Transcript Chapter 28 Simple Invertebrates

Chapter 28 Simple
Invertebrates
Sponges- the simplest
organisms
Plan for notes:
• As we discuss each aspect of simple
invertebrates, complete the spreadsheet you
have on your desk titled: Simple
Invertebrates
• Your job is to determine what information
goes where on the spreadsheet, I am not
going to tell you so don’t shout out questionsTHINK, READ, LISTEN before you speak!
• If you do not finish the spreadsheet as we
are discussing it, look in your textbook pages
617-636 for answers for homework.
Addition to notes
• Write page # 617-636 at top
of page to help with
homework if you don’t finish.
• Please add under the Animal
heading the word
EXAMPLES
General Features of Sponges
• They are animals but they completely
lack symmetry (asymmetry) and are just
a mass of specialized cells
• Sort of like the sand-man in
SpiderMan3- if you put the cells
through a mesh sieve they would find
each other and get back together again
making a new sponge.
General Features of a Sponge:
Body coverings, Locomotion
• OSTIA - small pores all over
the sponge through which
water enters.
• OSCULA - larger openings
through which water exits.
• SESSILE - they don’t move,
they attach themselves to
submerged surface and stay
there for their lives.
(locomotion)
• CHOANOCYTES - collar cells
that line the internal cavity of a
sponge. Have flagella on them
that beats water (and food) into
the cavity.
• AMOEBOCYTES - sponge
cells that supply the rest of the
sponge’s cell with nutrients
Sponge Diversity: Body Covering
• Brillantly colored
sponges abound in
warm, shallow sea
waters.
• Some may contain
hundreds of folds that
are visible as
fingerlike projections.
• The folds increase the
sponge’s size and
surface area.
Sponges – people like them.
Sponge Skeletons
• Does not have a fixed
skeleton like a human
• Composed of
SPICLULES tiny
needles composed of
silica or calcium
carbonate.
• Some sponges have
SPONGIN a resilient,
flexible protein fiber that
provides support for the
sponge.
Sponges – simple but important
Reproduction
• Sponges can reproduce asexually
• Can regenerate when cut into pieces –
each bit of sponge can become a new
sponge.
• In freshwater sponges, if life gets rough,
they form GEMMULES – clusters of
amoebocytes encased in protective coats.
When conditions improve, they grow.
Gemmules – how freshwater
sponges make it through the winter.
Looks sort of gross, but it is just
gemmules…
Can reproduce sexually too.
• Most sponges are hermaphrodites. Since eggs and
sperm are produced at different times, self-fertilization is
avoided.
• In most species of sponges, fertilization occurs sperm
from one sponge enter another sponge through pores.
• Collar cells pass sperm into mesohyl, where egg cells
are.
• Fertilized eggs develop into larva and leave sponge
• After brief free-swimming stage, the larvae attach
themselves to an object and develop into new sponges.
That’s all for Sponges!
If you were not
able to get the 6
columns of
information, the
movie on Sponges
will also give you
information, just
listen!!!
Cnidarians
(nih DAIRians)
Two Body Forms: You may fill in
these notes in the Cnidarians row
• Medusa – free floating have nerves and
muscle tissue (hint for locomotion),
jellylike and often umbrella shaped.
Radial symmetry
• Polyp- tubelike, sessile,(another hint for
locomotion) often attached to a rock or
some other substance. Radial symmetry
• Many cnidarians exist only as medusas,
while others exist only as polyps. Others
alternate between the two.
Cnidocytes – what makes
cnidarians sting! Example of body
coverings
• Cnidocytes are stinging
cells located on the
tentacles of the
gastrovascular cavity of
cnidarians.
• Nematocyst – Harpoons
inside the cnidocytes
used for defense and to
spear prey. Some have
deadly toxins, while
others contain chemicals
that stun.
