What is a sponge?

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What is a sponge?
Sponges are asymmetrical aquatic animals that
have a variety of colors, shapes, and sizes.
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What is a sponge?
Although sponges do not resemble more familiar
animals, they carry on the same life processes as
all animals.
Many are bright shades of red, orange, yellow,
and green.
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Sponges are pore-bearers
Sponges are classified in the invertebrate phylum
Porifera, which means pore bearer.
Most live in marine biomes, but about 150 species
can be found in freshwater environments.
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Sponges are pore-bearers
Water out
Central cavity
Sponges are mainly sessile organisms.
Because most adult sponges cant travel in search
of food, they get their food by a process called
filter feeding.
Water in
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Sponges are pore-bearers
Water out
Filter feeding is a method in which an organism
feeds by filtering small particles of food from
water that pass by or through some part of the
organism.
Central cavity
Water in
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Osculum
Direction of water flow through a sponge Water
flows IN through the pore cells and OUT through
the osculum
Epithelial-like cells
Pore cell
Amoebocyte
Spicules
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General physiology
Pinacocytes skin cells, thin, leathery and
tightly packed. Choanocytes striking
resemblance to choanoflagellates(a single-celled
protist). Their function is to create active
pumping of water and major site of nutrient
uptake. Archaeocytes These cells are
totipotent. They can change into all of the
other types of cells. Ingest and digest food
caught by choanocyte collars. Schlerocytes
Create and excrete spicules.
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Reproduction
--All sponges can reproduce sexually --Generally
monoecious and produce eggs and sperm at
different times. --Produce flagellated
parenchymella larva that exit via exhalent
current. --Larval motility is the principal
dispersal mechanism --Sponges have great powers
of regeneration
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Feeding
--Sponges feed on fine particulate material in
the inflowing water. --Food particles generally
range from 5- to 50 µm and are phagocytized by
archeocytes. --After digestion is complete, the
archeocytes and associated wastes are expelled
into the water.
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Cell organization in sponges
For some sponge species, if you took a living
sponge and put it through a sieve, not only would
the sponges cells be alive and separated out,
but these cells would come together to form new
sponges.
It can take several weeks for the sponges cells
to reorganize themselves.
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Cell organization in sponges
Many biologists hypothesize that sponges evolved
directly from colonial, flagellated protists,
such as Volvox.
Volvox
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Cell organization in sponges
More importantly, sponges exhibit a major step
in the evolution of animalsthe change from
unicellular life to a division of labor among
groups of organized cells.
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Reproduction in sponges
Sponges can reproduce asexually and sexually.
Depending on the species, asexual reproduction
can be by budding, fragmentation, or the
formation of gemmules.
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Reproduction in sponges

• An external growth, called a bud, can form on a
  sponge.

• If a bud drops off, it can float away, settle,
  and grow into a sponge.

• Sometimes, buds do not break off. When this
  occurs, a colony of sponges forms.

• Often, fragments of a sponge break off and grow
  into new sponges.

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Reproduction in sponges
Some freshwater sponges produce seed-like
particles, called gemmules, in the fall when
waters cool.
The adult sponges die over the winter, but the
gemmules survive and grow into new sponges in the
spring when waters warm.
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Reproduction in sponges
Most sponges reproduce sexually.
Some sponges have separate sexes, but most
sponges are hermaphrodites. A hermaphrodite is an
animal that can produce both eggs and sperm.
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Reproduction in sponges
Eggs and sperm form from amoebocytes.
During reproduction, sperm released from one
sponge can be carried by water currents to
another sponge, where fertilization can occur.
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Reproduction in sponges
Fertilization in sponges may be either external
or internal.
A few sponges have external fertilizationfertili
zation that occurs outside the animals body.
Most sponges have internal fertilization, in
which eggs inside the animals body are
fertilized by sperm carried into the sponge with
water.
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Reproduction in sponges
In sponges, the collar cells collect and
transfer sperm to amoebocytes.
The amoebocytes then transport the sperm to ripe
eggs.
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Support and defense systems in sponges
Sponges are soft-bodied invertebrates, that can
be found at depths of about 8500 m.
Their internal structure gives them support and
can help protect them from predators.
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Support and defense systems in sponges
Some sponges have sharp, hard spicules located
between the cell layers.
Spicules may be made of glasslike material or of
calcium carbonate.
Spicules
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Support and defense systems in sponges
Other sponges have an internal framework made of
silica or of spongin, a fibrous protein-like
material.
Sponges can be classified according to the shape
and makeup of their spicules and/or frameworks.
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Support and defense systems in sponges
Besides sharp spicules, some sponges may have
other methods of defense.
Some sponges contain chemicals that are toxic to
fishes and to other predators.
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Common Sponges
And OF COURSE
Barrel Sponges
Finger Sponges
Rope Sponges
Tube Sponges
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Squarepants!