Porifera- Morphological Characteristics A sponges body is made
up of two layers of cells separated by a substance made of mainly
collagen called mesohyl. The mesohyl cells also act as the
organisms endoskeleton. Hollow bodies. Inner surface covered in
choanocytes- cells with whipping flagella that move water
throughout the body. Ostia- channels that go inside through
mesohyl. Pinacocytes- cells that act as plates, cover the mesohyl
where the choanocytes are not.
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Porifera- Morphological Characteristics Their mesohyl skeletons
encrust hard surfaces for soft sponges. Usually mesohyl is
stiffened by spicules- provide structural support, made of silica,
calcium or sponging. Some sponges form large calcium carbonate
exoskeletons. They are not symmetrical. Cells are not bound
together.
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Porifera- Body types Asconoid- Simplest shape, long tubular.
Syconoid- Increases pumping capacity making the diameter larger.
Leuconoid- Greatest diameter
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Porifera- Body Systems Sponges dont have distinct circulatory,
respiratory, digestive, or excretory systems. Sponge cells absorb
oxygen by diffusion as water flows through the body.
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Porifera-Nutrition Larger objects that they dont fit through
their ostia are externally engulfed and digested. Food that is able
to fit through the ostia are consumed by pinacocytes which stick
out of the walls of the ostia. Bacteria sized particles get
digested by the choancytes. Their waste leaves through their
oscula.
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Porifera- Reproduction Asexual- They use the method of budding-
smaller pieces of sponge grow off of the larger sponge and get
carried off with the currents. Sexual- Most sponges are
hermaphroditic, they have functions of both sexes. They have no
reproductive organs. Sperm are produced by the choanocytes, eggs
are formed by archeocytes- cells in the sponge that can change into
any type of cell. Sperm are usually expelled out of the osculum to
find another sponge of its species.
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Porifera- Examples Spongia officinalis or the bath sponge. This
sponge is used commercially. Turns yellow when dried, grey when
alive. Is hermaphroditic. Found in the Mediterranean Sea.
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Cnidaria- Morphological Characteristics Four main groups:
Anthozoa (sea anemones, coral, sea pens), Syphozoa (jellyfish),
Cuboza (box jellyfish), Hydroza. Either swimming medusae or sessile
polyps. Radially symmetrical They have no heads so their ends are
called oral and aboral, mouth and anus. Most have tentacles around
their edges Medusae swim by propelling themselves with jets of
water
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Cnidaria- Morphological Structures The only supporting
structure in the Medusae is mesoglea- a jelly like substance that
is between two epithelial layers. A basic type of tissue. Sea
anemones fill up with water act as a skeleton in a cavity when they
are not feeding. Sea pens harden their mesoglea with calcium
carbonate spicules. Corals make calcium carbonate exoskeletons
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Cnideria- Morphological Structures Cnideria are diploblastic-
two main cell layers, form epithelia. One cell thick. Mesoglea
separates the layers. Layer on the outside- ectoderm has:
cnidocytes, nerve cells that send messages to the motor nerve cells
between bases of muscle cells.
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Cnideria- Anatomy
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Cnideria- Cnidocytes Cnidocytes are like Harpoons Three types:
nematocyst- inject venom Spirocysts meant to entangle victim
Ptychocysts- build protectoral tube, found on tube anemones
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Cnideria- Senses They have no brains or central nervous system.
They have sensory neurons to provoke stimulus. Most have simple
eyes to tell which direction light is coming from. Box jellies have
true eyes that can sense light and can detect solid colored
objects. Respiration- cell layers absorb oxygen and expel carbon
dioxide Others with the central cavity replace stale water flushing
out unused nutrients.
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Cnideria- Nutrition Predation- absorb organic nutrients Filter
food out of the water Some depend completely on their
endosymbiontants- algae that works with coral and other sessile
cnideria to get nutrients Predators use their cnidocytes to disable
or entangle their prey. They also inject digestive enzymes into
their prey and they push the animal into their digestive cavity
where it is made into an absorbable liquid.
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Cnideria- Reproduction Life cycle of jellyfish
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Cnideria- reproduction Sessile organisms send out their sperm
hoping it reaches an egg. The fertile egg becomes a hollow
sphere/blastula which progresses into a digestive cavity through
gastrulation. Asexual- This is based on regeneration. If certain
parts of the organism are cut off then the part can regenerate to
make a whole.
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Cnideria- Example Physalia physalis or otherwise know as the
Portuguese Man of War. Tentacles are usually 10 meters long. They
are always fishing with their tentacles. No means of propulsion,
pushed by currents and wind Usually found in warm tropical
waters.
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Ctenophores- Morphological Characteristics Swim by their cilia
Body made of mesoglea between epithelia bound by inter cell
connection. Two layers instead of one Outer layer of skin is
covered in mucus to protect it, colloblasts on their tentacles to
catch prey. The inside layer has the nerve net instead of a brain,
and cells acting as muscles There is an inner cavity that is like a
stomach and there is a canal system on the inside.
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Ctenophores-Types Cydippids- Round shape Lobates- Have two
lobes Beroids- Large mouth, no feeding appendages
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Ctenophores- Morphological Characteristics Almost radially
symmetrical
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Ctenophores- Respiration Water flows through its body, so it
absorbs oxygen from the water that passes through it.
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Ctenophores- Nutrition Food is put into the throat and digested
by enzymes to make it digestible. Nutrients are dispersed
throughout the organism, absorbed by nutritive cells. Most waste is
regurgitated.
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Ctenophores- Reproduction Almost all are hermaphroditic. Except
in the genus ocryoposis where two species have single sex
individuals. Reproductive organs are located underneath the combs
in the canals. Eggs and sperm are released through pores in the
skin. However platyctenids have internal fertilization. Juveniles
resemble mini adults They produce eggs and sperm as long as they
have enough food.
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Ctenophores- Bioluminescent Most of these creatures are
bioluminescent. Photocytes are activated which are photo proteins
in cells. Normally under the combs.
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Ctenophores- Example Cestum veneris or the Venus Girdle. Looks
like transparent ribbon. Found in subtropical waters, open
water.