels, are sessile.
While most bivalves are benthic as adults, they
have a planktonic larval stage to allow for them
to populate new areas of sea floor.
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Class Gastropoda
The gastropods (stomach-foot) make up about 70
of Molluscan species (around 35,000).
Most gastropods have spiral shells, like the
conchs, snails, and whelks. A few species do not
have any shell.
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Gastropods

• The gastropods occupy a wide variety of niches,
  all benthic. Some gastropods are benthic
  scavengers others are predatory.

Many have a radula that is used to bore through
the shell of a clam or snail to eat the animal
inside.
Conchs snails are an important source of protein
in many tropical island areas of the Caribbean.
There are a few cone shells in the central
Pacific Ocean that can shoot a poison dart up to
a few inches that is lethal to humans.
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Sea Hares and Nudibranches

• The sea hares and nudibranches are colorful
  gastropods known as the slugs of the sea
  because they lack shells.

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Class Cephalopoda
While cephalopods (head-footed) look different
from the other mollusks, they are similar in
internal construction.
The most obvious difference between most
cephalopods and other mollusks is the apparent
lack of a shell. The octopods do not have shells
at all the squid have a small internal shell.
Nautiluses are the only cephalopods with an
external shell.
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Squids

• The squids are pelagic predators that range in
  size from a small local one only a few inches
  long to the giant squid over 60 feet long!

Squids have a streamlined tube shape, with 10
tentacles, two being longer and having suction
cups on the end.
Squids swim normally with a pair of fleshy fins
on each side, and can go in either direction, or
just hover in one place.
However, they can escape swiftly with a jet
propulsion by blasting water out of their mantle
cavity through their siphon, even adding ink to
confuse a predator.
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The Far Side, by Gary Larson
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Octopods

• The octopus has only eight tentacles. The local
  species is only several feet long, but the one in
  the cooler waters of the Pacific Northwest may go
  up to 10 or 12 feet long.

The octopus is a benthic predator, feeding mainly
on crabs.
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Nautilus

• The chambered nautilus is a cephalopod having an
  external shell.

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Phylum Bryozoa
The Bryozoa (moss animals) are benthic filter
feeders, consuming bits of detritus and plankton
as the water passes by .
Bryozoans form colonies attached to rocks and
other hard surfaces, and are often among the
first organisms to grow on hard substrate
(natural or artificial).
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Phylum Arthropoda
Arthropods (joint-foot) have jointed
appendages. This class includes crabs, lobsters,
shrimp, barnacles.
Arthropods have rigid exoskeletons made of
chitin, a type of carbohydrate with nitrogen.
Aquatic species often have calcium carbonate in
it for extra strength. The skeleton provides
protection for the animals, and gives support for
the internal attachment of the arthropods
muscles.
Although arthropods grow, their exoskeletons do
not grow with them. So they must periodically
shed, or molt their exoskeletons in favor of a
new one. Lost limbs can gradually be regenerated
after successive moltings.
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Arthropod Classes
Class Example 1. Copepoda Copepods 2. Euphausiac
ea Krill 3. Ostracoda Ostracods 4. Brachiopoda
Brine shrimp 5. Cirripedia Barnacles 6. Decopoda
Shrimp, lobster, crabs 7. Xiphosura Horseshoe
crabs 8. Stomatopoda Mantis shrimp
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Class Copepoda
Copepods are small crustaceans that are the most
important zooplankton. They are found almost
everywhere where water is available and they
constitute the biggest source of protein in the
oceans. Most of the economically important
fisheries depend on copepods.
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Class Euphausiacea
After copepods, Euphausiids are the second most
important zooplankton group in the world oceans.
Most are herbivorous, but some are omnivorous
feeders.
Commonly known as krill, they are a major food
source for adult fish, seals, whales and birds.
Larval and immature fish feed on the smaller
juvenile euphausiids.
Krill live in the dark, at 100 meters or more by
day. Many adults migrate to the surface at night
to feed on the phytoplankton.
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Class Ostracoda
A feature that distinguishes an ostracod from
other crustaceans is the carapace that encloses
the body.
Within the carapace are several pairs of short
limbs which enable the animal to scramble around
and feed on the floor of the sea.
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Class Brachiopoda
Commonly referred to as brine shrimp.
Despite a superficially similar appearance to
clams, they are actually completely different in
their anatomy.
They use a fringe of tentacles known as the
lophophore to sweep food particles into their
mouths.
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Class Cirripedia
Barnacles attach themselves upside down on a rock
with their feet in the water.
Inside the shell of a barnacle is a segmented
body with six pairs of segmented legs used for
filter-feeding from the water.
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Class Decopoda
More than 8,000 species of crustaceans that
include shrimp, lobsters, crayfish, hermit crabs,
and crabs. Decapods are arthropods with ten main
legs. One or more of the five pair may be
modified as claws. The walking legs are
associated with a skeletal structure called the
carapace, which covers both the head and the
thorax.
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Class Xiphosura
Horseshoe crabs, common in Tampa Bay, have
evolved little in the last 250 million years.
They have survived because of their hard, curved
shell, which makes it difficult for predators to
overturn them and expose their soft, vulnerable
undersides. The horseshoe crab can go a year
without eating and endure extreme temperatures
and salinity.
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Class Stomatopod
Stomatopods are predatory crustaceans that live
in the shallow waters of tropical and subtropical
seas. They are not closely related to shrimps or
the other decapod crustaceans, although they are
commonly known as mantis shrimp due to the
raptorial appendages that they use to efficiently
capture and subdue prey.
These animals range in size from 1-2 cm to more
than 30 cm, and are one of the most aggressive
and pugnacious of all creatures.
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Chaetognaths