The Three Classes of Cnidarians
and examples of each
• Hydrozoans – most primitive, polyp and
medusa stages, freshwater and marine, many
individuals (medusa and polyps) live together
in a colony example: Portuguese man-of-war,
• Scyphozoans – true jellyfish, active
predators, both medusa and polyp stages, box
jellies
• Anthozoans – exist only as polyps,
examples sea anemones and corals
Marine Hydrozoa
• Much more complicated.
Colonies incorporate both
medusa and polyps
together
• Example: Physalia,
Portugese Man of War
• Gas filled polyp helps it
float, other medusa and
polyps help it reproduce
and eat.
• A single colony can
contain 1,000 individual
medusas and polyps.
Fertilization and Reproduction in
Hydrozoans
• Asexually by budding
– Buds turn into polyps
– Polyps turn into medusa
Fertilization:
Medusa male and female release sperm and
eggs
– Produce zygotes that develop into free
swimming, ciliated larvae called planulae.
– Planulae eventually settle on ocean bottom
and develop into new polyps.
Hydrozoans
• Body coverings:
Polyps form calcium
carbonate skeletons
2nd Class of CnidariansScyphozoans
• True
jellyfish(example)
• Active predators,
ensnare and sting
prey with tentacles
(body coverings)
• Live as both polyps
and medusas
(skeletal structure)
2nd Class of CnidariansScyphozoans
• Body symmetry:
Radial
2nd Class of CnidariansScyphozoans
• Locomotion: Free
swimming medusa,
sessile polyp stage
2nd Class of Scyphozoans
Reproduction and Fertilization
• Most medusas reproduce sexually
• Some have polyp stage reproduce
asexually
• Medusa release sperm and eggs into
water, fertilized zygote forms polyp
eventually medusa
3rd Class of Cnidarians:
anthozoans
• Largest class of cnidarians
• Exist only as polyps (skeletal structure)
• Thick stalklike body topped by tentacles
(skeletal structure) tentacles (body
covering)
• Examples: Sea anemones, corals
(skeletal structure of corals: hard
outer covering of calcium carbonate)
Fertilization and Reproduction of
anthozoans
• Fertilization: sperm and eggs released
into ocean, where fertilization occurs
• Reproduction: asexually form buds, also
reproduce sexually by the above method
of releasing sperm and eggs into ocean
Examples of Anthozoans: Sea
Anemones
Examples of anthozoans: Corals
Radially symmetric
Final simple invertebrates:
Flatworms and Roundworms
• Flatworm examples: marine, tapeworms,
flukes
• Skeletal structure: acoelomate, flat
ribbonlike,
• Body symmetry: bilaterally symmetric
meaning they have left and right halves
that mirror each other
Flatworms
• Some flatworms reproduce asexually by
tearing in two, each half regenerates
• Some reproduce sexually:
hermaphrodites that fertilize each
other’s eggs.
• Fertilization occurs when sperm and egg
form zygote. Zygotes released in
clusters in a protective capsule
Examples of Flatworms: Marine
Flatworms Locomotion:
ribbonlike, undulating
Examples of Flatworms:
Tapeworms
Examples of Roundworms: vinegar eels, parasitic
roundworms, pinworms, hookworms, heartworms (in dogs),
and ascaris (intestinal roundworm). Humans can contract
parasitic worms by eating under cooked beef or pork
Roundworms
• Skeletal structure: pseudocoelom have
one way gut
• Fertilization: Internal in the female
• Reproduction: Reproduction is usually
sexual. Males are usually smaller than
females (often much smaller) and often
have a characteristically bent tail
Roundworms cause elephantitis
Roundworms (picture is of a
hookworm)
• Body coverings
of both
flatworms and
roundworms:
flexible thick
outer covering
and cuticle
(tegument)
Roundworm Locomotion
• Locomotion:
wriggling or
thrashing,
muscles on one
side contracting,
while the other
side expands
If you have not completed all the
blanks on the spreadsheet, find
the answers in your textbook for
homework, pages 617-636
We are now going to watch a
video on Sponges, you will take a
quiz as you are watching the
video- pass this in at the end of
the period.