Transcript Phylum Porifera

Phylum Porifera
The “Pore Bearers”
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Phylum Porifera : The Sponges
A few examples
Stovepipe Sponges
Red Volcano Sponge
Yellow Tube Sponge
Identifying Characteristics of the
members of Phylum Porifera
• Non-coelomates (therefore do not possess any true body
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systems although they do have highly specialized cells that
perform many functions)
Mostly asymmetric (some exhibit radial symmetry)
Possess a GASTROVASCULAR CAVITY (GVC)
Filter Feeders : through pores and special cells that line
the GVC
Posses a skeleton made up SPICULES composed of either
calcium, silica or spongin
Hermaphroditic : can reproduce sexually (do not self
fertilize) or asexually by regeneration or budding
Sessile (anchored to the ocean floor as an adult)
Found mainly in marine habitats
Basic Structure of a Sponge
The Gastrovascular Cavity
 Has only one opening
 Serves two primary functions
1. “Gastro”
digests and absorbs food and nutrients
2. “vascular”
serves as a primitive circulatory system as it moves
nutrients around to other parts of the body
Basic Functions of the Internal Cavity
1. To filter water as it
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3.
passes through the
sponge for food and
oxygen (see collar cell
enlargement)
To extract particles of
food from passing
water and digest food
either in collar cell
food vacuoles or by
roaming amoeboid
cells.
To get rid of waste
products through the
osculum
Collar Cells at work bringing in water and
retrieving oxygen and food for the sponge
Ecological Importance of Sponges
• Sponges provide
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Sea Crab living inside a
Fluorescent sponge
shelter and food for
other ocean creatures
Sponges can release
chemicals that help to
break up old shells
Because sponges are
filter feeders they are
very sensitive to water
pollution as it will
quickly clog their pores
and destroy the
sponge. Therefore a
lack of sponges in a
certain area is a good
indication that there is
pollution in the area
and more of the ocean
life is potentially at risk
Economical Importance of Sponges
• At one time there was
Sea sponge Skeleton to be used
in the bathroom for washing
a market for sponges
to be used in the
bathroom and the
kitchen because of
their ability to absorb
water, however
synthetic sponges
have replaced this
industry
Super Cool Sponge Facts
• Each species of sponge
somehow knows
exactly which day of the
year the other members
of its species will
release their gametes
into the water. This is
how sponges are able
to cross fertilize.
• The Loofah “Sponge”
sold in many stores is
not actually a sponge at
all…. It’s the inside of a
plant known as a gourd!
Purple Vase Sponge and a sea fan
Phylum Cnidaria
Cnidos = “Stinging Needle”
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4 Classes of Phylum Cnidaria
HYDROZOA – Obelia, Hydra (above),
Portuguese Man O War
ANTHOZOA – anemones (above),
corals, sea fans
SCHYPHOZOA - Jellyfish
CUBOZOA – box jellies (sea wasps)
Identifying Characteristics of the
members of Phylum Cnidaria
• Non-coelomates & therefore do not possess any true
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body systems or organs. 3 germ layers include ectoderm
(protection), endoderm (inner lining) and mesoglea
Exhibit radial symmetry
Possess tentacles used in transportation and for
capturing food and stinging cells called nematocysts.
Possess a Gastrovascular Cavity (GVC)
Primitive Nervous System (Nerve net)
Hermaphroditic : can reproduce sexually (do not self
fertilize) or asexually by regeneration or budding
Have a motile (medusa) and a sessile (polyp) stage in
their lives
Found in marine habitats
Gastrovascular Cavity (GVC)
• The inner cavity responsible for digestion,
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circulation, respiration and excretion.
Disadvantages of having a GVC include:
– There is only one opening….. The mouth is the anus…..
Mouth and Anus
Tentacle
Tentacle
Gastrovascular Cavity
Calcified Shell (Coral)
Note: This diagram shows the
GVC in the polyp body type.
2 Body Types Present in Phylum Cnidaria
1. Polyp
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Sessile (no movement
as they are anchored to
the ground))
Tentacles face up
asexual
Ex. Hydra, sea
anemones, coral
2. Medusa
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Motile
Tentacles face down
sexual
Ex. Jellyfish, sea wasps
The stinging cells: Nematocysts
• Nematocysts are most
commonly located at the
end of tentacles
• Are composed of special
cells called cnidocytes
that produce a toxin
• When a trigger is
stimulated it releases a
barbed needle that
penetrates the flesh and
injects toxins.
• Nematocysts are used to
ward off predators or
attack prey
A discharged
nematocyst
Life cycle of a typical Jellyfish
#1-10 exhibit the formation of the
polyp life form.
#11 shows the polyp undergoing
asexual reproduction in the form
of budding. The top of the polyp
breaks off and goes on to form
the medusa stage of the
jellyfish’s life. #12-14 shows the
formation of the adult medusa
The medusa will then go on to
produce and release egg and
sperm into the water. The eggs
will be cross fertilized by the
sperm of another medusa and
eventually develop into a new
polyp
This alternating between two life forms is termed
ALTERNATION OF GENERATIONS
Brooding Anemones
From a single anemone other polyps are forming which will
eventually break off and settle on the ocean floor to form
new anemones. This is why many of the same type of
anemone are often observed in the same area as the new
polyps are not capable of traveling far distances.
Ecological Importance of Cnidarians
• Filter and clean the water
• Form symbiotic
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The clownfish are immune to
the stinging cells of the
clownfish anemone. Therefore
the anemone provides
protection and shelter for the
clownfish and in turn the
clownfish clean the anemone.
relationships will other
ocean life
– Examples.
• Clownfish and
anemone
(remember Finding
Nemo?)
Coral will die as the
temperature of the water
increases. Death of coral
often precedes death of
entire ecosystems
Super Cool Killer Cnidarians
The Portuguese Man O’ War
• Looks like a jellyfish but is
actually a colony of specialized
polyps and medusas
• The sting from their tentacles
causes excruciating pain and
sometimes death
• Named for its air bladder which
looks like the sails of a
Portuguese fighting ship
Super cool fact: Loggerhead
turtles are actually immune to
their toxins and feed on the
Portuguese Man O’ War
Portuguese Man O’ War
Physalia physalis
A common sign to
observe near
Australian Beaches
Box Jellyfish
• Possess the most deadly
venom (toxins) in the
animal kingdom which
cause anaphylaxis shock
and death
• In Nov. – April they are
abundant in Australian
waters but it is not known
where they go for the
winter
• Through ultrasonic tagging
it has been found that they
sleep on the ocean floor
between 3pm and dawn to
conserve energy and avoid
predators
• Possess 22 very simple
light sensing eyes
Box Jellyfish Chironex flecker
This jellyfish has had an ultrasonic
tag attached (very carefully!) to it
in order to help learn more about
the migration patterns of these
cnidarians
Jelly FISH OUT OF WATER