• The arrow worms are very abundant zooplankton
  predators.

Up to 4 cm in length, arrow worms, which are not
actually worms, have elongated transparent bodies
with fin-like appendages that give the appearance
of an arrow.
They remain almost motionless in the water, but
are capable of swift darting motions when
pursuing prey.
Arrow worms feed voraciously on smaller
zooplankton, which they capture with a cluster of
small chitinous hooks located near the mouth.
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Phylum Echinodermata
There are about 6000 species of this phylum,
whose name literally means spiny skin. Starfish
and sea urchins are several well known members of
this group.
General Characteristics
Echinoderms live in the sea only, none inhabit
land or fresh water. All echinoderms exhibit
radial symmetry, that is, the creatures have
appendages (or body construction) which point
outward from the center of the body like the
spokes on a bicycle wheel. These appendages
usually occur in multiples of five, although
there are a few exceptions.
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Echinoderm Classes
Class Examples 1. Crinodea Sea
Lilly 2. Asteroidea Starfish 3. Holothuroidea Se
a cucumber 4. Echinoidea Sea urchin sand
dollar 5. Ophiuroidea Brittle star Basket star
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Class Crinoidea
Sea lilies and feather stars. All crinoids are
passive suspension feeders. They produce no
feeding/respiratory current but rely on ambient
water movement.
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Class Asteroidea
Asteroids, or sea stars, have arms which seem to
connect together in such a way as to make it
difficult to discern where the arms end and the
central disk begins. Sea stars are capable of
regenerating limbs in the event that one or more
is severed or damaged.
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Class Holothuroidea
This class is composed of animals known as sea
cucumbers. The sea cucumber feeds by positioning
itself in a spot on the sea floor where a current
will bring a steady supply of food (plankton and
other organic particles) its way. The tentacles
are opened to collect the food. Then, the
cucumber sticks each tentacle in its mouth, one
at a time, and licks them off.
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Class Echinoidea
Sea urchins, heart urchins, cake urchins and
familiar sand dollars. Most sea urchins have a
large number of sharp spines pointing out in all
directions. These spines offer protection from
many would-be predators.
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Class Ophiuroidea
Brittle stars and basket stars. Ophiuroids have a
distinct central body part (called a central
disk) with arms radiating out from the body.
Adjacent arms do not connect with each other.
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Phylum Chordata

• The chordates have three main characteristics
  that separate them from other species of marine
  fauna.

1. Notochord
rod-like, semi-rigid supporting structure
2. Dorsal Hollow Nerve Tube
the top of the nerve tube is often enlarged to
form the brain
3. Gill Slits
always present in embryonic stages, fish retain
them as adults while mammals develop lungs
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Subphylum Urochordta

• Urochordates are commonly known as tunicates or
  sea squirts.

Tunicates that are common in local waters are
benthic filter feeders.
They are named for their outer coating, or
tunic that is indigestible to predators.
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Subphylum Cephalochordata

• The cephalochordates are a little known group
  that includes Amphioxus, a lancelet.

These species are only two to four inches long
and live in grass bottom communities filter
feeding with a very efficient pharynx.
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Subphylum Vertebrata

• The vertebrates have jointed backbones as a
  lateral support structure.

There are seven classes of vertebrates, only six
have marine species.
Agnatha
Chondrichthyes
Osteichthyes
Reptilia
Aves
Mammalia
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Class Agnatha

• The agnatha are the jawless fishes.

While the first agnathans were detritus feeders,
modern ones are parasites or scavengers.
The lamprey is an eel like fish that attaches
to the sides of host fish and sucks its body
fluids until it is near dead, then moves on to
another fish.
The hagfish are eel like scavengers that burrow
into the body cavity of dead fish and eat from
the inside out.
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Class Chondrichthyes

• The Chondrichthyes are the cartilaginous fish
  such as sharks and rays.

Sharks and rays are both pelagic and benthic
predators or scavengers, feeding on everything
from mollusks to large fish.
These fish have flexible skeletons made of
cartilage instead of bone. Only their teeth (and
in some cases the vertebrae or scales) have
calcium.
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Sharks

• Sharks have a keen sense of smell but poor
  eyesight.

Many shark species have a lateral line, a line of
sensory organs running down the side of the body,
that detects minute changes in water pressure
caused by a fish swimming nearby.
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Skates and Rays

• Skates and rays are also examples of
  cartilaginous fish, a group that consists of
  about 1,000 living species.

Most rays are benthic predators, feeding on crabs
and other shellfish.
They are generally not a threat to humans, but
the stingray can deliver a very painful sting if
stepped on.
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Class Osteichthyes

• The Osteichthyes are the bony fishes, having true
  bone in their skeleton.

This class includes most of what we typically
call fish, for example trout, grouper, goldfish,
and sea horses.
They occupy a wide variety of niches from
herbivores to top predators.
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Class Reptilia

• There are a few species of marine reptiles,
  including turtles, snakes, and crocodiles.

There are eight species of sea turtles, five are
found in Florida waters.
All sea turtles come ashore to deposit eggs on
the beach.
All eight species of sea turtles are endangered
and protected by state and federal laws.
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Sea Snakes
Another member of marine reptiles are the sea
snakes.
All sea snakes are deadly poisonous, much like a
cobra and a coral snake, but fortunately for
humans, they are fairly docile.
Some sea snakes bear their young live some come
ashore to lay their eggs.
Sea snakes are found only in the Pacific and
Indian Oceans.
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Crocodile
The crocodile is also a marine reptile, living in
both fresh water and in estuaries.
The type in Florida is not considered dangerous
to humans, but the type found in Africa and
Australia is very dangerous and even attacks a
few humans every year.
There is also a marine lizard that lives in parts
of the Pacific that feeds on benthic algae but
spends much of its time on rocks along the shore.
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Class Aves

• There are a few species of marine birds, most
  notably the penguin.

The penguin has given up flight and now uses its
wings as swimming flippers and feeds on fish and
krill.
Other birds spend much of their time at sea
feeding on fish, but must come ashore to build
their nests and lay their eggs.
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Class Mammalia

• The mammals evolved on land, but a few have moved
  into the sea, mainly the whales, dolphins, and
  manatees.

Even though these mammals do not live on land
now, they still must breathe air through lungs.
The seals, sea lions, and sea otters are also
mammals that spend much of their life at sea but
also can live on land, if necessary.
All marine mammals are protected by both state
and federal Laws.